Patent Application
20230126645
The instant application contains a Sequence Listing that has been submitted electronically as a text file in ASCII format and is hereby incorporated by reference in its entirety. Said text file, created on May 23, 2022, is named 022548_C5044_SL.txt and is 5,321 bytes in size.
Thyroid cancer is a collection of diseases in which there is uncontrolled growth of cells derived from the thyroid. Thyroid cancer commonly has been classified as differentiated thyroid cancer, including papillary, follicular and Hurthle cell cancer, and other thyroid cancers, including medullary and anaplastic cancer. Over time, some differentiated thyroid cancers become less well differentiated, and may be classified as de-differentiated or poorly-differentiated cancer. Administration of Thyroid Stimulating Hormone (TSH) to patients can play a role in the diagnostic or therapeutic approach for various thyroid diseases, including goiter and thyroid cancer. For these diseases, the pharmacokinetic profile of the administered TSH may be important for the optimal success of the diagnostic or therapeutic procedures.
Recombinant human TSH (rhTSH), marketed as THYROGEN® Thyroid Stimulating Hormone (Genzyme Corp., NDA 20898), is dosed in multiple injections on consecutive days, followed by RAI dosing and blood draw for tumor diagnostics on day 3 and 5. This strict dosing regimen has been necessitated by the relatively short duration of action of TSH, which also results in reduced efficacy and side effects. A TSH composition with prolonged duration of action will likely improve treatment and detection of various thyroid diseases and reduce side effects.
Thus, a need exists for improved TSH-containing compositions that optimize the pharmacokinetics of TSH release and reduce the need of multiple injections.
The present invention relates to compositions of Thyroid Stimulating Hormone (TSH) conjugated with a (one or more) polyalkylene glycol polymer, such as polyethylene glycol (PEG), that prolong the duration TSH action in vivo. Additionally, the invention relates to compositions of mutant TSH, wherein the TSH has been mutated to introduce additional sites that can be conjugated with a polyalkylene glycol polymer. The TSH compositions of the present invention described herein are useful as preparing pharmaceutical compositions and can be used for treatment of patients in need thereof with thyroid conditions.
In accordance to one embodiment, the invention pertains to compositions comprising TSH, wherein at least one polyalkylene glycol polymer is attached to a carbohydrate site of the TSH. In certain aspects, the TSH of the compositions is isolated from a mammal, for example, a human, or the TSH is recombinant mammalian TSH, for example, recombinant human TSH (rhTSH).
In certain embodiments, the carbohydrate site of the TSH is a sialic acid on an amino acid, for example, asparagine residues ASN52 of the rhTSH a subunit, ASN78 of the rhTSH a subunit, or ASN23 of the rhTSH β subunit and combinations thereof.
In yet other embodiments, the carbohydrate site on TSH is galactose on an amino acid, for example, asparagine. In particular embodiment, the galactose group is located at a site on TSH, for example, amino acid ASN52 of the rhTSH a subunit, the amino acid ASN78 of the rhTSH a subunit, or the amino acid ASN23 of the rhTSH β subunit and combinations thereof.
In related aspects of the invention, the compositions of the invention exhibits an enhanced T4 response compared to a control.
In other related aspects of the invention, the polyalkylene glycol polymer attached to the carbohydrate site of TSH is polyethylene glycol (PEG). In particular embodiments, the PEG has an average molecular weight of between about 3,000 and about 100,000 Daltons. In other embodiments, one or more than one linear or branched PEG molecules is/are attached to TSH.
In yet another related embodiment of the invention, a composition comprising a mutated Thyroid Stimulating Hormone (TSH) and at least one polyalkylene glycol polymer, wherein the mutated TSH comprises a TSH in which one or more amino acid residues has been substituted with a cysteine residue, wherein the polyalkylene glycol polymer is attached to the mutated TSH at the cysteine residues, and the mutated TSH is biologically active is described.
In certain embodiments, the amino acid residue that has been substituted with cysteine is located on the alpha subunit of TSH. In a particular embodiment, the amino acid residue that has been substituted with cysteine is located at an amino acid position of recombinant human TSH selected from the group consisting of ASN52, ASN78, MET71, ASN66, THR69, and GLY22, and combinations thereof.
In still other embodiments, the amino acid residue that has been substituted with cysteine is located on the beta subunit of TSH. In a particular embodiment, the amino acid residue that has been substituted with cysteine is located at an amino acid position of recombinant human TSH selected from the group consisting of ASN23, VAL118, THR21, GLU63, and ASP56, and combinations thereof. In certain aspects, the mutated TSH with the cysteine modification has attached polyethylene glycol (PEG) as the polyalkylene glycol polymer. In particular embodiments, the PEG has an average molecular weight of between about 3,000 and about 100,000 Daltons. In other embodiments, one or more than one linear or branched or combinations of PEG molecules is/are attached to TSH.
In accordance with other embodiments of the invention, pharmaceutical compositions comprising an effective therapeutic amount of a composition of the invention along with a pharmaceutically acceptable carrier are described.
These pharmaceutical compositions are used in methods of treating a thyroid condition in a patient in need thereof, by administering to the patient an effective amount of the pharmaceutical compositions of the invention. In particular embodiments, the thyroid condition is thyroid cancer. In other embodiments, the composition is delivered by intramuscular injection.
The invention also relates to methods of producing a PEGylated, biologically active thyroid stimulating hormone (TSH) comprising attaching at least one polyalkylene glycol polymer to a carbohydrate site of a TSH.
In another related aspect, the invention pertains to a method of producing a PEGylated, biologically active mutated thyroid stimulating hormone (TSH) comprising (a) introducing one or more additional cysteine residues into the amino acid sequence of TSH, thereby producing a mutated TSH; (b) attaching one or more polyalkylene glycol polymers to the one or more cysteine residues introduced in step (a), thereby producing a PEGylated, biologically active mutated TSH. In particular embodiments, the cysteine residue replaces an endogenous amino acid residue in TSH.
The invention also relates to methods of treating a thyroid condition in a subject in need thereof, comprising administering an effective amount of a PEGylated, biologically active thyroid stimulating hormone (TSH).
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
THYROGEN®, Thyroid Stimulating Hormone (Genzyme Corp., NDA 2-898) is recombinant human TSH (rhTSH) currently marketed for the diagnosis and/or treatment of thyroid cancer. It is sold as a lyophilized powder for reconstitution with water prior to intramuscular administration.
Such existing formulations of TSH have rigid dosing regimes, require multiple, injections, have limited pharmacokinetic profiles and produce side effects, such as nausea. These shortcomings are addressed by the TSH compositions and mutated TSH compositions of the present invention. Longer-acting thyroid-stimulating hormone (TSH) compositions that reduce frequency of injection, provide flexible administration regimes, improve therapeutic index and have better efficacy for stimulating thyroid tissue are described herein. In addition, other potency parameters are positively affected by the longer acting TSH compositions of the invention including prolonged half life of TSH and increased duration of T4 release.
