Patent Application
20210145929
The contents of the text file named “NIGH-013/001WO_SeqList.txt,” which was created on Apr. 4, 2019 and is 60 KB in size, are hereby incorporated by reference in their entirety.
The disclosure relates to the fields of human therapeutics, biologic drug products, viral delivery of human DNA sequences and methods of manufacturing same.
There is a long-felt and unmet need for AAV-based delivery vectors and improved methods of manufacturing these AAV-based delivery vectors.
The disclosure provides a method for the purification of an AAV (AAV) particle from a mammalian host cell culture, comprising the steps of: (a) culturing a plurality of mammalian host cells in a culture media under conditions suitable for the formation of a plurality of AAV particles, wherein the plurality of mammalian host cells have been transfected with a plasmid vector comprising an exogenous sequence, a helper plasmid vector, and a plasmid vector comprising a sequence encoding a viral Rep protein and a viral Cap protein to produce a plurality of transfected mammalian host cells; (b) harvesting the culture media comprising the plurality of transfected mammalian host cells; (c) harvesting a plurality of AAV particles from the plurality of transfected mammalian host cells; (d) concentrating the plurality of AAV particles by tangential flow filtration (TFF) to produce a concentrated plurality of AAV particles; (e) enriching the concentrated plurality of AAV particles for full AAV particles by density gradient ultracentrifugation to produce an enriched plurality of full AAV particles; (f) purifying the enriched plurality of full AAV particles by anion exchange (AEX) chromatography or affinity chromatography to produce an eluate comprising a purified and enriched plurality of full AAV particles; and (g) diafiltering and concentrating the eluate from (f) into a formulation buffer by tangential flow filtration (TFF) to produce a final composition comprising the purified and enriched plurality of full AAV particles and the formulation buffer. In some embodiments, a full AAV comprises an exogenous sequence under the control of a promoter capable of expressing the exogenous sequence in a mammalian or human cell.
The disclosure provides a method for the purification of a recombinant AAV (rAAV) particle from a mammalian host cell culture, comprising the steps of: (a) culturing a plurality of mammalian host cells in a culture media under conditions suitable for the formation of a plurality of rAAV particles, wherein the plurality of mammalian host cells have been transfected with a plasmid vector comprising an exogenous sequence, a helper plasmid vector, and a plasmid vector comprising a sequence encoding a viral Rep protein and a viral Cap protein to produce a plurality of transfected mammalian host cells; (b) harvesting the culture media comprising the plurality of transfected mammalian host cells; (c) harvesting a plurality of rAAV particles from the plurality of transfected mammalian host cells; (d) concentrating the plurality of rAAV particles by tangential flow filtration (TFF) to produce a concentrated plurality of rAAV particles; (e) enriching the concentrated plurality of rAAV particles for full rAAV particles by density gradient ultracentrifugation to produce an enriched plurality of full rAAV particles; (f) purifying the enriched plurality of full rAAV particles by anion exchange (AEX) chromatography or affinity chromatography to produce an eluate comprising a purified and enriched plurality of full rAAV particles; and (g) diafiltering and concentrating the eluate from (f) into a formulation buffer by tangential flow filtration (TFF) to produce a final composition comprising the purified and enriched plurality of full rAAV particles and the formulation buffer. In some embodiments, a full rAAV comprises an exogenous sequence under the control of a promoter capable of expressing the exogenous sequence in a mammalian or human cell.
The disclosure provides a method for the purification of a recombinant AAV (rAAV) particle from a mammalian host cell culture, comprising the steps of: (a) culturing a plurality of mammalian host cells in a culture media under conditions suitable for the formation of a plurality of rAAV-REP1 particles, wherein the plurality of mammalian host cells have been transfected with a plasmid vector comprising an exogenous sequence wherein the exogenous sequence comprises a sequence encoding a human Rab escort protein 1 (REP1) protein, a helper plasmid vector, and a plasmid vector comprising a sequence encoding a viral Rep protein and a viral Cap protein to produce a plurality of transfected mammalian host cells; (b) harvesting the culture media comprising the plurality of transfected mammalian host cells; (c) harvesting a plurality of rAAV particles from the plurality of transfected mammalian host cells; (d) concentrating the plurality of rAAV particles by tangential flow filtration (TFF) to produce a concentrated plurality of rAAV particles; (e) enriching the concentrated plurality of rAAV particles for full rAAV particles by density gradient ultracentrifugation to produce an enriched plurality of full rAAV particles; (f) purifying the enriched plurality of full rAAV particles by anion exchange (AEX) chromatography or affinity chromatography to produce an eluate comprising a purified and enriched plurality of full rAAV particles; and (g) diafiltering and concentrating the eluate from (f) into a formulation buffer by tangential flow filtration (TFF) to produce a final composition comprising the purified and enriched plurality of full rAAV particles and the formulation buffer.
In some embodiments of the methods of the disclosure, the sequence encoding the human REP1 protein comprises or consists of the nucleic acid sequence of:
in which the the Kozac consensus is indicated by underlining and the start codon is indicated by bold.
In some embodiments of the methods of the disclosure, the human REP1 protein comprises or consists of the amino acid sequence of
In some embodiments of the method of the disclosure, the culture media comprises reduced fetal bovine serum. In some embodiments, the culture media does not comprise reduced fetal bovine serum.
In some embodiments of the methods of the disclosure, the culture media comprises Dulbecco's Modified Eagle's medium (DMEM).
In some embodiments of the methods of the disclosure, the culture media comprises glycine, L-Arginine hydrochloride, L-Cysteine dihydrochloride, L-Glutamine, L-Histidine hydrochloride-H2O, L-Isoleucine, L-Leucine, L-Lysine hydrochloride, L-Methionine, L-Phenylalanine, L-Serine, L-Threonine, L-Tryptophan, L-Tyrosine disodium salt dehydrate, L-Valine, Choline chloride, D-Calcium pantothenate, Folic Acid, Niacinamide, Pyridoxine hydrochloride, Riboflavin, Thiamine hydrochloride, i-Inositol, Calcium Chloride (CaCl2) (anhyd.), Ferric Nitrate (Fe(NO3)3″9H2O), Magnesium Sulfate (MgSO4) (anhyd.), Potassium Chloride (KCl), Sodium Bicarbonate (NaHCO3), Sodium Chloride (NaCl), Sodium Phosphate monobasic (NaH2PO4-H2O), and D-Glucose (Dextrose).
In some embodiments of the methods of the disclosure, the culture media comprises a serum-free media. In some embodiments, the culture media consists of a serum-free media.
In some embodiments of the methods of the disclosure, the culture media comprises a clarified media. In some embodiments, the culture media consists of a clarified media. In some embodiments of the methods of the disclosure, the harvest media comprises a protein-free media. In some embodiments of the methods of the disclosure, the harvest media consists of a protein-free media.
In some embodiments of the method of the disclosure, the mammalian cells have been transfected with a composition comprising a PEI transduction reagent.
In some embodiments of the method of the disclosure, the plasmid vector comprising an exogenous sequence further comprises a sequence encoding a 5′ inverted terminal repeat (ITR) and a sequence encoding a 3′ ITR. In some embodiments, the sequence encoding a 5′ ITR is derived from a sequence encoding a 5′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 5′ ITR comprises a sequence that is identical to a sequence encoding a 5′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 5′ ITR comprises a sequence that is not identical to a sequence encoding a 5′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 3′ ITR is derived from a sequence encoding a 3′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 3′ ITR comprises a sequence that is identical to a sequence encoding a 3′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 3′ ITR comprises a sequence that is not identical to a sequence encoding a 3′ITR of an AAV of serotype 2 (AAV2). In some embodiments, the sequence encoding a 5′ ITR or the sequence encoding a 3′ ITR comprises 145 base pairs (bp).
In some embodiments of the method of the disclosure, the plasmid vector comprising an exogenous sequence, the helper plasmid vector or the plasmid vector comprising a sequence encoding a viral Rep protein and a viral Cap protein, further comprises a sequence encoding a selection marker. In some embodiments, the plasmid vector comprising an exogenous sequence further comprises a sequence encoding a selection marker. In some embodiments, the helper plasmid vector further comprises a sequence encoding a selection marker. In some embodiments, the plasmid vector comprising a sequence encoding a viral Rep protein and a viral Cap protein further comprises a sequence encoding a selection marker. In some embodiments, the sequence encoding a selection marker conveys resistance to kanamycin.
In some embodiments of the method of the disclosure, the harvesting step (c) comprises a mechanical disruption of the plurality of transfected mammalian cells to release recombinant AAV (rAAV) particles produced by the plurality of transfected mammalian cells. In some embodiments, the mechanical disruption comprises a microfluidization.
In some embodiments of the method of the disclosure, the concentrating step further comprises (1) clarifying the concentrated plurality of rAAV particles by a depth filtration to produce a concentrated and clarified plurality of rAAV particles.
In some embodiments of the method of the disclosure, the concentrating step further comprises (2) freezing the concentrated and clarified plurality of rAAV particles at −80° C. to produce a process intermediate.
In some embodiments of the method of the disclosure, the enriching step (e) comprises an iodixanol density gradient ultracentrifugation to produce an enriched plurality of rAAV particles. In some embodiments, the density gradient is a discontinuous density gradient. In some embodiments, the iodixanol density gradient comprises one or more of an iodixanol composition having a concentration of 15%, 25%, 40% and 57%, respectively. In some embodiments, the enriched plurality of rAAV particles are isolated from an iodixanol density gradient. In some embodiments, the enriched plurality of rAAV particles are isolated from the interface of an iodixanol composition having a concentration of 40% and an iodixanol composition having a concentration of 57%. In some embodiments, the concentrated and clarified plurality of rAAV particles are applied to a density gradient of the disclosure and subsequently subjected to an ultracentrifugation step. In some embodiments, following the ultracentrifugation step, an enriched plurality of rAAV or full rAAV particles is isolated from the density gradient.
In some embodiments of the method of the disclosure, the affinity chromatography of the purifying step (f) comprises an AVB Sepharose matrix.
In some embodiments of the method of the disclosure, the formulation buffer comprises Tris, MgCl2, and NaCl. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8 with poloxamer 188 at 0.001%.
In some embodiments of the methods of the disclosure, the AEX Chromatography comprises the use of UnoSphere Q or Poros AEX chromatography. In some embodiments, the AEX Chromatography further comprises the steps of generating an AEX Chromatogram and selecting a peak on the AEX Chromatogram containing full rAAV particles.
In some embodiments of the methods for the purification of a recombinant AAV (rAAV) particle of the disclosure, the method further comprises a dilution step prior to step (g), wherein the dilution step comprises (1) diluting the first purified plurality of rAAV particles from step (d) by 20× prior to step (e) when the chromatography comprises contacting the first purified plurality of rAAV particles with UnoQ or (2) diluting the first purified plurality of rAAV particles from step (d) by 6× prior to step (e) when the chromatography comprises contacting the first purified plurality of rAAV particles with AVB. In some embodiments, the dilution step comprises adding a dilution buffer to the first purified plurality of rAAV particles, wherein the chromatography comprises contacting the first purified plurality of rAAV particles with UnoQ and wherein the dilution buffer comprises 10 mM Tris at pH 9. In some embodiments, the dilution step comprises adding a dilution buffer to the first purified plurality of rAAV particles, wherein the chromatography comprises contacting the first purified plurality of rAAV particles with AVB and wherein the dilution buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8. In some embodiments, step (e) produces a composition comprising a second purified plurality of rAAV particles and an elution buffer. In some embodiments, the chromatography comprises UnoQ and wherein the elution buffer comprises 10 mM Tris, 650 mM NaCl at pH 9. In some embodiments, the chromatography comprises AVB and wherein the elution buffer comprises 10.8 mM NaHPO4, 44.6 mM citric acid, 400 mM NaCl at pH 2.6. In some embodiments, the elution buffer is eluted into a neutralization buffer. In some embodiments, the neutralization buffer comprises 1M Tris at pH 8.8.
In some embodiments of the methods of the disclosure, the TFF of step (d) or step (g) is performed using a 100 kDa hollow fiber filter (HFF). In some embodiments, the TFF of step (d) or step (g) is performed using a 70 kDa HFF. In some embodiments, the TFF of step (d) or step (g) is performed using a 50 kDa HFF. In some embodiments, step (g) the method further comprises a second TFF, the TFF of step (d) and the first TFF of step (g) are performed using a 100 kDa HFF and the second TFF of step (g) is performed using a 50 kDa or a 70 kDa HFF.
In some embodiments of the methods of the disclosure, the host cell is isolated or derived from a cultured cell line. In some embodiments, the host cell is an HEK293 cell.
In some embodiments of the methods of the disclosure, the host cell is isolated or derived from a primary cell line. In some embodiments, the host cell is an immortalized cell or a stem cell.
The disclosure provides a pharmaceutical composition comprising a plurality of rAAV particles produced by a method of the disclosure.
In some embodiments of the pharmaceutical compositions of the disclosure, the pharmaceutical composition comprises (a) between 0.5 and 2.5×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (rAAV); (b) less than 50% empty capsids; (c) less than 4 ng/mL residual host cell protein per 1.0×1012 vg/mL; and (d) less than 7×10−3 pg/ml residual host cell DNA per 1.0×1012 vg/mL.
In some embodiments of the pharmaceutical compositions of the disclosure, the pharmaceutical composition further comprises (e) a plurality of functional vg/mL, wherein each of functional vector genomes is capable of expressing an exogenous sequence in a cell following transduction.
In some embodiments of the pharmaceutical compositions of the disclosure, following transduction of a cell with the pharmaceutical composition, the plurality of functional vg/mL express the exogenous sequence at a 2-fold increase when compared to a level of expression of a corresponding endogenous sequence in a nontransduced cell. In some embodiments, following transduction of a cell with the pharmaceutical composition, the plurality of functional vg/mL express the exogenous sequence at a 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 11-fold, 12-fold, 13-fold, 14-fold, 15-fold, 16-fold, 17-fold, 18-fold, 19-fold, 20-fold, or any other increment fold increase in between, when compared to a level of expression of a corresponding endogenous sequence in a nontransduced cell. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical, but the corresponding polypeptide is identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence have at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of identity. In some embodiments, the exogenous sequence is codon-optimized for expression in a mammal or a human when compared to the corresponding endogenous sequence. In some embodiments, including those wherein the exogenous sequence is codon-optimized for expression in a mammal or a human when compared to the corresponding endogenous sequence, the exogenous sequence and the corresponding endogenous sequence have at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of homology.
In some embodiments of the pharmaceutical compositions of the disclosure, following transduction of a cell with a pharmaceutical composition of the disclosure, the exogenous sequence encodes a protein. In some embodiments, the protein encoded by the exogenous sequence has an activity level equal to or greater than an activity level of a protein encoded by a corresponding sequence of a nontransduced cell. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical, but the corresponding polypeptide is identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence have at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of identity. In some embodiments, including those wherein the exogenous sequence is codon-optimized for expression in a mammal or a human when compared to the corresponding endogenous sequence, the exogenous sequence and the corresponding endogenous sequence have at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of homology. In some embodiments, the activity comprises binding to, activating, and/or transferring one or more functional groups to a ligand or a substrate. In some embodiments, the protein comprises a REP-1 protein and the activity comprises a prenylation of REP-1 substrate.
In some embodiments of the pharmaceutical compositions of the disclosure, the pharmaceutical composition comprises (a) between 1.0 and 2.0×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (AAV). In some embodiments, the pharmaceutical composition comprises (a) about 1.0×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (AAV). In some embodiments, the pharmaceutical composition comprises (a) 1.0×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (AAV).
In some embodiments of the pharmaceutical compositions of the disclosure, the pharmaceutical composition comprises (b) less than 50% empty capsids. In some embodiments of the pharmaceutical compositions of the disclosure, the pharmaceutical composition comprises (b) less than 30% empty capsids.
In some embodiments of the pharmaceutical compositions of the disclosure, the replication-defective and recombinant adeno-associated virus (rAAV) contains a sequence isolated or derived from an AAV of serotype 2 (AAV2). In some embodiments, the sequence isolated or derived from an AAV2 comprises a sequence encoding an inverted terminal repeat (ITR). In some embodiments, the replication-defective and recombinant adeno-associated virus (rAAV) contains a sequence encoding a 5′ ITR and a sequence encoding a 3′ ITR. In some embodiments, the sequence encoding a 5′ ITR and the sequence encoding a 3′ ITR comprise a wild type sequence of an AAV2 ITR.
In some embodiments of the pharmaceutical compositions of the disclosure, the host cell is isolated or derived from a cultured cell line. In some embodiments, the host cell is an HEK293 cell.
In some embodiments of the pharmaceutical compositions of the disclosure, the host cell is isolated or derived from a primary cell line. In some embodiments, the host cell is an immortalized cell or a stem cell.
In some embodiments of the pharmaceutical compositions of the disclosure, each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′: (a) a sequence encoding an AAV2 5′ ITR, (b) a sequence encoding an early enhancer element, (c) a sequence encoding a promoter, (d) a sequence encoding an exon and intron, (e) a sequence encoding a splice acceptor site, (f) a sequence encoding a Rab escort protein 1 (REP1) protein, (g) a sequence encoding a post-transcriptional regulatory element (PRE), (h) a sequence encoding a polyadenylation (polyA) site, and (i) a sequence encoding an AAV2 3′ ITR. (see also, U.S. Pat. No. 9,834,788, the contents of which are incorporated herein in their entirety).
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the early enhancer element comprises a sequence isolated or derived from a Cytomegalovirus (CMV). In some embodiments, the early enhancer element comprises or consists of the nucleic acid sequence of
241 ATTACCATGG (SEQ ID NO: 3). In some embodiments, the early enhancer element comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the promoter comprises or consists of a sequence isolated or derived from a sequence encoding a chicken beta actin (CBA) gene. In some embodiments, the sequence encoding the promoter comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the exon and intron comprises or consists of a sequence isolated or derived from a sequence encoding a chicken beta actin (CBA) gene. In some embodiments, the sequence encoding the exon and intron comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the splice acceptor site comprises a sequence isolated or derived from a sequence encoding an Oryctolagus cuniculus beta globin splice acceptor site. In some embodiments, the sequence encoding the Oryctolagus cuniculus beta globin splice acceptor site comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence comprising the early enhancer element, the sequence comprising the promoter, the sequence comprising the intron and exon and the sequence comprising the splice acceptor site, comprise or consist of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence comprising the early enhancer element, the sequence comprising the promoter, the sequence comprising the intron and exon and the sequence comprising the splice acceptor site, comprise or consist of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the REP1 protein comprises a sequence isolated or derived from a mammalian REP1 sequence. In some embodiments, the mammalian REP1 sequence is isolated or derived from a mouse, a rat, a rabbit, a non-human primate or a human. In some embodiments, the mammalian REP1 sequence is isolated or derived from a human. In some embodiments, the sequence encoding the human REP1 protein comprises or consists of the nucleic acid sequence of
In some embodiments, the human REP1 protein comprises or consists of the amino acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the PRE comprises a sequence isolated or derived from a Woodchuck Hepatitis virus (WPRE). In some embodiments, the sequence encoding the WPRE comprises or consists of a nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding a polyadenylation (polyA) site comprises a sequence isolated or derived from a mammalian gene. In some embodiments, the sequence encoding a polyadenylation (polyA) site comprises a sequence isolated or derived from a bovine growth hormone gene (BGH). In some embodiments, the sequence encoding the polyA site comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the AAV2 5′ITR comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the sequence encoding the AAV2 3′ITR comprises or consists of the nucleic acid sequence of
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the nucleic acid comprising, from 5′ to 3′, elements (a) through (i) comprises or consists of a DNA sequence. In some embodiments, the nucleic acid comprising, from 5′ to 3′, elements (a) through (i) comprises or consists of a single-stranded DNA sequence.
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), each rAAV of the plurality of full rAAV of the final composition comprises a capsid protein isolated or derived from an AAV2. In some embodiments, the AAV2 capsid protein comprises a sequence having at least 95% identity to the amino acid sequence
In some embodiments, the AAV2 capsid protein comprises the amino acid sequence
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the pharmaceutical composition further comprises a formulation buffer. In some embodiments, the formulation buffer comprises Tris, MgCl2, and NaCl. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8 with poloxamer 188 at 0.001%.
In some embodiments of the pharmaceutical compositions of the disclosure, including those wherein each full rAAV of the plurality of full rAAVs of the final composition further comprises: a nucleic acid sequence comprising, from 5′ to 3′, elements (a) through (i), the plurality of full rAAVs are at a concentration of between 1×108 genome particles (gp)/mL and 1×1014 gp/mL, inclusive of the endpoints. In some embodiments, the plurality of full rAAVs are at a concentration of between 0.5×1010 gp/mL and 2.5×1012 gp/mL, inclusive of the endpoints. In some embodiments, the plurality of full rAAVs are at a concentration of between 1×1011 gp/mL and 5×1013 gp/mL inclusive of the endpoints. In some embodiments, the plurality of full rAAVs are at a concentration of between 1×1011 gp/mL and 2×1012 gp/mL, inclusive of the endpoints. In some embodiments, the plurality of full rAAVs are at a concentration of 1×1012 gp/mL. In some embodiments, the plurality of full rAAVs are at a concentration of 1×1011 gp/mL. In some embodiments, the concentration of the plurality of full rAAVs is measured using qPCR. In some embodiments, the qPCR uses a supercoiled plasmid vector as a standard. In some embodiments, the qPCR uses a linearized plasmid vector as a standard.
The disclosure provides a delivery device comprising the pharmaceutical composition of the disclosure. In some embodiments, the delivery device comprises one or more of a syringe, a catheter and a needle. In some embodiments, the delivery device is suitable for administering the pharmaceutical composition by injection. In some embodiments, the delivery device is suitable for administering the pharmaceutical composition by infusion. In some embodiments, the delivery device is suitable for administering the pharmaceutical composition by a subretinal route. In some embodiments, the delivery device is suitable for administering the pharmaceutical composition by a suprachoroidal route.
The disclosure provides a method of treating a disease or disorder in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition of the disclosure.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the disease or disorder is a retinal disease or disorder. In some embodiments, the disease or disorder is Choroideremia.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount comprises an amount between a minimally effective amount and a maximally tolerable amount of the pharmaceutical composition.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the minimally effective amount comprises an amount of the pharmaceutical composition sufficient to transduce at least one neuron of a retina or a target portion thereof. In some embodiments, the minimally effective amount comprises an amount of the pharmaceutical composition sufficient to transduce at least 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of the neurons of a retina or a target portion thereof. In some embodiments, the minimally effective amount comprises an amount of the pharmaceutical composition sufficient to improve visual acuity of the subject. In some embodiments, the minimally effective amount comprises an amount of the pharmaceutical composition sufficient to reduce a sign or symptom of a retinal disease. In some embodiments, the retinal disease is Choroideremia.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the maximally tolerable amount comprises an amount of the pharmaceutical composition sufficient to induce an adverse event. In some embodiments, the adverse effect comprises an immune response to the pharmaceutical composition. In some embodiments, the immune response comprises inflammation. In some embodiments, the inflammation is systemic. In some embodiments, the inflammation is local. In some embodiments, the adverse event is severe. In some embodiments, the adverse event cannot be prevented, reduced or controlled by administering a secondary medical treatment to the subject. In some embodiments, the secondary medical treatment comprises a suppressant of the immune system. In some embodiments, the suppressant comprises an anti-inflammatory agent. In some embodiments, the anti-inflammatory agent comprises a corticosteroid. In some embodiments, the corticosteroid comprises prednisone or prednisolone.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount of the pharmaceutical composition comprises an amount having a multiplicity of infection (MOI) of between 104 and 107, inclusive of the endpoints. In some embodiments, the therapeutically effective amount of the pharmaceutical composition comprises an amount having a multiplicity of infection (MOI) of between 1×106 and 9×106, inclusive of the endpoints. In some embodiments, the therapeutically effective amount of the pharmaceutical composition comprises an amount having a multiplicity of infection (MOI) of between 104 and 105, inclusive of the endpoints. In some embodiments, the therapeutically effective amount of the pharmaceutical composition comprises an amount having a multiplicity of infection (MOI) of 105.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount comprises between 1×108 gp and 1×1013 gp, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises between 6×109 gp and 1×1013 gp, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises between 6×109 gp and 7×1012 gp, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises between 6×109 gp and 5×1012 gp, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises between 1×1010 gp and 1×1012 gp, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises or consists of 1×1010 gp. In some embodiments, the therapeutically effective amount comprises or consists of 1×1011 gp. In some embodiments, the therapeutically effective amount comprises or consists of 1×1012 gp.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount comprises or consists of a volume between 10 μL and 200 μL, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises or consists of a volume between 10 μL and 50 μL, between 50 μL and 100 μL, between 100 μL and 150 μL or between 150 μL and 200 μL, inclusive of the endpoints, for each range. In some embodiments, the therapeutically effective amount comprises or consists of a volume between 70 μL and 120 μL, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises or consists of a volume a volume of 100 μL.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount comprises or consists of at least one injection of a volume between 10 μL and 200 μL, inclusive of the endpoints. In some embodiments, the therapeutically effective amount comprises or consists of at least 2, 3, 4, 5, 6, 7, 8, 9, 10 injections of a volume between 10 μL and 200 μL, inclusive of the endpoints. In some embodiments, two or more injections are made into a subretinal space during the same medical procedure on the same eye. In some embodiments, two or more injections are made into two or more distinct subretinal spaces during the same medical procedure on the same eye. In some embodiments, the area of the subretinal space contacted by the therapeutically-effective amount of the vector comprises or consists of between 5 and 20 mm2. In some embodiments, the area of the subretinal space contacted by the therapeutically-effective amount of the vector comprises or consists of 10 mm2. In some embodiments, one or more injections are made into at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 distinct areas of the retina of an eye. In some embodiments, one or more injections are made into at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 distinct areas of the retina of an eye during a single procedure. In some embodiments, one or more injections are made into at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 distinct areas of the retina of an eye over the course of two or more procedures.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount comprises or consists of at least one injection of a volume between 10 μL and 200 μL, inclusive of the endpoints, administered from the same device. In some embodiments of the methods of treating a disease or disorder of the disclosure, the therapeutically effective amount is delivered by the same device as a split dose, divided between one or more injections. The split dose may be administered to the same subretinal space or to two or more distinct subretinal spaces within the same eye.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the administering step comprises an injection or an infusion. In some embodiments, the administering step comprises a subretinal, a suprachoroidal or an intravitreal route. In some embodiments, the administering step comprises a subretinal injection or infusion. In some embodiments, the subretinal injection or infusion comprises a 2 step subretinal injection. In some embodiments, the administering step comprises a suprachoroidal injection or infusion.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the subject is male. In some embodiments, the subject is at least 18 years of age. In some embodiments, the subject has a genetically confirmed diagnosis of choroideremia. In some embodiments, the subject has been identified as having a mutation in the REP1 gene. In some embodiments, the subject presents a clinical sign of choroideremia in a macula of at least one eye. In some embodiments, the subject has a Best Corrected Visual Acuity (BCVA) score of 34-73 letters in at least one eye. In some embodiments, the subject has mild or early stage choroideremia. In some embodiments, the subject has advanced or severe choroideremia.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method comprises treating 10 mm2 of a retina of at least one eye. In some embodiments, the method comprises treating between 5 mm2 and 10 mm2, inclusive of the endpoints, of a retina of at least one eye. In some embodiments, the method comprises treating between 2 mm2 and 15 mm2, inclusive of the endpoints, of a retina of at least one eye.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the pharmaceutical composition is administered to one eye of the subject. In some embodiments, the pharmaceutical composition is administered to both eyes of the subject. In some embodiments, the eyes of the subject are treated simultaneously. In some embodiments, both eyes of the subject are treated sequentially. In some embodiments, at least one eye of the subject had been treated for choroideremia prior to administration of the pharmaceutical composition to the subject.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method comprises administering between 1 and 12 doses per eye, inclusive of the endpoints. In some embodiments, the method comprises administering at least one dose at least once per day, once per week, once per month, once every three months, once every 6 months, or once per year. In some embodiments, the method comprises administering multiple doses and wherein each dose comprises the same amount of the pharmaceutical composition. In some embodiments, the method comprises administering multiple doses and wherein each dose does not comprise the same amount of the pharmaceutical composition. In some embodiments, the method comprises administering multiple doses and wherein each successive dose comprises a greater number of full rAAV than the previous dose. In some embodiments, the method comprises administering multiple doses and wherein each successive dose comprises a lesser number of full rAAV than the previous dose.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method comprises administering between 1 and 12 doses per eye, inclusive of the endpoints. In some embodiments, the doses are provided following a period of recovery. In some embodiments, the period of recovery is at least 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or any number of minutes in between. In some embodiments, the period of recovery is at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 hours. In some embodiments, the period of recovery is at least 1, 2, 3, 4, 5, 6, or 7 days. In some embodiments, the period of recovery is at least 1, 2, 3, or 4 weeks. In some embodiments, the period of recovery is at least 1, 2, 3, 4, 5 6, 7, 8, 9, 10, 11, or 12 months. In some embodiments, the period of recovery is at least 1, 2, 3, 4, 5 or 6 years.
