Patent Application
20220298223
Chimeric antigen receptors (CARs), which are at times referred to as artificial T cell receptors, chimeric T cell receptors (cTCR), or chimeric immunoreceptors, are engineered receptors now well known in the art. They are used primarily to transform immune effector cells, in particular T cells, to provide those cells with a desired engineered specificity. Adoptive cell therapies using CAR-T cells are particularly under investigation in the field of cancer therapy. In these therapies, T cells are removed from a patient and modified so that they express CARs specific to the antigens found in a particular form of cancer. The CAR-T cells, which can then recognize and kill the cancer cells, are reintroduced into the patient.
First generation CARs provide a TCR-like signal, most commonly using a CD3 zeta (z) intracellular signaling domain, and thereby elicit tumoricidal functions. However, the engagement of CD3z-chain fusion receptors may not suffice to elicit substantial IL-2 secretion and/or T cell proliferation in the absence of a concomitant co-stimulatory signal. In physiological T cell responses, optimal lymphocyte activation requires the engagement of one or more co-stimulatory receptors such as CD28 or 4-1BB.
Second (2nd) generation CARs have been constructed to transduce a functional antigen-dependent co-stimulatory signal in human primary T cells in addition to antigen-dependent TCR-like signal, permitting T cell proliferation in addition to tumoricidal activity. Second generation CARs most commonly provide co-stimulation using co-stimulatory domains (synonymously, co-stimulatory signaling regions) derived from CD28 or 4-1BB. The combined delivery of co-stimulation plus a CD3 zeta signal renders 2nd generation CARs clearly superior in terms of function as compared to their first generation counterparts (CD3z signal alone). An example of a 2nd generation CAR is found in U.S. Pat. No. 7,446,190, incorporated herein by reference.
More recently, so-called 3rd generation CARs have been prepared. These combine multiple co-stimulatory domains (synonymously, co-stimulatory signaling regions) with a TCR-like signaling domain in cis, such as CD28+4-1BB+CD3z or CD28+OX40+CD3z, to further augment potency. In the 3rd generation CARs, the co-stimulatory domains are aligned in series in the CAR endodomain and are generally placed upstream of CD3z or its equivalent.
In general, however, the results achieved with these third generation CARs have been disappointing, showing only a marginal improvement over 2nd generation configurations, with some 3rd generation CARs being inferior to 2nd generation configurations.
We have recently described a new format in which immuno-responsive cells such as T cells are engineered to express two constructs in parallel, a 2nd generation CAR and a chimeric co-stimulatory receptor (CCR). The 2nd generation CAR comprises, from C-terminus to N-terminus (from intracellular to extracellular), the following domains: (a) a signaling region; (b) a co-stimulatory signaling region; (c) a transmembrane domain; and (d) a first binding element that specifically interacts with a first epitope on a first target antigen. The CCR comprises, from C-terminus to N-terminus (from intracellular to extracellular), (a) a co-stimulatory signaling region which is different from the co-stimulatory signaling region of the CAR; (b) a transmembrane domain; and (c) a second binding element that specifically interacts with an epitope on a target antigen. The CAR and CCR may recognize an identical epitope, different epitopes on the same antigen, or epitopes found on two distinct antigens. Unlike the CAR, the CCR lacks a TCR-like signaling region such as CD3z. These parallel CAR (pCAR)-engineered T cells demonstrate superior activity and resistance to exhaustion as compared to 1st generation CAR-T cells, 2nd generation CAR-T cells, and 3rd generation CAR-T cells. See US pre-grant publication 2019/0002521, incorporated herein by reference in its entirety.
These properties of pCAR-T cells make them attractive candidates for treatment of refractory malignancies, where 1st, 2nd and 3rd generation CAR-T cells show limited efficacy in part due to T cell exhaustion. However, there is an additional need for antigen target combinations that enable the broadened therapeutic application of this technology.