As shown herein, conjugating a polyalkylene glycol polymer, e.g., polyethylene glycol to TSH, beneficially altered the pharmacokinetic profile and pharmacodynamic profile of TSH. As described in greater detail below, N-terminal PEGylation, lysine PEGylation and carbohydrate polymer attachment of TSH were studied. The expectation was that N-terminal PEGylation of TSH would result in a TSH with prolonged duration of action, whereas lysine PEGylation and carbohydrate PEGylation of TSH would result in a severe decrease in the potency of TSH. The study results described herein show that carbohydrate PEGylation of TSH has a positive effect on the potency of TSH and both N-terminal PEGylation and lysine PEGylation of TSH greatly reduced the potency of TSH.
Accordingly, in one aspect, the invention is directed to a composition comprising Thyroid Stimulating Hormone (TSH), wherein at least one polyalkylene glycol polymer is attached to a carbohydrate site of the TSH. Also shown herein is site-specific PEGylation of TSH which has been mutated to introduce cysteine residues targeted for PEGylation that results in a positive effect on the potency of TSH. Thus, in another aspect, the invention is directed to a composition comprising a mutated Thyroid Stimulating Hormone (TSH) and at least one polyalkylene glycol polymer, wherein the mutated TSH comprises a TSH in which one or more amino acid residues has been substituted with a cysteine residue, wherein the polyalkylene glycol polymer is attached to the mutated TSH at the cysteine residues, and the mutated TSH is biologically active. The PEGylated TSH compositions provided herein have one or more of the following improved therapeutic index effects relative to TSH that is not conjugated to a polyethylene glycol polymer: enhanced solubility, decreased proteolysis, decreased immunogenicity, reduced rate of kidney clearance, prolonged blood circulation lifetime, increased duration of action and altered distribution and absorption.
TSH is a glycoprotein having two subunits, the alpha and the beta subunit. The a (alpha) subunit (i.e., chorionic gonadotropin alpha) is identical to that of human chorionic gonadotropin, luteinizing hormone, and follicle-stimulating hormone (FSH). The 13 (beta) subunit is unique to TSH, and determines its function.
rhTSH refers to recombinantly synthesized TSH. The recombinant DNA methods described herein are generally those set forth in Sambrook et al., Molecular Cloning: A Laboratory Manual (Cold Spring Harbor Laboratory Press, 1989, and/or Current Protocols in Molecular Biology (Ausubel et al., eds., Green Publishers Inc., and Wiley and Sons 1994, with Supplements). The term “recombinant” refers to a polynucleotide synthesized or otherwise manipulated in vitro (e.g., “recombinant polynucleotide”), and to methods of using recombinant polynucleotides to produce gene products in cells or other biological systems, and to a polypeptide (“recombinant protein”) encoded by a recombinant polynucleotide.
TSH used in the methods and compositions described herein can be purified from naturally-occurring mammalian sources, such as bovine, porcine, primate, or human, or alternatively isolated in a recombinant form from non-naturally-occurring sources using methods known in the art, such as described in U.S. Pat. Nos. 5,840,566 and 6,365,127.
It is known that conjugation of macromolecules to polymers, (e.g., polysaccharides, polymers of sialic acid, hydroxyethyl starch and polyalkylene glycols (e.g., polypropylene glycol, polybutylene glycol, polyethylene glycol) and other like moieties) can be used for effectively altering the in vivo efficacy of drugs by changing the balance between their pharmacodynamic and pharmacokinetic properties. However, such conjugation often leads to loss of binding affinity of the drug and, in effect, loss of potency. In limited cases, a decrease of potency is offset by a longer circulating half-life of the polymer-modified drugs making the resultant pharmacokinetic (PK) and pharmacodynamic (PD) profiles useful for therapy.
While conjugation of polyethylene glycol (PEG), referred to as PEGylation, to certain macromolecules retains most activity, PEGylated hormones and cytokines, whose activity generally require high affinity interactions with cell surface receptors, show significant reduction in activity. Frequently, PEGylation to hormones adversely affects the PD profile and PK profile of the hormone.
Polyethylene glycol (PEG) is a non-antigenic inert polymer that has been shown to prolong the length of time a protein circulates in the body. Typically, these common PEG reagents attach to primary and secondary amines on proteins, generally at lysine residues and/or at the N-terminal amino acid. PEG is commercially available in different sizes and, once attached, can be tailored for individual indications by using the variation of sizes and multiple attachments to a single drug molecule. PEG has been shown to improve plasma half-life of the injected PEGylated protein but as stated above, potency can be lost due to steric hindrance by PEG (Fishburn, C. S., J Pharm Sci 97:4167 (2008)). To avoid potency problems and generate desirable PD and PK profiles, a detailed understanding of structure-function relationship of the target protein to be PEGylated is helpful for generating PEGylated products that retain maximum functional activity.
Recently, progress was made in the determination of the structures of members of the growth hormone superfamily, which has led to potential therapeutics. Understanding how these proteins interact with their targets coupled with the structural information has generated effective drugs by using structural information to design polymer conjugates for maximizing the therapeutic benefits of the protein on their respective target. Unfortunately, structural information for the complex structure of TSH with its receptor is not available; however, the crystal structure of a related protein follicle-stimulating hormone (FSH) complexed to the FSH receptor (FSHR) has been resolved (Fan and Hendrickson, Nature 433:269 (2004)).
TSH has high homology with FSH, sharing the identical alpha subunit and similar beta subunit. Likewise, the TSH receptor and FSH receptor are highly homologous. Thus, the FSH-FSH receptor complex may serve as an initial model for TSH interaction with its receptor.
As shown herein, when the TSH sequence was superimposed onto a 3D structural model of the FSH-FSHR complex (PDB coordinate 1XWD), the N-termini appear to be most distant from the receptor interaction region, and thus are likely ideal sites for PEG attachment to minimize loss of receptor binding upon PEGylation (See
TSH is a glycosylated protein. The carbohydrate chains constitute 15-25% of its weight and include three asparagine-linked carbohydrate chains. Two of these chains are found on the alpha subunit of TSH, linked to asparagine 52 (ASN 52) and asparagine 78 (ASN 78), respectively, and the third is on the beta subunit of TSH, linked to asparagine 23(ASN 23). Asparagine-linked carbohydrate chains are potential PEG conjugation sites, however, on the TSH protein their respective proximities to the receptor interaction region, in particular, ASN 52, suggests that PEG conjugation at such sites would likely have a negative effect on receptor binding. Thus, selecting potential sites for conjugation of polymers to TSH presented much uncertainty.
Furthermore, deglycosylation of TSH has long been known to result in loss of efficient signal transduction upon receptor binding (Szkudlinski et al., Physiol Rev. 82:473 (2002)). While removal of the terminal sialic acids from the carbohydrates of TSH improved in vitro activity, greatly reduced circulation time in vivo was observed, presumably due to clearance by hepatic asialoglycoprotein receptor. Thotakura, N. R., Szkudlinski, M. W. and Weintraub, B. D., Glycobiology 4, 525-533 (1994). Deleting individual carbohydrate sites also enhanced in vitro functional activity, especially for the alpha chain amino acid position 52, again suggesting that the carbohydrates may be close enough to the receptor for electrostatic repulsion between the negative charges of the sialic acids and negative charges on the receptor. All together, this structure function analysis of TSH indicated that N-terminal PEGylation is far more preferable than carbohydrate PEGylation to minimize effect on functional potency. As described herein, N-terminal PEGylation, lysine PEGylation and carbohydrate polymer attachment were studied.