In some embodiments of the methods of treating a disease or disorder of the disclosure, including those wherein the method comprises administering between 1 and 12 doses per eye, inclusive of the endpoints, the subject has experienced an adverse event following a therapeutically effective dose and the subsequent dose comprises a lesser number of full rAAV than the previous dose that induced the adverse event. In some embodiments, the subject recovers from the adverse event and a subsequent dose of the pharmaceutical composition is administered to the subject. In some embodiments, the therapeutically effective dose that induced the adverse event and the subsequent dose contain an equal number of full rAAV. In some embodiments, the therapeutically effective dose that induced the adverse event and the subsequent dose does not contain an equal number of full rAAV.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method further comprises administering an amount of a plurality of placebo rAAVs to the subject prior to administration of a therapeutically effective amount of the pharmaceutical composition, wherein each placebo rAAV is an empty rAAV. In some embodiments, the empty rAAV does not contain either a promoter to express an exogenous sequence or an exogenous sequence. In some embodiments, administration of the amount of a plurality of placebo rAAVs is systemic. In some embodiments, administration of the amount of a plurality of placebo rAAVs is local. In some embodiments, the method further comprises (a) determining whether the plurality of placebo rAAVs induced an immune response in the subject and/or (b) determining whether the subject developed an immune tolerance to the plurality of placebo rAAVs, thereby indicating that administration of a therapeutically effective amount of the pharmaceutical composition should not induce an immune-mediated adverse event in the subject.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method further comprises administering to the subject a suppressant of an immune response. In some embodiments, the suppressant comprises an anti-inflammatory agent. In some embodiments, the anti-inflammatory agent comprises a corticosteroid. In some embodiments, the corticosteroid comprises prednisone or prednisolone. In some embodiments, the administration of the suppressant of an immune response is systemic. In some embodiments, the suppressant of an immune response is administered orally. In some embodiments, the administration of the suppressant of an immune response is local. In some embodiments, the suppressant of an immune response is administered to the eye treated with the pharmaceutical composition. In some embodiments, the pharmaceutical composition and the suppressant of an immune response are administered simultaneously. In some embodiments, the pharmaceutical composition and the suppressant of an immune response are administered on the same day. In some embodiments, the pharmaceutical composition and the suppressant of an immune response are administered sequentially. In some embodiments, the administration of the suppressant precedes the administration of the pharmaceutical composition by at least one day. In some embodiments, the administration of the pharmaceutical composition precedes the administration of the suppressant by at least one day.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the method further comprises determining an initial severity of choroideremia-mediated damage in at least one eye of the subject. In some embodiments, the method further comprises determining a subsequent severity of choroideremia-mediated damage in the at least one eye of the subject following administration of the pharmaceutical composition to the at least one eye. In some embodiments, the initial or subsequent severity of choroideremia-mediated damage is determined by determining a Best Corrected Visual Acuity (BCVA) test score, measuring an area or a volume of viable retinal tissue, measuring a preserved ellipsoid zone, measuring retinal sensitivity, measuring contrast sensitivity, measuring color vision, measuring low luminance visual acuity, measuring speed reading or any combination thereof. In some embodiments, the BCVA test utilizes an (Early Treatment of Diabetic Retinopathy Study) ETDRS chart. In some embodiments, the BCVA test comprises an assessment of one or more of finger counting, hand movement, light perception and a combination thereof. In some embodiments, the viable retinal tissue comprises fundus autofluorescence and wherein measuring viable retinal tissue comprises detecting a level or pattern of fundus autofluorescence. In some embodiments, the measuring a preserved ellipsoid zone comprises Spectral Domain Optical Coherence Tomography (SD-OCT). In some embodiments, the measuring retinal sensitivity comprises microperimetry.
In some embodiments of the methods of treating a disease or disorder of the disclosure, the administration of the therapeutically effective amount of the pharmaceutical composition inhibits or reduces progression of a sign or a symptom of choroideremia. In some embodiments, the administration of the therapeutically effective amount of the pharmaceutical composition reduces a sign or a symptom of choroideremia. In some embodiments, a sign or a symptom of choroideremia comprises a loss of photoreceptor cells, a loss of RPE cells, a decreased visual acuity, decreased low luminescence visual acuity, total area of preserved autofluorescence (AF), a low score on a BCVA test, a decreased area of preserved ellipsoid zone, decreased retinal sensitivity, decreased contrast sensitivity, decreased or faded color vision, decreased rates of speed reading or any combination thereof. In some embodiments, the severity of the sign or symptom of choroideremia is determined relative to a healthy retina. In some embodiments, the healthy retina belongs to an age-matched control subject.
The disclosure provides a method of determining a therapeutically effective amount of a pharmaceutical composition of the disclosure, the method comprising: (a) measuring an area of a retina of a subject to be treated, (b) determining whether the area of (a) is in the central 0.5 mm2 foveal area or in the macula, (c) calculating the number of rods, cones and retinal pigment epithelial (RPE) cells within the area of (a), and (d) multiplying the total number of cells by a multiplicity of infection (MOI) of 1×105 to calculate a number of genome particles (gp) to be included in the therapeutically effective amount, wherein the maximal area of the retinal to be treated is 10 mm2, wherein the density of RPE cells in the retina is 5,000 cells per mm2, wherein the density of rods in the retina is 75,000 rods per mm2 exclusive of the central 0.5 mm2 foveal area, wherein the density of cones in the retina is 150,000 cones per mm2 in the central 0.5 mm2 foveal area and the density of cones in the retina is 25,000 per mm2 in the macula outside the central 0.5 mm2 foveal area.
The disclosure provides a pharmaceutical composition of the disclosure for use in treating a disease or a disorder in a subject in need thereof.
The disclosure provides a vector of the disclosure for use in treating a disease or a disorder in a subject in need thereof.
The disclosure provides an AAV or a rAAV of the disclosure for use in treating a disease or a disorder in a subject in need thereof.
The disclosure provides methods for the purification of a recombinant AAV (rAAV) particle of the disclosure. The disclosure provides pharmaceutical compositions comprising rAAV particles produced by the methods of the disclosure. In some embodiments, the pharmaceutical compositions comprising rAAV particles produced by the methods of the disclosure comprise (a) between 0.5 and 2.5×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (rAAV); (b) less than 50% empty capsids; (c) less than 4 ng/mL residual host cell protein per 1.0×1012 vg/mL; and (d) less than 7×10−3 pg/ml residual host cell DNA per 1.0×1012 vg/mL.
The disclosure provides a method of treating a disease or disorder in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition of the disclosure. In some embodiments, the disease or disorder is a retinal disease or disorder. In some embodiments, the disease or disorder is Choroideremia.
The disclosure provides a pharmaceutical composition comprising: (a) between 0.5 and 2.5×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (rAAV); (b) less than 50% empty capsids; (c) less than 4 ng/mL residual host cell protein per 1.0×1012 vg/mL; and (d) less than 7×10−3 pg/ml residual host cell DNA per 1.0×1012 vg/mL.
In some embodiments, the pharmaceutical composition comprises: (a) between 0.5 and 2.5×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (rAAV); (b) less than 50% empty capsids; (c) less than 4 ng/mL residual host cell protein per 1.0×1012 vg/mL; (d) less than 7×10−3 pg/ml residual host cell DNA per 1.0×1012 vg/mL; and (e) a plurality of functional vg/mL, wherein each of functional vector genomes is capable of expressing an exogenous sequence in a cell following transduction. In some embodiments, following transduction of a cell with a pharmaceutical composition of the disclosure, the plurality of functional vg/mL express the exogenous sequence at a 2-fold increase when compared to a level of expression of a corresponding endogenous sequence in a nontransduced cell. In some embodiments, following transduction of a cell with a pharmaceutical composition of the disclosure, the plurality of functional vg/mL express the exogenous sequence at a 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 11-fold, 12-fold, 13-fold, 14-fold, 15-fold, 16-fold, 17-fold, 18-fold, 19-fold, 20-fold, or any other increment fold increase in between, when compared to a level of expression of a corresponding endogenous sequence in a nontransduced cell. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence have at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of identity.
In some embodiments, the pharmaceutical composition comprises: (a) between 0.5 and 2.5×1012 vector genomes (vg)/mL of replication-defective and recombinant adeno-associated virus (rAAV); (b) less than 50% empty capsids; (c) less than 4 ng/mL residual host cell protein per 1.0×1012 vg/mL; (d) less than 7×10−3 pg/ml residual host cell DNA per 1.0×1012 vg/mL; and (e) a plurality of functional vg/mL, wherein each of functional vector genomes is capable of expressing an exogenous sequence in a cell following transduction. In some embodiments, following transduction of a cell with a pharmaceutical composition of the disclosure, the exogenous sequence encodes a protein. In some embodiments, the protein encoded by the exogenous sequence has an activity level equal to or greater than an activity level of a protein encoded by a corresponding sequence of a nontransduced cell. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence are not identical. In some embodiments, the exogenous sequence and the corresponding endogenous sequence have at least 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or any percentage in between of identity. In some embodiments, the activity comprises binding to, activating, and/or transferring one or more functional groups to a ligand or a substrate. In some embodiments, the protein comprises a REP-1 protein and the activity comprises prenylation of REP-1 substrate.
Compositions of the disclosure comprise a therapeutic Construct suitable for systemic or local administration to a mammal, and preferable, to a human. Exemplary Constructs of the disclosure comprise a sequence encoding a gene or a portion thereof. Preferably, Constructs of the disclosure comprise a sequence encoding a human gene or a portion thereof. Exemplary Constructs of the disclosure may further comprise one or more sequence(s) encoding regulatory elements to enable or to enhance expression of the gene or a portion thereof. Exemplary regulatory elements include, but are not limited to, promoters, introns, enhancer elements, response elements (including post-transcriptional response elements or post-transcriptional regulatory elements), polyadenosine (polyA) sequences, and a gene fragment to facilitate efficient termination of transcription (including a β-globin gene fragment and a rabbit β-globin gene fragment).
In some embodiments of the compositions of the disclosure, the Construct comprises a human gene or a portion thereof corresponding to a human Rab Escort Protein type 1 (REP-1) protein or a portion thereof. In some embodiments of the compositions of the disclosure, the Construct comprises a human gene or a portion thereof comprising a codon-optimized sequence. In some embodiments, the sequence is codon-optimized for expression in mammals. In some embodiments, the sequence is codon-optimized for expression in humans.
In some embodiments of the compositions of the disclosure, wherein the Construct comprises a human REP-1 protein or a portion thereof, the Construct is referred to as “AAV2-REP1 or AAV2.REP1” and the International Nonproprietary Name (INN) is timrepigene emparvovec. In some embodiments, the Construct comprises or consists of the sequence of:
CTGCGCGCTC GCTCGCTCAC TGAGGCCGCC CGGGCAAAGC CCGGGCGTCG GGCGACCTTT
61 GGTCGCCCGG CCTCAGTGAG CGAGCGAGCG CGCAGAGAGG GAGTGGCCAA CTCCATCACT
121 AGGGGTTCCT TGTAGTTAAT GATTAACCCG CCATGCTACT TATCTACGTA GCCATGCTCT
181 AGGTACCATT GACGTCAATA ATGACGTATG TTCCCATAGT AACGCCAATA GGGACTTTCC
241 ATTGACGTCA ATGGGTGGAG TATTTACGGT AAACTGCCCA CTTGGCAGTA CATCAAGTGT
301 ATCATATGCC AAGTACGCCC CCTATTGACG TCAATGACGG TAAATGGCCC GCCTGGCATT
361 ATGCCCAGTA CATGACCTTA TGGGACTTTC CTACTTGGCA GTACATCTAC GTATTAGTCA
421 TCGCTATTAC CATGGTCGAG GTGAGCCCCA CGTTCTGCTT CACTCTCCCC ATCTCCCCCC
481 CCTCCCCACC CCCAATTTTG TATTTATTTA TTTTTTAATT ATTTTGTGCA GCGATGGGGG
541 CGGGGGGGGG GGGGGGGCGC GCGCCAGGCG GGGCGGGGCG GGGCGAGGGG CGGGGCGGGG
601 CGAGGCGGAG AGGTGCGGCG GCAGCCAATC AGAGCGGCGC GCTCCGAAAG TTTCCTTTTA
661 TGGCGAGGCG GCGGCGGCGG CGGCCCTATA AAAAGCGAAG CGCGCGGCGG GCGGGAGTCG
721 CTGCGCGCTG CCTTCGCCCC GTGCCCCGCT CCGCCGCCGC CTCGCGCCGC CCGCCCCGGC
781 TCTGACTGAC CGCGTTACTC CCACAGGTGA GCGGGCGGGA CGGCCCTTCT CCTCCGGGCT
841 GTAATTAGCG CTTGGTTTAA TGACGGCTTG TTTCTTTTCT GTGGCTGCGT GAAAGCCTTG
901 AGGGGCTCCG GGAGGGCCCCT TTGTGCGGGG GGAGCGGCTC GGGGCTGTCC GCGGGGGGAC
961 GGCTGCCTTC GGGGGGGACG GGGCAGGGCG GGGTTCGGCT TCTGGCGTGT GACCGGCGGC
1021 TCTAGAGCCT CTGCTAACCA TGTTCATGCC TTCTTCTTTT TCCTACAGCT CCTGGGCAAC
1081 GTGCTGGTTA TTGTGCTGTC TCATCATTTT GGCAAAGAAT TGGATCCTAG CTTGATATCG
1141 AATTCCTGCA GCCCGGCGGC ACCATGGCGG ATACTCTCCC TTCGGAGTTT GATGTGATCG
1201 TAATAGGGAC GGGTTTGCCT GAATCCATCA TTGCAGCTGC ATGTTCAAGA AGTGGCCGGA
1261 GAGTTCTGCA TGTTGATTCA AGAAGCTACT ATGGAGGAAA CTGGGCCAGT TTTAGCTTTT
1321 CAGGACTATT GTCCTGGCTA AAGGAATACC AGGAAAACAG TGACATTGTA AGTGACAGTC
1381 CAGTGTGGCA AGACCAGATC CTTGAAAATG AAGAAGCCAT TGCTCTTAGC AGGAAGGACA
1441 AAACTATTCA ACATGTGGAA GTATTTTGTT ATGCCAGTCA GGATTTGCAT GAAGATGTCG
1501 AAGAAGCTGG TGCACTGCAG AAAAATCATG CTCTTGTGAC ATCTGCAAAC TCCACAGAAG
1561 CTGCAGATTC TGCCTTCCTG CCTACGGAGG ATGAGTCATT AAGCACTATG AGCTGTGAAA
1621 TGCTCACAGA ACAAACTCCA AGCAGCGATC CAGAGAATGC GCTAGAAGTA AATGGTGCTG
1681 AAGTGACAGG GGAAAAAGAA AACCATTGTG ATGATAAAAC TTGTGTGCCA TCAACTTCAG
1741 CAGAAGACAT GAGTGAAAAT GTGCTATAG CAGAAGATAC CACAGAGCAA CCAAAGAAAA
1801 ACAGAATTAC TTACTCACAA ATTATTAAAG AAGGCAGGAG ATTTAATATT GATTTAGTAT
1861 CAAAGCTGCT GTATTCTCGA GGATTACTAA TTGATCTTCT AATCAAATCT AATGTTAGTC
1921 GATATGCAGA GTTTAAAAAT ATTACCAGGA TTCTTGCATT TCGAGAAGGA CGAGTGGAAC
1981 AGGTTCCGTG TTCCAGAGCA GATGTCTTTA ATAGCAAACA ACTTACTATG GTAGAAAAGC
2041 GAATGCTAAT GAAATTTCTT ACATTTTGTA TGGAATATGA GAAATATCCT GATGAATATA
2101 AAGGATATGA AGAGATCACA TTTTATGAAT ATTTAAAGAC TCAAAAATTA ACCCCCAACC
2161 TCCAATATAT TGTCATGCAT TCAATTGCAA TGACATCAGA GACAGCCAGC AGCACCATAG
2221 ATGGTCTCAA AGCTACCAAA AACTTTCTTC ACTGTCTTGG GCGGTATGGC AACACTCCAT
2281 TTTTGTTTCC TTTATATGGC CAAGGAGAAC TCCCCAGTG TTTCTGCAGG ATGTGTGCTG
2341 TGTTTGGTGG AATTTATTGT CTTCGCCATT CAGTACAGTG CCTTGTAGTG GACGAAAGAAT
2401 CCAGAAAATG TAAAGCAATT ATAGATCAGT TTGGTCAGAG AATAATCTCT GAGCATTTCC
2461 TCGTGGAGGA CAGTTACTTT CCTGAGAACA TGTGCTCACG TGTGCAATAC AGGCAGATCT
2521 CCAGGGCAGT GCTGATTACA GATAGATCTG TCCTAAAAAC AGATTCAGAT CAACAGATTT
2581 CCATTTTGAC AGTGCCAGCA GAGGAACCAG GAACTTTTGC TGTTCGGGTC ATTGAGTTAT
2641 GTTCTTCAAC GATGACATGC ATGAAAGGCA CCTATTTGGT TCATTTGACT TGCACATCTT
2701 CTAAAACAGC AAGAGAAGAT TTAGAATCAG TTGTGCAGAA ATTGTTTGTT CCATATACTG
2761 AAATGGAGAT AGAAAATGAA CAAGTAGAAA AGCCAAGAAT TCTGTGGGCT CTTTACTTCA
2821 ATATGAGAGA TTCGTCAGAC ATCAGCAGGA GCTGTTATAA TGATTTACCA TCCAACGTTT
2881 ATGTCTGCTC TGGCCCAGAT TGTGGTTTAG GAAATGATAA TGCAGTCAAA CAGGCTGAAA
2941 CACTTTTCCA GGAAATCTGC CCCAATGAAG ATTTCTGTCC CCCTCCACCA AATCCTGAAG
3001 ACATTATCCT TGATGGAGAC AGTTTACAGC CAGAGGCTTC AGAATCCAGT GCCATACCAG
3061 AGGCTAACTC GGAGACTTTC AAGGAAAGCA CAAACCTTGG AAACCTAGAG GAGTCCTCTG
3121 AATAATCTAG TCGATTCGAA TTCGATATCA AGCTTATCGA TAATCAACCT CTGGATTACA
3181 AAATTTGTGA AAGATTGACT GGTATTCTTA ACTATGTTGC TCCTTTTACG CTATGTGGAT
3241 ACGCTGCTTT AATGCCTTTG TATCATGCTA TTGCTTCCCG TATGGCTTTC ATTTTCTCCT
3301 CCTTGTATAA ATCCTGGTTG CTGTCTCTTT ATGAGGAGTT GTGGCCCGTT GTCAGGCAAC
3361 GTGGCGTGGT GTGCACTGTG TTTGCTGACG CAACCCCCAC TGGTTGGGGC ATTGCCACCA
3421 CCTGTCAGCT CCTTTCCGGG ACTTTCGCTT TCCCCCTCCC TATTGCCACG GCGGAACTCA
3481 TCGCCGCCTG CCTTGCCCGC TGCTGGACAG GGGCTCGGCT GTTGGGCACT GACAATTCCG
3541 TGGTGTTGTC GGGGAAATCA TCGTCCTTTC CTTGGCTGCT CGCCTGTGTT GCCACCTGGA
3601 TTCTGCGCGG GACGTCCTTC TGCTACGTCC CTTCGGCCCT CAATCCAGCG GACCTTCCTT
3661 CCCGCGGCCT GCTGCCGGCT CTGCGGCCTC TTCCGCGTCT TCGCCTTCGC CCTCAGACGA
3721 GTCGGATCTC CCTTTGGGCC GCCTCCCCGC ATCGATACCG TCGACTCGCT GATCAGCCTC
3781 GACTGTGCCT TCTAGTTGCC AGCCATCTGT TGTTTGCCCC TCCCCCGTGC CTTCCTTGAC
3841 CCTGGAAGGT GCCACTCCCA CTGTCCTTTC CTAATAAAAT GAGGAAATTG CATCGCATTG
3901 TCTGAGTAGG TGTCATTCTA TTCTGGGGGG TGGGGTGGGG CAGGACAGCA AGGGGGAGGA
3961 TTGGGAAGAC AATAGCAGGC ATGCTGGGGA TGCGGTGGGC TCTATGGCTT CTGAGGCGGA
4021 AAGAACCAGC TGGGGCTCGA CTAGAGCATG GCTACGTAGA TAAGTAGCAT GGCGGGTTAA
4081 TCATTAACTA CAAGGAACCC CTAGTGATGG AGTTGGCCAC TCCCTCTCTG CGCGCTCGCT
4141 CGCTCACTGA GGCCGGGCGA CCAAAGGTCG CCCGACGCCC GGGCGGCCTC AGTGAGCGAG
4201 CGAGCGCGCA GAG (SEQ ID NO: 16). In some embodiments, the Construct comprises or consists of a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of:
In some embodiments, the Construct comprises or consists of a sequence encoding a human REP1 sequence having the sequence of
1 ATGGCGGATA CTCTCCCTTC GGAGTTTGAT GTGATCGTAA TAGGGACGGG TTTGCCTGAA
61 TCCATCATTG CAGCTGCATG TTCAAGAAGT GGCCGGAGAG TTCTGCATGT TGATTCAAGA
121 AGCTACTATG GAGGAAACTG GGCCAGTTTT AGCTTTTCAG GACTATTGTC CTGGCTAAAG
181 GAATACCAGG AAAACAGTGA CATTGTAAGT GACAGTCCAG TGTGGCAAGA CCAGATCCTT
241 GAAAATGAAG AAGCCATTGC TCTTAGCAGG AAGGACAAAA CTATTCAACA TGTGGAAGTA
301 TTTTGTTATG CCAGTCAGGA TTTGCATGAA GATGTCGAAG AAGCTGGTGC ACTGCAGAAA
361 AATCATGCTC TTGTGACATC TGCAAACTCC ACAGAAGCTG CAGATTCTGC CTTCCTGCCT
421 ACGGAGGATG AGTCATTAAG CACTATGAGC TGTGAAATGC TCACAGAACA AACTCCAAGC
481 AGCGATCCAG AGAATGCGCT AGAAGTAAAT GGTGCTGAAG TGACAGGGGA AAAAGAAAAC
541 CATTGTGATG ATAAAACTTG TGTGCCATCA ACTTCAGCAG AAGACATGAG TGAAAATGTG
601 CCTATAGCAG AAGATACCAC AGAGCAACCA AAGAAAAACA GAATTACTTA CTCACAAATT
661 ATTAAAGAAG GCAGGAGATT TAATATTGAT TTAGTATCAA AGCTGCTGTA TTCTCGAGGA
721 TTACTAATTG ATCTTCTAAT CAAATCTAAT GTTAGTCGAT ATGCAGAGTT TAAAAATATT
781 ACCAGGATTC TTGCATTTCG AGAAGGACGA GTGGAACAGG TTCCGTGTTC CAGAGCAGAT
841 GTCTTTAATA GCAAACAACT TACTATGGTA GAAAAGCGAA TGCTAATGAA ATTTCTTACA
901 TTTTGTATGG AATATGAGAA ATATCCTGAT GAATATAAAG GATATGAAGA GATCACATTT
961 TATGAATATT TAAAGACTCA AAAATTAACC CCCAACCTCC AATATATTGT CATGCATTCA
1021 ATTGCAATGA CATCAGAGAC AGCCAGCAGC ACCATAGATG GTCTCAAAGC TACCAAAAAC
1081 TTTCTTCACT GTCTTGGGCG GTATGGCAAC ACTCCATTTT TGTTTCCTTT ATATGGCCAA
1141 GGAGAACTCC CCCAGTGTTT CTGCAGGATG TGTGCTGTGT TTGGTGGAAT TTATTGTCTT
1201 CGCCATTCAG TACAGTGCCT TGTAGTGGAC AAAGAATCCA GAAAATGTAA AGCAATTATA
1261 GATCAGTTTG GTCAGAGAAT AATCTCTGAG CATTTCCTCG TGGAGGACAG TTACTTTCCT
1321 GAGAACATGT GCTCACGTGT GCAATACAGG CAGATCTCCA GGGCAGTGCT GATTACAGAT
1381 AGATCTGTCC TAAAAACAGA TTCAGATCAA CAGATTTCCA TTTTGACAGT GCCAGCAGAG
1441 GAACCAGGAA CTTTTGCTGT TCGGGTCATT GAGTTATGTT CTTCAACGAT GACATGCATG
1501 AAAGGCACCT ATTTGGTTCA TTTGACTTGC ACATCTTCTA AAACAGCAAG AGAAGATTTA
1561 GAATCAGTTG TGCAGAAATT GTTTGTTCCA TATACTGAAA TGGAGATAGA AAATGAACAA
1621 GTAGAAAAGC CAAGAATTCT GTGGGCTCTT TACTTCAATA TGAGAGATTC GTCAGACATC
1681 AGCAGGAGCT GTTATAATGA TTTACCATCC AACGTTTATG TCTGCTCTGG CCCAGATTGT
1741 GGTTTAGGAA ATGATAATGC AGTCAAACAG GCTGAAACAC TTTTCCAGGA AATCTGCCCC
1801 AATGAAGATT TCTGTCCCCC TCCACCAAAT CCTGAAGACA TTATCCTTGA TGGAGACAGT
1861 TTACAGCCAG AGGCTTCAGA ATCCAGTGCC ATACCAGAGG CTAACTCGGA GACTTTCAAG
1921 GAAAGCACAA ACCTTGGAAA CCTAGAGGAG TCCTCTGAAT AA (SEQ ID NO: 17) or
a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of
In some embodiments, the Construct comprises or consists of a sequence encoding a CAG promoter having the sequence of
1 CCATTGACGT CAATAATGAC GTATGTTCCC ATAGTAACGC CAATAGGGAC TTTCCATTGA
61 CGTCAATGGG TGGAGTATTT ACGGTAAACT GCCCACTTGG CAGTACATCA AGTGTATCAT
121 ATGCCAAGTA CGCCCCCTAT TGACGTCAAT GACGGTAAAT GGCCCGCCTG GCATTATGCC
181 CAGTACATGA CCTTATGGGA CTTTCCTACT TGGCAGTACA TCTACGTATT AGTCATCGCT
241 ATTACCATGG TCGAGGTGAG CCCCACGTTC TGCTTCACTC TCCCCATCIC CCCCCCCTCC
301 CCACCCCCAA TTTTGTATTT ATTTATTTTT TAATTATTTT GTGCAGCGAT GGGGGCGGGG
361 GGGGGGGGGG GGCGCGCGCC AGGCGGGGCG GGGCGGGGCG AGGGGCGGGG CGGGGCGAGG
421 CGGAGAGGTG CGGCGGCAGC CAATCAGAGC GGCGCGCTCC GAAAGTTTCC TTTTATGGCG
481 AGGCGGCGGC GGCGGCGGCC CTATAAAAAG CGAAGCGCGC GGCGGGCGGG AGTCGCTGCG
541 CGCTGCCTTC GCCCCGTGCC CCGCTCGGCC GCCGCCTCGC GCCGCCCGCC CCGGCTCTGA
601 CTGACCGCGT TACTCCCACA GGTGAGCGGG CGGGACGGCC CTTCTCCTCC GGGCTGTAAT
661 TAGCGCTTGG TTTAATGACG GCTTGTTTCT TTTCTGTGGC TGCGTGAAAG CCTTGAGGGG
721 CTCCGGGAGG GCCCTTTGTG CGGGGGGAGC GGCTCGGGGC TGTCCGCGGG GGGACGGCTG
781 CCTTCGGGGG GGACGGGGCA GGGCGGGGTT CGGCTTCTGG CGTGTGACCG GCGGCTCTAG
841 AGCCTCTGCT AACCATGTTC ATGCCTTCTT CTTTTTCCTA CAGCTCCTGG GCAACGTGCT
901 GGTTATTGTG CTGTCTCATC ATTTTGGCAA AGAATTGGAT CC (SEQ ID NO: 18) or
a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of
In some embodiments, the Construct comprises or consists of a sequence encoding a mutated WPRE signal having the sequence of
1 ATCGATAATC AACCTCTGGA TTACAAAATT TGTGAAAGAT TGACTGGTAT TCTTAACTAT
61 GTTGCTCCTT TTACGCTATG TGGATACGCT GCTTTAATGC CTTTGTATCA TGCTATTGCT
121 TCCCGTATGG CTTTCATTTT CTCCTCCTTG TATAAATCCT GGTTGCTGTC TCTTTATGAG
181 GAGTTGTGGC CCGTTGTCAG GCAACGTGGC GTGGTGTGCA CTGTGTTTGC TGACGCAACC
241 CCCACTGGTT GGGGCATTGC CACCACCTGT CAGCTCCTTT CCGGGACTTT CGCTTTCCCC
301 CTCCCTATTG CCACGGCGGA ACTCATCGCC GCCTGCCTTG CCCGCTGCTG GACAGGGGCT
361 CGGCTGTTGG GCACTGACAA TTCCGTGGTG TTGTCGGGGA AATCATCGTC CTTTCCTTGG
421 CTGCTCGCCT GTGTTGCCAC CTGGATTCTG CGCGGGACGT CCTTCTGCTA CGTCCCTTCG
481 GCCCTCAATC CAGCGGACCT TCCTTCCCGC GGCCTGCTGC CGGCTCTGCG GCCTCTTCCG
541 CGTCTTCGCC TTCGCCCTCA GACGAGTCGG ATCTCCCTTT GGGCCGCCTC CCC (SEQ ID NO: 19) or a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of
In some embodiments, the Construct comprises or consists of a sequence encoding a polyadenylation signal of the bovine growth hormone having the sequence of
1 CGCTGATCAG CCTCGACTGT GCCTTCTAGT TGCCAGCCAT CTGTTGTTTG CCCCTCCCCC
61 GTGCCTTCCT TGACCCTGGA AGGTGCCACT CCCACTGTCC TTTCCTAATA AAATGAGGAA
121 ATTGCATCGC ATTGTCTGAG TAGGTGTCAT TCTATTCTGG GGGGTGGGGT GGGGCAGGAC
181 AGCAAGGGGG AGGATTGGGA AGACAATAGC AGGCATGCTG GGGATGCGGT GGGCTCTATG
241 GCTTCTGAGG CGGAAAGAAC CAGCTGGGG (SEQ ID NO 20) or a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of
In some embodiments, the Construct comprises or consists of a sequence encoding a 5′ITR having the sequence of
1 CTGCGCGCTC GCTCGCTCAC TGAGGCCGCC CGGGCAAAGC CCGGGCGTCG GGCGACCTTT
61 GGTCGCCCGG CCTCAGTGAG CGAGCGAGCG CGCAGAGAGG GAGTGGCCAA CTCCATCACT
121 AGGGGTTCCT (SEQ ID NO: 21) or a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identity to the sequence of
In some embodiments, the Construct comprises or consists of a sequence encoding a 3′ITR having the sequence of
1 AGGAACCCCT AGTGATGGAG TTGGCCACTC CCTCTCTGCG CGCTCGCTCG CTCACTGAGG
61 CCGGGCGACC AAAGGTCGCC CGACGCCCGG GCGGCCTCAG TGAGCGAGCG AGCGCGCAGA
121 G (SEQ ID NO: 22) or a sequence having at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any percentage in between of identify to the sequence of
In some embodiments of the compositions of the disclosure, wherein the Construct comprises a human REP-1 protein or a portion thereof, the Construct is referred to as “AAV2-REP1 or AAV2.REP1” and the International Nonproprietary Name (INN) is timrepigene emparvovec. In some embodiments of the compositions of the disclosure, wherein the Construct comprises a human REP-1 protein or a portion thereof, the AAV2-REP1 product consists of a purified recombinant serotype 2 adeno-associated viral vector (rAAV) encoding the cDNA of human Rab escort protein type 1 (REP1). In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence of 4173 bp in length (plus short cloning sites flanking each element) comprising: a 177 bp 5′ inverted terminal repeat (ITR), a 934 bp Cytomegalovirus enhancer/chicken-beta actin (CBA) hybrid promoter, a 1962 bp human REP1 cDNA, a 589 bp Woodchuck hepatitis virus post-transcriptional regulatory element (WPRE), a 242 bp Bovine growth hormone polyadenylation sequence (BGH-polyA), and a 165 bp 3′ ITR. In some embodiments, a pAAV.REP-1-Kan plasmid used to generate the AAV2-REP1 vector is shown in
In some embodiments of the compositions of the disclosure, the Construct further comprises a sequence corresponding to a 5′ inverted terminal repeat (ITR) and a sequence corresponding to a 3′ inverted terminal repeat (ITR). In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are identical. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are not identical. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are isolated or derived from an adeno-associated viral vector of serotype 2 (AAV2). In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a wild type sequence. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a truncated wild type AAV2 sequence. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a variation when compared to a wild type sequence of the same AAV serotype. In some embodiments, the variation comprises a substitution, an insertion, a deletion, an inversion, or a transposition. In some embodiments, the variation comprises a truncation or an elongation of a wild type or a variant sequence.