The applicants have found that effective T cell responses can be induced using a combination of constructs in which multiple co-stimulatory regions are arranged in distinct constructs. In particular, provided herein are effective pCAR-T cells having parallel CAR (pCAR) constructs that bind to one or more antigens present on a target cell derived from the B cell lineage. In some embodiments, the pCAR constructs comprise a CAR (chimeric antigen receptor) comprising a binding element that specifically binds to an epitope found in CD19 on a target cell and a CCR (chimeric costimulatory receptor) that binds either to CD19, or to another B cell lineage specific marker. Examples of the latter include, but are not restricted to CD20, CD22, CD23, CD79a and CD79b.
Thus, according to some embodiments, provided herein is an immuno-responsive cell expressing:
When a T cell expressing a B cell targeting pCAR construct binds to a cell expressing one or more antigens with both epitope targets (for the CAR and CCR), both the CAR and CCR send stimulatory signals to enhance the response of the T cell.
Constructs of the type of the invention may be called “parallel chimeric activating receptors” or “pCAR.” The applicants have found that the pCARs described herein are superior to 2nd generation CAR-T cells having similar elements in both in vitro and in vivo experiments.
In addition, the proliferation of the T cells, their ability to retain cytotoxic potency and to release IL-2 is maintained over many repeated rounds of stimulation with antigen-expressing tumor cells.
In some embodiments, the first epitope recognized by the CAR component of the pCAR is an epitope on a CD19 target antigen. In some embodiments, said first binding element comprises the complementarity determining regions (CDRs) of the FMC63 antibody and have sequences of SEQ ID NO: 10, 11, 12, 13, 14 and 15. In some embodiments, said first binding element comprises the variable heavy (VH; GenBank accession number CAA74659.1) and variable light (VL; GenBank accession number CAA74660.1) domains of the FMC63 antibody and have sequences of SEQ ID NO: 16 and 17. In some embodiments, said first binding element comprises an FMC63 single-chain variable fragment (scFv), which comprises the variable heavy (VH) and variable light (VL) domains of the FMC63 antibody and has the sequence of SEQ ID NO: 18 or 19. In some embodiments, the FMC63 scFv was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 118.
In some preferred embodiments, the said first binding element comprises a variant of the FMC63 antibody or scFv in which a single G->A or Y->A mutation has been introduced into the CDR3 of the VH domain and have the modified VH CDR3 sequences of SEQ ID NO: 20, 21, 22, 23, 24, 25 and 26. In some preferred embodiments, the mutated FMC63 scFv was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 119, 120, 121, 122, 123, 124 or 125.
In some embodiments, the second epitope recognized by the chimeric co-stimulatory receptor (CCR) component of the pCAR is also an epitope on a CD19 target antigen. In some embodiments, the second binding element comprises the complementarity determining regions (CDRs) of the FMC63 antibody and have sequences of SEQ ID NO: 10, 11, 12, 13, 14 and 15. In some embodiments, the second binding element comprises the variable heavy (VH) and variable light (VL) domains of the FMC63 antibody and have sequences of SEQ ID NO: 16 and 17. In some preferred embodiments, said second binding element comprises an FMC63 antibody or scFv, which comprises the variable heavy (VH) and variable light (VL) domains of the FMC63 antibody and has the sequence of SEQ ID NO: 18 or 19. In some preferred embodiments, the FMC63 scFv was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 118.
In some embodiments, the CAR and CCR bind to the same epitope within the CD19 antigen. In some preferred embodiments, the pCARs were designated FBB/G01, FBB/G02, FBB/Y01, FBB/Y02, FBB/Y03, FBB/Y04 and FBB/Y05 respectively and have the sequence of SEQ ID NO: 47, 48, 49, 50, 51, 52 or 53. Nomenclature derives from an abbreviation of the following elements: CCR binder (FMC63 scFv), CCR signaling domain (4-1BB)/CAR binder (G01-Y05 mutated scFv respectively). In some embodiments, the CAR of FBB/G01, FBB/G02, FBB/Y01, FBB/Y02, FBB/Y03, FBB/Y04 and FBB/Y05 comprises the sequences of SEQ ID NOs: 56, 58, 59, 60, 61, 62, and 63 respectively and the CCR comprises the sequence of SEQ ID NO: 57. In some preferred embodiments, these pCARs were expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 109, 110, 111, 112, 113, 114 or 115 respectively. In some embodiments, the pCAR is a polypeptide having at least 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 47, 48, 49, 50, 51, 52 or 53. In some embodiments, the pCAR is a polypeptide having at least about 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 47, 48, 49, 50, 51, 52 or 53.