Accordingly, carbohydrate polymer methodology to produce polymer conjugated TSH is one aspect of the present invention. In one embodiment, the polymer is polyalkylene glycol. As used herein, “polyalkeylene glycol (PAG)” includes polyethylene glycol (PEG), polypropylene glycol (PPG), polybutylene glycol, and the like. The polymers can be linear or branched. The PAG is attached covalently to a molecule. As used in the present context, the term “attachment” or “attached” refers to the coupling or conjugation of a site or moiety of the TSH protein and a polymer, such as a polyalkylene glycol, e.g., either directly covalently joined to one another, or else is indirectly covalently joined to one another through an intervening moiety or moieties, such as a bridge, spacer, or linkage moiety or moieties. An attached or conjugated polymer to TSH is differentiated from the polymer being admixed, commingled, or in solution with the TSH.
“Carbohydrate site” refers to a carbohydrate side chain found on TSH. The site can be a naturally glycosylated site or a site that has been enzymatically provided. In certain embodiments, the carbohydrate site is specifically selected to meet desired criteria for optimal TSH interaction with the receptor or for other functional requirements such as folding or mobility of the protein. The carbohydrate site is available for attachment of a polymer moiety such as PEG. Typical carbohydrate sites on the protein are asparagine, serine or threonine. TSH has three asparagine-linked carbohydrate chains.
In certain embodiments, a single polymer is attached to TSH. In other embodiments, multiple polymers are attached the TSH. The multiple attached polymers can be of a single specie or multiple species. For example, in the case where a single PEG molecule is attached to the protein the protein is referred to as “monoPEGylated” and in the case where more than one PEG molecule is attached the protein is referred to as “multiPEGylated”. When the protein is multiPEGylated, an individual PEG attached to the protein (vis a vis other attached PEGs) can have the same or a different molecular weight, and can be of a linear or branched structure. The molecular weight range of the PEG molecule is 3,000-100,000 Daltons. In certain embodiments, the molecular weight of the PEG attached is 5 kD, 10 kD, 20 kD, 30 kD, 40 kD, or 60 kD or combinations thereof.
Provided herein are three alternative schemes for carbohydrate PEGylation of TSH: (i) sialic acid-mediated PEGylation (referred to as “SAM”), (ii) galactose-mediated PEGylation (referred to as “GAM(−)”), and (iii) sialic acid removal coupled with galactose-mediated PEGylation (referred to as “GAM(+)”). Briefly, as shown in
Site-specific methods of PEGylation to TSH are also included in the present invention. One such method attaches PEG to cysteine residues using cysteine-reactive PEGs. A number of highly specific, cysteine-reactive PEGs with different reactive groups (e.g., maleimide, vinylsulfone) and different size PEGs (2-40 kDa) are commercially available. At neutral pH, these PEG reagents selectively attach to “free” cysteine residues, i.e., cysteine residues not involved in disulfide bonds in the target protein. Alternatively, one of two cysteines involved in a native disulfide bond may be deleted or substituted with another amino acid, leaving a native cysteine (the cysteine residue in the protein that normally would form a disulfide bond with the deleted or substituted cysteine residue) free and available for chemical modification. Preferably the amino acid substituted for the cysteine would be a neutral amino acid such as serine or alanine.
Through in vitro mutagenesis using recombinant DNA techniques, additional cysteine residues can be introduced at any useful position on the protein. The newly added “free” cysteines can then serve as sites for the specific attachment of a PEG molecule using cysteine-reactive PEGs. The added cysteine residue is a substitution for an existing amino acid in a protein. Cysteine residues can be added preceding the amino-terminus of the protein, after the carboxy-terminus of the protein, or inserted between two amino acids in the protein. The term “mutant TSH,” as used herein refers to a TSH where one or more amino acids of the wild-type TSH have been substituted with another amino acid that permits the formation of one or more glycosylation sites on the TSH molecule. Accordingly the amino acid substitution of TSH enables site-specific coupling of at least one polymer, such as a polyalkylene glycol. For example, site-specific coupling with PEG molecules to the mutant TSH allows the generation of a TSH that possesses the pharmacodynamic and pharmacokinetic benefits of a polyethylene-glycosylated TSH.
In particular embodiments, amino acid substitution with cysteine can be at the positions shown for the mutants in Tables 1 and 2.
In a preferred embodiment, the substitution does not substantially change the structural characteristic of native TSH. In certain embodiments, the amino acid residue that has been substituted with cysteine is located on the alpha subunit of TSH or the beta subunit. In particular embodiments, the amino acid residue that has been substituted with cysteine is located at an amino acid position on the alpha subunit of recombinant human TSH selected from the group consisting of ASN52, ASN78, MET71, ASN66, THR69, and GLY22, and combinations thereof or is located at an amino acid position on the beta subunit of recombinant human TSH selected from the group consisting of ASN23, VAL118, THR21, GLU63, and ASP56, and combinations thereof.
The TSH compositions described herein are biologically active. “Biologically active” means that the TSH compositions of the invention have one or more of the following effects: longer duration of action, prolonged half-life, increased duration of T4 release, higher AUEC, positive shift in Tmax, and a lower peak-to-trough exposure that can reduce side effects. In certain embodiments, the compositions are compared to a control and the effect is substantially similar, somewhat less or somewhat greater or substantially greater. The biological activity of TSH compositions produced according to the present invention can be assessed using a variety of techniques known to those of skill in the art.
When assessing the biological activity of a TSH composition of the present invention, the biological activity can be compared to a control. As appreciated by one of skill in the art, a variety of suitable controls can be used. In one embodiment “control” as used herein refers to native (wild-type) TSH or rhTSH.
The compositions of this invention, when administered to a patient in need thereof (e.g., a thyroid cancer patient who had near-total or total thyroidectomy), will provide a blood serum concentration of TSH that has been tailored for the indicated use. In a certain embodiment, the duration of action for the compositions described herein is increased by at least 2-fold over rhTSH. In another embodiment, the duration of action for the TSH compositions is increased by at least 3-fold over rhTSH. Such embodiments having increased duration of action effectively reduce the frequency of administration while maintaining comparable efficacy to the current formulation of rhTSH.
In one embodiment, the compositions provide longer half-life (t1/2), compared to rhTSH. In particular embodiments, the t1/2 is up to 23-fold longer than rhTSH in rat.
In another embodiment, the T4 level is shown to have a greater sustained effect over rhTSH. In rat, T4 level in rhTSH group was back to vehicle level by 48 hours post-dose whereas in one embodiment T4 was sustained for 168 hours post-dose.
An “effective Tmax” as used herein refers to a “Time of the Peak Height Concentration”, which is characteristic of the composition in reference. An “effective Cmax” as used herein refers to a “Peak Height Concentration”, which is characteristic of the composition in reference. In many situations, an effective Tmax and Cmax provide a blood (or serum or plasma) concentration time curve in which the concentration of a drug is in a therapeutic range. “t1/2” refers to the duration of action of a drug is known and the period of time required for the concentration or amount of drug in the body to be reduced by one-half.