In some embodiments of the compositions of the disclosure, an AAV comprises a sequence corresponding to a 5′ inverted terminal repeat (ITR) and a sequence corresponding to a 3′ inverted terminal repeat (ITR). In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are identical. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are not identical. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR are isolated or derived from an adeno-associated viral vector of serotype 2 (AAV2). In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a wild type sequence. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a truncated wild type AAV2 sequence. In some embodiments, the sequence encoding the 5′ ITR and the sequence encoding the 3′ITR comprise a variation when compared to a wild type sequence of the same AAV serotype. In some embodiments, the variation comprises a substitution, an insertion, a deletion, an inversion, or a transposition. In some embodiments, the variation comprises a truncation or an elongation of a wild type or a variant sequence.
In some embodiments of the compositions of the disclosure, an AAV comprises a viral sequence essential for formation of a replication-deficient AAV. In some embodiments, the viral sequence is isolated or derived from an AAV of the same serotype as one or both of the sequence encoding the 5′ITR or the sequence encoding the 3′ITR. In some embodiments, the viral sequence, the sequence encoding the 5′ITR or the sequence encoding the 3′ITR are isolated or derived from an AAV2. In some embodiments, the viral sequence, the sequence encoding the 5′ITR and the sequence encoding the 3′ITR are isolated or derived from an AAV2.
In some embodiments of the compositions of the disclosure, an AAV comprises a viral sequence essential for formation of a replication-deficient AAV, a sequence encoding the 5′ITR and a sequence encoding the 3′ITR, but does not comprise any other sequence isolated or derived from an AAV. In some embodiments, the AAV is a recombinant AAV (rAAV), comprising a viral sequence essential for formation of a replication-deficient AAV, a sequence encoding the 5′ITR, a sequence encoding the 3′ITR, and a sequence encoding a Construct of the disclosure.
In some embodiments, a plasmid DNA used to create the rAAV in a host cell comprises a selection marker. Exemplary selection markers include, but are not limited to, antibiotic resistance genes. Exemplary antibiotic resistance genes include, but are not limited to, ampicillin and kanamycin. Exemplary selection markers include, but are not limited to, drug or small molecule resistance genes. Exemplary selection markers include, but are not limited to, dapD and a repressible operator including but not limited to a lacO/P construct controlling or suppressing dapD expression, wherein plasmid selection is performed by administering or contacting a transformed cell with a plasmid capable of operator repressor titration (ORT). Exemplary selection markers include, but are not limited to, a ccd selection gene. In some embodiments, the ccd selection gene comprises a sequence encoding a ccdA selection gene that rescues a host cell line engineered to express a toxic ccdB gene. Exemplary selection markers include, but are not limited to, sacB, wherein an RNA is administered or contacted to a host cell to suppress expression of the sacB gene in sucrose media. Exemplary selection markers include, but are not limited to, a segregational killing mechanism such as the parAB+ locus composed of Hok (a host killing gene) and Sok (suppression of killing).
The AAV2-Construct product consists of a purified recombinant serotype 2 adeno-associated viral vector (rAAV) encoding the cDNA encoding a therapeutic construct. An exemplary diagram is provided in
In some embodiments, the AAV2-Construct comprises one or more of a sequence encoding a 5′ ITR, a sequence encoding a 3′ ITR and a sequence encoding a capsid protein that is isolated and/or derived from a serotype 2 adeno-associated viral vector (AAV2). In some embodiments, the AAV2-Construct comprises a sequence encoding a 5′ ITR, a sequence encoding a 3′ ITR and a sequence encoding a capsid protein that is isolated and/or derived from a serotype 2 adeno-associated viral vector (AAV2). In some embodiments, the AAV2-Construct comprises a truncated sequence encoding a 5′ ITR and a sequence encoding a 3′ ITR that is isolated and/or derived from a serotype 2 adeno-associated viral vector (AAV2). In some embodiments, the AAV2-Construct comprises wild type AAV2 ITRs (a wild type 5′ ITR and a wild type 3′ ITR).
In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, and (d) a 3′ ITR.
In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 145 bp 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, and (d) a 145 bp 3′ ITR. In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, and (d) a 3′ ITR, wherein the 5′ ITR or the 3′ ITR comprises or consists of 134, 135, 136, or 137 bp.
In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 145 bp5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, (e) a polyadenylation sequence (polyA), and (f) a 145 bp3′ ITR. In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, (e) a polyadenylation sequence (polyA), and (f) a 3′ ITR, wherein the 5′ ITR or the 3′ ITR comprises or consists of 134, 135, 136, or 137 bp.
In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 145 bp 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, (d) a post-transcriptional regulatory element (PRE), (e) a polyadenylation sequence (polyA), and (f) a 145 bp 3′ ITR. In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 5′ inverted terminal repeat (ITR), (b) a promoter suitable for expression in mammalian cells, (c) a cDNA encoding a therapeutic construct, (d) a post-transcriptional regulatory element (PRE), (e) a polyadenylation sequence (polyA), and (f) a 3′ ITR, wherein the 5′ ITR or the 3′ ITR comprises or consists of 134, 135, 136, or 137 bp.
In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 145 bp 5′ inverted terminal repeat (ITR), (b) a promoter, optionally, a 934 bp Cytomegalovirus enhancer/chicken-beta actin (CBA) hybrid promoter, (c) a cDNA encoding a therapeutic construct, (d) a 589 bp Woodchuck hepatitis virus post-transcriptional regulatory element (WPRE), (e) a 242 bp Bovine growth hormone polyadenylation sequence (BGH-polyA), and (f) a 145 bp 3′ ITR. In some embodiments, each 20 nm AAV virion contains a single stranded DNA insert sequence (plus short cloning sites flanking each element) comprising: (a) a 5′ inverted terminal repeat (ITR), (b) a promoter, optionally, a 934 bp Cytomegalovirus enhancer/chicken-beta actin (CBA) hybrid promoter, (c) a cDNA encoding a therapeutic construct, (d) a 589 bp Woodchuck hepatitis virus post-transcriptional regulatory element (WPRE), (e) a 242 bp Bovine growth hormone polyadenylation sequence (BGH-polyA), and (f) a 3′ ITR, wherein the 5′ ITR or the 3′ ITR comprises or consists of 134, 135, 136, or 137 bp.
AAVs or Constructs of the disclosure may comprise a sequence encoding a promoter capable of expression in a mammalian cell. Preferably, AAVs or Constructs of the disclosure may comprise a sequence encoding a promoter capable of expression in a human cell. Exemplary promoters of the disclosure include, but are not limited to, constitutively active promoters, cell-type specific promoters, viral promoters, mammalian promoters, and hybrid or recombinant promoters. In some embodiments of the compositions of the disclosure, the therapeutic Construct of an AAV2-Construct is under the control of a chicken beta-actin promoter (CBA) Promoter. In some embodiments of the compositions of the disclosure, the CBA promoter comprises a sequence encoding a cytomegalovirus (CMV) enhancer and a sequence encoding a chicken beta-actin promoter (variously termed CBA or CAG).
AAVs or Constructs of the disclosure may comprise a sequence encoding a post-transcriptional regulatory element (PRE). Exemplary PREs of the disclosure include, but are not limited to, a Woodchuck hepatitis virus post-transcriptional regulatory element (WPRE). In some embodiments of the compositions of the disclosure, the AAV comprises a 589 bp WPRE, originating from the 3′ region of the viral S transcript, directly downstream of the cDNA encoding a therapeutic Construct of the disclosure. This WPRE is important for high-level expression of native mRNA transcripts, acting to enhance mRNA processing and transport of intronless genes. In some embodiments of the compositions of the disclosure, the WPRE has been modified to prevent expression of the viral X antigen by ablation of the translation initiation site. This has been achieved by deleting the We2 promoter/enhancer and mutating the We1 promoter.
AAVs or Constructs of the disclosure may comprise a polyadenosine (polyA) sequence. Exemplary polyA sequences of the disclosure include, but are not limited to, a bovine growth hormone polyadenylation (BGH-polyA) sequence. The BGH-polyA sequence is used to enhance gene expression and has been shown to yield three times higher expression levels than other polyA sequences such as SV40 and human collagen polyA. This increased expression is largely independent of the type of upstream promoter or transgene. Increasing expression levels using both BGH-polyA and WPRE sequences allows a lower overall dose of AAV or plasmid vector to be injected, which is less likely to generate a host immune response.
In one illustrative embodiment, the pBC-hREP1 vector comprises or consists of the nucleic acid sequence set forth in SEQ ID NO:24.
In some embodiments of the compositions of the disclosure, the composition comprises a Drug Substance. As used herein, a Drug Substance comprises a rAAV of the disclosure comprising a Construct of the disclosure.
In some embodiments of the compositions of the disclosure, the composition comprises a Drug Product. As used herein, a Drug Product comprises a drug substance, formulated for administration to a subject for the treatment or prevention of a disease or disorder.
The components of an exemplary Drug Product of the disclosure, their functions and specifications are listed in Table 1.
Compositions of the disclosure may be formulated for systemic or local administration.
Compositions of the disclosure may be formulated as a Suspension for Injection or Infusion.
Compositions of the disclosure may be formulated for injection or infusion by any route, including but not limited to, an intravitreous injection or infusion, a subretinal injection or infusion, or a suprachoroidal injection or infusion.
Compositions of the disclosure may be formulated at a concentration of between 1.0×10{circumflex over ( )}10 DRP/mL and 1.0×10{circumflex over ( )}14 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of about 1.0×10{circumflex over ( )}12 DRP/mL. In some embodiments, compositions of the disclosure may be formulated at a concentration of 1.0×10{circumflex over ( )}12 DRP/mL. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.1×10{circumflex over ( )}12 DRP/mL and 10.0×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.1×10{circumflex over ( )}12 DRP/mL and 5.0×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.1×10{circumflex over ( )}12 DRP/mL and 2.0×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.5×10{circumflex over ( )}12 DRP/mL and 1.5×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.7×10{circumflex over ( )}12 DRP/mL and 1.3×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.8×10{circumflex over ( )}12 DRP/mL and 1.2×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints. In some embodiments, compositions of the disclosure may be formulated at a concentration of between 0.9×10{circumflex over ( )}12 DRP/mL and 1.1×10{circumflex over ( )}12 DRP/mL, inclusive of the endpoints.
Compositions of the disclosure may be diluted prior to administration using a using a diluent of the disclosure. In some embodiments, the diluent is identical to a formulation buffer used for preparation of the AAV2-Construct Drug Product. In some embodiments, the diluent is not identical to a formulation buffer used for preparation of the AAV2-Construct Drug Product.
Compositions of the disclosure, including the AAV2-Construct Drug Product described in Table 1, may be formulated as a Suspension for Injection containing 1.0×10{circumflex over ( )}12 DRP/mL. If required by the protocol, AAV2-Construct Drug Product may be diluted in the clinic (i.e. by a medical professional) before administration using a diluent of the disclosure. In some embodiments, this diluent is the same formulation buffer used for preparation of the AAV2-Construct Drug Product.
Compositions of the disclosure may comprise a Drug Substance. In some embodiments, the Drug Substance comprises or consists of an AAV2-Construct. In some embodiments, the Drug Substance comprises or consists of an AAV2-Construct and a formulation buffer. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8. In some embodiments, the formulation buffer comprises 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8 with poloxamer 188 at 0.001%.
Compositions of the disclosure may comprise a Drug Product. In some embodiments, the Drug Product comprises or consists of a Drug Substance and a formulation buffer. In some embodiments, the Drug Product comprises or consists of a Drug Substance diluted in a formulation buffer. In some embodiments, the Drug Product comprises or consists of an AAV2-Construct Drug Substance diluted to a final Drug Product AAV2-Construct vector genome (vg) concentration in a formulation buffer.
Compositions of the disclosure may be formulated to comprise, consist essentially of or consist of an AAV2-Construct Drug Substance at an optimal concentration for ocular injection or infusion.
Compositions of the disclosure may comprise one or more buffers that increase or enhance the stability of an AAV of the disclosure. In some embodiments, compositions of the disclosure may comprise one or more buffers that ensure or enhance the stability of an AAV2 of the disclosure. Alternatively, or in addition, compositions of the disclosure may comprise one or more buffers that prevent, decrease, or minimize AAV particle aggregation. In some embodiments, compositions of the disclosure may comprise one or more buffers that prevent, decrease, or minimize AAV2 particle aggregation.
Compositions of the disclosure may comprise one or more components that induce or maintain a neutral or slightly basic pH. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a neutral or slightly basic pH of between 7 and 9, inclusive of the endpoints. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a pH of about 8. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a pH of between 7.5 and 8.5. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a pH of between 7.7 and 8.3. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a pH of between 7.9 and 8.1. In some embodiments, compositions of the disclosure comprise one or more components that induce or maintain a pH of 8.
Following contact of a composition of the disclosure and a cell, the AAV2-Construct expresses a gene or a portion thereof, resulting in the production of a product encoded by the gene or a portion thereof. In some embodiments, the cell is a target cell. In some embodiments, the target cell is a retinal cell. In some embodiments, the retinal cell is a neuron. In some embodiments, the neuron is a photoreceptor. In some embodiments, the cell is in vivo, in vitro, ex vivo or in situ. In some embodiments, including those wherein the cell is in vivo, the contacting occurs following administration of the composition to a subject. In some embodiments, the AAV2-Construct expresses a gene or a portion thereof, results in the production of a product encoded by the gene or a portion thereof at a therapeutically-effective level of expression of the gene product. In some embodiments, the gene product is a protein.
Compositions of the disclosure may be manufactured at a scale of between 1 to 1000 vials per batch, inclusive of the endpoints. In some embodiments of the compositions of the disclosure, a composition, Drug Substance, or Drug Product may be manufactured at a scale of between 50 to 500 vials per batch, inclusive of the endpoints. In some embodiments of the compositions of the disclosure, a composition, Drug Substance, or Drug Product may be manufactured at a scale of between 100 to 415 vials per batch, inclusive of the endpoints.
Exemplary batches of the disclosure may comprise between 0.01 mL and 5 mL, inclusive of the endpoints, of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise between 0.01 mL and 1 mL, inclusive of the endpoints, of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise between 0.1 mL and 1 mL, inclusive of the endpoints, of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise between 0.1 mL and 5 mL, inclusive of the endpoints, of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise between 0.25 mL and 0.35 mL, inclusive of the endpoints, of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise about 0.3 mL of a composition, Drug Substance, or Drug Product of the disclosure. In some embodiments, a batch of the disclosure may comprise 0.3 mL of a composition, Drug Substance, or Drug Product of the disclosure.
In some embodiments of the methods of the disclosure for preparation of the Drug Product, a Drug Substance is thawed at +35±2° C., and diluted as required in sterile formulation buffer to the target concentration (1.0×10{circumflex over ( )}12 DRP/mL).
In some embodiments of the compositions of the disclosure, the target final DRP titre of the AAV2-Construct Drug Product is 1×10{circumflex over ( )}12 DRP/mL, the minimum and maximum acceptable titre is 0.8×10{circumflex over ( )}12 DRP/mL and 1.5×10{circumflex over ( )}12 DRP/mL, respectively. The AAV2-Construct Drug Product is sterile filtered and filled into 3 mL 2R Type I glass vials with bromobutyl rubber stoppers at volumes of 0.3 mL per vial. The vials are then frozen and stored at ≤−60° C. For labelling and storage prior to QP release and distribution to site, the Drug Product is transferred to the qualified clinical distributor. The Drug Product is stored at ≤−60° C. in a temperature monitored freezer until QP release and distribution.
In some embodiments of the compositions of the disclosure, including those wherein the composition comprises a Drug Product and the composition is supplied in a sterile vial, the composition may be stored at below zero (° C.). In some embodiments, the compositions may be thawed and frozen without loss of efficacy of the Drug Product or integrity to the sterile packaging. In some embodiments, the compositions may undergo multiple rounds of thawing and freezing without loss of efficacy of the Drug Product or integrity to the sterile packaging.
In some embodiments of the compositions of the disclosure, including those wherein the composition comprises a Drug Product and the composition is supplied in a sterile vial, the composition may be stored at room temperature.
Starting materials used in the preparation of buffers and media of the disclosure are certified as free from material of animal origin.
Foetal bovine sera are of animal origin. Source, manufacturer and usage of these raw materials is summarized in Table 5.
Filters used for the filtration of the Drug Substance and Drug Product are Sartopore 0.45 μm and 0.2 μm filters. The filters are non-sterile when purchased and are sterilized in house at the contract manufacturer by autoclaving. They are integrity tested by bubble point testing at 3.2 Bars.
All chromatographic materials are released on a Certificate of Analysis prior to use. Columns are purchased prepacked and are sanitized prior to use.
An overview of an exemplary manufacturing process for AAV2-Construct Drug Substance is illustrated in
Exemplary changes to Process 1 are provided in Table 6 below. Some embodiments of Process 2 may include the changes described in Table 6.
The starting material for Process 1 was initiated from a single vial of HEK293 cells from a development cell bank (DCB). This DCB was produced using a single vial of ATCC HEK293 cells. CS10 were used to culture the HEK293 cells but the scale of this culture was increased from 12 CS10 to 24 CS10 to generate additional material for subsequent process development that was being performed concurrently. The procedure proceeded with 2×12 CS10 up until the point of transduction, at which time, the 24 CS10 were treated within the same operation.
Cell Culture Vessels and Raw Materials: Table 7 highlights key differences between the raw materials used for two different manufacturing processes and provides notes regarding any significance of the change.
Cell Culture: The source of cells used for the improved process were from a single vial of the DCB HEK293 cells. As this was a different bank used to produce the batch of the original process, albeit the same original source of ATCC cells, the scale of culture was increased (12 CS10 to 24 CS10) and a different source of serum was used to support cell growth during the cell amplification, this stage was adapted accordingly. The pre-culture cell growth of the improved process included 8 passages compared to 10 passages for the batch produced by the original process. In addition, cell densities post passage were variable according to the original process but fixed according to the improved process.
Cell growth was assessed between the original and improved processes using cell density measurements. Results indicated that the cells produced by the improved processes grew faster. This could be potentially attributed to a different source of serum and/or the cell passaging regime based on fixed seeding densities of the improved processes. For both processes, the population doubling time was shown to be 20-30 hr once cell growth had stabilized (
In some embodiments of Process 2, including those utilizing the raw materials listed in Table 7 (with the exception of the serum), the cell culture and/or cell growth media comprises or consists of a serum-free media.
Transduction: Transduction as part of the improved process was performed using the same method as the original process.
Cell Harvest: According to the improved process, the harvest was split into 2 harvests of 12 CS10 to be representative of the original process (1×12 CS10). Following harvest, the cells were disrupted using a PANDA device and the titre of the vector determined. The PANDA device used during the improved process was a different manufacturer compared to the cell disrupter used during the original process (see Table 8 below), but has the capability to perform cell lysis at the same pressure as the cell disrupter of the original process (80 bar).
Vector Titre Post Upstream Processing: The titre of the upstream process vector material from 1×12 CS10 (6.4×1015 DRP/batch) (according to improved process) was comparable to that generated from the same scale of upstream process (1.44×1015 DRP/batch) (according to the original process).
The downstream process that was transferred from the original to the improved process is illustrated in
Experimental and Raw Materials: Where possible, the same equipment and raw materials and suppliers were selected for use in the downstream “improved” process as those used in the original process.
Downstream Performance: Observations at individual process stages are summarized below.
Heparin Dialysis, Diafiltration and Filtration Steps: The product was limpid and colorless from the Iodixanol gradient step to the final product. No unexpected observations were evident during these steps.
A batch of product is prepared from a single production campaign consisting of 24 Corning 10-stack vessels containing plasmid DNA transfected HEK293 cells that produce the AAV2-Construct biologic product. The cell mass and cell culture media is harvested and pooled from the 24 Corning 10-stack vessels and followed by a single purification process. A batch of product prepared from a single campaign is expected to produce ≥5×1013 viral particles (vp; also referred to herein as vector particles) of Drug Substance.
An overview of an exemplary manufacturing process for AAV2-Construct Drug Substance is illustrated in
In some embodiments of Process 2, the cell culture media harvested and pooled from the 24 Corning 10-stack vessels comprises a serum free media. In some embodiments of Process 2, the cell culture media harvested and pooled from the 24 Corning 10-stack vessels consists of a serum-free media.
See
Step 1: Thawing and seeding of cells used to produce AAV2-Construct Drug Substance. Temperatures, durations, spin speed, and volumes below may be adjusted for optimal results depending upon the cell type used. For the exemplary embodiment described below, conditions were optimized for the use of HEK293 Cells.
Thawing of HEK293 Cells and Seeding into 1 T75 flask: A vial of the HEK293 MCB is thawed at 37±2° C. Cells are transferred in a 15 mL tube containing 9 mL of cold growth medium (DMEM media with 5% FBS). The vial is rinsed with 1 mL of growth medium. The suspension is centrifuged at 4° C. for 5 minutes at 300 g, the supernatant is discarded and cells are suspended in 10 mL of pre-warmed growth medium. Cell density is determined and the cell suspension is transferred to a T75 cm2 flask containing 10.5 mL of growth medium to obtain a final volume of 20 mL. The T75 cm2 flask is transferred to an incubator at 37±1° C. under humidified 4-6% CO2 atmosphere. 24±4 hours after thawing, the growth medium is replaced by 20 mL of pre-warmed growth medium.
In some embodiments of the steps of thawing of HEK293 Cells and seeding into 1 T75 flask, cells are transferred in a 15 mL tube containing 9 mL of cold growth medium. In some embodiments, the growth medium comprises or consists of glycine, L-Arginine hydrochloride, L-Cysteine dihydrochloride, L-Glutamine, L-Histidine hydrochloride-H2O, L-Isoleucine, L-Leucine, L-Lysine hydrochloride, L-Methionine, L-Phenylalanine, L-Serine, L-Threonine, L-Tryptophan, L-Tyrosine disodium salt dehydrate, L-Valine, Choline chloride, D-Calcium pantothenate, Folic Acid, Niacinamide, Pyridoxine hydrochloride, Riboflavin, Thiamine hydrochloride, i-Inositol, Calcium Chloride (CaCl2)) (anhyd.), Ferric Nitrate (Fe(NO3)3″9H2O), Magnesium Sulfate (MgSO4) (anhyd.), Potassium Chloride (KCl), Sodium Bicarbonate (NaHCO3), Sodium Chloride (NaCl), Sodium Phosphate monobasic (NaH2PO4-H2O), and D-Glucose (Dextrose). In some embodiments, the growth medium comprises or consists of a serum-free media. In some embodiments, the growth medium comprises or consists of a clarified media.
Step 2: Expansion of cells used to produce AAV2-Construct Drug Substance. Temperatures, durations, and volumes below may be adjusted for optimal results depending upon the cell type used. For the exemplary embodiment described below, conditions were optimized for the use of HEK293 Cells.
Expansion 1 T75 Flask to 1×T175CB or 3 T75 Flasks: Media is discarded and cells washed with pre-warmed PBS. The cells are loosened with TrypLE cell dissociation reagent. The T-flasks or Cell Stacks are incubated 5 to 10 minutes in an incubator set at 37±1° C. and the cells are fully dislodged by gently tapping the vessel. Growth medium is added to inhibit the TrypLE. The volumes of growth medium, PBS and TrypLE used for different supports are presented in Table 14. All cell suspensions are then pooled.
Cell count and cell viability is determined and the cells are seeded, incubated and passaged in accordance with Table 15.
In Process Controls (IPCs): Cell Count and Cell Viability
Step 3: Expansion 1 T175CB to 4 T175CB or 3 T75 Flasks to 4 T175CB: See Step 2.
IPCs: Cell Count and Cell Viability.
Step 4: Expansion 4 T175CB to 8 T175CB: See Step 2.
IPCs: Cell Count and Cell Viability.
Step 5: Expansion 6 T175CB to 3 CS2CB: See Step 2.
IPCs: Cell Count and Cell Viability.
Step 6: Expansion 2 CS2CB to 3 CS10CB: See Step 2.
IPCs: Cell Count and Cell Viability.
Step 7: Expansion 2 CS10CB to 8 CS10CB: See Step 2.
IPCs: Cell Count and Cell Viability.
Step 8: Expansion 8 CS to 24 CS10CB. See step 2.
IPCs: Cell Count and Cell Viability
Step 9: Transfection of cells used to produce AAV2-Construct Drug Substance. Temperatures, durations, spin speed, and volumes below may be adjusted for optimal results depending upon the cell type used. For the exemplary embodiment described below, conditions were optimized for the use of HEK293 Cells.
The HEK293 cells are transfected with three plasmids using Polyethylenimine (PEI).
The three plasmids (pAAV.Construct-Kan, pHELP-Kan, and pNLRep-Cap2-Kan) are added in a sequential way with a specific ratio.
The plasmids and the PEI are prepared with growth medium.
The required amount of plasmid DNA is presented in Table 17.
The required amount of PEI mix is transferred in the DNA mix to form the PEI-DNA complex, shake for 10 seconds and incubate at room temperature. The PEI-DNA complex is transferred into 8.2 L growth medium. The mixture of growth medium and PEI-DNA complex is homogenized, the PEI-DNA complex bottle is rinsed and the mixture of the growth medium and the PEI-DNA complex is homogenized again. The medium is drained from the CS10CB and 2 L of growth medium/PEI-DNA complex mixture is transferred to the CS10CB. The transfected CS10CB are transferred into an incubator set at 37±1° C. under humidified 4-6% CO2 atmosphere.
The transfection mixture is left on the cells for 24±1 hours and then the media is replaced with DMEM Glutamax.
IPCs: Cell Count and Cell Viability.
Step 10: Harvest of cells used to produce AAV2-Construct Drug Substance. Temperatures, durations, spin speed, and volumes below may be adjusted for optimal results depending upon the cell type used. For the exemplary embodiment described below, conditions were optimized for the use of HEK293 Cells.