The nucleic acid sequence of the alpha subunit of human TSH is:
The amino acid sequence of the alpha subunit of human TSH is:
The nucleic acid sequence of the beta subunit of human TSH is:
The amino acid sequence of the beta subunit of human TSH is:
As used herein, the term “amino acid residues corresponding to amino acid residues of the subunits of TSH is intended to indicate the amino acid residues corresponding to the sequence of wild-type TSH subunits (SEQ ID NOs: 2 and 4) when the sequences are aligned. Amino acid sequence homology/identity is conveniently determined from aligned sequences, using a suitable computer program for sequence alignment, such as, e.g., the ClustalW program, version 1.8, 1999 (Thompson et al., 1994, Nucleic Acid Research, 22: 4673-4680).
Sodium periodate oxidation: 25 mM sodium periodate (Sigma, 311448) in 100 mM sodium acetate, pH 5.6 was added to 4.5 mg/ml TSH in 100 mM sodium acetate, pH 5.6 to final concentrations ranging from 0.2 mM to 2 mM, in a glass vial wrapped in aluminum foil. The mixture was gently shaken on ice in the dark for 30 minutes. After 30 minutes, 50% glycerol was added to 3% of the reaction volume and then shaken for 15 minutes. The mixture was then buffer exchanged to 100 mM sodium acetate, pH 5.6, and concentrated to a TSH concentration of at least 4.3 mg/ml in order to perform the PEGylation.
PEGylation: The appropriate size aminoxy PEG (100 mg/ml in dH2O) was added to the oxidized TSH to varying (PEG:Protein) molar ratios. The reaction volume was adjusted with 100 mM sodium acetate, pH 5.6, to a final TSH concentration of 4 mg/ml. The mixture was then incubated at 25° C. for 16 hours or at 8° C. for 16 hours with gentle shaking. After incubation, a 50 molar excess of 0.05M hydroxylamine was added to quench the reaction mix and incubated at 25° C. for 6 hours with gentle shaking.
Neuraminidase Treatment: 20 mU neuraminidase (His6-Clostridium neuramindase (520 mU/u1)) was added per mg TSH and incubated at 37° C. for 6 hours.
Catalase/Galactose Oxidase Treatment: 2 U Catalase (Sigma 442 U/μ1) per mg TSH was added to the neuraminidase treated TSH. 4 μg galactose oxidase (Worthington GAO, 1.2 mg/ml) per mg TSH was added to the mixture and then incubated at 37° C. for 16 hours. After incubation the mixture was buffer-exchanged and concentrated into 100 mM sodium acetate, pH 5.6, to a concentration of at least 5.5 mg/ml in order to perform the PEGylation.
PEGylation: The appropriate size aminoxy PEG (100 mg/ml in dH2O) was added to the oxidized and buffer-exchanged TSH to the (PEG:Protein) molar ratio of 1:1. The reaction volume was adjusted with 100 mM sodium acetate, pH 5.6, so that the final TSH concentration in the reaction was 5 mg/ml. The mixture was then incubated at 25° C. for 16 hours with gentle shaking. A 50 molar excess of 0.05M hydroxylamine (m.w. 69.49) was then added to the reaction mix and incubated at 25° C. for 6 hours with gentle shaking.
Catalase/Galactose Oxidase Treatment: 2 U Catalase (Sigma 442 U/μ1) per mg and 4 μg galactose oxidase (Worthington GAO, 1.2 mg/ml) per mg were added to TSH. The mixture was then incubated at 37° C. for 16 hours. After incubation the mixture was buffer-exchanged and concentrated into 100 mM sodium acetate, pH 5.6, to a final concentration of at least 5.5 mg/ml in order to perform the PEGylation.
PEGylation: The appropriate size aminoxy PEG (100 mg/ml in dH2O) was added to the oxidized and buffer-exchanged TSH to the (PEG:Protein) molar ratio of 1:2. The reaction volume was adjusted with 100 mM sodium acetate, pH 5.6, so that the final TSH concentration in the reaction was 5 mg/ml. The mixture was then incubated at 25° C. for 16 hours with gentle shaking. A 50 molar excess of 0.05M hydroxylamine (m.w. 69.49) was then added to the reaction mix and incubated at 25° C. for 6 hours with gentle shaking.
Appropriate size aldehyde PEG (100 mg/ml in reaction buffer) was added to a final concentration of 5 mg/ml rhTSH at varying (PEG:Protein) ratios in 100 mM sodium acetate, pH 5 or pH 5.6, with 20 mM sodium cyanoborohydride. Incubation was done at 25° C. for 16 hours or 8° C. for up to 2 days, before quenching the reaction with 0.1 volume of 1M Tris, pH 7.5, for 3 hours at 25° C.
PEGylation at the N-terminus yielded conjugates that lost greater TSH receptor binding affinity than carbohydrate conjugation. N-terminal mono-PEGylation with 40 kD PEG resulted in an 11.1-fold decrease of in vitro TSH receptor binding affinity, compared to the rhTSH control.
Appropriate size NHS (N-hydroxysuccinimide) PEG (50 mg/ml in dH2O) was added to a final concentration of 0.8 mg/ml rhTSH at varying (PEG:Protein) ratios (e.g., (0.5:1), (1;1), (2:1), (4:1), (8:1)) in PBS (phosphate-buffered saline) buffer, pH 7.2. Incubation was done at 25° C. for 1.5 hours.
Lysine conjugation with N-hydroxysuccinimide ester (NHS) PEG was explored. For 40 kDa PEGS, different (PEG:protein) ratios and different incubation times were tested in the PBS (phosphate-buffered saline) buffer, pH 7.2. Final TSH concentration was 0.8 mg per ml. PEGylation was done at 25° C. or 37° C. for 1.5 hours or 19.5 hours. The short incubation time tested (1.5 hour) showed the same results as long incubation time (19.5 hours). This was presumably due to a rapid hydrolysis of NHS PEG in aqueous solution. The extent of PEGylation depended on the (PEG:Protein) molar ratios, with higher PEG molar excess producing more multi-PEGylated conjugates.
Size exclusion chromatography (SEC) fractions of mono-PEGylated species were collected and submitted for in vitro TSH receptor binding assay. In vitro TSH receptor binding assay results showed that mono-40 kDa NHS PEG-TSH (Lysine PEGylation) has 31.2-fold lower affinity than the control TSH, starting material, while mono-40 kDa aminoxy PEG-TSH (SAM PEGylation) has 5.3-fold lower affinity.
TSH single mutants were designed and prepared to introduce cysteines for site-specific PEGylation. These mutants were designed to minimize its effect on protein folding, receptor binding and for their potentials to be effectively conjugated.
The following considerations were applied to design sites to introduce cysteine mutants based on a structural model of TSH/TSH receptor: 1) The mutation site should not be located at or adjacent to a receptor binding site; 2) The mutation site should not be located at or adjacent to an alpha/beta subunit dimerization interface; 3) The mutation site should not be located at or adjacent to a disulfide bond; 4) Avoid sites that when mutated, result in dramatic loss in specific activity based on reported literature; 5) The mutation site should be solvent exposed for subsequent PEGylation; 6) Select sites that would evenly cover most of the TSH surface opposite of the receptor binding site to fully evaluate PEGylation feasibility at each region. Some of these considerations are summarized in Table 1. The beta-carbon positions of the selected mutants were exposed to solvent in our structure model as shown in
DNAs encoding rhTSH genes (including its signal peptides) were synthesized and cloned into a Gateway entry vector (for example, pDONOR221). Oligonucleotide-based site-directed mutagenesis was used to introduce Cys mutations at multiple sites on both TSH subunits. The resulting wild-type and mutant vectors were shuffled into expression vectors (for example, pCEP4.DEST) via Gateway cloning. Proteins were prepared from transiently transfected HEK293 cell media and characterized by biochemical and cell-based assays, e.g., gel electrophoresis, Western blotting, SEC-HPLC chromatography, PEG modification yield and cell reporter assays.