The harvest is done 60±13 hours post transfection.
The product is harvested by the following steps:
First half of medium is transferred to the harvest bag.
The CS10CB are shaken and the remaining medium and cells are harvested.
200 mL of HBSS-EDTA are transferred to the CS10CB and incubated at room temperature for 10 minutes.
At the end of the incubation time, the buffer is drained to the harvest bag.
This harvesting process is repeated with all vessels.
After the harvest, MgCl2 1M is added to a final concentration of 5 mM and benzonase is added to a final concentration of 90 U/mL.
IPC: Adventitious Viruses, Bioburden, Mycoplasma, Physical titre.
Step 11: Microfluidization Lysis.
The PANDA disrupter is equilibrated with minimum 3 L of Tris 20 mM, MgCl2 1 mM, NaCl 50 mM pH 8 buffer. The bag containing the harvest treated with Benzonase is connected to the lysis assembly. The product is loaded on to the PANDA system at a pressure of 80±10 bars and collected in a new bag. After loading the product, the system is rinsed with 2×200 mL of Tris 20 mM, MgCl2 1 mM, NaCl 50 mM pH 8 buffer. Both rinses are pooled with the lysed product.
IPC: Physical Titre
Step 12: Benzonase Incubation:
The microfluidized cells are incubated overnight at room temperature for a maximal duration of 18 hours for benzonase endonuclease activity.
Step 13: Freeze/Thaw:
The final lysis step is a freeze at −15 to −25° C. followed by a thaw overnight at room temperature to promote aggregation of cellular debris to facilitate the clarification step.
Step 14: Clarification of Microfluidized Lysate.
The filtration process utilizes a pre-filter (Sartopure GF 0.65 μm 0.4 m2) followed by a filter for bioburden reduction (Sartopore 2, 0.2 μm, 0.2 m2) and Tris 20 mM, MgCl2 1 mM, NaCl 50 mM pH 8 buffer for flushing.
IPCs: Picogreen, Physical Titre
Step 15: Large Scale TFF Concentration and Diafiltration.
This process achieves volume reduction and an initial purification using the principle of Tangential Flow Filtration (TFF). The volume reduction can be as large as a 100 fold. Salt and surfactant solution (SSS, 4.14 M NaCl+nonionic surfactant) is added to the clarified lysate with 1/10 of the lysate weight. The purification is achieved by diafiltration (100 kDa) of the concentrate with 20 mM Tris pH 8.0, 1 mM MgCl2, 500 mM NaCl, 0.1% nonionic surfactant to “wash” smaller molecular weight impurities from the sample. This part is required in order to achieve high levels of concentration without protein/AAV particle precipitation.
IPCs: Physical Titre, Total Particles (ELISA), Full/Empty Particles Ratio.
Step 16: Iodixanol Purification.
This process is designed to purify rAAV using a four layer discontinuous iodixanol gradient (15%, 25%, 40%, 57%). This orthogonal purification step greatly enriches the preparation for DNA containing rAAV particles, while removing the bulk of rAAV particles that are devoid of DNA (empty particles) based on the differential buoyant density of these particles in the iodixanol gradient medium following ultracentrifugation. The density of DNA containing rAAV results in the migration of rAAV into the 40% iodixanol layer, while the majority of contaminating cellular proteins migrate to the 25%/40% interface. Aggregation of rAAV with proteins and DNA can alter the particles buoyant density, so inclusion of 1M NaCl in the 15% iodixanol layer minimizes this aggregation.
Separation is achieved by a discontinuous gradient of iodixanol (Optiprep 57% solution) that is subjected to high g forces in an ultracentrifuge. The 40% fraction is harvested until reaching the impurity band (˜3 mL).
The collected fractions are pooled and stored at +2/+8° C. until subsequent purification steps.
Step 17: Dilution:
The fraction obtained at the end of the purification step is diluted 20 times with Tris 10 mM, pH 9.0 buffer for purification of GMP lot G214/REP1/FC001 by anion exchange chromatography. For purification by AVB affinity, the pooled fraction at the end of the Purification (density gradient) step is diluted 6 fold with 20 mM Tris, 1 mM MgCl2, and 200 mM NaCl at pH 8 buffer.
IPCs: Physical Titre, Total Particles (ELISA), Full/Empty Particles Ratio, Picogreen
Step 18: Anion Exchange Chromatography.
The Anion exchange chromatography is performed at room temperature with a Unosphere Q (UnoQ) media (Biorad) packed at a flow rate of 14 mL/min with Tris 10 mM, NaCl 200 mM pH 9 in a Vantage VL 11×250 column (packed volume ˜9.5 mL). The column is conditioned first with Tris 10 mM, NaCl 1 M pH 9 buffer and second with Tris 10 mM, pH 9 buffer to obtain a pH equal to pH 9.0±0.2 and a conductivity equal to the Tris 10 mM, pH 9.0 Conductivity ±10%.
The diluted product is filtered through a Sartoscale 0.2 μm 17 cm2 filter.
It is loaded on the column and the column is rinsed with equilibration buffer. After a second wash with Tris 10 mM, NaCl 45 mM pH 9 buffer, the product is eluted with minimum 30 column volumes of Tris 10 mM, NaCl 650 mM pH 9 buffer.
The eluted product is stored at +2/+8° C. until the next step.
IPCs: Picogreen, Physical Titre
Step 18 with AVB Sepharose Affinity Chromatography.
The affinity chromatography is performed at room temperature with AVB Sepharose HP (GE Healthcare) packed in a Vantage-L VL22×250 column (8±1 cm bed height) packed and flushed in Tris 20 mM, MgCl2 1 mM, NaCl 200 mM pH 8 buffer and then is sanitized with H3PO4 0.17M, NaCl 1 M for 30 minutes. Following sanitization, the column is equilibrated in Tris 20 mM, MgCl2 1 mM, NaCl 200 mM pH 8 buffer prior to loading product (pooled fractions from step 16) diluted in Tris 20 mM, MgCl2 1 mM, NaCl 200 mM pH 8. The diluted product is filtered through a Sartoscale 0.2 μm 17 cm2 filter prior to column loading. Once loaded, the column is washed with approximately 35 column volumes of Tris 20 mM, MgCl2 1 mM, NaCl 200 mM pH 8 buffer and then eluted with approximately 20 column volumes of Na2HPO4 10.8 mM, citric acid 44.6 mM, NaCl 400 mM pH 2.6 buffer. Immediately following elution, the eluate is neutralized with approximately 4 column volumes of Tris 1 M pH8 buffer.
The eluted product is stored at +2/+8° C. until the next step.
IPCs: Picogreen, Physical Titre
Step 19: Dialysis and Final Formulation.
This process utilizes dialysis to formulate the AAV product into the desired Final Formulation buffer (20 mM Tris, pH 8, 1 mM MgCl2, 200 mM NaCl, optionally with poloxamer at 0.001%).
Tangential flow filtration of the Elution product is conducted using a hollow fiber cartridge with a molecular weight cut-off of 100 kDa (Spectrum). The cartridge and the system are equilibrated with Tris 20 mM, MgCl2 1 mM, NaCl 200 mM pH 8 buffer to obtain a pH8.0±0.2 on the Permeate side.
The product is concentrated to the minimum volume before the diafiltration in continuous mode against minimum 6 volumes of Formulation Buffer. The retentate is collected. The system is rinsed with Formulation Buffer. This rinse is collected in a different vessel.
IPCs: Physical Titre.
Step 20: Submicron Filtration of Purified Bulk Drug Substance.
If required for longer term storage (>60 days) the product is submicron filtered using a 0.2 μm filter. Once the Drug Substance is completely filtered, the filter is rinsed with the final formulation buffer.
After QC sampling, the purified bulk Drug Substance is stored at <−60° C.
Method of Making a Drug Product from a Drug Substance
The disclosure provides several exemplary processes/methods of making a Drug Product from a Drug Substance (as a starting material). Two of these exemplary methods are Process 1 (the original process) and Process 2 (the improved process). As described herein, Process 2 includes changes and/or improvements made to Process 1.
In both Process 1 and Process 2, the Drug Substance is thawed, diluted, sterile filtered and filled into the primary packaging containers. However, the improved process (Process 2) introduced the following changes to the original procedure (the in-process controls remain unchanged):
Change in thawing temperature from room temperature to +35±2° C.
Change in the primary packaging from 0.5 mL polypropylene cryovials to 3 mL type I glass vials and bromobutyl rubber stoppers
Change in filling size per single vial from 0.1 mL/vial to 0.3 mL/vial
Compositions of the disclosure may be supplied as liquids. In some embodiments of the compositions of the disclosure, including those wherein the composition comprises a Drug Product, the Drug Product is supplied in sterile glass vials. In some embodiments, the sterile glass vials are sterile clear glass vials. In some embodiments, the sterile glass vials are capped with stoppers. In some embodiments, the stoppers are plastic. In some embodiments, the sterile glass vials are capped and further enclosed with overseals.
Following review of the original manufacturing process (Process 1), opportunities to improve the quality of future clinical and commercial product and/or to make a more robust process were identified and implemented as Process 2. The process development activities undertaken fall into two categories: (1) Process Changes; (2) Process Optimization. A summary of the process development strategy and rationale is provided in Table 18 and each category is discussed in more detail below.
In summary, to generate Process 2, changes were made to the source of cells from which the MCB is generated, the antibiotic selection gene of the three plasmids, the scale of the upstream processing step, the transduction reagent, the affinity chromatography step and the final product container and closure.
HEK293 Master Cell Bank
Process 1: The MCB used to produce the first clinical batch was generated from cells optimized AAV2 production. There is limited traceability of the history of this cell line both in terms of how the cells were optimized and exposure to materials of animal origin.
Change to Process 1: An original vial of HEK293 cells deposited at ATCC (the precursor cell bank from which the Process 1 were generated) was used to initiate manufacture of a new GMP MCB. This MCB, now characterized and tested, is used to support clinical AAV vector manufacture and can be used for commercial manufacture. Full traceability of cell passage number, materials used, methods followed and cell bank characterization studies performed provides increased reassurance of product quality, traceability and safety. A working cell bank was subsequently generated from a single vial of the GMP MCB under conditions of Good Manufacturing Process (GMP) to form a GMP WCB. This WCB, now characterized and tested, can be used for commercial manufacture. Full traceability of cell passage number, materials used, methods followed and cell bank characterization studies performed provides increased reassurance of product quality, traceability and safety.
The ATCC sourced HEK293 cells were assessed for comparability following a defined protocol whereby vector production, as assessed by genomic titre, was directly compared with that from the original Stratagene cells. Vector titre was assessed in triplicate and concurrently from cells at comparable passage limits, including both low and high passage. Cells were also assessed for growth kinetics and viability. In addition cells were treated with a green fluorescent protein (GFP) expression vector to assess transduction efficacy.
The ATCC sourced cells were also assessed as part of a full-scale non-GMP engineering run in combination with the plasmid changes (see below) following the same batch manufacturing protocol as the original clinical batch. This batch was tested against the full panel of in-process control tests, bulk harvest, Drug Substance and Drug Product tests (with the exception of those tests for bioburden, endotoxin, sterility and adventitious agents) and compared against the same test results, which were previously obtained from the clinical batch (original process).
Once suitability of the ATCC HEK293 cells was established, a GMP MCB was prepared and fully tested for adventitious agents, identity, purity and safety. The GMP MCB was QA released for subsequent GMP manufacture.
Vector Plasmids
Process 1: The three plasmid constructs used to produce the AAV2-Construct vector containing a gene encoding ampicillin resistance, used for selection during plasmid production. Although ampicillin, a β-lactam antibiotic, is not used in the manufacturing process of the AAV2-Construct vector, removal of the AmpR is preferable to avoid the potential for any carry-over of residual ampicillin from the plasmid production process to the AAV2-Construct production process and also removes the potential for the gene encoding ampicillin resistance to be present in the final packaged product.
Change to Process 1: Each plasmid was modified to replace the ampicillin resistance gene with a gene encoding kanamycin resistance. The remainder of the plasmid backbone was not changed. During plasmid manufacture, ampicillin used for plasmid selection could be carried over into the AAV2-Construct production process and pose a potential risk for patients with sensitivity to β-lactam antibiotics. In addition, the presence of an ampicillin resistance gene from the plasmid material could end up packaged into the final vector product and theoretically confer or transfer antibiotic resistance to recipients. Although the likelihood of either risk is considered low, it is understood that where possible the use of β-lactams should be avoided. Therefore, the safety profile of the product was improved by replacing the AmpR with a KanR.
The new plasmids were fully sequenced and this sequencing provided confirmation that only the resistance gene had changed.
A comparability study to evaluate AAV2-Construct production using the new plasmids was conducted following a defined protocol. Both AmpR (old) and KanR (new) plasmids were used to transfect HEK293 cells concurrently and vector production compared by assessing genomic titre. Triplicate testing was performed and the comparison of vector titre reported.
Following demonstration of acceptable titre, the modified plasmids were also assessed as part of a full-scale non-GMP production run in combination with the cell changes (detailed above) following the same batch manufacturing protocol as the original clinical batch. The batch was tested against the full panel of bulk harvest, drug substance and drug product tests (with the exception of those tests for bioburden, endotoxin, sterility and adventitious agents) and compared against the same test results obtained from the clinical batch (original process). Once data from this technical run had been generated and considered acceptable, manufacture of plasmid suitable for use in GMP product manufacture was implemented.
Heparin Chromatography
Process 1: An affinity chromatography column was used to selectively purify AAV2-Construct. The animal-derived matrix used within the column (e.g. heparin) can be supplied as GMP material suitable for use in the manufacture of human therapeutic products. Whilst the source, manufacture and supply of the animal-derived matrix is accredited from a GMP and human use perspective, a viral safety risk remains with the use of any animal derived raw materials.
Change to Process 1: Alternative, non-animal derived chromatography matrices were explored as a replacement for the current affinity column filled with an animal-derived matrix (e.g. heparin). An ion exchange chromatography resin was initially used to replace the animal-derived matrix for the first GMP batch according to the improved process and subsequently a non-animal derived affinity chromatography resin was introduced. This change was implemented to achieve a reduction in the biosafety risks associated with animal derived raw materials.
Different chromatography matrices were assessed and suitability was based on the purity/impurity profile, titre and potency of the final product.
Final Product Container and Container Closure
Original Process: The Drug Product was filled into 0.5 mL sterile, polypropylene, screw-capped, gasketed vials at volumes of 0.1 mL per vial.
Change to Process 1: Filling of 0.3 mL Drug Product into Type 1 borosilicate glass injection vials, with a bromobutyl stopper and crimped (tamper evident) vial overseal closure. This change was implemented to achieve improved integrity of final Drug Product, improved containment during use, improved pharmaceutical acceptability of the primary container product contacting materials, ease of visual inspection and safety (security provided by tamper evident overseal).
Assessment of compatibility of Drug Product in glass vials was performed by product recovery and product stability.
Scale Up of Upstream Process Steps
Process 1: Expansion and scale-up of a single vial of HEK293 MCB, through serial passaging, to 12 ten-layer cell stacks.
Change to Process 1: Expansion and scale-up of a single vial of HEK293 MCB, through serial passaging, to 24 ten-layer cell stacks. This change was implemented to achieve increased scale of upstream process to allow additional material for in process testing and controls as well as increased Drug Substance volume for testing and fill finish. Furthermore, this change was implemented to achieve increased Drug Product availability.
Analysis of cell viability, growth rate and cell yield were assessed to determine optimal and consistent performance.
Process Optimization
A number of process steps from the original manufacturing process remained unchanged in terms of physical and chemical definition; however they were further evaluated in order to improve process understanding and characterization and to ensure optimal process performance in terms of process consistency and robustness.
HEK293 Cell Culture and Expansion
Process 1: Expansion and scale-up of a single vial of HEK293 MCB, through serial passaging, to 12 ten-layer cell factories.
Process Optimization: Concurrent with the change in cell culture scale from 12 CS10 to 24 CS10, studies to optimize seeding density and assess growth kinetics for optimal cell culture performance were performed. Operational (non-process) changes were optimized to improve control and reproducibility of process steps to ensure process consistency and robustness. Specifically, this aspect of the process was optimized to increase from 12 CS10 to 24 CS10 to improve yield.
Analysis of cell viability, growth rate and cell yield was performed to determine optimal and consistent performance.
Plasmid Triple Transfection and Harvest
Process 1: The three plasmid transfection of HEK293 cells was performed by calcium phosphate DNA precipitation following chloroquine pre-treatment of cells.
Process Optimization: Optimize transfection, including cell seeding conditions, comparison of calcium phosphate and polyethylenimine. Optimize plasmid concentration/ratio. Determine optimal day post-transfection for medium exchange and harvest. Operational (non-process) changes were optimized to improve control and reproducibility of process steps to ensure process consistency and robustness. Chloroquine was removed from the process to improve safety.
Further optimizations were performed at small scale, including cell seeding density, media for cell growth, FBS concentration and DNA:PEI ratio. Once an optimized transfection process had been established, the process was performed at full scale using PEI and compared to the same process using calcium phosphate to demonstrate comparability.
Microfluidization for Cell Disruption
Process 1: This process uses mechanical lysis of cells to release intracellular virus using a microfluidizer.
Process Optimization: No changes to this process step were performed. Development studies focused on optimization and definition of operating conditions using a sanitary microfludizer suitable for GMP manufacture and containment._Operational (non-process) changes were implemented to improve control and reproducibility of process steps and to improve process understanding and characterization to ensure process consistency and robustness._Consistency of in-process control tests for product purity and vector titre were determined.
Density Gradient Ultracentrifugation
Process 1: Density gradient purification to reduce process impurities.
Process optimization: As the current gradient purification method is manual, it is possible that it could contribute to process variability. Whilst the principles of the purification method remain unchanged, opportunities to make this process step more robust and semi-automated were assessed._Operational (non-process) changes were implemented to improve control and reproducibility of process steps and to improve process understanding and characterization to ensure process consistency and robustness._Consistency of tests for product purity and vector titre were determined.
Ultrafiltration (UF)/Diafiltration (DF)
Process 1: Buffer exchange through UF/DF and dialysis.
Process Optimization: Each process step involving buffer exchange through UF/DF and dialysis was optimized to establish the critical process parameters, as well as ensure acceptability of contact materials for product quality. This change was implemented to ensure process consistency and robustness, to improve process understanding and characterization and to ensure suitability of product contact materials. The virus yield and impurity profile was assessed.
The AAV2-Construct clinical vector expressing a therapeutic construct is produced via a transient transduction platform utilizing three plasmids; a vector plasmid containing the therapeutic construct/transgene and promoter with inverted terminal repeat sequences, an AAV helper plasmid that contains the AAV2-Rep and Cap sequences and finally a helper plasmid that encodes the essential Adenovirus genes E2A, E4 and VA. All three plasmids used for the production of the AAV2-Construct clinical vector produced according to the original process contained an ampicillin (Amp) selectable marker. To avoid concerns over patient sensitivity to residual ampicillin and a theoretical transfer of the AmpR gene to the final vector the plasmids were re-engineered to swap the Amp selectable marker sequence for a kanamycin (Kan) resistance sequence. Full sequencing was performed to confirm that the remainder of the plasmid backbone remains the same for all three plasmids. These plasmids were evaluated for their yield performance in producing rAAVs in small scale in vitro studies to establish their suitability for use in cGMP production. This experimental analysis of the plasmids was via a head to head comparison of yield with a control consisting of the plasmids previously used for production of the AAV2-Construct clinical vector and is described below. Once plasmid suitability was determined in small scale in vitro studies, the KanR plasmids were assessed in a full scale, non-GMP process.
The production of the AAV2-Construct clinical vector from the original process utilized an HEK293 cell line that was derived, tested and banked by the GMP facility (original process 1) from an HEK293 cell line that is commercially available through Stratagene. This cell bank was fully tested and characterized but a full documented history of the cell bank was not available. To ensure full traceability of the HEK293 cells, new cells were sourced from the ATCC, evaluated for comparability against the original process 1 cells and used for GMP MCB production. Three cell lines (two HEK293 cell lines and one 293T cell line) were screened in a head to head comparison of the following parameters to determine the optimal cell line for the production of AAV2-Construct vector: 1) Generic transduction efficiency via GFP Mean Fluorescence Intensity & Percent GFP using an AAV-based eGFP plasmid, 2) Specific transduction efficiency for AAV2-Construct product assessing yield of AAV2-Construct via DRP (DNase Resistant Particle) analysis, 3) Growth kinetics by cell counts and percent of viable cells, and 4) Continued passage and retest for yield and transduction efficiency to compare transduction efficiency with cells at a later passage.
Animal derived (e.g. heparin) affinity column step in the original Phase 1/2 manufacturing process was replaced with a non-animal derived ion exchange (AEX) column, UnoQ, to improve potential safety concerns (potential of adventitious contaminants from animal derived matrix).
To address the narrow salt range required prior to AEX, an alternative non-animal derived affinity chromatography column, AVB Sepharose from GE Healthcare, was assessed. Following a comprehensive development phase to ensure maintenance of product comparability as described below the affinity column (with an animal-derived matrix) was replaced with AVB for manufacture of subsequent GMP batches.
AVB Sepharose is an affinity medium with affinity for adeno associated viruses used in AAV2 purification to enable high purity and yield production. The affinity ligand is a 14 kDa fragment from a single chain antibody, expressed in yeast. The AVB column allows for good binding and elution of AAV2-Construct and can be performed in higher salt (conductivity). Thus, the AVB column represents a robust process step that minimizes product losses. AVB is non-animal derived so its use poses no risk to safety from adventitious contaminants.
Exemplary Drug Substances are characterized by the tests listed in Table 19.
Analytical Procedures
Physical Titre: Genomic titre is determined using qPCR. This method allows quantification of genomic copy number. Samples of the vector stock are diluted in buffer. The samples are DNase treated and the viral capsids lysed with proteinase K to release the genomic DNA. A dilution series is then made. Replicates of each sample are subjected to qPCR using a Taqman based Primer/Probe Set specific for the CAG sequence. A standard curve is produced by taking the average for each point in the linear range of the standard plasmid dilution series and plotting the log copy number against the average CT value for each point. The titre of the rAAV vector can be calculated from the standard curve and is expressed as DNase Resistant Particles (DRP)/mL.
Infectious Unit (IU) Titre: This assay quantifies the number of infectious particles of AAV. Quantification is performed by infecting RC32 cells (HeLa expressing AAV2 Rep/Cap) with serial dilutions of the vector sample and uniform concentrations of wild type adenovirus to provide helper function. Several days post infection, the cells are lysed diluted to reduce PCR inhibitors and assayed by qPCR in the same manner as described in the physical titre assay above, except that the DNase and Proteinase K digestion is omitted and only the qPCR portion is performed. Individual wells are scored as Positive or Negative for AAV amplification. The scored wells are used to determine the TCID50 in IU/mL using the Karber Method.
Total Particles: The assay uses an ELISA technique (AAV2 Titration ELISA KIT). A monoclonal antibody specific for a conformational epitope on assembled AAV2 capsids is coated onto microtitre strips and is used to capture AAV2 particles from the specimen. Captured AAV particles are detected in two steps. First a biotin-conjugated monoclonal antibody to AAV2 is bound to the immune complex. In the second step streptavidin peroxidase conjugate reacts with the biotin molecules. Addition of substrate solution results in a color reaction which is proportional to the amount of specifically bound viral particles. The absorbance is measured photometrically at 450 nm.
Full:empty Ratio (Transmission Electron Microscopy): The full:empty ratio of AAV2 particles may be determined using negative staining transmission electron microscopy (TEM). Samples are applied to a grid fixed. Samples are visualized using a transmission electron microscope and counts are performed of the full (i.e. containing DNA) and empty AAV2 capsid particles based on their morphology. The ratio of full:empty particles is calculated from the particle counts.
Full:empty Ratio (Analytical Ultracentrifugation): The full:empty ratio of AAV2 particles may be determined using analytical ultracentrifugation (AUC). AUC has an advantage over other methods of being non-destructive, meaning that samples may be recovered following AUC for additional testing. Samples comprising empty and full AAV2 particles are applied to a liquid composition through which the AAV2 move during an ultracentrifugation. A measurement of sedimentation velocity of one or more AAV2 particles provides hydrodynamic information about the size and shape of the AAV particles. A measure of sedimentation equilibrium provides thermodynamic information about the solution molar masses, stoichiometries, association constants, and solution nonideality of the AAV2 particles. Exemplary measurements acquired during AUC are radial concentration distributions, or “scans”. In some embodiments, scans are acquired at intervals ranging from minutes (for velocity sedimentation) to hours (for equilibrium sedimentation). The scans of the methods of the disclosure may contain optical measurements (e.g. light absorbance, interference and/or fluorescence). Ultracentrifugation speeds may range from between 10,000 rotations per minute (rpm) and 75,000 rpm, inclusive of the endpoints. As full AAV2 particles and empty AAV2 particles demonstrate distinct measurements by AUC, the full/empty ratio of a sample may be determined using this method.
Vector Identity (DNA): This assay provides a confirmation of the viral DNA sequence. The assay is performed by digesting the viral capsid and purifying the viral DNA. The DNA is sequenced with a minimum of 2 fold coverage both forward and reverse where possible (some regions, e.g., ITRs are problematic to sequence). The DNA sequencing contig is compared to the expected sequences to confirm identity.
Total Protein: This assay quantifies the total amount of protein present in the test article by using a Micro-BCA kit. In order to eliminate matrix effects of the formulation buffer samples are precipitated with acetone and the precipitated protein re-suspended in an equal volume of water prior to analysis. The protein concentration determination is performed by mixing test article or diluted test article with a Micro-BCA reagent provided in the kit. The same is performed using dilutions of a Bovine Serum Albumin (BSA) Standard. The mixtures are incubated at 60° C. and the absorbance measured at 562 nm. A standard curve is generated from the standard absorbance and the known concentrations using a linear regression fit. The unknown samples are quantified according to the linear regression.
Purity: This assay provides a semi-quantitative determination of AAV purity. Based on the results of the AAV2 capsid particle ELISA, samples are concentrated by SpeedVac and either 4×10{circumflex over ( )}10 or 1×10{circumflex over ( )}11 particles are loaded and the capsid proteins are separated on an SDS-PAGE gel. Densitometry analysis of the SYPRO Orange stained gels allows calculation of the approximate impurity levels relative to the capsid proteins (Vp1, Vp2 and Vp3).
Replication Competent AAV: Test article is used to transduce HEK293 cells in the presence or the absence of wild type adenovirus. Three successive rounds of cell amplification will be conducted and total genomic DNA is extracted at each amplification step.
The rcAAV2 are detected by real-time quantitative PCR. Two sequences are isolated genomic DNA; one specific to the AAV2 Rep gene and one specific to an endogenous gene of the HEK293 cells (human albumin). The relative copy number of the Rep gene per cell is determined. The positive control is the wild type AAV virus serotype 2 tested alone or in the presence of the rAAV vector preparation.
The limit of detection of the assay is challenged for each tested batch. The limit of detection is 10 rcAAV per 1×10{circumflex over ( )}8, or 1×10{circumflex over ( )}10, genome copies of test sample. If a test sample is negative for Rep sequence, the result for this sample will be reported as: NO REPLICATION, <10 rcAAV per 1×10{circumflex over ( )}8 (or 1×10{circumflex over ( )}10) genome copies of test sample. If a test sample is positive for Rep sequence, the result for this sample will be reported as: REPLICATION.
HEK293 Host Cell Protein: The HEK293 host cell protein (HCP) assay is an immunoenzymetric assay. Samples of purified virus are reacted in microtitre strips coated with an affinity purified capture antibody. A secondary horseradish peroxidase (HRP) conjugated enzyme is reacted simultaneously, resulting in the formation of a sandwich complex of solid phase antibody-HCP-enzyme labelled antibody. The microtitre strips are washed to remove any unbound reactants. The quantity of HEK293 HCPs is detected by the addition of 3,3′,5,5′ tetramethyl benzidine peroxidase, an HRP substrate, to each well. The amount of hydrolyzed substrate is read on a plate reader and is directly proportional to the concentration of HEK293 HCPs present.
Total DNA: Picogreen reagent is an ultra-sensitive fluorescent nucleic acid stain that binds double-stranded DNA and forms a highly luminescent complex (λexcitation=480 nm-λemission=520 nm). This fluorescence emission intensity is proportional to dsDNA quantity in solution. Using a DNA standard curve with known concentrations, DNA content in test samples is obtained by converting measured fluorescence.
HEK293 Host Cell DNA: The original process measured size and quantity of 3 different amplicons whereas the improved process measures total hcDNA including high molecular weight and sheared DNA. The qualification data the improved process demonstrates that the assay is specific and sufficiently sensitive to meet the requirements in assessing hcDNA per dose of <10 ng/dose (WHO Expert Committee on Biological Standardization, 2013).
Residual BSA: Residual BSA is quantified using a commercially available ELISA kit manufactured and marketed by Bethyl. The scientific principle to the ELISA kit is very similar to that specified for the Host Cell Protein ELISA.
Residual Benzonase: This assay uses purified polyclonal antibodies specific to Benzonase endonuclease to detect residual Benzonase in the test sample by sandwich ELISA. Accurate measurement is achieved by comparing the signal of the sample to the Benzonase endonuclease standards assayed at the same time.