The results were evaluated and compared for their expression level, aggregation (dimerization) tendency, PEGylation efficacy and perturbation to TSH function. For example, silver stain analysis of purified mutant TSH revealed that mutants TSH N66C(alpha), TSH G22C(alpha), TSH M71C(alpha), TSH T69C(alpha), and TSH V118C (beta) had the best expression levels (See
Larger scale Cys mutants were prepared from CHO pools. DNAs encoding the wild-type (WT) and mutant rhTSH genes were codon-optimized and synthesized. These genes were cloned into CHO expression vectors (for example, pGEN600, pGEN620) for transient transfection into CHO cells. Transfected CHO cells were amplified with methotrexate (MTX) selection. The resulting CHO pools were used for scale-up protein production.
The cysteine TSH mutants were found to be capped at the introduced cysteine after expression and purification, thus additional reducing methodology was needed to create PEGylated mutant TSH. The mutant TSH first needed to be reduced with a mild reductant to release the cap from the introduced cysteine without irreversibly breaking the native disulfide bonds that would inactivate the protein.
Accordingly, multiple methods were employed in an effort to reduce the capped cysteine. For example, various concentrations of TCEP (Tris(2-carboxyethyl)phosphine HCl) solution were incubated with rhTSH mutants for reduction. While removal of the cysteine cap was effective using this method, there also appeared to be some reduction of other disulfide bonds which led to non-specific PEGylation later. Another reducing method using immobilized beads with TCEP seemed to be milder in reducing rhTSH however, this method also resulted in some low levels of disulfide reduction. We found that 1-10 mM cysteine (as a reductant) was particularly effective to reduce the capped Cys without breaking the existing disulfide bonds in rhTSH.
The cysteine reductant was removed together with the cap to allow the disulfides to reform. The “de-capped” introduced cysteine was then selectively conjugated to a cysteine-reactive PEG reagent. Although this method has been demonstrated in other proteins such as FVIII (Mei et al., Blood 116:270-9 (2010)) and antibody fragments (Yang et al., Protein Engineering 16:761-770 (2003)), however, there are no known reports of attempting this on a cysteine knot-containing protein. Whereas the previous reported examples had only 1-2% cysteine content, TSH has 11% cysteine content (23/210 amino acids), which makes the introduction of a 24th cysteine into TSH without scrambling the native disulfides (and thus dramatically lowering receptor binding affinity) particularly difficult. Consequently, we had to screen multiple positions for introducing the cysteine mutation, with only a few that could be successfully conjugated with a PEG.
Site-specific Cys PEGylation: G22C rhTSH was produced from CHO cells for site-specific PEGylation. Cysteine was added to G22C rhTSH (1-2 mg/ml) to a final concentration of 2 mM after optimization experiments shown in
The SEC-HPLC profiles of several PEGylation reactions are shown in
Samples were purified over a monoS column (GE Healthcare) and eluted using a gradient with 10 mM sodium acetate pH5 and 10 mM sodium acetate, 1M sodium chloride pH5 at a flow rate of 4 ml/min. The gradient started with 0% mobile phase B (10 mM sodium acetate, 1M sodium chloride pH5) then increased to 50% mobile phase B over 25 column volumes followed by 100% mobile phase B to wash the column.
Pre-poured gradient gels (4-12% Bis Tris, Invitrogen) were loaded with 4-5 μg TSH. MOPS (3-(N-morpholino)propanesulfonic acid) running buffer (Invitrogen) was prepared. The electrophoresis apparatus was placed in an ice bucket with ice. The gel ran for approximately 50 minutes at 200V and was then rinsed three times, 5 minutes each with distilled water. 50 ml 5% barium chloride was added to the gel and then shaken for 10 minutes. The barium chloride was removed by rinsing the gel for 5 minutes with distilled water. The distilled water was then removed and the gel was first stained for PEG with 1×potassium iodide/iodine solution until the bands were visible. The gel was then destained with distilled water and scanned immediately. For protein staining, Coomassie destain (10% acetic acid, 20% methanol) was used to remove all traces of the PEG stain and the gel was then stained with Coomassie blue stain. SDS-PAGE analysis results of purified carbohydrate PEGylated rhTSH conjugates are shown in
Samples were run on a Superdex 200 10/300GL column (GE Healthcare) and eluted at a flow rate of 0.4 ml per min. in 50 mM sodium phosphate, 150 mM sodium chloride buffer pH7. Representative SEC-HPLC profiles of the 40 kD SAM reaction and purified PEGylated rhTSH conjugates are shown in
Twenty micrograms of each sample was diluted into 0.1 M Tris, pH 8.5 containing 6 M guanidine hydrochloride and 38 mM dithiothreitol, overlaid with nitrogen, and incubated at 25° C. overnight. After incubation, iodoacetamide was added at 50 mM. The samples were then overlayed with nitrogen and incubated at 25° C. for 2 hours. The alkylation reaction was quenched by adding 1/1 (v/v) 0.25% trifluoroacetic acid and the samples were dialyzed into 0.1 M Tris, pH 8.5 using 3,500 MWCO Slide-A-Lyzer mini dialysis units (Thermo Scientific). Samples were digested with 1:25 (Enzyme:Sample) ratio overnight at 37° C. Digest reactions were quenched with 1/1 (v/v) 0.25% trifluoroacetic acid. Trypsin-digested samples were fractionated using an Agilent 1200 HPLC equipped with an automated injector and fraction collector, a binary solvent pump, a thermostated column compartment, and a variable wavelength detector. Samples were loaded onto a Poroshell 300SB-C8 column (2.1×75 mm, 5 μm particles, Agilent Technologies, CA) that was held at 50° C. and pre-equilibrated in 98% solvent A (0.1% trifluoroacetic acid in water) and 2% solvent B (0.08% trifluoroacetic acid in acetonitrile). Tryptic peptides were eluted using a linear gradient of solvent B from 2% to 60% over 25 min at a flow rate of 0.4 ml/min. PEGylated fragments, eluting at a greater % B than the un-PEGylated fragments, were collected and dried in a centrifugal concentrator (Thermo Scientific, MA). Automated N-terminal sequence analysis was performed using a Procise protein sequencer (Applied Biosystems, CA). Two hundred pmol of sample and control were subjected to 18 cycles of the automated Edman degradation using the preprogrammed pulsed liquid method.