Bioburden Assay: This procedure is used to determine quantitatively (if detectable) the amount of bioburden present in a sample. The method used involves membrane filtration of half of the sample onto each of two membranes. The membranes are placed onto separate agar media plates which are incubated in aerobic and anaerobic conditions sequentially at 20-25° C. and 30-35° C. At the conclusion of incubation; aerobe, anaerobe, and fungal counts are expressed as CFU/mL of sample.
Endotoxin Assay: This assay is used to determine if bacterial endotoxins are present in the test article. A quantitative procedure is performed by the kinetic-chromogenic method. Known amounts of endotoxin are tested in parallel with the test article for an accurate determination of the level of bacterial endotoxin. The potential for interference by the test article is examined by spiking the test article plus LAL reagent with specified levels of endotoxin. Following the inhibition/enhancement test, the endotoxin content of the test article is determined.
Residual AVB: Residual AVB analysis is performed using a commercial ELISA kit, CaptureSelect™ AVB Sepharose HP Ligand Leakage ELISA, manufactured by Life Technologies. The sandwich ELISA principle involves coating microtitre plates with anti-affinity ligand polyclonal goat antibodies to capture AVB present in the sample. Detection is via a biotinylated affinity-purified anti-AVB ligand polyclonal goat antibodies and streptavidin horseradish peroxidase conjugate. Concentration of residual AVB in the sample is determined by measurement against a standard curve.
Compositions of the disclosure maintain long term stability when stored at <−60° C. For example, compositions of the disclosure maintain long term stability when stored at temperature between −80° C. and 40° C. (approximately human body temperature), inclusive of the endpoints. For example, compositions of the disclosure maintain long term stability when stored at temperature between −80° C. and 5° C., inclusive of the endpoints. For example, compositions of the disclosure maintain long term stability when stored at −80° C., −20° C. or 5° C. In some embodiments, compositions of the disclosure are formulated as liquids or suspensions, aliquoted into one or more containers (e.g. vials), and stored at <−60° C. In some embodiments, compositions of the disclosure are formulated as liquids or suspensions, aliquoted into one or more containers (e.g. vials), and stored at −80° C., −20° C. or 5° C.
Compositions of the disclosure may be provided in a container with an optimal surface area to volume ratio for maintaining long term stability when stored at <−60° C. Compositions of the disclosure may be provided in a container with an optimal surface area to volume ratio for maintaining long term stability when stored at −80° C., −20° C. or 5° C. In some embodiments, compositions of the disclosure are formulated as liquids or suspensions, aliquoted into one or more containers (e.g. vials), and stored in one or more containers with a surface area to volume ratio as large as possible when all storage requirements are considered.
Compositions of the disclosure maintain long term stability when stored at ambient relative humidity.
Choroideremia (CHM) is a hereditary X-linked retinal dystrophy first described in the 19th century. A deletion or mutation of the CHM gene, encoding REP1 leads to degeneration of the choroid, RPE and retina. Choroideremia is characterized by progressive chorioretinal degeneration in affected males and milder signs in carrier females. Symptoms in affected males may evolve from night blindness to peripheral visual field loss, with central vision preserved until late in life. Although carrier females are generally asymptomatic, signs of chorioretinal degeneration can be observed with careful fundus examination. These signs become more readily apparent after the second decade.
CHM is caused by mutations in the CHM gene (Xq21), which encodes component A of Rab geranyl-geranyl-transferase, referred to as REP1. REP1 is required for intra-cellular trafficking, and is therefore essential for normal retinal function. When REP1 is deficient, as is the case in CHM sufferers, there is a gradual loss of function and atrophy of the retinal pigment epithelium, photoreceptors and the choroid, which ultimately leads to blindness. Prior to the development of the pharmaceutical compositions of the disclosure, no treatment was available for CHM.
Retinal gene therapy dosing using an adeno-associated viral (AAV) vector involves the calculation of a single dose which may give lifelong effects. In traditional systemic drug dosing, the half-life of the drug is measured in the blood and this determines the frequency of repeat doses administered throughout the day, so that the peak levels are non-toxic and the trough levels are sufficient to maintain pharmacodynamic activity. With traditional dosing regimens it is possible to use healthy volunteers to work out drug clearances and hence calculate the half-life of the drug and thereby estimate the required plasma levels in order to calculate the dose and frequency of administration. Adjustments can be made—for instance, dosing may be reduced for drugs metabolized by the liver in cases of liver failure. In pediatric cases, dosing can be adjusted according to weight which recognizes the smaller blood volume and target organs. These traditional methods of actively titrating the dosage present challenges with ophthalmic gene therapy administration because, in preferred embodiments of the methods of treatment and uses of the pharmaceutical compositions of the disclosure, the aim of the treatment is to give only one dose that will achieve lifelong therapeutic effects.
In some embodiments of the methods of the disclosure, the pharmaceutical composition is administered to the eye via a sub-retinal injection to target RPE and photoreceptor cell layers. As part of the surgical procedure for a sub-retinal injection, a vitrectomy is performed on the eye to be treated prior to the sub-retinal rejection. This vitrectomy is followed by a sub-retinal infusion of balanced salt solution to form a hemispherical bleb. In some embodiments of the disclosure, the hemispherical bleb is approximately 10 mm2 in area or the hemispherical bleb is 10 mm2 in area. In some embodiments of the disclosure, a pharmaceutical composition of the disclosure is formulated in a final volume of 0.1 mL and injected into the preformed bleb, allowing the pharmaceutical composition to evenly distribute itself across the retinal surface (e.g. across the 10 mm2 retinal surface). Thus, in those embodiments in which a hemispherical bleb is formed into which the pharmaceutical composition may be injected, the bleb facilitates an even distribution of full rAAVs of the composition across the RPE cell layer of the retina. Following the injection of the pharmaceutical composition, the bleb resolves within a few hours post-surgery.
A potential complication of the vitrectomy/sub-retinal surgery is reduced visual acuity (VA) immediately post-surgery. Another potential and longer-term complication is the formation of cataracts. Both these factors affect the vision when a VA test is performed, and therefore, these factors are considered when determining the outcome of dose-ranging, especially when VA is the sole predictor of the effective dose determination.
Choosing the appropriate dose in gene therapy trials is different to traditional ways of assessing dose-ranging. The goal is to administer the highest efficacious dose possible that is known to be safe. The reasons for this are primarily driven by the fact that the multiplicity of infection (MOI) for retinal photoreceptors is very high in the order of 105 genome particles (gp) per retinal cell. Given that, in some embodiments, and depending upon the biology of the individual subject being treated, the maximum area of retina that can be treated is approximately 10 mm2, and that the area of retina that is treatable is around the macula, the total number of rods, cones and retinal pigment epithelium (RPE) cells in this area amount to approximately 1×106 cells, the low dose cohort (1010 gp) in the study (described in Example 13) provides an MOI of 1×104 gp only, whereas the high dose arm (1011 gp) in the same study provides an MOI of 1×105 gp.
Phase I/II data are provided in Example 13. The high dose of this study (1011 gp) has been shown to be safe and efficacious. In certain embodiments, a steroid therapy regime may be used to address any immune response of the subject to the AAV of the pharmaceutical composition. As described in Example 13, a dose of 1011 gp of the pharmaceutical composition of the disclosure results in an MOI in a preferred range of 105 gp.
One parameter to measure is an improvement in visual function. This assumes that the visual function parameter is adversely affected by the genetic defect and might therefore be reversible to some extent so the improvement can be measured following successful gene transfer. In some embodiments of methods of treating CHM, visual function parameters are measured, including, but not limited to visual acuity (VA), retinal sensitivity and measurements of dark adapted vision. For some subjects, however, depending on the severity of the defect and the stage of the degeneration, some of the above visual function parameters may be considered normal. In some embodiments of the methods of treatment of the disclosure, the visual function parameter of a subject improves following treatment and the improvement results in visual function parameter measurements that are equal to those measurements obtained from a healthy subject (who does not have CHM) and who did not receive the treatment. In some embodiments, the healthy subject is an age-matched individual, for example, to account for natural age-related vision deterioration that is independent of CHM. Moreover, as men and women can differ in their color vision acuity, in some embodiments, the healthy subject is an individual having the same XY chromosome composition. In some embodiments of the methods of treatment of the disclosure, including those embodiments in which the subject has already experienced significant retinal damage (neuronal loss) or in which the unaffected areas of the retina are small and/or discontinuous, a full recovery of visual function may not be expected. In those embodiments in which only a partial recovery is possible, an improvement of visual function may be apparent when the improvement is compared to the subject's baseline function (the function assessed in this subject and in the treated eye prior to administration of the pharmaceutical composition). Even in the embodiments in which only a partial recovery is possible, the treatment raises the baseline function of the eye and the subject's vision function such that CHM and/or age-related retinal degeneration are postponed or reduced, thereby prolonging the lifetime of useful vision for the subject.
In order to calculate the MOI for clinical treatments in vivo, the total number of vector particles and the number of target cells in the region to be treated are determined. These number depend on the area of retina exposed to vector and the density of each of the different cell types in that region.
Pharmaceutical compositions of the disclosure are administered in CHM patients via a sub-retinal injection following an induced retinal detachment. For example, if it is assumed that the retinal detachment has linear dimensions of approximately 2-3 disc diameters, this area of retinal detachment is equivalent to a circle with a diameter of 3-4 mm, or an area of approximately 10 mm2.
The disclosure provides exemplary cellular densities for exemplary dose calculations, however, the doses of the pharmaceutical compositions of the disclosure are not bound by these exemplary calculations. In the central macula, the density of RPE cells in normal human subjects is 5,000 cells per mm2 (based on post-mortem studies in patients in the 40-50 year age group). In the central macula, the density of rod cells in normal human subjects is 75,000 cells per mm2 but excludes central foveal area of approx. 0.5 mm2. In the central macula, the density of cone cells in normal human subjects is 150,000 per mm2 in the central 0.5 mm2 fovea (75,000 total)+25,000 per mm2 in the macula outside the foveal area. Thus, in some embodiments of the disclosure that are based on these exemplary cell densities, the total number of each of the three cell types exposed to rAAV of the pharmaceutical compositions of the disclosure in a standard 10 mm2 detachment can be calculated from the above as follows: (a) RPE: 5,000 cells per mm2—TOTAL=5×104 in 10 mm2; (b) Rods: 75,000 cells per mm2, but excluding the central 0.5 mm2 fovea—TOTAL=7.1×105 in 10 mm2; and (c) Cones: 150,000 cells per mm2 in central 0.5 mm2 fovea (75,000), but only 25,000 per mm2 extra-foveal—TOTAL=3.1×105 in 10 mm2. The density of RPE, rods and cones differs in the central 10 mm2 of the macula and varies by about one log unit, with the lowest density (and hence highest MOI) seen in relation to the RPE.
AAV Adeno-Associated Viral
AmpR Ampicillin Resistance
ATCC American Type Culture Collection
AVG Average
BCA Bicinchoninic Acid
BGH-polyA Bovine Growth Hormone Polyadenylation Sequence
bp Base Pairs
BSA Bovine Serum Albumin
BSE Bovine Spongiform Encephalopathy
BSS Balanced Salt Solution
° C. Degrees Centigrade
CBA Cytomegalovirus Enhancer/Chicken-Beta Actin
CEP Certificates of Suitability
c.f. Conferre (Compare)
CFU Colony Forming Units
CI Confidence Interval
cm Centimetre
CT Cycle Threshold
CV Coefficient of Variation
cGMP current Good Manufacturing Practice
CHM Choroideraemia
CMV Cytomegalovirus
CNS Central Nervous System
DCB Development Cell Bank
DF Diafiltration
DLS Dynamic Light Scattering
DMEM Dulbecco's Modified Eagle Medium
DNA Deoxyribonucleic Acid
DP Drug Product
DRP DNase Resistant Particle Assay
dsDNA Double Stranded DNA
EDTA Ethylenediaminetetraacetic Acid
EF Elongation Factor
EFS Elongation Factor 1 Alpha Short
ERA Effective Filtration Area
EGFP Enhanced Green Fluorescent Protein
ELISA Enzyme-Linked Immunosorbant Assay
EP European Pharmacopoeia
et al. et alii (and others)
EtBr Ethidium Bromide
FACS Fluorescence-Activated Cell Sorting
FBS Fetal Bovine Serum
FC Final Container
FTM Fluid Thioglycollate Medium
g x gravity
GAD Glutamic Acid Decarboxylase
GGPP Geranylgeranylpyrophosphate
GF Gel Filtration
GFP Green Fluorescent Protein
GLP Good Laboratory Practice
GMP Good Manufacturing Practice
gp Genome Particles
gp/mL Genome Particles per mL
h Hour
HBSS Hanks' Balanced Salt Solution
HCP Host Cell Protein
HEK Human Embryonic Kidney
HI-FBS Heat Inactivated FBS
HPLC High Performance Liquid Chromatography
HRP Horse Radish Peroxidase
HSA Human Serum Albumin
INN International Non-Proprietary Name
IPC In Process Control
IST Investigator Sponsored Trial
ITR Inverted Terminal Repeat
IU Infectious Units
KanR Kanomycin Resistance
kb Kilobase
kDa Kilodaltons
kg Kilogram
kGy Kilogray
L Litre
LOQ Limit of Quantitation
LAL Limulus Amoebocyte Lysate
LOD Limit of Detection
μL Microlitres
μm Micrometre
m Metre
M Molar
mbars Millibars
MCB Master Cell Bank
mDa Mega Daltons
mg Milligrams
MIA (IMP) Manufacturer/Importer Authorisation
min Minute
mL Millilitre
mm Millimetre
mM Millimolar
mOsm Milliosmoles
MSC Microbiological Safety Cabinet
N/A Not Applicable
ND Not Determined
NEAA Non-Essential Amino Acids
ng Nanogram
NF National Formulary
nm Nanometre
No. Number
OCT Optimal Cutting Temperature
OD Optical Density
OD600 Optical Density Measured at 600 nm
ONL Outer Nuclear Layer
p Probability
Pa Pascals
PAGE Polyacrylamide Gel Electrophoresis
PB Purified Bulk
PBDS Purified Bulk Drug Substance
PCR Polymerase Chain Reaction
PDA Photodiode Array Detector
PEI Polyethylenimine
PETG Polyethylene Terephthalate Glycol
pfu Plaque Forming Units
pg Picograms
ppm Parts per Million
PSG Pure Steam Generator
psi Pounds per Square Inch
PTC Points to Consider
QC Quality Control
QP Qualified Person
QFPERT Quantitative Fluorescent Product Enhanced Reverse Transcriptase
qPCR Quantitative Polymerase Chain Reaction
qs Quantum Sufficit
rAAV Recombinant AAV
R&D Research and Development
rcAAV Replication Competent AAV
rDNA Recombinant DNA
REP1 Rab Escort Protein Type 1
RH Relative Humidity
RO Reverse Osmosis
RPE Retinal Pigment Epithelium
RPE65 Retinal Pigment Epithelium 65 Protein
rpm Revolutions per Minute
s Second
SCDM Soybean-Casein Digest Medium
SDA Sabouraud Dextrose Agar
SDS Sodium Dodecyl Sulphate
SLO Scanning-Laser Ophthalmoscopy
SOP Standard Operating Procedure
SSS Salt and Surfactant Solution
ST DEV Standard Deviation
TAMC Total Aerobic Microbial Count
TBA To Be Assigned
TCID50 Tissue Culture Infectious Dose 50
TFF Tangential Flow Filtration
TSA Trypticase Soy Agar
TT Technology Transfer
TYMC Total Yeast/Mould Count
U Units
UF Ultrafiltration
USP United States Pharmacopoeia
UV Ultraviolet
vg Vector Genome
vp Viral Particles
v/v Volume to Volume
WFI Water for Injection
WPRE Woodchuck Hepatitis Virus Post-Transcriptional Regulatory Element
WT Wild Type
μl Microlitre
μm Micrometer
Samples from the original process were provided for use in data analysis of the improved process so that data could be generated from both sets of batches using the same methods (where applicable) to allow for a direct relative comparison of data generated, unless stated otherwise. For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
The intermediate products generated by the improved process were analyzed for physical titre (qPCR), total protein (Micro-BCA), total DNA (Picogreen) and purity (SDS-PAGE/Sypro Orange stain).
The genomic titre data for samples from the original process were taken from the testing documentation provided.
The total protein and total DNA data from the original in-process intermediate samples presented here were generated according to the improved process from the starting material produced from the original process.
The Electron Microscopy (EM) analysis used for full to empty particle ratio determination was not fully established at the time that the process was transferred from the original to the improved process. The original process did not involve any testing at the time of manufacture to determine the ratio of full to empty particles within the clinical batch, either to assess the purification (density gradient) step or to measure final Drug Product, therefore no data was available for comparison of the purification (density gradient) process step from the improved process with that from the original process. Therefore, the full to empty particle ratio was not used as an assessment of comparability. Instead, determination of physical titre (or genome particles) as measured by qPCR was considered a suitable determination of successful transfer of the entire process and of successful transfer of individual process steps as this is specific to the vector product and therefore representative of full capsids. However, for the original process, a method based on analytical ultracentrifugation (AUC) was used to assess the full to empty ratio for information only. The result of this test was presented in Table 33.
EM is the preferred method and has been performed on all batches manufactured to date. Additionally, EM analysis has been used retrospectively to test both batches from the original process to give an understanding of the full to empty ratio. This testing has demonstrated that the improved process is capable of generating a comparable ratio of full to empty capsids as shown in Table 20.
The analytical results from the starting material and the reference material (both from the original process), are summarized in Table 21.
The harvest material produced by the improved process contained a higher total protein concentration than the harvest material produced by the original process. However, the purity profiles of the final Drug Substance were similar between the original and improved processes with no major impurities detected. The titre recovery between the original and improved processes was also similar.
With regards to the acceptance criteria defined for a successful technology transfer of the process, the improved process was controlled and the performance of the individual process steps of the improved process were similar to those observed during the original process. The process recovery (vector titre) from the improved process was within 20% of that obtained by the original process. The final product purity (DNA/protein content) from the improved process was within 20% of those obtained by the original process, with similar SDS-PAGE profile.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
Plasmid Triple Transfection and Harvest
Process 1: The three plasmid transfection of HEK293 cells was performed by Calcium phosphate DNA precipitation following chloroquine pre-treatment of cells.
Process Optimization: Optimize transfection, including cell seeding conditions, comparison of Calcium phosphate and polyethylenimine. Optimize plasmid concentration/ratio. Determine optimal day post-transfection for medium exchange and harvest. Operational (non-process) changes were optimized to improve control and reproducibility of process steps to ensure process consistency and robustness. Chloroquine was removed from the process to improve safety.
An analysis of vector titre yield was performed. Polyethylenimine (PEI) transfection reagent was compared with Calcium phosphate (used for Process 1) to determine if the former could be used to replace Calcium phosphate as a more robust transfection agent. The requirement for a pre-treatment with chloroquine was also evaluated. All parameters were assessed by determining the physical titre by qPCR using a non-validated method.
Table 22 presents the initial results where the titre of vector following transfection with PEI was compared directly with the titre obtained using Calcium phosphate, both in the presence and absence of chloroquine. All studies were performed with DMEM media containing Glutamax, which is the media used for all upstream process steps.
This work demonstrated successful transduction using PEI, albeit with lower physical titre results when compared to transfection using Calcium phosphate. This work also showed that when PEI was used as a transfection reagent the chloroquine pre-treatment was not required and could be removed from the process.
Based on this result, further optimizations were performed at small scale, including cell seeding density, media for cell growth, FBS concentration and DNA:PEI ratio. Once an optimized transfection process had been established, the process was performed at full scale using PEI and compared to the same process using Calcium phosphate to demonstrate comparability.
Table 23 shows the data obtained from the full-scale manufacture, which demonstrates the suitability and comparability of PEI as a transfection reagent. Based on this data PEI was selected as the transfection reagent of choice to allow a more robust process step when compared to Calcium phosphate.
Furthermore, the overall productivity and process yield of batches produced by the improved process are comparable to those produced by the original process (Table 24) demonstrating the suitability of PEI as a transfection reagent.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
Study Materials and Procedure
The ampicillin containing plasmids used for production of the clinical batch produced by the original process served as the control for analysis of AAV2. Construct vector yield in terms of DNase resistant particles (DRP)/cm2. The experiments were performed from the same cell thaw event and all cells received the same treatments, media, reagents and growth conditions throughout the experiment.
Plasmids Tested: pAAV.Construct (KAN); pNLREP-CAP2 (KAN); pHELP (KAN); pAAV.Construct, CN1055CM (Original Process; Amp version, used as control); pNLREP-CAP2, CN1054CM (Original Process; Amp version, used as control), pHELP, CN2291CM (Original Process; Amp version, used as control).
Triplicate testing was performed for each set of plasmids. Three 1-Stacks were transfected with pAAV.Construct (KAN), pNLREP-CAP2 (KAN) and pHELP (KAN). Three 1-Stacks were transfected with the equivalent AmpR containing plasmids. Cells were re-fed at 16 to 26 hours post transduction, and the media and cells harvested at 44 to 52 hours post transduction, and the yield of DRP determined for each 1-Stack determined.
Results
The average DRP/cm2 was determined among the 3 replicates tested via qPCR. The yields from both the media and the cell lysate were analyzed separately then added to determine the total vector yield per replicate which was then divided by the number of square centimetres.
The acceptance criteria for the re-engineered (Kan) plasmids used for manufacture of the Drug Substance and Drug Product was defined as being no less than fourfold of the yield of the control plasmids. The re-cloned Kan versions of the plasmids met the acceptance criteria. Based on the similar yield of DRP obtained and the sequence confirmation, the KanR containing plasmids are considered suitable for production of clinical batches of AAV2-Construct.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
Study Materials and Procedures
The Original Process 1 cell line used for production of the GMP batch by the original process served as the control for transfection efficiency and yield of AAV2-Construct vector. Continued passage and re-testing for yield and transfection efficiency had not formerly been assessed for the Original Process 1 used cells and testing is for information only. The experiments for transfection efficiency, yield analysis and growth kinetics were performed from the same cell thaw event(s) and all cells received the same treatments, media, reagents and growth conditions throughout the screening experiment.
Cell Lines Tested: ATCC=[HEK-293] (ATCC® CRL-1573TM), Bioreliance=293 Cells (G95001 2), Process 1 cell line, and 293T=293T/17 [HEK 293T/17] (ATCC® CRL-1 1268TM). Of note, the 293T Cell line was included as an alternate source.
For transfection efficiency and yield analysis, monolayers of each cell line were transfected with the relevant plasmids and re-fed at 16 to 26 hours post transfection. Harvesting of cells and media for GFP or AAV2-Construct DRP analysis was conducted at 44 to 52 hours post transduction.
Growth kinetics was evaluated by seeding T175 flasks with either 10{circumflex over ( )}7 or 2.5×10{circumflex over ( )}6 cells/flask and the cell health, confluency, cell count and viability recorded at days 1, 2, 3, 4 and 7 post seeding. This was repeated at a passage ≥15.
Results
Mean Fluorescence Intensity: Mean fluorescence intensity was analyzed via flow cytometry to measure levels of GFP protein expression coupled with number of cells transfected as an indicator of overall gene expression in correlation with viral yield.
Percent GFP: The percentage of GFP positive cells as determined by Flow Cytometry is shown in
AAV2-Construct Yield Analysis: DRP titre assay results were generated for head to head comparative analysis of AAV2-Construct yield in the harvested cells+media for each treatment (1-Stack) per qPCR analysis.
The acceptance criterion for a cell line to be suitable for use in clinical manufacture was deemed to be a difference of no more than fourfold of the control (Original Process 1 cells) per treatment. Experiment 1 (Exp1) was carried out at cell passage 7 and Experiment 2 (Exp2) at passage 15.
Growth Kinetics: Growth kinetics were evaluated by recording cell counts and viability of T175 flasks, seeded at two densities simultaneously, on days 1, 2, 3, 4 & 7 post seeding. Each experiment consisted of two replicates on consecutive passages. Experiment 1 was carried out at passage 7 & repeated at passage 8 from thaw. Experiment 2 was carried out at passage 15 & repeated at passage 16 from thaw. The quantity and percentage of viable cells was determined by Trypan Blue staining.
All four cell lines expressed GFP at levels consistent with those expected for good transduction efficiency based on previous experience relative to the correlating yield analysis. The two cell lines from ATCC, HEK293 (CRL-1573) and 293T (CRL-11268) exhibited good cell growth and expansion from thaw. It is notable that the Bioreliance cell line had a slower initial growth and expansion with poorer overall cell health relative to the other cell lines and control. The Bioreliance cell line also failed to meet the acceptance criteria of yielding within fourfold of the control for both experiments where both of the ATCC cell lines fell within the minimum acceptance criteria.
For further production of the AAV2-Construct vector, the ATCC cell line HEK293 (CRL-1573) was chosen based on the results presented above for exemplary embodiments of the manufacturing processes of the disclosure.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
As part of the strategy for transferring from the original to an improved manufacturing process, an analytical strategy was developed in parallel. Where possible, methods developed for the original process were transferred to the improved process or to next-generation process.
Both Original and Improved rcAAV assays utilize human embryonic kidney cells (HEK293) that are infected with dilutions of the AAV2-construct or wild type (wt) AAV as a control. The cells are then co-infected with adenovirus serotype 5 (Ad5) to provide helper functions for rcAAV (if present). At maximum cytopathic effect (CPE) the cells are lysed. This constitutes the end of passage 0 (P0) of the vector. In passage 1 (amplification 1), a portion of the P0 lysates are used to inoculate HEK293 cells co-infected with and without Ad5. The cells without Ad5 serve to determine the input level of DNA into the cells while the cells with Ad5 permit amplification of the rcAAV2-Construct, or wt AAV in the case of the controls. In the Original assay, when the Ad5 positive samples reach maximum CPE after the first amplification the cells are analyzed by PCR. In the Improved assay, the cell lysis/amplification step is performed a total of 3 times prior to PCR analysis.
The assay has been validated as a limit test of the improved process. Neither the Original clinical nor the engineering batch were analyzed as part of this validation so a direct comparison of the results obtained is not possible. The Original assay was not validated. In conclusion, the two methods provide results that are not significantly different.
The hcDNA measurements from the Original and Improved process both use qPCR on the Taqman instrument. The Original assay measured three different amplicons (102, 401 and 765 bp) with a sensitivity (LOD) of 20 pg/mL for each amplicon. The assay used by the improved process has a single amplicon and a sensitivity (LOQ) of 1.3156 ng/mL. A head-to-head comparison of the methods was not conducted, however, the hcDNA method has subsequently been qualified and demonstrated fit for purpose. Thus, there is not an adverse impact on the comparability assessment.
Residual BSA was measured by the Original Process using a commercially available ELISA kit from Bethyl Laboratories, Cat #E10-113. The sensitivity of this kit, used in the Original process, was 12.6 ng/mL. A commercially available ELISA kit, Alpha Diagnostics Cat #8100, is used in the improved process. This kit has not been validated but the sensitivity is defined as the lowest calibration standard i.e. 1 ng/mL. The manufacturers of the primary antibodies used in both kits assert that the primary antibodies are specific for the detection of human BSA. A head-to-head comparison of the methods was not conducted; however, all batches tested to data have demonstrated very low levels of residual BSA (below the sensitivity of the method).
Therefore, it was concluded that all batches contain comparably low levels of residual BSA.
In addition, because BSA can cause allergic reactions in humans the World Health Organization (WHO) has set a guidance of 50 ng or less residual BSA per vaccine dose. For example, for a dose of AAV2-Construct of 100 μL, the concentration limit of BSA would be 500 ng/mL. Both ELISA kit assays used in the Original and Improved processes have levels of sensitivity below this required limit and are therefore considered comparable in measuring residual BSA within acceptable limits.
Infectious Titre
The infectious titre assay was transferred from the Original to the improved process. Both the cell culture part of the assay and the PCR were performed as part of this transfer following the procedure used in the Original Process. AAV2-Construct (non-GMP) (by Original process) was analyzed on 3 occasions during the assay transfer and the results obtained were compared with the infectious titre, 2.90×1010 IU/mL. The data obtained are provided in Table 30.
The data obtained from the assay transfer study are not significantly different, i.e. within a 4-fold range of the result obtained from the Original process.
The AAV-Construct (non-GMP) produced by the Original process was analyzed on 3 occasions according to the Improved process and the results are provided in Table 31 relative to the reported titre (4.95×10{circumflex over ( )}12 DRP/mL) (Original Process). Data was considered acceptable if it was within a 3-fold range of the result reported according to the Original process.
The assay has subsequently been validated and the additional values in Table 32 were obtained for the AAV-Construct (non-GMP) (from Original process) material (1000 and 10,000 dilution results only).
The AAV2-Construct (non-GMP) material (from Original process) is routinely analyzed in DS and DP sample analysis as an internal reference control (primary reference) with system suitability acceptance criteria set as within 3-fold difference from the nominal titre (4.95×10{circumflex over ( )}12 DRP/mL) (determined by Original process) to ensure continued comparable performance of the method.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
To demonstrate that the change process changes/optimizations (to Process 1 to generate Process 2) have not affected the critical quality attributes of the vector material produced, a Comparability Assessment was performed.
Once the process changes were made to the cells, plasmids, transfection conditions, affinity chromatography column, scale and final container, and the optimization work had been completed with respect to Process 1, a new process for manufacture of Clinical Phase 3 material was defined and a full scale ‘engineering’ batch performed to measure process performance and equivalence of Drug Substance and Drug Product to the material produced by the Original process.
The analyses below compare the data generated from the full scale engineering batch and GMP batches from the improved process to the engineering batch and clinical material generated by the Original process.
An engineering batch produced by the Original process (AAV2-Construct (non-GMP)), for which additional testing was performed (see Table 33 below) to provide information for comparison to the engineering batch produced by the Improved process.
**
Testing performed on Drug Product (final container)
Testing performed by analytical ultracentrifugation, not electron microscopy
Additional Analytical Information and Data
Physical Titre: The target physical titre for the filled drug product clinical material (GMP product) was 1×10{circumflex over ( )}12 DRP/mL (produced by Original process). For the engineering batch manufactured by the Original process (non-GMP product), there was no target titre and AAV2-Construct (non-GMP) represented Drug Substance that would be diluted to the target fill concentration had this batch been progressed to Drug Product. For AAV2-Construct (non-GMP) produced by the Improved process, the target concentration was 1-2×10{circumflex over ( )}12 DRP/mL. The reported titre of 1.87×10{circumflex over ( )}11 DRP/mL for AAV2-Construct (non-GMP) is lower than expected, but this is due to the minimum hold up volume in the final tangential flow ultrafiltration step (TFF2) limiting the extent to which the final Drug Substance could be concentrated. Specifically, this incomplete concentration resulted in the batch being 6-fold less concentrated. If the physical and infectious titre is corrected for this 6-fold dilution then the physical titre, infectious titre and physical:infectious titre ratios are similar between the batches, as summarized in Table 34. The use of a lower hold-up volume (smaller) TFF cartridge has been evaluated to achieve a higher concentration factor.
Purity: Purity is measured by analysis with Sypro Orange stained, reduced SDS polyacrylamide gel electrophoresis.
Construct Protein Expression: Prior to the introduction of a quantitative assay for Construct protein expression (via an ELISA method), preliminary analysis was performed using a qualitative non-GMP assay. This cell based, in vitro assay, described below, is capable of measuring both Construct expression and biological activity of the expressed Construct in a human cell line. The assay has 3 components:
Cell culture and viral vector transduction
Western blot for the detection of Construct protein expression
Assay for the detection of Construct protein activity
Cell culture is performed using HEK293 cells which are transduced with a known and comparable physical titre of AAV2-Construct vector. These cells express Construct protein at a level below or at the limit of that detected within this assay, allowing for a comparative qualitative assessment of increased Construct protein expression due to cell transduction and expression from the AAV2-Construct vector. Following transduction and incubation, cell lysates are collected and the cytosolic fraction is used in Western blot and in an in vitro assay to determine Construct protein expression and activity, respectively. Protein detection is performed using a monoclonal antibody specific to the Construct protein and expression levels are normalized against, for example, intracellular B-actin expression to provide a semi-quantitative analysis.
Product of Optimized Process:
Safety: Bioburden and endotoxin data indicated no issues with safety relating to introduction of new contaminants. The batches from Original and Improved processes are not significantly different in this regard.
Impurities: Levels of process related impurities (HCP, residual benzonase, BSA, Total Protein) were not significantly different for all batches.
Some differences in host cell DNA (hcDNA) levels are noted. The difference between the AAV2-Construct (non-GMP) and AAV2-Construct (GMP), both produced by the Original process may be due to the fact that AAV2-Construct (non-GMP) was produced in non-GMP laboratories whereas AAV2-Construct (GMP) was produced in GMP clean rooms where there is more control of process steps, process operations, sampling, testing and raw materials, allowing better and more reproducible results to be obtained. In addition, a longer incubation time following plasmid transduction of cells was used to produce AAV2-Construct (non-GMP); 72 hours from cell feeding until harvest compared to 23 hours for the cells used to produce AAV2-Construct (GMP). The longer incubation can allow more cell growth and more hcDNA to be released by those cells.
These differences can account for the differences observed in hcDNA levels between the 2 lots of material produced by the Original process.
Conversely, for the AAV2-Construct (non-GMP) and the 2 GMP lots, all of which were produced by the Improved process, the hcDNA levels are much lower (530 pg/mL or <LOD respectively). In the process used to produce these batches there is a chromatography purification and polishing step which is capable of removing residual DNA.
Product Characteristics: Appearance, pH and osmolality were not significantly different for all batches.
Vector Characteristics: The non-GMP and GMP batches produced by the improved process show comparable Construct expression and biological activity when assessed in a non-quantitative assay. These batches also had comparable purity to batches generated by the Original process with no detectable impurities.
Data on the ratio of full to empty vector capsids are similar, and data from the Construct expression and activity presented above confirm that the ratio of full to empty vector capsids in the (non-GMP) batch produced by the Improved process is equivalent to GMP batches produced by the Original process and does not negatively impact the ability of vector to transduce human cells and demonstrate biological activity.
Data on the identity (vector sequence) confirms homology across the full sequence for all batches with no mutations introduced. Identity is also confirmed by ability to detect in vitro Construct expression and biological activity, both of which rely on an intact and functional Construct protein flanked by AAV ITRs.
Replication competent AAV has not been detected in any batch. Presence of an rcAAV is unlikely due to the nature of the plasmid and vector genetics but will continue to be assessed for any GMP batch prior to release for clinical studies to assure patient safety.
Process Yield:
Table 35 summarizes the overall process yield of the Improved process. From twice the number of 10 stack cell factories (24 c.f. 12 for the Original process), twice the number of virus particles (DRP) are made (6.7×10{circumflex over ( )}13 c.f. 3.4×10{circumflex over ( )}13 for the Original process). Overall process recovery is lower but this is partly due to the additional in-process and quality control testing performed during the improved process development that was not included during the Original batch production.
Based on the data presented above the AAV2-Construct non-clinical batch produced from the new optimized process is considered comparable to the non-clinical and clinical batches generated by the Original process. This process was used to produce the first GMP batch according to the improved process.
All testing parameters relating to product quality and efficacy were assessed following introduction of AVB and there was no detectable change in the quality or efficacy profile of the AVB chromatography derived product, as detailed in Table 36 to Table 41.
In addition, a new method for the detection of residual AVB ligand was introduced and demonstrated no detectable AVB ligand in any of the material manufactured using the AVB Sepharose column.
Seven AVB engineering runs performed with AAV2-Construct harvest material (
Following demonstration of product comparability and improved process robustness by small scale development runs and scaled up production lots using the AVB affinity chromatography step, AAV2-Construct GMP was manufactured using the AVB process. All analytical test results for this GMP batch have met specification and expectation.
The preliminary analytical results for AAV2-Construct GMP drug substance and drug product (produced by the improved process) are summarized below in Table 38 and Table 39. All tests meet specification and expectation.
The purification process improvement has resulted in comparable AAV2-Construct drug substance and improved process robustness when compared to the process and product from the Original process.
During manufacture by the improved process, the ratio of full to empty particles is determined as a characterization test.
Potential product-related impurities are given in Table 40.
Potential process-related impurities and their control are given in Table 41.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
Validation of Analytical Procedures: Summaries of method validation results, where available, are presented below.
Physical Titre: This assay has been validated to fulfil the following criteria (see Table 42). The “Actual Value” is a value for an exemplary AAV2-Construct of the disclosure.
DRP:IU Ratio—Calculation: No validation required. Value determined by calculation from physical titre and infectious unit titre assay data.
Total Particles: The total particles assay has been validated. A summary of the validation results is presented in Table 43. The “Actual Value” is a value measured for an exemplary AAV2-Construct of the disclosure.
Full:Empty Ratio: Drug specific assay validation not performed. Counting of full and empty AAV2 particles on transmission electron microscope images performed in GMP compliant facility.
Vector Identity (DNA): Drug specific assay validation not performed. DNA sequencing is performed using qualified method and equipment in a GMP compliant facility.
Total Protein Assay: This assay is validated to fulfil the following criteria (see Table 44).
Purity Assay (SDS-PAGE): The purity assay has been validated. A summary of the validation results is presented (in Table 45). The “Actual Value” is a value measured for an exemplary AAV2-Construct of the disclosure.
Replication Competent AAV: The replication competent AAV assay has been validated to fulfil the relevant validation requirements as specified in ICH Q2(R1) for a limit test for impurities (see Table 46). A summary of the validation results is presented below. The “Actual Value” is a measurement of an exemplary AAV2-Construct of the disclosure.
Total DNA: The total DNA assay has been validated. A summary of the validation results is presented (see Table 47). The “Actual Value” provided is a measurement of an exemplary AAV2-Construct of the disclosure.
HEK293 Host Cell DNA: The HEK293 Host Cell DNA assay has been qualified (see Table 48). A summary of the qualification results is presented below. The “Actual Value” provided is a measurement of an exemplary AAV2-Construct of the disclosure.
Bioburden Assay: This is a compendial method harmonized to meet EP 2.6.12 and USP <61> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeial monographs.
Endotoxin Assay: This is a compendial method harmonized to meet EP 2.6.14 and USP <85> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeia monographs.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
Batch analysis data from 2 non-GMP and 2 GMP batches are presented below in Table 50.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
One clinical GMP batch has been manufactured according to Process 1. Batch analysis data from this batch of Drug Substance, is provided in Table 51.
1Results from IPC testing.
Aliquots of AAV2-Construct Drug Substance are analyzed for long term stability to support the AAV2-Construct Drug Substance storage condition of <−60° C. This study augments the ongoing Drug Product real time and accelerated stability studies at −80° C., −20° C. and 5° C.
AAV2-Construct Drug Substance is aliquoted into small containers (5 mL PETG screw cap bottles) representative of the full size AAV2-Construct Drug Substance containers to ensure sufficient containers are available for stability testing over time. These containers have the same product contacting materials and are chosen to best represent the final AAV2-Construct Drug Substance containers, with the exception of surface area to volume ratio. The smaller volume and larger surface area to volume ratio in the small container aliquots is believed to represent a ‘worst case scenario’ with respect to long term stability of the AAV2-Construct Drug Substance.
The aliquoted AAV2-Construct Drug Substance is placed at −80±10° C. with ambient relative humidity.
If insufficient aliquots of AAV2-Construct Drug Substance are available to complete the full 36 Month study, the study will be truncated at an earlier time point.
A reduced supportive stability study has been initiated using material from a small-scale AAV2-Construct (non-GMP) batch. This study uses 100 μl aliquots in 2 mL polypropylene cryotubes stored at <−60° C. The smaller fill volume and larger surface area to volume ratio in the small container aliquots are believed to represent a “worst case scenario” with respect to long term stability of the AAV2-Construct Drug Substance. The study will assess Drug Substance stability at 2, 6 and 12-month time points. Additional details of this study are presented below.
Test Requirements
Assays have been selected for the primary stability protocol based on the following rationale (see Table 52)
Assays have been selected for the supportive stability protocol to include physical titre, purity, total particles and potency as indicated in Table 53. These stability tests and time points (Table 54 and Table 57) were considered the most appropriate for the amount of material available to perform the study. An assessment of vector aggregation was not included in this study as the method is currently under development for AAV2 vector material. Container integrity was also excluded from the study since this is a reduced supportive stability study.
For the data provided below, the measurements are taken from one or more batches of AAV2-Construct, wherein the Construct is identical in all batches.
The analytical procedures which are performed for release testing of AAV2-Construct Drug Product are detailed in Table 58, in addition to the respective specifications.
Analytical Procedures: The methods used to control the Drug Product are summarized below.
Appearance (EP 2.2.1, 2.2.2 and 2.9.20 and USP <631>): The product will be inspected visually for transparency, color and the absence/presence of foreign particles. The product will be inspected against white and black backgrounds.
pH (EP 2.2.3 and USP <791>): The pH of the product will be determined using a micro pH electrode with temperature compensation.
Osmolality (EP 2.2.35 and USP <785>): Osmolality is determined by the Freezing Point Depression method.
Physical Titre: Physical titreing on the final product will be performed as described in herein.
Infectious Unit Titre Assay: The infectious titre assay on the final product will be performed as described herein.
Potency: This assay is used to demonstrate that Construct protein is over produced, and is active, in cells transduced with the test article. The cells, HEK293, express endogenous Construct protein at a very low level, allowing for a comparative assessment of increased Construct protein expression due to cell transduction and expression from the AAV2-Construct vector compared to non-transduced cells. Following transduction, cells are lysed and the Construct concentration in the lysates is measured by Western blotting or ELISA. The activity of the expressed Construct protein is measured on the cell lysates using a reaction which measures the incorporation of biotin-labelled GPP into a substrate using Wester blotting or ELISA.
Sterility Test (EP 2.6.1 and USP <71>): This procedure is used to determine if the test article is free from viable bacterial and fungal contamination. The test article is aseptically transferred into Soybean-Casein Digest Medium (SCDM) and Fluid Thioglycollate Medium (FTM). These broths are incubated for 14 days and inspected for evidence of bacterial and fungal growth.
Endotoxin (EP 2.6.14 and USP <85>): This assay is used to determine if bacterial endotoxins are present in the test article. A quantitative procedure is performed by the kinetic-chromogenic method. Known amounts of endotoxin are tested in parallel with the test article for an accurate determination of the level of bacterial endotoxin. The potential for interference by the test article is examined by spiking the test article plus LAL reagent with specified levels of endotoxin. Following the inhibition/enhancement test, the endotoxin content of the test article is then determined.
Validation of Analytical Procedures: Summaries of method validation results, where available, are presented below.
Appearance: This is a compendial method harmonized to meet EP 2.2.1/2.2.2 and USP <631> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeial monographs.
pH: This is a compendial method harmonized to meet EP 2.2.3 and USP <791> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeial monographs.
Osmolality: This is a compendial method harmonized to meet EP 2.2.35 and USP <785> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeial monographs.
Sterility: This is a compendial method harmonized to meet EP 2.6.1 and USP <71> requirements. Qualification/validation is conducted in accordance with the relevant pharmacopoeial monographs.
Choroideremia is a rare currently incurable X-linked recessive retinal degeneration that presents in late childhood and leads to blindness. This example provides the primary endpoint of a non-randomised, two year, phase 1-2 open label clinical trial assessing retinal gene therapy, using an adeno-associated viral type 2 (AAV2) vector expressing the choroideremia transgene (NCT01461213). Initially 12 patients were recruited, 5 of whom received 1×1010 genome particles (gp) of AAV.REP1 and 6 received 1×1011 gp. A surgical complication in one patient led to retinal thinning and a reduced vector dose of less than 1010 gp. The primary outcome measure of safety and efficacy was visual acuity at two years. Retinal sensitivity and anatomical changes were secondary endpoints. Over the entire group of 14 patients, by two years the median visual acuity improved by 4.5 letters in the treated eyes compared with a loss of 1.5 letters in the untreated eyes (p=0.03). For the 12 patients receiving gene therapy without complications, the treated eyes had gained 5.5 letters above their baseline level by two years (p=0.02). Compared to the untreated eyes, this represented a median 4.5 letter gain in favour of the eyes receiving gene therapy by two years (p=0.003). By this time 6 of the 12 treated eyes had gained more than one line of vision (>5 letters), compared with none of the 12 untreated eyes. At the last follow up (range 2-5 years), visual acuity had been maintained or increased in all 12 study eyes that had received the gene therapy as per protocol, compared with only 4 of the 12 untreated eyes. This was equivalent to a mean difference of 15.9 letters (>3 lines) between eyes. No statistically significant differences were seen in secondary endpoints, such as microperimetry, retinal thickness or loss of the outer rim of retina between treated and untreated eyes during the two year follow up. Retinal gene therapy for choroideremia appears safe and may benefit visual acuity.
In this unmasked, non-randomized, prospective interventional gene therapy clinical trial, 14 participants were recruited with informed consent and underwent gene therapy treatment to one eye using the AAV2.REP1 vector. Generally the eye selected for treatment had the worse visual acuity at baseline but in 3 cases the eye with better acuity was chosen because of other factors, such as visual field constriction. All participants were male ranging from 25 to 73 years of age with confirmed null mutations in the CHM gene. The primary objective of the trial was to assess safety in relation to maintaining vision by two years after surgery. Initially 12 patients were to be recruited into two dose cohorts of six patients, each of whom would be monitored for 24 months. Complications in two patients however led to a 24 months delay midway through the trial and a change in protocol relating to the surgical technique and immune suppression regimen used. The ethics committee approved an extension of the trial together with the recruitment of two further patients so that 12 patients in total received the gene therapy treatment as per the protocol without complications.
In the first cohort of 6 patients, a subretinal injection of up to 1×1010 genome particles (gp) assayed using a supercoiled plasmid vector reference was injected under the retina in a two-step procedure. This comprised an initial detachment of the retina with balanced salt solution delivered through a 41 gauge (G) Teflon cannula (DORC BV, Zuidland, Netherlands) and secondary injection of the AAV.REP1 vector into the newly created subretinal space. In patient six (C1) difficulties in detaching the retina and stretching of the papillomacular bundle resulted in a reduced gene therapy dose of <6×109 and subsequent retinal thinning, but all other patients received either the full low dose of 1×1010 gp (L1-5) or high dose of 1×1011 gp (C2 and H1-7), as per the protocol. Initially oral prednisolone was administered at 1 mg/kg for 3 days before and 7 days after gene therapy, but C2 developed vitritis and retinitis at 2 weeks post-operatively which adversely affected his vision. The protocol was subsequently amended so that H1-7 received an extension of the prednisolone regime: 0.5 mg/kg (days 8-14), 0.25 mg/kg (days 15-16), then 0.125 mg/kg (days 17-18). An air bubble in the injection system expanded into the subretinal space in H3 and vector administration was deferred because it was felt the vector would be displaced by the subretinal air. The injection system was amended in order to allow more controlled infusion of vector into the subretinal space and reduce the possibility of trapped air bubbles. The protocol allowed for deferred vector administration if indicated for surgical reasons and H3 was brought back for retinal gene therapy at a later date when the full dose of vector was administered without complication.
To aid visualizing the retinal detachment and monitor retinal stretch, intra-operative optical coherence tomography (OCT) imaging was introduced in H3-7. This comprised a vertically aligned Heidelberg Spectralis that was moved in and out of the operating field at various stages to assess the plane of subretinal injection and degree of retinal stretch.
In choroideremia, unlike many other retinal degenerations, loss of the RPE leads to a scarring reaction of the underlying choroid which then becomes firmly adherent to the residual retina. The central island of functional retina however remains intact and a tissue plane for vector administration between RPE and photoreceptors can be identified within it. If however fluid is injected into this plane too quickly, then the developing fluid bleb will form a tight bubble and stretch the central retina, because the peripheral scar tissue will prevent subretinal fluid from propagating outwards into the retinal periphery. This retinal stretch reaction has two negative consequences. First it may directly damage the neurosensory retina—in C1 the papillomacular bundle was subject to stretch as reported previously, because the outer nuclear layer was deficient in this area making it thinner than the central retina and subject to more stretch at a given pressure according to Hooke's Law. Second a higher fluid pressure in the bleb will result in reflux of vector suspension back through the widened retinotomy into the vitreous, thereby reducing the therapeutic dose delivered and increasing the risk of inflammation. Hence following the complication in C1 in which the vector was injected manually from a 1 ml syringe, a new vector administration device was designed and tested, which allowed a precise foot-pedal controlled slow infusion of the vector. This was used successfully in H3-7 in whom vector administration was uncomplicated. A bubble of heavy liquid, perfluoro-n-octane (Bausch & Lomb, Rochester, N.Y., USA) was used to stabilize focal areas of retinal thinning in P10 and P11 during vector infusion.
Visual function was assessed with best-corrected visual acuity (BCVA) according to the Early Treatment for Diabetic Retinopathy Study (ETDRS) protocol. In addition, Pelli-Robson contrast sensitivity testing was performed at baseline, 1 year and 2 years. Microperimetry testing using the MAIA microperimeter (CenterVue SpA, Padova, Italy) followed the protocol described previously [MacLaren et al., 2014] except in H3-7, standard non-customized 20° (38 stimuli) central grids were used. For participants with profound visual field restriction who could achieve barely detectable or 0 dB mean threshold sensitivities on the 20° grids (H4-6), a 10° central grid was used instead. Following subjective reports of improved color vision in L3, color vision assessment using the Farnworth-Munsell 100 hue (FM100) test was added in the protocol change and included in H1-7. While further subjective descriptions of improved color perception in the treated eye were reported by H2, H5, H6 and H7, the test proved difficult to perform in patients with advanced visual field loss. Anatomical assessments included spectral domain optical coherence tomography (OCT) using the Spectralis (Heidelberg Engineering, Heidelberg, Germany) and fundus autofluorescence (AF) imaging (BluePeak, Heidelberg Engineering). Immunology tests to assess T-cell responses to AAV (ELISpot) followed the methodology described previously [MacLaren et al., 2014].
Due to the ceiling effects of including eyes with near maximal visual acuity in the study, the ETDRS scores were found to be skewed (Shapiro-Wilk normality test at 0.05 alpha) and are therefore presented as median values with interquartile ranges (IQR). Changes between treated and control eyes were compared using the Wilcoxon signed rank test. Microperimetry data and anatomical assessments were found to be normally distributed and compared using the paired t-test.
In total 14 patients were recruited, 13 of whom received either 1×1010 gp (L1-5) or 1×1011 gp (C2 and H1-7) of the AAV.REP1 vector (Table 59). There were significant adverse events (AEs) relating to vector administration in two patients: C1 and C2. In C1, a surgical complication resulted in retinal thinning and the vector administration was under-dosed. In C2, there was significant retinal inflammation at 2 weeks post-operatively that was most likely related to the vector. In H3 a subretinal air bubble prevented vector administration at the first attempt, but secondary vector delivery was successful without complication at a later date. The change in protocol, particularly with regard to the surgery, has been designed to reduce the chance of these adverse events occurring in the future. The ethics committee approved the recruitment of two further patients, thereby providing 12 patients treated as per the protocol with two year follow up, including 5 at lose-dose (L1-5) and 7 at high-dose (H1-7).
All participants are Caucasian males with genetically confirmed choroideremia and are listed in order of undergoing gene therapy surgery. L1-5 and H1-7 underwent uncomplicated gene therapy at the low dose and high dose, respectively. The surgery in C1 was complicated by retinal stretch resulting in underdosing. C2 developed marked post-operative intra-ocular inflammation, which led to an acute reduction in visual acuity followed by slow rebound once the inflammation had resolved.
Assessments of Visual Acuity
In total, 12 received the AAV.REP1 vector by subretinal injection without complications and 2 were treated off-protocol as a result of adverse events. At the 2 years trial end-point, the median visual acuity in the 14 treated eyes had improved by 4.5 letters (IQR: −2.0 to 8.8) and in the 14 untreated eyes had declined by −1.5 letters (IQR: −5.0 to 0.0). Hence favoring the treated eyes overall, despite significant complications in 2 patients (Wilcoxon Signed rank test, W=68, z=2.12, p=0.034). Hereafter, for the purpose of evaluating efficacy of the investigational medicinal product (IMP), the 12 patients receiving the gene therapy treatment as per protocol (L1-5 and H1-7) are reported separately to the 2 patients with surgical or medical complications (C1 and C2).
Due to the delay midway through the trial to optimize the surgical technique, the first 5 patients (L1-5) have 5 years of follow-up whereas the last 5 (H3-7) have only recently reached the 2 years follow-up, with intermediate follow-up periods in between. The data are therefore presented in two ways: the first is across all 12 patients at 2 years, as per the original end-point defined in the protocol and the second is the last point of follow-up, for which L1-5 and H1-2 extend beyond 2 years.
By 2 years, the median visual acuity improved by 5.5 letters (IQR: 2.5 to 9.0) in the 12 treated eyes (Wilcoxon signed rank test, W=60, z=2.33, p=0.020). In contrast, there was a small loss of −1.0 letters (IQR: −5.0 to +1.0) in the untreated eyes over this period (Table 60 and
By the last follow up, visual acuity had been maintained or increased in all 12 treated eyes that had received gene therapy, but 8 of the 12 untreated eyes had deteriorated by variable amounts during this period. Visual acuity is a biological reading that is variable, but testing was performed in a standard manner and none of the untreated eyes had gained more than one line (>5 letters) by 24 months. In contrast, 6 of the 12 treated eyes (50%) gained more than one line by 24 months. Compared with the untreated eye, gains of two lines or more were seen in 4 of 12 patients at 24 months (Table 60: Bold). This increased further to 6 of 12 (50%) by the last follow up with 4 of these having a gain of three lines or greater (≥15 letters) in favor of the treated eyes (Table 60: Bold). At the last follow-up, the visual acuity in the treated eye had improved relative to the untreated eye in every one of the 12 patients (median=8.5 letters, IQR: 4.0 to 18.5), equivalent to a mean gain of 15.9 letters (>3 lines) in favor of the eyes receiving gene therapy
14
14
10
23
17
83
23
11
10
23
17
Microperimetry assesses mean retinal sensitivity across a wider area of the macula than visual acuity, but takes longer to perform and requires concentration, particularly for patients with poor fixation [Jolly et al., 2017]. The mean retinal sensitivity in the treated eyes was 4.0±0.7 decibels (dB) at baseline and 3.3±0.6 at 2 years, representing a small statistically insignificant decline (p=0.07). In contrast, the untreated eyes fell significantly from 4.8±0.8 dB at baseline to 3.3±0.7 dB at 2 years (p=0.004). Although there was a relative gain favoring the treated eyes over the untreated eyes of 0.8±0.53 dB (95% CI: −0.3 to 1.8 dB) at the 2 year study endpoint, it was not statistically significant (p=0.17). The data and interim analysis at 1 year are shown in
Microperimetry also provides useful information about fixation, that is, the retinal locus that has maximal sensitivity (usually the fovea). All patients except L1 still retained some degree of foveal or parafoveal fixation, consistent with the centripetal nature of visual field loss in this disease. It was previously noted that L1 changed his fixation (or preferred retinal locus) to use this treated island, whilst bypassing the untreated island of retina. This was maintained up to 5 years in this patient, consistent with the sustained improvement in visual acuity.
Preservation of retinal structure: Anatomical assessments included optical coherence tomography (OCT), which gives a cross-sectional view to measure retinal thickness and autofluorescence, which generates a map that can be used to estimate the surviving retinal area. The eyes were not randomized, with the more advanced eye in terms of visual acuity selected for gene therapy in 9 of the 12 study patients (Table 59).
OCT was used primarily for safety to assess retinal thinning that might occur, for instance, from surgical trauma, or if there were a long-term toxic effect from REP1 protein over-expression. The mean thickness of the 12 protocol treated eyes at the point of fixation (as indicated by microperimetry) at baseline was 224.8 μm compared with 251.9 μm in the untreated eyes. By 24 months, the treated eyes have reduced to a mean of 207.7 μm and the untreated to 245.6 μm, which was statistically significant (n=12, p=0.04). Further subgroup analysis however revealed that in the first 7 eyes that received manual injection of vector into the subretinal space (L1-5 & H1-2), retinal thinning was greater in the treated eyes (mean 23.1 μm) than the untreated eyes (6.4 μm) (n=7, p=0.02). However in eyes that received automated injection after improvement to the vector delivery system (H3-7), no significant difference was detected (n=5, p=0.72).
For area measurements, the autofluorescence area is correlated to the area of surviving photoreceptors calculated from multiple slices through the ellipsoid zone. Across the whole group of 12 patients, 81.1±3.2% of autofluorescence area was preserved in the treated eyes, whereas 80.8±2.1% was preserved in the untreated eyes by 2 years, which was similar. It should be noted however that AF shrinkage only occurs from the outer most retinal cells at the leading edge of the degeneration and 2 years is insufficient time to assess the long-term effects of retinal gene therapy on the healthier central zones. Only one patient (H5) had no measureable decline (100% preservation) by 2 years and it was observed in his treated eye only. Long-term (5 year) follow-up of 5 patients showed a similar pattern, with 66.1±5.0% remaining autofluorescence in the treated eyes compared with 64.9±3.6% in the untreated eyes (Table S2B). It should however be noted that this was a mixed picture, with the patients with large visual acuity gains doing far better than others. Furthermore, over this time period significant inter-patient differences in the measured rate of degeneration emerged even in the unoperated eyes, which ranged from 58% to 78%. This highlights the need not to over-interpret a limited non-randomized dataset.
Adverse Events
All patients were enrolled without visually significant cataract at baseline because of the need for a clear view of the 41 gauge retinotomy, but cataract formation is a well-known and almost inevitable side effect of vitrectomy surgery. In 2 participants (H5 and H6), cataract surgery had been performed previously. One patient developed visually-significant cataract which was removed at 1 year after gene therapy (H3) but four other patients (L2, L4, L5, H2) had cataract surgery after completion of the 2 years follow-up. Cataract surgery has not yet been performed in the remaining five patients (L1, L3, H1, H4 and H7), although all have signs of cataract progression on LOCS III cataract grading. Across the whole group of 14 patients and even including the two patients with complications, the visual acuity in the treated eyes improved relative to the untreated eyes over this period. Considering only the 12 patients who underwent uncomplicated retinal gene therapy without protocol deviations, by the 2 year endpoint, the visual acuity had improved in the treated eyes compared to their baseline. At the latest time point analyzed which is up to 5 years, all 12 treated eyes had maintained or gained visual acuity above their baseline levels, despite variable losses in visual acuity in 8 of the 12 untreated eyes during this period. The beneficial effects on visual acuity combined with good safety profile warrant further assessment of choroideremia gene therapy as a potential treatment in a fully randomized prospective Phase III clinical trial (see Example 14).