Subunit-specific PEGylation was calculated by measuring the relative amount of unPEGylated a and 13 subunits after isolating them from the PEGylated subunits, using two consecutive reversed-phase HPLC runs. This method of inference was used because chromatographic conditions that resolve PEGylated a and 13 subunits could not be identified. Samples (100 μg) were concentrated to 20 μl by centrifugal ultrafiltration and then denatured in 6 M guanidine hydrochloride, 10 mM sodium phosphate, 100 mM sodium chloride, pH 7.0. After overnight incubation at 25° C., the samples were loaded onto a Poroshell 300SB-C8 column (2.1×75 mm, 5 μm particles, Agilent Technologies, CA) pre-equilibrated with 75% solvent A (10 mM sodium phosphate, pH 6.5) and 25% solvent B (40% 10 mM sodium phosphate, pH 6.5, 60% acetonitrile). The column was eluted with 25-50% B over 5 min followed by 50-75% B over 20 min at 0.4 ml/min at 25° C. The peak fraction corresponding to unPEGylated TSH subunits (˜9.5-12.5 min) was collected (
Purified PEGylated conjugates were analyzed by in vitro porcine TSH receptor binding assay using the TSH Receptor Autoantibody 2nd Generation ELISA kit from RSR Limited (Kronus, Star, Id.). Instead of using the biotinylated human monoclonal autoantibody to the TSH receptor provided by the kit, we biotinylated Thyrogen® (rhTSH) to use for competitive inhibition of binding to TSH receptor. Binding of biotinylated rhTSH to immobilized porcine TSH receptor was inhibited by either rhTSH control or PEGylated rhTSH conjugates and IC50 values were measured.
Thyrogen® was biotinylated with 1.7 to 1.8 biotins per protein using the ChromaLink™ Biotin Labeling Reagent according to the manufacturer's protocol (QED Bioscience Inc., San Diego, Calif.) and buffer exchanged into 50 mM sodium phosphate, 150 mM sodium chloride pH 7.0 with a Zeba™ Desalt Spin Column (Thermo Scientific, Rockford, Ill.). In vitro measurement of receptor binding was performed by competition of biotinylated Thyrogen® and PEG-rhTSH conjugate for binding to porcine TSH receptor immobilized onto 96-well plates supplied with the TSH Receptor Autoantibody 2nd Generation ELISA kit from RSR Limited (Kronus, Star, Id.). PEG-rhTSH conjugates were serially diluted 1:5 from 16 μM to 41 pM in assay buffer (100 mM HEPES pH 7.5, 20 mM EDTA, 1% BSA, 0.5% Triton X-100) and mixed 1:1 with biotinylated Thyrogen® diluted 1000-fold in assay buffer. The mixture was added to each receptor-coated well and incubated at 25° C. for 25 minutes. Unbound rhTSH was washed away and streptavidin peroxidase was added at 25° C. for 20 minutes according to the RSR Limited ELISA protocol to determine the amount of biotinylated Thyrogen® bound to the plate. The plate was then washed three times to remove excess unbound streptavidin peroxidase and then tetramethylbenzidine (TMB) was added to each well and incubated in the dark at 25° C. for 30 minutes. The reaction which was quenched with 0.5M sulfuric acid stop buffer and the absorbance of each well was read at 450 nm using a SpectraMax® 340pc plate reader (Molecular Devices, Sunnyvale, Calif.). The data was fit using a sigmoidal dose response equation with GraphPad Prism software to generate IC50 values.
N-terminus and lysine PEGylation yielded conjugates with lower TSH receptor affinity than carbohydrate conjugation. N-terminal mono-PEGylation with 40 kD PEG resulted in 10.8-fold lower receptor binding affinity compared to the TSH control. Lysine-PEGylation with 40 kD PEG resulted in 31.2-fold lower receptor binding affinity compared to the TSH control. In contrast, GAM+ mono-PEGylation resulted in 2.2-fold lower receptor binding affinity for 20 kD PEG conjugation and 3.6-fold lower receptor binding affinity for 40 kD PEG conjugation. SAM mono-PEGylation also resulted in moderate decrease in in vitro TSH receptor binding affinity compared to N-terminal PEGylation, ranging from 2.1- to 5.3-fold decrease, depending on the size of PEG conjugated. GAM(−) mono-PEGylation caused the greatest loss among all the carbohydrate PEGylation strategies, with 20 kD PEG conjugation causing 2.7-fold decrease and 40 kD PEG conjugation, 8.0-fold decrease in in vitro TSH receptor binding affinity. (See Tables 3a and 3b and
The pharmacokinetics of rhTSH and PEGylated rhTSH (20 kD SAM, 20 kD GAM(−), 20 kD GAM(+), 40 kD GAM(+)) was evaluated in male and female rats following a single intramuscular (IM) injection.
A single dose of rhTSH or PEGylated rhTSH (20 kD SAM, 20 kD GAM(−), 20 kD GAM(+), 40 kD GAM(+)) was administered IM to fasted male and female jugular vein cannulated rats at a dose of 0.5 mg/kg. Due to dose volume limitations, animals received test articles in the form of two or three intramuscular injections into quadriceps muscle. Legs were alternated for dosing. Blood samples were collected from the animals pre-dose and at the following post-dosage time points: 0.5, 1, 2, 4, 8, 24, and 48 hours. Food was removed from the animal cages on the evening prior to test article administration. Animals had access to water during this time. Food was added back to cages following pre-dose sample collections and test article administration. Food was removed again at the end of the day such that animals were fasted for the 24 hour post-dose sample collection. Food was added back to cages following sample collection and removed again at the end of the day such that animals were fasted for the 48 hour post-dose sample collection. Blood was collected from the single port jugular cannula. Approximately 400 μl of whole blood was collected into serum separator tubes and processed for serum. The serum was separated into two tubes (˜100 μl each). All samples were stored at −80° C. until they were analyzed for rhTSH or PEGylated rhTSH concentration by TSH ELISA. Following the last sample collection animals were euthanized with CO2.
The PK data showed that 20 kD SAM and 20 kD GAM(−) have >5-fold prolonged t1/2, prolonged Tmax and increased exposure (area under the curve, AUC) compared to rhTSH control. The PK profile of 20 kD GAM(+) showed less improvement compared to 20 kD SAM and 20 kD GAM(−), and 40 kD GAM(+) showed only a moderate improvement. Increased value of Vz (apparent volume of distribution) indicated that GAM(+) conjugates may undergo a receptor-mediated clearance. (See
The pharmacokinetics of PEGylated rhTSH (10 kD multiSAM, 10 kD SAM, 40 kD SAM, 40 kD GAM(−)) was evaluated in male and female rats following a single intramuscular (IM) injection.
A single dose of rhTSH or PEGylated rhTSH (10 kD multiSAM, 10 kD SAM, 40 kD SAM, 40 kD GAM(−)) was administered IM to fasted male and female jugular vein cannulated rats at a dose of 0.5 mg/kg. Due to dose volume limitations, animals received test articles in the form of two or three intramuscular injections into quadriceps muscle. Legs were alternated for dosing. Blood samples were from the animals pre-dose and at the following post-dosage time points: 0.5, 1, 3, 6, 24, 48, 72, and 96 hours. Food was removed from the animal cages on the evening prior to test article administration. Animals had access to water during this time. Food was added back to cages following pre-dose sample collections and test article administration. Food was removed again at the end of each day such that animals were fasted for the post-dose sample collection in the following mornings. Food was added back to cages after each post-dose sample collection. Blood was collected from the single port jugular cannula. Approximately 400 μl of whole blood was collected into serum separator tubes and processed for serum. The serum was separated into two tubes (˜100 μl each). All samples were stored at −80° C. until they were analyzed for rhTSH or
PEGylated rhTSH concentration by TSH ELISA. Following the last sample collection animals were euthanized with CO2.