While there was no significant difference in the visual acuity gains between the low dose or high dose cohorts, it should however be noted that this was a very small study group with only 5 patients treated at the lower (1×1010) dose. Given the heterogeneous nature of the human innate anti-viral immune system, it is likely that a threshold dose may be therapeutic in some, but not all patients. Hence it may be advantageous to treat with a maximal tolerated dose, as long as no toxic effects are seen. The excellent preservation of visual function in the high dose patients over time supports this approach. It is also worth bearing in mind that the patients selected for this study were generally end-stage with very small islands of residual retina and therefore not many remaining retinal cells to treat. The low dose might be insufficient for earlier stage patients in whom a much larger target area would be exposed to vector. It should also be noted that the pharmaceutical formulation used for this study does not comprise a PRE or WPRE element, which may improve therapeutic efficacy.
With the exception of H5, further constriction of the area of autofluorescence in the remaining patients was not consistent with other preclinical models in which improvements in visual function resulting from single gene replacement are invariably associated with slowing of retinal degeneration. Here, however, it is important to bear in mind that the advancement of degeneration measured over the 2 year time frame is only at the extreme edges of the retinal degeneration and this part may be too advanced for rescue. The visual acuity gains in contrast arose mainly from the central retina. Also the retina in choroideremia is difficult to detach beyond the edges of the surviving retina resulting in stretching of the overlying bleb. The concave shape of the subretinal space will increase the height of the bleb centrally, which will therefore be the last part of the retina to reattach as the fluid is reabsorbed. This could potentially provide the central retina with several additional hours of exposure to the vector compared with the extreme periphery. Finally it should be noted that the eyes were not randomized and inter-eye differences in the area of surviving retina seen in some patients at baseline is indicative of asymmetric rates of degeneration. By treating the worse eye, there will by definition be a bias towards treating the eye with the more rapid degeneration.
Whilst visual acuity was maintained or increased in all treated eyes throughout the duration of the study, retinal sensitivity measured with microperimetry showed a trend towards decline and although numerically better than the untreated eyes, there was no statistically significant difference between the two. This is most likely due to the increased variability in performing microperimetry compared with reading single letters on a high contrast eye chart. Nevertheless the tests do have subtle differences in what they measure. Microperimetry assesses retinal function from many points averaged out over 10-30 degrees of central retina, whereas visual acuity is a measurement taken from a single point that generally has maximal sensitivity and is centrally located. Maintaining retinal sensitivity therefore is improved from a successful transduction of the entire area being measured right up to the edges of the surviving retina. For instance, if only 20% of retinal pigment epithelial cells centrally are successfully transduced by the vector, then this might be sufficient to see a visual acuity gain if these cells are beneath the fovea. The remaining 80% of non-transduced cells however would continue to degenerate and this decline would be reflected in a gradual decline in microperimetry over time, but visual acuity would remain stable. If however gene therapy is successful in stopping the degeneration in the areas successfully transduced, then eventually only the transduced cells would remain and the microperimetry readings would then stabilize to remain constant over time. This ‘plateau’ effect is now emerging in L1 who has also maintained his visual acuity gain and who has the longest follow up. Alternatively it might be a simple factor that retinal sensitivity measured by microperimetry is more sensitive to cataract formation than high contrast visual acuity. At the 2 year post-vitrectomy time point, only one of the 10 phakic protocol-treated patients had undergone cataract surgery.
The success of surgery is a critical factor when interpreting outcomes in this and any other gene therapy study that involves delivery of vector under the retina. One potentially adverse event of retinal stretch was related to surgery. The other significant adverse event of inflammation might equally be related to surgery if during the injection there was reflux of vector into the vitreous, which is known to trigger inflammation. Following the protocol change midway through the trial, an automated system of subretinal injection was adopted that allowed precise and controlled delivery of vector into the subretinal space. This was further facilitated by intra-operative retinal scanning (OCT) which provided a real time cross-sectional image of the retina being detached and helped identify the subretinal space in some of the more advanced patients. These additional surgical refinements will improve safety in future gene therapy studies. Nevertheless the results of this Phase I/II clinical trial show that gene therapy for choroideremia is generally safe.
This is a multi-centre, open-label, prospective, bilateral interventional safety study of AAV2-REP1 in adult male subjects with genetically confirmed CHM.
The study will consist of a Screening Visit followed by 2 treatment periods (Period 1 and Period 2) with up to 9 visits per period (
At Period 1, Visit 1 (Day 0, Injection Day Visit for SE1), subjects undergo a vitrectomy with retinal detachment and receive a sub-retinal injection of AAV2-REP1 in SE1. Visits 2-9 are conducted according to the Schedule of Study Procedures, unless Period 2 commences during this time. Ophthalmic assessments during Period 1, Visits 2-9 are performed on both eyes.
At Period 2, Visit 1 (Day 0, Injection Day Visit for SE2) subjects undergo a vitrectomy with retinal detachment and sub-retinal injection of AAV2-REP1 in the contralateral, untreated eye (SE2). Subjects no longer follow the Period 1 visit schedule, but instead attend Period 2, Visits 2-9 according to the Schedule of Study Procedures. Ophthalmic assessments scheduled for Period 2, Visits 2-9 will be performed on both eyes.
Subjects are assessed for safety and efficacy throughout the study; assessments are outlined in the Schedule of Study Procedures. Subjects who develop cataracts may undergo cataract surgery if deemed clinically necessary. If cataract surgery is performed, it is carried out at least 4 weeks before Month 12 (Visit 9) for the respective eye.
The primary endpoint is the evaluation of safety following bilateral administration of AAV2-REP1. Secondary endpoints of the study include a change from baseline in best corrected visual acuity (BCVA) as measured by the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart, a change from baseline in autofluorescence (AF), a change from baseline in spectral domain optical coherence tomography (SD-OCT), and a change from baseline in microperimetry.
Inclusion Criteria:
At the Screening Visit, subjects are eligible for study participation if they meet all of the following inclusion criteria. Inclusion criteria: (1)_are willing and able to give informed consent for participation in the study to have both eyes treated, (2) are male and ≥18 years of age, (3) have a genetically-confirmed diagnosis of CHM, (4) have active disease clinically visible within the macular region of both eyes, (5) have a BCVA of: ≥74 ETDRS letters (equivalent to better than or equal to 6/9 or 20/32 Snellen, decimal 0.63, LogMar 0.2) in both eyes, if no prior treatment with AAV2-REP1≥74 ETDRS letters (equivalent to better than or equal to 6/9 or 20/32 Snellen, decimal 0.63, LogMar 0.2) in the untreated eye, if prior treatment with AAV2-REP1 was received in an alternative study. If previously treated with AAV2-REP1 in an alternative study, subjects may be eligible for participation following Sponsor approval.
Exclusion Criteria:
At the Screening Visit, subjects are not eligible for study participation if they meet any of the following exclusion criteria. Exclusion criteria: (1) have a history of amblyopia or inflammatory disorder in either eye, (2) are unwilling to use barrier contraception methods, for a period of 3 months following treatment with AAV2-REP1 in either eye, (3) have had previous intraocular surgery performed within 3 months of the Screening Visit in either eye, (4) have any other significant ocular or non-ocular disease/disorder which, in the opinion of the investigator, may either put the subjects at risk because of participation in the study, or may influence the results of the study, or the subject's ability to participate in the study, and (5) have participated in another research study involving an investigational product in the past 12 weeks or received a gene/cell-based therapy at any time previously, except if treated within another study with AAV2-REP1. This significant ocular or non-ocular disease/disorder which, in the opinion of the investigator, may either put the subjects at risk because of participation in the study, or may influence the results of the study, or the subject's ability to participate in the study includes but is not limited to a potential subject: a) with a contraindication to oral corticosteroid (e.g. prednisolone/prednisone), b) with clinically significant cataract in either eye, c) who, in the clinical opinion of the Investigator, is not an appropriate candidate for sub-retinal surgery.
Test product, dosage, and mode of administration: For each eye, subjects will undergo vitrectomy and retinal detachment and receive a volume of 0.1 mL sub-retinal injection of study drug containing 1×1011 AAV2-REP1 genome particles.
Criteria for Evaluation: The safety evaluation is based on full ophthalmic examination (including intraocular pressure [IOP], slit lamp examination, lens opacity grading and dilated ophthalmoscopy); fundus photography; adverse event (AE) reporting; vector shedding and immunogenicity sampling; and vital signs.
Efficacy: The efficacy evaluation is based on BCVA (as measured by the ETDRS chart), fundus autofluorescence, SD-OCT and microperimetry.
Statistical Methodology: No formal sample size calculation was performed. Continuous variables are summarized over time using descriptive statistics (i.e., mean, standard deviation, 95% confidence interval [CI], median, Q1, Q3, P05, P95, min, and max). Categorical variables are described over time using counts, percentages, and 95% CIs. Summaries are tabulated by visit and eye. No formal statistical testing is performed. AEs are summarized by system organ class, preferred term and eye. Both the number of subjects and the number of eyes experiencing an AE, as well as the number of events, are summarized. Similar summaries will be produced for study drug/procedure-related AEs, AEs leading to discontinuation, and serious AEs. AEs are also summarized by maximum severity, relationship to study drug/procedure, and time to onset and resolution. Vector shedding and immune response profiles will be described. The remaining safety evaluations are analyzed using descriptive statistics.
CHM is incurable and, prior to the development of the pharmaceutical compositions of the disclosure, treatment was supportive at best. The pharmaceutical composition administered to subjects of this trial, AAV2-REP1 is an AAV2 particle encapsulating 1.962 kB complementary deoxyribonucleic acid (cDNA) of the wild-type human REP1 gene. AAV2-REP1 expresses high levels of human REP1 protein, restores REP1 to human CHM fibroblasts, provides functional rescue of human CHM cells, expresses protein in the retina of CHM mice in vivo, and is non-toxic when over-expressed by one log unit. Further, over-expression of the human REP1 protein does not significantly negatively affect retinal function.
Considering that CHM affects both eyes, this study demonstrates bilateral AAV2-REP1 administration. Emerging data from non-clinical and clinical studies with AAV2 vectors demonstrate that AAV2 vectors illicit a minimal immune response, including after bilateral administration. The aim of this study is to provide important insight into the safety and tolerability of sequential, bilateral treatment with AAV2-REP1.
Treatments Administered
Eligible subjects undergo vitrectomy and retinal detachment in each eye. At Period 1, Visit 1 (Day 0, the Injection Day Visit for SE1), subjects receive a volume of 0.1 mL sub-retinal injection of study drug containing 1×1011 AAV2-REP1 gp in SE1. At Period 2, Visit 1 (Day 0, the Injection Day Visit for SE2), subjects receive the same sub-retinal injection of AAV2-REP1 in SE2.
Description of Pharmaceutical Composition
The AAV2 vector contains recombinant human cDNA encoding REP1 (AAV2-REP1). The vector genome (AAV2-CBA-hREP1-WPRE-BGH) is comprised of a strong constitutive expression cassette, a hybrid CBA promoter, the human cDNA encoding REP1, a modified woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) sequence, and a bovine growth hormone polyadenylation (BGH-polyA) sequence flanked by AAV2 inverted terminal repeats. The cDNA fragment was originally isolated from a human retinal cDNA library from unaffected individuals.
The AAV2-REP1 drug product is formulated in a sterile, 20 mM Tris-buffered solution, pH 8.0, and contains 1 mM MgCl2, 200 mM NaCl and 0.001% PF68. The drug product is a clear to slightly opalescent, colorless, sterile-filtered suspension with a target concentration of 1×1012 gp/mL.
AAV2-REP1 is supplied in sterile vials, stoppered and capped. A total of 0.3 mL vector suspension is supplied for each eye to be treated. Prior to shipment, each vial is placed in a labeled secondary container. The drug product is to be stored at <−60° C. (<−76° F.) in a controlled access, temperature monitored freezer.
Vitrectomy Procedure and Injection of AAV2-REP1
Injection of AAV2-REP1 is performed by an appropriately qualified and experienced retinal surgeon. Due to the complexity and unpredictability of detaching the retina in CHM, in which the retina and choroid can be extremely thin and fused in places, a modification to the technique of sub-retinal gene therapy has been developed. This involves performing the vector delivery in 2 steps after vitrectomy. An advantage of a 2-step procedure is that any unexpected complications of retinal detachment can be managed conservatively, minimizing concerns about the vector escaping into the vitreous. Further, the injection could be deferred until a later date if, for instance, a macular hole was created which required treatment with gas. Also, since the volume of fluid required to detach the fovea is variable, by removing the vector from the first step, a precise consistent dose in terms of genome particles can still be applied into the sub-retinal space.
Initially, subjects undergo a standard vitrectomy and detachment of the posterior hyaloid in the respective study eye (
In the second step of the procedure, the BSS cannula is removed from the eye and AAV2-REP1 is prepared for injection. A dose of 1.0×1011 AAV2-REP1 gp is injected into the sub-retinal space through the same entry site. The vector needs to be primed in the 1 mL syringe to avoid formation of air bubbles, and a connector is used so that the 1 mL syringe can be connected to the constant pressure line of the vitrectomy machine. The subretinal injection will target any area of the macula but also include the fovea if possible. In each case, the vector is injected so that the sub-retinal fluid overlies all edge boundaries of the central region that has yet to undergo chorioretinal degeneration, as identified by fundus autofluorescence. After wound closure, care is taken to dispose of all irrigating fluids that may have passed through the eye to limit potential vector spread.
Concomitant Therapy:
Subjects cannot have participated in another research study involving an investigational product in the past 12 weeks or received a gene/cell-based therapy at any time previously, except if treated within another study with AAV2-REP1. Throughout the study, investigators may prescribe any concomitant medications or treatments deemed necessary to provide adequate supportive care. Details of concomitant medications are collected at the Screening Visit and updated at every study visit (including the ET Visit, if applicable). Concomitant medications (including oral corticosteroid) taken during the study are to be recorded in the subject's medical records and eCRF; an exception to this is any medication used in the course of conducting a study procedure (e.g., anaesthesia, dilating eye drops).
To minimize inflammation resulting from surgery and potential or unexpected immune responses to vector/transgene, all subjects will be given a 21-day course of oral prednisone/prednisolone prior to each surgery. Hence, for each surgery, this would be 1 mg/kg/day prednisone/prednisolone for a total of 10 days (beginning 2 days before vector injection, on the day of injection, and then for 7 days); followed by 0.5 mg/kg/day for 7 days; 0.25 mg/kg/day for 2 days; and 0.125 mg/kg/day for 2 days (21 days in total). Details of corticosteroid usage are captured by each subject in a diary card.
Study Procedures
At each study visit, an attempt should be made to perform all procedures in both eyes.
Screening Visit
The investigator explains the study purpose, procedures and subject responsibilities to each potential study subject. Screening procedures will consist of the following (all ophthalmic assessments will be conducted on both eyes): Demography, medical and ocular history, Vital signs, Weight, Vector shedding sampling—blood, tears (both eyes), urine, saliva, Immunogenicity sampling (enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunospot [ELISPOT]), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, Microperimetry, 7-field color fundus photography (including stereo photographs for fields 1, 2, and 3), Serious AE (SAE) monitoring, Medication review.
Subjects who meet all of the inclusion criteria and none of the exclusion criteria will are assigned a subject number and enrolled into the study. The investigator assigns the order in which the eyes are treated (i.e., SE1 and SE2, respectively). This will be done in collaboration with the subject; however, the worse eye is generally be selected for treatment first. The target interval between the surgical procedure in SE1 and SE2 is determined at this visit.
For each subject, the interval between SE1 and SE2 treatment is expected to range from a few weeks to months. While this interval is decided on a case-by-case basis, an effort should be made to schedule varying treatment intervals (e.g. 1, 3 or 6+ months apart) in order to better characterize the immunological and safety profile of sequential treatment administration.
The next study visit (Period 1, Visit 1) is to be scheduled within 10 weeks of the Screening Visit. Subjects will attend Period 1 Visits 2-9 unless the second surgery visit (Period 2, Visit 1) begins, which will mark the start of study Period 2. Given that the timing of the second surgery visit (Period 2, Visit 1) will vary between subjects, the duration of study Period 1 will also be variable.
Subjects are given two 21-day courses of oral corticosteroid (e.g., prednisolone/prednisone) and instructed to start taking the drug 2 days before their next surgery, at Period 1, Visit 1 for SE1 and Period 2, Visit 1 for SE2. Subjects will be issued a diary card to capture corticosteroid compliance throughout each 21-day period. Subjects are instructed to use barrier contraception for a period of 3 months from the time they are treated.
The schedule of procedures is identical for Periods 1 and 2; during each period, procedures are to be conducted in both SE1 and SE2.
If a subject has previously participated in a clinical trial of AAV2-REP1 for the treatment of CHM and has received AAV2-REP1 in one eye, the untreated eye will be assigned as SE2 at the Screening Visit and the subject will immediately enter Period 2.
Period 1 and 2, Visit 1 (Day 0, Injection Day Visit)
At Visit 1 (Day 0, Injection Day Visit), the following assessments are performed: Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), AE/SAE monitoring, and concomitant medication review (including review of the corticosteroid diary card).
Subjects then undergo vitrectomy and receive a volume of 0.1 mL sub-retinal injection of AAV2-REP1, containing 1×1011 gp in their first (SE1) eye.
Subjects are carefully monitored for the occurrence of AEs during the procedure. Subjects return to the site 1, 3, 7 and 14 days after surgery for post-operative follow-up (Visit 2 [Day 1], Visit 3 [Day 3], Visit 4 [Day 7] and Visit 5 [Day 14], respectively).
To allow accurate characterization of AAV2-REP1 safety and immunogenicity profile, treatment of SE2 should not occur if a previous intraocular surgery was performed on the same eye within 3 months of the planned treatment date. If intraocular surgery has occurred within 3 months, treatment of SE2 should be delayed until such a time that the 3-month interval has elapsed and there is complete post-operative recovery of the eye.
Period 1 and 2, Visit 2 (Post-Operative Visit on Day 1)
For Visit 2, ocular assessments and procedures are performed on each eye. At Visit 2 (Day 1), subjects return to the site for their first post-operative visit for the same eye that underwent surgery at Visit 1 (Period 1 [SE1] or Period 2 [SE2]). The following assessments are performed: Vital signs, Vector shedding sampling—blood, tears (both eyes), urine, saliva, Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, AE/SAE monitoring, Medication review (including review of the corticosteroid diary card).
Period 1 and 2, Visit 3 (Day 3)
For Visit 3 (Day 3), ocular assessments and procedures are performed on each eye. At Visit 3 (Day 3), subjects return to the site for their second post-operative visit for the same eye that underwent surgery at Visit 1 (Period 1 [SE1] or Period 2 [SE2]). The following assessments will be performed: Vital signs, Vector shedding sampling—blood, tears (both eyes), urine, saliva, BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), AE/SAE monitoring, and Medication review (including review of the corticosteroid diary card).
Period 1 and 2, Visit 4 (Day 7)
For Visit 4 (Day 7±1 day), ocular assessments and procedures are performed on each eye. At Visit 4 (Day 7±1 day), subjects return to the site for their third post-operative visit for the same eye that underwent surgery at Visit 1 (Period 1 [SE1] or Period 2 [SE2]). The following assessments will be performed: Vector shedding sampling—blood, tears (both eyes), urine, saliva, Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, AE/SAE monitoring, and Medication review (including review of the corticosteroid diary card).
Period 1 and 2, Visit 5 (Day 14)
For Visit 5 (Day 14±3 days), ocular assessments and procedures are performed on each eye. At Visit 5 (Day 14±3 days), subjects return to the site for their fourth postoperative visit for the same eye that underwent surgery at Visit 1 (Period 1 [SE1] or Period 2 [SE2]). The following assessments will be performed: Vector shedding sampling—blood, tears (both eyes), urine, saliva, Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, AE/SAE monitoring, and Medication review (including review of the corticosteroid diary card)
Period 1 and 2, Visit 6 (Month 1) and Visit 7 (Month 3)
For Visit 6 (Month 1±7 days) and Visit 7 (Month 3±14 days), ocular assessments and procedures will be performed on each eye. The following assessments are performed: Vector shedding sampling—blood, tears (both eyes), urine, saliva, Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, Microperimetry, AE/SAE monitoring, and Medication review (including review and return of the corticosteroid diary card).
Period 1 and 2, Visit 8 (Month 6) and Visit 9 (Month 12)
For Visit 8 (Month 6±14 days) and Visit 9 (Month 12±14 days), ocular assessments and procedures are performed on each eye. The following assessments are performed: Vital signs (Visit 9, Month 12 only), Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, Microperimetry, -field color fundus photography (including stereo photographs for fields 1, 2, and 3) (Visit 9, Month 12 only), AE/SAE monitoring, and Medication review.
Early Termination
In the event that a subject discontinues the study at any time, the site should use every reasonable effort to ensure that an ET Visit is conducted. The following assessments should be performed (all ophthalmic assessments will be conducted on both eyes): Vital signs, Vector shedding sampling—blood, tears (both eyes), urine, saliva (only if the ET Visit occurs within 3 months post-treatment), Immunogenicity sampling (ELISA and ELISPOT), BCVA, Full ophthalmic examination (including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination), SD-OCT, Autofluorescence, Microperimetry, 7-field color fundus photography (including stereo photographs for fields 1, 2, and 3), AE/SAE monitoring, and Medication review.
Adverse Event
An AE is any untoward medical occurrence in a clinical investigation subject, which does not necessarily have a causal relationship with the study medication/surgical procedure. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study medication/surgical procedure, whether or not related to the investigational product or with the surgical procedure described in this protocol. AEs are to also include any pre-existing condition (other than CHM) or illness which worsens during the study (i.e., increases in frequency or intensity).
Serious Adverse Event
An SAE is defined as any untoward medical occurrence that: Results in death, Is life-threatening, Requires inpatient hospitalization or prolongation of existing hospitalization, Results in persistent or significant disability/incapacity, Is a congenital anomaly/birth defect, Results in vision loss or is vision threatening, Is another important medical event(s). The term ‘life-threatening’ in the definition of ‘serious’ refers to an event in which the subject is at risk of death at the time of the event. It does not refer to an event that hypothetically might cause death if it were more severe. Hospitalization for a pre-existing condition, including elective procedures, which has not worsened, does not constitute an SAE. Other events that may not result in death, are not life threatening or do not require hospitalization, may be considered an SAE when, based upon appropriate medical judgment, the event may jeopardize the subject and may require medical or surgical intervention to prevent one of the outcomes listed above.
The following vision loss or vision-threatening events are to be reported as SAEs: Sustained decrease in VA of ≥15 letters on ETDRS chart compared to baseline, except for surgery-related events. Sustained is defined as lasting 48 hours or more until recovery; recovery defined as VA returned to within 5 letters of baseline VA.
Surgery-related events of VA decrease are defined as VA decreases occurring in close temporal association (within <24 hours) with the surgical administration of the study medication, and which are resolving at Day 7 (Period 1/2, Visit 4) post-surgery. These events are not to be reported as an AE or SAE. However, they should be reported as an AE if in the investigator's opinion, their evolution in terms of duration or severity cannot be explained by the procedure. This would include, but not be limited to instances where the abnormal course of post-surgery VA decrease is associated with another complication attributable to the surgery or the study medication, or where the abnormal course of post-surgery VA decrease can be attributed to another identifiable cause. AEs that in the opinion of the investigator, actually or potentially require any surgical or medical intervention to prevent permanent loss of sight.
Laboratory Assessments
Vector Shedding
Blood, tears (both eyes), urine and saliva samples are collected and tested using an appropriate assay for evidence of vector shedding and dispersion.
Immunogenicity
For the evaluation of immunogenicity, blood will be collected at the times indicated in Table 61 (Schedule of Study Procedures). Immunoassays are planned to assess antibody and cell based responses against AAV2-REP1. ELISPOT assays will be used for T-cell mediated immune responses to transgene, and antibody responses will be assayed using ELISA-based methods.
Vital Signs
Vital signs (pulse and systolic and diastolic blood pressure) will be taken at the times indicated in Table 61 (Schedule of Study Procedures). Vital signs should be taken after the subject is seated for at least 5 minutes.
Full Ophthalmic Examination
A full ophthalmic examination will be performed for both eyes at the times indicated in Table 61 (Schedule of Study Procedures). Each ophthalmic examination will include IOP, slit lamp examination, lens opacity grading, and dilated ophthalmoscopy. The same slit lamp machine and lighting conditions should be used across study visits for any given subject. In addition to the parameters listed above, subjects are carefully examined for the presence of intraocular inflammation after vector administration. Cataract can also develop as a result of the vitrectomy procedure and can potentially affect VA. Pre-operative grading of lens opacity and color should therefore be documented. Subjects who develop cataracts may undergo cataract surgery if deemed clinically necessary. If cataract surgery is performed, it should be carried out at least 4 weeks before Month 12 (Visit 9) for the respective eye.
7-Field Color Fundus Photography
Seven-field color fundus photography will be performed for both eyes at the times indicated in Table 61 (Schedule of Study Procedures). Fundus photography will be performed by certified technicians following pupil dilation. Stereo photos should be performed for fields 1, 2 and 3. All fundus photographs will be sent by the sites to the Central Reading Centre (CRC) for review; the CRC will enter the data into the electronic data capture (EDC) system. For complete technical specifications for fundus photography, refer to the Study Operations Manual (which will include procedures from the CRC regarding how measurements are to be taken).
Assessment of Efficacy
Visual Acuity
To evaluate changes in visual acuity (VA) over the study period, BCVA is assessed using the ETDRS VA chart and performed for both eyes at the times indicated in Table 61 (Schedule of Study Procedures). The BCVA test should be performed prior to pupil dilation, and distance refraction should be carried out before BCVA is measured. Initially, letters are read at a distance of 4 meters from the chart. If <20 letters are read at 4 meters, testing at 1 meter should be performed. BCVA is to be reported as number of letters read correctly by the subject. For BCVA, assessors will be appropriately qualified for conducting the assessment.
Fundus Autofluorescence
To assess changes in the area of viable retinal tissue, fundus autofluorescence is performed on both eyes at the times indicated in Table 61 (Schedule of Study Procedures).
Spectral Domain Optical Coherence Tomography (SD-OCT)
SD-OCT are performed on both eyes at the times indicated in Table 61 (Schedule of Study Procedures). SD-OCT is used to quantify integrity of the ellipsoid zone and reduction in the signal from the outer nuclear layer and choroid. In addition, foveal changes are assessed.
Microperimetry
Microperimetry is conducted on both eyes at the times indicated in Table 61 (Schedule of Study Procedures). Microperimetry is conducted to assess changes in retinal sensitivity within the macula.
indicates data missing or illegible when filed
This study is an open label, outcomes-assessor masked, prospective, randomized, parallel controlled group, multi-center, global, interventional study. The study consists of 8 visits with a 12-month evaluation period. At the Screening/Baseline Visit, each subject is assessed for eligibility. For eligible subjects a study eye are assigned, and the subjects are randomized in a 2:1:2 ratio to receive either AAV2-REP1 high dose (1.0×1011 genome particles [gp]), AAV2-REP1 low dose (1.0×1010 gp) or to enter the untreated Control group.
At the Injection Day Visit (Visit 2, Day 0), subjects in the AAV2-REP1 high and low dose treatment arms undergo vitrectomy and receive a sub-retinal injection of the assigned treatment dose of AAV2-REP1 in their study eye in a double-masked manner; these subjects then return to the site for 2 post-operative follow up visits on Day 1 (Visit 3) and Day 7 (Visit 4). Subjects in the Control group do not undergo surgery, receive any study drug in their study eye (i.e., Control-study eye) or attend the 2 on-site post-operative visits. Instead a telephone contact from the site occurs for the Control group on Day 0 (Visit 2), Day 1 (Visit 3) and Day 7 (Visit 4). All subjects are followed for 12 months from Visit 2 (Day 0).
Study data are collected for both eyes of each subject. Since AAV2-REP1 treatment requires an invasive surgical procedure under general anaesthesia, the sponsor, investigator and the subject are unmasked to the study procedure (i.e., vitrectomy and sub-retinal injection), however within the treated groups, the sponsor, investigator and subject is masked to the assigned dose (1.0×1011 gp or 1.0×1010 gp). To further minimize potential bias of the treated and non-treated eye evaluations, all subjective ophthalmic assessments at the Screening/Baseline Visit (Visit 1) and from Month 1 (Visit 5) onwards (including the Month 12 Primary Endpoint evaluation) will be conducted by a masked assessor.
Subjects are assessed for efficacy and safety throughout the study as indicated in the Schedule of Study Procedures. Subjects who develop cataracts may undergo cataract surgery if deemed clinically necessary; if surgery is performed, it should be carried out at least 4 weeks before the Month 12 Visit/End of Study (EOS) Visit.
Subjects
Approximately 140 subjects randomized in a 2:1:2 ratio; 56 subjects in the AAV2-REP1 high dose (1.0×1011 gp) group, 28 subjects in the AAV2-REP1 low dose (1.0×1010 gp) and 56 subjects in the untreated control group.