The PK data showed that 10 kD multi-SAM, 40 kD SAM, and 40 kD GAM(−) have 14-23-fold prolonged t1/2, prolonged Tmax and increased exposure (area under the curve, AUC) compared to rhTSH control. (See
In vivo rat pharmacokinetic studies of PEG conjugates (Examples 13 and 14): Overall, plasma half-life was increased proportional to the size of PEG conjugated to rhTSH as expected. For the same PEG-size SAM and GAM(−) conjugates, there was no apparent difference between the two PEGylation strategies for improvement of PK parameters, unlike receptor binding affinity, suggesting that effect on PK is only PEG-size dependent and not PEGylation-site dependent. For example, both 40 kD SAM and 40 kD GAM(−) showed 23-fold increase in plasma half-life compared to rhTSH control (3.42±0.61 hour) to 77.9±16.9 hours and 80.1±16.1 hours, respectively. MultiPEGylation (10 kD multiSAM) had a greater increase of plasma half-life compared to monoPEGylation of the same size PEG (10 kD SAM). 10 kD multiSAM had 13.7-fold increase to 46.8±10.4 hours compared to rhTSH control whereas 10 kD SAM had only 4.6-fold increase to 15.8±1.23 hour. (See Table 7) PEG-size dependent delay in concentration peak time (Tmax) was also observed. For example, 10 kD, 20 kD and 40 kD SAM showed Tmax at 5.40±1.34 hour, 16.0±8.76 hours and 30.0±12.0 hours, respectively, compared to rhTSH control at 2.00±0.00 hour or 1.50±1.18 hour. (See Table 5 and Table 7).
High binding 96-well ELISA plates were coated with murine anti-hCG capture antibody at 1.33 μg/mL diluted in 0.1M sodium bicarbonate buffer at pH 9.2, and added at 100 μL per well. A standard rhTSH or PEGylated rhTSH curve was prepared from purified protein and diluted in sample dilution buffer (SDB) consisting of 1.0% w/v BSA in 1× plate wash. The standard was diluted from 25-1.463 ng/mL, 8.334-0.488 ng/mL or 5.556 to 0.325 ng/mL using a 2:3 serial dilution scheme, depending on the qualified linear range of rhTSH or PEGylated rhTSH species per assay. Samples were diluted in SDB at no less than a 1:10 dilution. 500 ng/mL, and 25 ng/mL rhTSH controls prepared in normal rat serum are diluted 1:100 and 1:10 respectively in SDB. A 0.5 ng/mL rhTSH control prepared in SDB was added undiluted. Coated plates were washed and 100 μL of samples, standards and controls were added to the plates and incubated for 1 hour at 37° C.
Biotinylated anti-rhTSH monoclonal detection antibody (clone TS8) was diluted in SDB according to the appropriate dilution specific to each lot. Plates were washed and 100 μL of the diluted biotinylated detection antibody was added to the wells and incubated for 1 hour at 37° C.
Streptavidin-horseradish peroxidase conjugate (SA-HRP) was diluted in SDB according to the appropriate dilution specific to each lot. Plates were washed and 1004, of the diluted SA-HRP was added to the wells and incubated for 15 minutes at 25° C.
The plates were washed and 100 μL of tetramethyl benzidine (TMB) substrate was added to all wells, and incubated for 20 minutes at 25° C.
100 μL of TMB stop buffer was added to all wells, and the plate was read at 450 nm.
The pharmacodynamics of PEGylated rhTSH was evaluated in male mice following a single IP injection, three days post T3 pellet implantation. In this mouse PD model, the endogenous mouse T4 was suppressed during the study period by implantation of slow-release T3 pellet three days prior to dosing (See vehicle group in
Animals were anesthetized with isoflurane and a 0.1 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation, a single dose of rhTSH (0.4 or 4.0 mg/kg) or PEGylated rhTSH (4 mg/kg) was administered IP to male mice (ICR strain, 6 weeks of age, Taconic Farms). Animals were anesthetized with isoflurane and blood samples were collected from the retro-orbital plexus. Group 1 blood samples were collected pre-dose (animals 1-4), 6 (animals 5-8), 24, 48 and 72 hours following test article administration. Blood samples from all other groups were collected at 6, 24, 48, and 72 hours following test article administration. Approximately 60 μl of whole blood was collected into micro-hematocrit capillary tubes and processed for serum. Following the last sample collection, animals were euthanized with CO2. All serum samples were stored at −80° C. until they were analyzed for T4 concentrations by the ACE® clinical chemistry T4 assay. Serum T4 concentration was measured by ACE clinical chemistry system (Alfa Wassermann Diagnostic Technologies, LLC) according to manufacturer's protocol.
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. At 6 hours, all treatments significantly (p<0.001) increased T4 compared to vehicle (
The pharmacodynamics of PEGylated rhTSH (40 kD SAM) was evaluated at three different dose levels in male mice following a single intraperitoneal (IP) injection, three days post T3 pellet implantation.
Animals were anesthetized with isoflurane and a 0.1 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation a single dose of rhTSH or PEGylated rhTSH (40 kD SAM) was administered IP to male mice (ICR strain, 6 weeks of age, Taconic Farms) at a dose of 0.04 mg/kg (
Following the last sample collection, animals were euthanized with CO2. All serum samples were stored at −80° C. until they were analyzed for T4 concentrations by the ACE® clinical chemistry T4 assay. Serum T4 concentration was measured by ACE clinical chemistry system (Alfa Wassermann Diagnostic Technologies, LLC) according to manufacturer's protocol.
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. All doses of rhTSH showed equivalent AUEC and elicited an apparent maximal effect at the top of the dose response curve. 40 KD SAM exhibited AUEC representing a full dose response curve, from no effect, to modest effect, to apparent maximal effect. The rhTSH treatment increased T4 levels at all doses at 6 hours and then decreased to the vehicle-like levels of T4 at 24 hours except for the highest dose, 4 mg/kg, which showed T4 levels returning to vehicle levels at 48 hours post-dose. Prolongation of effect with 40 KD SAM was dependent upon dose in this mouse PD model, most significant at 4 mg/kg dose level. Only a mild enhancement of effect was seen with 0.4 mg/kg level.
The pharmacodynamics of PEGylated rhTSH was evaluated in male and female rats following a single intramuscular (IM) injection, three days post T3 pellet implantation.