Inclusion Criteria: Subjects are eligible for study participation if they meet all of the following inclusion criteria: (1) are willing and able to give informed consent for participation in the study, (2) are male and ≥18 years of age, (3) have a genetically-confirmed diagnosis of CHM, (4) have active disease clinically visible within the macular region in the study eye, (5) have a BCVA of 34-73 ETDRS letters (equivalent to worse than or equal to 6/12 or 20/40 Snellen acuity, but better than or equal to 6/60 or 20/200 Snellen acuity) in the study eye.
Exclusion Criteria: Subjects are not eligible for study participation if they meet any of the following exclusion criteria: (1) have a history of amblyopia in the eligible eye, (2) are unwilling to use barrier contraception methods, for a period of 3 months, if treated with AAV2-REP1, (3) previous intraocular surgery performed in the study eye within 3 months of Visit 1, (4) have any other significant ocular or non-ocular disease/disorder which, in the opinion of the investigator, may either put the subjects at risk because of participation in the study, or may influence the results of the study, or the subject's ability to participate in the study (including, but not limited to, a contraindication to oral corticosteroid (e.g. prednisolone/prednisone), with a clinically significant cataract, who, in the clinical opinion of the Investigator, is not an appropriate candidate for sub-retinal surgery), and (5) have participated in another research study involving an investigational product in the past 12 weeks or received a gene/cell-based therapy at any time previously.
Test product, dosage, and mode of administration: All subjects receiving active treatment undergo vitrectomy and receive a volume of 0.1 mL sub-retinal injection of study drug containing either high dose (1.0×1011 gp) AAV2-REP1 or low dose (1.0×1010 gp) AAV2-REP1 in their study eye.
Criteria for Evaluation:
The primary efficacy endpoint is the proportion of subjects with a ≥15-letter improvement from Baseline in best corrected visual acuity (BCVA) at Month 12 as measured by the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart. The key secondary endpoint is the proportion of subjects with a ≥15-letter improvement from Baseline in BCVA at Month 12 when compared with the change in BCVA over 12 months. Other secondary endpoints include (1) proportion of subjects with a >10 letter increase from Baseline in BCVA at Month 12, (2) mean of the mean change from Baseline in BCVA collected over Months 4, 8 and 12, (3) change from baseline in total area of preserved autofluorescence (AF) at Month 12, (4) change from baseline in the area of preserved ellipsoid zone (spectral domain optical coherence tomography [SD-OCT]) at Month 12, (5) change from baseline in microperimetry at Month 12, (6) change from baseline in contrast sensitivity score at Month 12, (7) change from baseline in color vision at Month 12, (8) change from baseline in reading speed test at Month 12, (9) maintenance of BCVA at Month 12, as measured by the ETDRS chart, (10) change from baseline in the 25-item Visual Function Questionnaire (VFQ-25) at Month 12. An exploratory efficacy endpoint includes tan evaluation of other anatomical and functional outcome measures. A safety endpoint includes an evaluation of safety assessments, including adverse events (AEs).
Efficacy: The efficacy evaluation are based on BCVA, fundus AF, SD-OCT, microperimetry, contrast sensitivity, color vision, reading speed test assessments, VFQ-25 and low luminance visual acuity (LLVA).
Safety: The safety evaluation are based on full ophthalmic examination (including intraocular pressure, slit lamp examination, lens opacity grading, and dilated ophthalmoscopy), fundus photography, AE reporting, immunogenicity, and vital signs. Any safety information collected as a result of the efficacy assessments (e.g., BCVA) is used in the overall safety evaluation, as appropriate.
Study Design
At the Screening/Baseline Visit (Visit 1), each subject is assessed for eligibility of both eyes. If a subject has only 1 eligible eye, that eye is designated as the “study eye” and the subject's other (non-eligible) eye is designated as the “fellow eye.” If a subject has 2 eligible eyes, the selection of the “study eye” is made on clinical grounds and is generally be the worse eye affected. This decision is discussed in detail and agreed with each subject as part of the informed consent process. Subject choice is considered in cases where the degeneration is relatively symmetrical between the two eyes.
At the Screening/Baseline Visit, eligible subjects will be randomized in a 2:1:2 ratio to either the AAV2-REP1 high dose group (1.0×1011 gp), the AAV2-REP1 low dose group (1.0×1010 gp) or the untreated Control group. To facilitate understanding of the study design, eyes are classified into 4 categories based on treatment group assignment and designation of study/fellow eye: AAV2-REP1-study eye (includes high and low dose); AAV2-REP1-fellow eye (includes high and low dose); Control-study eye; and Control-fellow eye.
At the Injection Day Visit (Visit 2, Day 0), subjects in the AAV2-REP1 treatment groups undergo vitrectomy and retinal detachment before receiving a sub-retinal injection of AAV2-REP1 high dose (1.0×1011 gp) or AAV2-REP1 low dose (1.0×1010 gp) in their study eye (i.e., AAV2-REP1-study eye) in a double-masked manner; these subjects then return to the site for 2 post-operative follow up visits on Day 1 (Visit 3) and Day 7 (Visit 4). Subjects in the Control group does not undergo surgery, receive study drug or attend the 2 on-site safety post-operative visits. Instead a telephone contact from the site occurs for the Control group on Day 0 (Visit 2), Day 1 (Visit 3) and Day 7 (Visit 4). All subjects are followed for 12 months from Visit 2 (Day 0).
Study data are collected for both eyes of each subject. Since AAV2-REP1 treatment requires an invasive surgical procedure under general anaesthesia, the sponsor, investigator and the subject are unmasked to the study procedure (i.e. vitrectomy and sub-retinal injection), however within the treated groups, the sponsor, investigator and subject are masked (i.e. double-masking) to the assigned dose (1.0×1011 gp or 1.0×1010 gp). To further minimize potential bias of the treated and non-treated eye evaluations, all subjective ophthalmic assessments at the Screening/Baseline Visit (Visit 1) and from Month 1 (Visit 5) onwards, are conducted by a masked assessor. Subjects are assessed for efficacy and safety throughout the study. The efficacy evaluation is based on BCVA, fundus AF, SD-OCT, microperimetry, contrast sensitivity, color vision, reading speed test, VFQ-25 and low luminance visual acuity (LLVA). The safety evaluation is based on full ophthalmic examination (including intraocular pressure [IOP], slit lamp examination, lens opacity grading, and dilated ophthalmoscopy), fundus photography, adverse event (AE) reporting, laboratory assessments (immunogenicity), and vital signs. Any safety information collected as a result of the efficacy assessments (e.g., BCVA) is used in the overall safety evaluation, as appropriate.
Subjects who develop cataracts may undergo cataract surgery if deemed clinically necessary; if surgery is performed, it should be carried out at least 4 weeks before the Month 12 Visit/End of Study (EOS) Visit (primary endpoint).
A subject is considered to have completed the study if he completes the Month 12 assessments. The end of the trial is the date the last subject completes his Month 12 assessments (or early termination [ET] assessments in the event of premature discontinuation) or the date of last data collection if the last subject is lost to follow-up. After study completion, treated subjects are invited to participate in a long term follow up study which permits continued efficacy and safety monitoring over a period of 5 years post-treatment.
Treatments Administered
At the Screening/Baseline Visit, eligible subjects are randomized in a 2:1:2 ratio to receive either an AAV2-REP1 low dose (1.0×1010 gp) or an AAV2-REP1 high dose (1.0×1011 gp), while subjects in the untreated Control group receive no sham surgery or study medication. At the Injection Day Visit (Visit 2, Day 0), AAV2-REP1 is administered as a sub-retinal injection after vitrectomy for subjects in the AAV2-REP1 groups.
Description of Pharmaceutical Composition
The AAV2 vector contains recombinant human cDNA encoding REP1 (AAV2-REP1). The vector genome (AAV2-CBA-hREP1-WPRE-BGH) is comprised of a strong constitutive expression cassette, a hybrid CBA promoter, the human cDNA encoding REP1, a modified woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) sequence, and a bovine growth hormone polyadenylation (BGH-polyA) sequence flanked by AAV2 inverted terminal repeats. The cDNA fragment was originally isolated from a human retinal cDNA library from unaffected individuals.
The AAV2-REP1 drug product is formulated in a sterile, 20 mM Tris-buffered solution, pH 8.0, and contains 1 mM MgCl2, 200 mM NaCl and 0.001% PF68. The drug product is a clear to slightly opalescent, colorless, sterile-filtered suspension with a target concentration of 1×1012 gp/mL.
AAV2-REP1 is supplied in sterile vials, stoppered and capped. A total of 0.3 mL vector suspension is supplied for each eye to be treated. Prior to shipment, each vial is placed in a labeled secondary container. The drug product is to be stored at <−60° C. (<−76° F.) in a controlled access, temperature monitored freezer.
Vitrectomy Procedure and Injection of AAV2-REP1
Injection of AAV2-REP1 is performed by an appropriately qualified and experienced retinal surgeon. Due to the complexity and unpredictability of detaching the retina in CHM, in which the retina and choroid can be extremely thin and fused in places, a modification to the technique of sub-retinal gene therapy has been developed. This involves performing the vector delivery in 2 steps after vitrectomy. An advantage of a 2-step procedure is that any unexpected complications of retinal detachment can be managed conservatively, minimizing concerns about the vector escaping into the vitreous. Further, the injection could be deferred until a later date if, for instance, a macular hole was created which required treatment with gas. Also, since the volume of fluid required to detach the fovea is variable, by removing the vector from the first step, a precise consistent dose in terms of genome particles can still be applied into the sub-retinal space.
Initially, subjects undergo a standard vitrectomy and detachment of the posterior hyaloid in the respective study eye (
In the second step of the procedure, the BSS cannula is removed from the eye and AAV2-REP1 is prepared for injection. A dose of 1.0×1011 AAV2-REP1 gp is injected into the sub-retinal space through the same entry site. The vector needs to be primed in the 1 mL syringe to avoid formation of air bubbles, and a connector is used so that the 1 mL syringe can be connected to the constant pressure line of the vitrectomy machine. The subretinal injection will target any area of the macula but also include the fovea if possible. In each case, the vector is injected so that the sub-retinal fluid overlies all edge boundaries of the central region that has yet to undergo chorioretinal degeneration, as identified by fundus autofluorescence. After wound closure, care is taken to dispose of all irrigating fluids that may have passed through the eye to limit potential vector spread.
Randomization
At the Screening/Baseline Visit all patients are assigned a screening identifier, which includes the center number and subject number. If the subject fulfils all eligibility criteria at the Screening/Baseline Visit, a study eye is assigned and the subject is randomized in a 2:1:2 ratio to receive either AAV2-REP1 high dose (1.0×1011 gp), AAV2-REP1 low dose (1.0×1010 gp) or to enter the untreated Control group. Randomization is generated using a validated system that automates the random assignment of treatment groups to randomization numbers, and stratified by surgical group.
Concomitant Therapy:
Subjects cannot have participated in another research study involving an investigational product in the past 12 weeks or received a gene/cell-based therapy at any time previously, except if treated within another study with AAV2-REP1. Throughout the study, investigators may prescribe any concomitant medications or treatments deemed necessary to provide adequate supportive care. Details of concomitant medications are collected at the Screening Visit and updated at every study visit (including the ET Visit, if applicable). Concomitant medications (including oral corticosteroid) taken during the study are to be recorded in the subject's medical records and eCRF; an exception to this is any medication used in the course of conducting a study procedure (e.g., anaesthesia, dilating eye drops).
To minimize inflammation resulting from surgery and potential or unexpected immune responses to vector/transgene, all subjects will be given a 21-day course of oral prednisone/prednisolone prior to each surgery. Hence, for each surgery, this would be 1 mg/kg/day prednisone/prednisolone for a total of 10 days (beginning 2 days before vector injection, on the day of injection, and then for 7 days); followed by 0.5 mg/kg/day for 7 days; 0.25 mg/kg/day for 2 days; and 0.125 mg/kg/day for 2 days (21 days in total). Details of corticosteroid usage are captured by each subject in a diary card.
Study Visits and Procedures
The schedule of study procedures is presented in Table 62: Schedule of Study Procedures.
Visit 1 (Screening/Baseline Visit)
The investigator explains the study purpose, procedures, and subject responsibilities to each potential study subject. The subject's willingness and ability to meet the protocol requirements is determined.
After informed consent has been obtained, the subject is allocated a subject identifier number and evaluated to determine eligibility. Screening/baseline procedures consist of the following (assessments can be spread over 2 consecutive days if necessary): Demography, medical and ocular history (Only subjects with a genetically confirmed diagnosis of CHM may enter the study. Genetic confirmation must be available prior to Visit 1); Vital signs; Weight; Immunoassay sampling (enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunospot [ELISPOT]); BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; Contrast sensitivity test; Color vision test; 7-field color fundus photography (including stereo photographs for fields 1, 2, and 3); Reading speed test (if applicable); VFQ-25; Serious AE (SAE) monitoring; Medication review; and Corticosteroid dispensing (if randomized to AAV2-REP1 groups). In order to capture accurate BCVA values at Visit 1 (Screening/Baseline) the following conditions apply to the BCVA assessment: If the BCVA value at Visit 1 (Screening/Baseline) is ≥±10 letter gain or loss in the study eye compared to the previous NIGHT study visit (if applicable), then BCVA must be repeated an additional 2 times, resulting in a total of 3 BCVA measures at Visit 1. To facilitate the additional BCVA measures this visit should be conducted over 2 days, with BCVA measured twice on Day 1 and once on Day 2 (prior to pupil dilation). All 3 BCVA values must be recorded in the eCRF. The highest score will be used to define subject eligibility. If the BCVA value at Visit 1 (Screening/Baseline) is <±10 letter difference in the study eye compared to the previous NIGHT study visit, then BCVA will be collected once and will not be repeated.
Subjects who meet all of the inclusion criteria and none of the exclusion criteria have a study eye assigned and are enrolled into the study. At this time, subjects are informed of the randomization outcome (i.e., AAV2-REP1 treatment or the Control group) and instructed to not reveal their treatment group assignment to the masked assessors during the study. Subjects randomized to the AAV2-REP1 treatment groups (along with the Investigators and sponsor) remain masked to the assigned dose.
The next study visit (Visit 2) is to be scheduled within 8 weeks of the Screening/Baseline Visit. Subjects randomized to the AAV2-REP1 groups are given a 21-day course of oral corticosteroid (e.g., prednisolone/prednisone) and instructed to start taking the drug 2 days before their next study visit (Visit 2). Subjects randomized to the AAV2-REP1 groups are instructed to use barrier contraception for a period of 3 months from the time they are treated.
If the subject is randomized to the Control group then Visit 2 consists of a telephone call.
Visit 2 (Day 0, Injection Day Visit or Telephone Contact)
At Visit 2 (Day 0), all subjects in the AAV2-REP1 groups will visit the surgical site, and the following assessments are performed: Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; AE/SAE monitoring; Concomitant medication review; and Corticosteroid compliance review.
Subjects in the AAV2-REP1 groups undergo vitrectomy and receive a sub-retinal injection of AAV2-REP1, containing either AAV2-REP1 low dose (1×1010 vg) or AAV2-REP1 high dose (1×1012 vg) in their study eye. Subjects are carefully monitored for the occurrence of AEs during the procedure. Subjects return to the site 1 and 7 days after surgery for post-operative follow-up (Visits 3 [Day 1] and 4 [Day 7], respectively).
Subjects in the Control group receive a study visit Telephone Call at the agreed upon date and time. Sites conduct the following assessments during the telephone call: AE/SAE monitoring and concomitant medication review.
Visit 3 (Day 1 Post-Operative Visit)
At Visit 3 (Day 1), subjects in the AAV2-REP1 groups return to the surgical site for a post-operative visit. The following assessments are performed: Vital signs; Immunoassay sampling (ELISA only); BCVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AE/SAE monitoring; Medication review; and Corticosteroid compliance review. Subjects are reminded of the requirement to use barrier contraception for a period of 3 months from the time of treatment.
Subjects in the Control group receive a study visit Telephone Call at the agreed upon date and time. Sites conduct the following assessments during the telephone call: AE/SAE monitoring and concomitant medication review.
Visit 4 (Day 7 Post-Operative Visit±3 Days)
At Visit 4 (Day 7±3 days), subjects in the AAV2-REP1 groups return to their host site (i.e. same site where their Visit 1 Screening/Baseline visit was performed) for a second post-operative visit. However, for those subjects that have travelled from a non-surgical site to a surgical site, and in the event of a post-operative complication or for any other safety reason considered appropriate by the study surgeon and surgical site Investigator, Visit 4 may be conducted at the surgical site. In this event post-operative follow-up should continue at the surgical site until the surgeon/surgical site Investigator, agrees to discharge the subject to the care of the non-surgical site. The following assessments are performed: Vital signs; Immunoassay sampling (ELISA and ELISPOT); BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry, AE/SAE monitoring; Medication review and Corticosteroid compliance review.
Subjects in the Control group receive a study visit Telephone Call at the agreed upon date and time. Sites conduct the following assessments during the telephone call: AE/SAE monitoring and concomitant medication review.
Visit 5 (Month 1±7 Days)
All subjects attend their host site (i.e. same site where their Visit 1 Screening/Baseline visit was performed) from Visit 5 onwards. At Visit 5 (Month 1±7 days), the following assessments are performed for all subjects (assessments can be spread over 2 consecutive days if necessary): Vital signs; Immunoassay sampling (ELISA and ELISPOT]); BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; AE/SAE monitoring; Medication review; Corticosteroid compliance review
Visit 6 (Month 4±7 Days)
At Visit 6 (Month 4±7 days), the following assessments are performed (assessments can be spread over 2 consecutive days if necessary): Immunoassay sampling (ELISA and ELISPOT); BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; Contrast sensitivity test; Color vision test; AE/SAE monitoring and Medication review.
Visit 7 (Month 8±14 Days)
At Visit 7 (Month 8±14 days), the following assessments are performed (assessments can be spread over 2 consecutive days if necessary): BCVA, LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; Contrast sensitivity test; Color vision test; AE/SAE monitoring and Medication review.
Visit 8 (Month 12±14 Days, End of Study Visit)
At Visit 8 (Month 12±14 days), the following assessments are performed (assessments can be spread over 2 consecutive days if necessary): Vital signs; BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; Contrast sensitivity test; Color vision test; 7-field color fundus photography (including stereo photographs for fields 1, 2, and 3); Reading speed test (if applicable); VFQ-25; AE/SAE monitoring and Medication review.
Early Termination Visit
In the event that a subject discontinues the study at any time, the site should use every reasonable effort to ensure that an ET Visit is conducted. The following assessments should be performed: Vital signs; Immunoassay sampling (ELISA and ELISPOT) if ET Visit occurs within Month 4; BCVA; LLVA; Full ophthalmic examination, including IOP, a slit-lamp examination, lens opacity, and dilated fundus examination; SD-OCT; AF; Microperimetry; Contrast sensitivity test; Color vision test; 7-field color fundus photography (including stereo photographs for fields 1, 2, and 3); Reading speed test (if applicable); VFQ-25; AE/SAE monitoring and Medication review.
Assessment of Efficacy
For all visits, an attempt should be made to perform all procedures in both eyes.
Best Corrected Visual Acuity
To evaluate changes in visual acuity (VA) over the study period, BCVA is assessed for both eyes using the ETDRS VA chart at the times indicated in Table 62: Schedule of Study Procedures. The BCVA test should be performed prior to pupil dilation, and distance refraction should be carried out before BCVA is measured. Initially, letters are read at a distance of 4 meters from the chart. If <20 letters are read at 4 meters, testing at 1 meter should be performed. BCVA is to be reported as number of letters read correctly by the subject. At the Screening/Baseline Visit, eyes with a BCVA of 34-73 ETDRS letters (equivalent to worse than or equal to 6/12 or 20/40 Snellen acuity, but better than or equal to 6/60 or 20/200 Snellen acuity) will be eligible for the study. If a subject cannot read any letters on the BCVA chart, the subject is tested for finger counting, hand movements or light perception.
Fundus Autofluorescence
To assess changes in the area of viable retinal tissue, fundus AF is performed for both eyes at the times indicated in Table 62: Schedule of Study Procedures. All fundus AF images are performed by certified technicians at the site after dilation of the subject's pupil.
Spectral Domain Optical Coherence Tomography (SD-OCT)
SD-OCT will be performed for both eyes at the times indicated in Table 2: Schedule of Study Procedures. SD-OCT measurements are taken by certified technicians at the site after dilation of the subject's pupil. SD-OCT issued to assess a number of variables, including quantifying the integrity of the ellipsoid zone and reduction in the signal from the outer nuclear layer and choroid. In addition, since progressive foveal thickening has been noted in the early phase of CHM, foveal changes are assessed.
Microperimetry
Microperimetry is conducted for both eyes at the times indicated in Table 62: Schedule of Study Procedures. Microperimetry is conducted by certified technicians to assess changes in retinal sensitivity within the macula.
Contrast Sensitivity
Contrast sensitivity is measured for both eyes at the times indicated in Table 62: Schedule of Study Procedures. Contrast sensitivity is measured prior to pupil dilation using a Pelli-Robson chart.
Color Vision
Color vision is tested for both eyes prior to pupil dilation at the times indicated in Table 62: Schedule of Study Procedures. Eyes are tested separately and in the same order at each assessment.
Low Luminance Visual Acuity
LLVA is measured for both eyes at the times indicated in Table 62: Schedule of Study Procedures. The test should be performed after BCVA testing, prior to pupil dilation, and distance refraction should be carried out before LLVA is measured. LLVA is measured by placing a 2.0-log-unit neutral density filter over the front of each eye and having the subject read the normally illuminated ETDRS chart. Initially, letters are read at a distance of 4 meters from the chart. If <20 letters are read at 4 meters, testing at 1 meter should be performed. LLVA is reported as number of letters read correctly by the subject.
Reading Speed Test
Reading performance will be evaluated prior to pupil dilation at the times indicated in Table 62: Schedule of Study Procedures using International Reading Speed Texts (IReST), which provide standardized assessment of reading performance in 17 languages (Trauzettel-Klosinski et al., 2012).
VFQ-25 Questionnaire
Subjects complete the VFQ-25 at the times indicated in Table 62: Schedule of Study Procedures. This questionnaire measures dimensions of self-reported vision-targeted health status that are most important to persons with eye disease (Mangione et al, 2001). Improvement in the VFQ-25 is evaluated using individual scores, subscale scores, and the overall composite score.
Assessment of Safety
Full Ophthalmic Examination
A full ophthalmic examination is conducted for both eyes at the times indicated in Table 62: Schedule of Study Procedures. For subjects in the AAV2-REP1 groups, the full ophthalmic examination is conducted prior to vitrectomy and administration of study medication at the applicable study visit. The ophthalmic examination will include IOP, slit lamp examination, lens opacity grading, and dilated ophthalmoscopy. The same slit lamp machine and lighting conditions should be used across study visits for any given subject.
In addition to the parameters listed above, relevant subjects are carefully examined for the presence of intraocular inflammation after vector administration. Cataract can also develop as a result of the vitrectomy procedure and can potentially affect VA. Pre-operative grading of lens opacity and color should therefore be documented by the established clinical lens opacities classification system. Cataract surgery is effective in subjects with CHM and without any specific risks. Hence, if clinically indicated, subjects who develop cataracts may undergo cataract surgery. If cataract surgery is performed, it should be carried out at least 4 weeks before the Month 12 Visit/EOS Visit.
Field Color Fundus Photography
To aid in the objective clinical assessment of progressive retinal changes, 7-field color fundus photography is performed for both eyes at the times indicated in Table 62: Schedule of Study Procedures. Fundus photography is performed by certified technicians following pupil dilation. Stereo photos should be performed for fields 1, 2, and 3.
Adverse Event
An AE is any untoward medical occurrence in a clinical investigation subject, which does not necessarily have a causal relationship with the study medication/surgical procedure. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study medication/surgical procedure, whether or not related to the investigational product or with the surgical procedure described in this protocol. AEs are to also include any pre-existing condition (other than CHM) or illness which worsens during the study (i.e., increases in frequency or intensity).
Serious Adverse Event
An SAE is defined as any untoward medical occurrence that: Results in death, Is life-threatening, Requires inpatient hospitalization or prolongation of existing hospitalization, Results in persistent or significant disability/incapacity, Is a congenital anomaly/birth defect, Results in vision loss or is vision threatening, Is another important medical event(s). The term ‘life-threatening’ in the definition of ‘serious’ refers to an event in which the subject is at risk of death at the time of the event. It does not refer to an event that hypothetically might cause death if it were more severe. Hospitalization for a pre-existing condition, including elective procedures, which has not worsened, does not constitute an SAE. Other events that may not result in death, are not life threatening or do not require hospitalization, may be considered an SAE when, based upon appropriate medical judgment, the event may jeopardize the subject and may require medical or surgical intervention to prevent one of the outcomes listed above.
The following vision loss or vision-threatening events are to be reported as SAEs: Sustained decrease in VA of ≥15 letters on ETDRS chart compared to baseline, except for surgery-related events. Sustained is defined as lasting 48 hours or more until recovery; recovery defined as VA returned to within 5 letters of baseline VA.
Surgery-related events of VA decrease are defined as VA decreases occurring in close temporal association (within <24 hours) with the surgical administration of the study medication, and which are resolving at Day 7 (Period 1/2, Visit 4) post-surgery. These events are not to be reported as an AE or SAE. However, they should be reported as an AE if in the investigator's opinion, their evolution in terms of duration or severity cannot be explained by the procedure. This would include, but not be limited to instances where the abnormal course of post-surgery VA decrease is associated with another complication attributable to the surgery or the study medication, or where the abnormal course of post-surgery VA decrease can be attributed to another identifiable cause. AEs that in the opinion of the investigator, actually or potentially require any surgical or medical intervention to prevent permanent loss of sight.
Efficacy Analyses
Statistical tests are performed at the alpha level of 0.05 (unless otherwise specified). Statistical tests and 95% CIs will be 2-sided.
Primary Efficacy Endpoint
The primary endpoint are calculated as the proportion of subjects with a ≥15 letter increase from baseline in BCVA at the Month 12 visit. If VA is missing at the Month 12 visit, then the missing value will be imputed using the LOCF method. The primary endpoint is summarized using the summary statistics for categorical data including the 95% CI.
The proportion of successes for the primary endpoint are compared between study arms (high dose vs control, low dose vs control) using the Fisher Exact test.
Key Secondary Efficacy Endpoint
The key secondary endpoint is a paired-sample analysis of the proportion of subjects with a ≥15 letter increase from baseline in BCVA at the Month 12 visit in treated study eyes within the STAR trial, compared to the proportion of subjects with a ≥15 letter BCVA gain from Month 4 (Visit 2) to Month 16 (Visit 5) in the NIGHT study (NSR-CHM-OS1). The analysis of the key secondary endpoint are performed on the Historical Control Full Analysis Set. The key secondary endpoint will be summarized, post-treatment (STAR data) and pre-treatment (NIGHT data), using the summary statistics for categorical data including the 95% CI. The proportion of successes for categorical variables will be compared between pre and post-treatment in each treatment arm separately using the McNemar test.
Other Secondary Efficacy Endpoints
Categorical secondary endpoints are summarized and analyzed using the same procedure as the categorical primary endpoint.
The continuous secondary endpoints are summarized using the summary statistics for continuous data, including the 95% CI. The treatment difference in mean change from baseline and its 95% CI is calculated based on the LSMEANS of the ANCOVA model including Surgery Group, baseline value of the assessment, study arms and the interaction between study arms and Surgery Group. Change from baseline is compared between study arms (high dose vs control, low dose vs control) using the above ANCOVA model. For the Overall Composite Score of VFQ-25, the covariates Age and Race is added to the model.
Safety Analyses
No significance testing is performed for safety analyses. Safety analyses are descriptive, with 95% CIs calculated where appropriate.
Adverse Events
AEs are coded using the Medical Dictionary for Regulatory Affairs. The version of the dictionary current at the time of the database lock will be used. Events are summarized by system organ class, preferred term, and group. Both the number of eyes/subjects experiencing an AE and the number of events is summarized. Similar summaries are produced for study drug/procedure-related AEs, AEs leading to discontinuation, and SAEs. AEs are summarized by maximum severity, relationship to study drug/procedure, and time to onset and resolution.
Full Ophthalmic Examination
IOP and change from Baseline in IOP are summarized by visit, by treatment and by eye. Abnormal slit lamp examination findings and dilated ophthalmoscopy findings, and shift from Baseline are summarized by visit, by treatment and by eye. Lens opacity categories and shift from Baseline are summarized by visit, by treatment and by eye.
Field Color Fundus Photography
Categories of color fundus photography findings and shift from Baseline are be summarized by visit, by treatment and by eye.
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Every document cited herein, including any cross referenced or related patent or application is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the disclosure have been illustrated and described, various other changes and modifications can be made without departing from the spirit and scope of the disclosure. The scope of the appended claims includes all such changes and modifications that are within the scope of this disclosure.
This application claims the benefit of provisional application U.S. Ser. No. 62/653,139, filed Apr. 5, 2018, U.S. Ser. No. 62/746,980, filed Oct. 17, 2018, and U.S. Ser. No. 62/773,975, filed Nov. 30, 2018, the contents of each of which are herein incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US19/26064 | 4/5/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62773975 | Nov 2018 | US | |
| 62746980 | Oct 2018 | US | |
| 62653139 | Apr 2018 | US |