Animals were anesthetized with isoflurane and a 1.5 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation, a single dose of rhTSH or PEGylated rhTSH was administered IM to male and female jugular vein cannulated rats at a dose of 0.0 mg/kg (vehicle), 0.04 mg/kg, 0.4 mg/kg, or 0.65 mg/kg. For 40 kD multiSAM and 50 kD multiSAM, 0.65 mg/kg dose was determined based on the content of monoPEGylated species. Due to dose volume limitations, animals received test articles in the form of two intramuscular injections into the quadriceps muscle. Legs were alternated for dosing. Blood samples were collected from the animals pre-dose and at the following post-dosage time points: 1, 3, 6, 24, 48, 72, 96, 120, 144, and 168 hours. Blood was collected from the single port jugular cannula. Approximately 250 μl of whole blood was collected into serum separator tubes and the blood was allowed to clot for a minimum of 30 minutes. Tubes were spun in a centrifuge at 10,000 rpm for 5 minutes and the serum was separated into two tubes (˜50 μl each). All samples were stored at −80° C. until they were analyzed for T4 concentrations by the ACE® clinical chemistry T4 assay. Following the last sample collection animals were euthanized with CO2. Serum T4 concentration was measured by ACE clinical chemistry system (Alfa Wassermann Diagnostic Technologies, LLC) according to manufacturer's protocol.
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. The Tmax of rhTSH occurred at 6 hours post-dose and returned to baseline (i.e., vehicle group levels) by 72 hour post-dose. 10 KD multiSAM Tmax occurred at 24 hours post-dose and returned to baseline at 72 hours post-dose for 0.04 mg/kg dose and 96 hours post-dose for 0.4 mg/kg dose. Low dose data showed decreased potency of 10 KD multiSAM relative to rhTSH in this model, which may reflect decreased TSH receptor binding affinity. High dose data confirmed enhanced pharmacodynamic effects with 10 KD multiSAM at 48 and 72 hours post-dose. All candidates including 40 kD multiSAM and 50 kD multiSAM showed enhanced T4 response compared to rhTSH at 0.4 mg/kg, which might have been in part mediated by shift in Tmax to 24 hours post-dose. Prolonged pharmacodynamic activity was observed through 96-120 hours post-dose. (For 40 kD multiSAM and 50 kD multiSAM, 0.65 mg/kg dose equaled to 0.4 mg/kg based on the percentage content of monoPEGylated species in these conjugates.) For all test articles, approximately 95% of the pharmacodynamic effects were observed within 96 hours post-dose following intramuscular administration. Higher AUECs observed with PEGylated conjugates is driven by higher T4 levels between 24-96 hours post-dose. For the 0-96 hour period, 10 KD multiSAM exhibited 1.3-fold of rhTSH AUEC, 40 KD SAM, 1.5-fold, 40 KD multiSAM, 1.7-fold, and 50 KD multiSAM, 1.9-fold. (Table 12,
The pharmacodynamics of PEGylated rhTSH was evaluated in male and female rats following a single intramuscular (IM) injection, three days post T3 pellet implantation.
Animals were anesthetized with isoflurane and a 1.5 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation, a single dose of rhTSH or PEGylated rhTSH was administered IM to male and female jugular vein cannulated rats at a dose of 0.0 mg/kg (vehicle), 0.4 mg/kg, or 0.65 mg/kg. For 50 kD multiSAM, 0.65 mg/kg dose was determined based on the content of monoPEGylated species. Due to dose volume limitations, animals received test articles in the form of two intramuscular injections into the quadriceps muscle. Legs were alternated for dosing. Blood samples were collected from the animals pre-dose and at the following post-dosage time points: 6 (
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. (See
The pharmacodynamics of PEGylated rhTSH (10KD MultiSAM and 40KD SAM) was evaluated in male and female rats following a single intramuscular (IM) injection, three days post T3 pellet implantation.
Animals were anesthetized with isoflurane and a 1.5 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation, a single dose of vehicle or PEGylated rhTSH (10KD MultiSAM or 40KD SAM) was administered IM to male and female jugular vein cannulated rats at a dose of 0.0 mg/kg (vehicle), 0.1, 0.2, 0.4, or 1.0 mg/kg as specified in Table 15. Due to dose volume limitations, animals received test articles in the form of two intramuscular injections into the quadriceps muscle. Legs were alternated for dosing. Blood samples were collected from the animals pre-dose and at the following post-dosage time points: 6, 24, 48, 72, 96, and 168 hours. Blood was collected from the single port jugular cannula. Approximately 250 μl of whole blood was collected into serum separator tubes and the blood was allowed to clot for a minimum of 30 minutes. Tubes were spun in a centrifuge at 10,000 rpm for 5 minutes and the serum was separated into two tubes (˜50 μl each). All samples were stored at −80° C. until they were analyzed for T4 concentrations by the ACE clinical chemistry T4 assay. Following the last sample collection animals were euthanized with CO2. Serum T4 concentration was measured by ACE clinical chemistry system (Alfa Wassermann Diagnostic Technologies, LLC) according to manufacturer's protocol.
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. (See
The pharmacodynamics of PEGylated Cys-Mutant TSH (40KD G22C) was evaluated and compared to the pharmacodynamics of rhTSH and 40 kD SAM PEGylated rhTSH in T3 pellet implanted Sprague Dawley rats.
Animals were anesthetized with isoflurane and a 1.5 mg T3 pellet (T-261, Innovative Research of America) was implanted subcutaneously using a trochar. At three days post pellet implantation, a single dose of vehicle, rhTSH, PEGylated rhTSH (40KD SAM), or PEGylated Cys-mutant TSH (40KD G22C) was administered IM to male and female jugular vein cannulated rats at a dose of 0.0 mg/kg (vehicle), 0.2 or 0.4 mg/kg. Due to dose volume limitations, animals received test articles in the form of two intramuscular injections into the quadriceps muscle. Legs were alternated for dosing. Blood samples were collected from the animals pre-dose and at the following post-dosage time points: 6, 24, 48, 72, 96, and 168 hours. Blood was collected from the single port jugular cannula. Approximately 250 μl of whole blood was collected into serum separator tubes and the blood was allowed to clot for a minimum of 30 minutes. Tubes were spun in a centrifuge at 10,000 rpm for 5 minutes and the serum was separated into two tubes (˜50 μl each). All samples were stored at −80° C. until they were analyzed for T4 concentrations by the ACE clinical chemistry T4 assay. Following the last sample collection animals were euthanized with CO2. Serum T4 concentration was measured by ACE clinical chemistry system (Alfa Wassermann Diagnostic Technologies, LLC) according to manufacturer's protocol.
Data from vehicle-treated animals indicated model validity due to T4 suppression for duration of study via subcutaneous T3 pellet. (See
The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
This application is a continuation of U.S. application Ser. No. 15/852,581, filed Dec. 22, 2017, which is a continuation of U.S. application Ser. No. 15/096,879, filed Apr. 12, 2016, now abandoned, which is a continuation of U.S. application Ser. No. 15/005,451, filed Jan. 25, 2016, now abandoned, which is a continuation of U.S. application Ser. No. 14/308,284, filed Jun. 18, 2014, now abandoned, which is a continuation of International Application PCT/US2012/067705, filed Dec. 4, 2012, which claims priority from U.S. Provisional Application 61/577,412, filed Dec. 19, 2011. The disclosures of the aforementioned priority applications are incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61577412 | Dec 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15852581 | Dec 2017 | US |
| Child | 17751433 | US | |
| Parent | 15096879 | Apr 2016 | US |
| Child | 15852581 | US | |
| Parent | 15005451 | Jan 2016 | US |
| Child | 15096879 | US | |
| Parent | 14308284 | Jun 2014 | US |
| Child | 15005451 | US | |
| Parent | PCT/US2012/067705 | Dec 2012 | US |
| Child | 14308284 | US |