In some embodiments, the CAR and CCR bind to distinct epitopes within the CD19 antigen.
In some embodiments, the CAR binds to CD19 while the CCR binds to a distinct B cell lineage antigen, such as CD20, CD22, CD23, CD79a or CD79b.
In some embodiments, the CAR binds to CD19 while the CCR binds to CD20. In some preferred embodiments, the second binding element which directs CCR specificity comprises the complementarity determining regions (CDRs) of the 1F5 antibody and have sequences of SEQ ID NO: 27, 28, 29, 30, 31 and 32. In some preferred embodiments, said second binding element comprises the variable heavy (VH; GenBank accession number AAL27650.1) and variable light (VL; GenBank accession number AAL27649.1) domains of the 1F5 antibody and have sequences of SEQ ID NO: 33 and 34. In some preferred embodiments, said second binding element comprises an 1F5 scFv, which comprises the variable heavy (VH) and variable light (VL) domains of the 1F5 antibody and has the sequence of SEQ ID NO: 35 or 36. In some preferred embodiments, the 1F5 scFv was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 126. In some preferred embodiments, the pCAR was designated 1BB/F and has the sequence of SEQ ID NO: 54. Nomenclature derives from an abbreviation of the following elements: CCR binder (1F5 scFv), CCR signaling domain (4-1BB)/CAR binder (FMC63 scFv). In some embodiments, the CAR of 1BB/F comprises the sequence of SEQ ID NO: 64 and the CCR of 1BB/F comprises the sequence of SEQ ID NO: 65. In some preferred embodiments, the 1BB/F pCAR was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 116. In some embodiments, the pCAR is a polypeptide having at least 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 54. In some embodiments, the pCAR is a polypeptide having at least about 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 54.
In some embodiments, the CAR binds to CD19 while the CCR binds to CD22. In some preferred embodiments, the second binding element which directs CCR specificity comprises the complementarity determining regions (CDRs) of the RFB4 antibody and have sequences of SEQ ID NO: 37, 38, 39, 40, 41 and 42. In some preferred embodiments, said second binding element comprises the variable heavy (VH; GenBank accession number CAJ09937.1) and variable light (VL; GenBank accession number CAJ09936.1) domains of the RFB4 antibody and have sequences of SEQ ID NO: 43 and 44. In some preferred embodiments, said second binding element comprises an RFB4 scFv, which comprises the variable heavy (VH) and variable light (VL) domains of the RFB4 antibody and have the sequence of SEQ ID NO: 45 or 46. In some preferred embodiments, the RFB4 scFv was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 127. In some preferred embodiments, the pCAR was designated RBB/F and has the sequence of SEQ ID NO: 55. Nomenclature derives from an abbreviation of the following elements: CCR binder (RFB4 scFv), CCR signaling domain (4-1BB)/CAR binder (FMC63 scFv). In some embodiments, the CAR of 1BB/F comprises the sequence of SEQ ID NO: 64 and the CCR of 1BB/F comprises the sequence of SEQ ID NO: 66. In some preferred embodiments, the RBB/F pCAR was expressed from a polynucleotide or set of polynucleotides of SEQ ID NO: 117. In some embodiments, the pCAR is a polypeptide having at least 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 55. In some embodiments, the pCAR is a polypeptide having at least about 85%, 90%, 95%, 97%, 98%, 99% or 100% sequence identity to SEQ ID NO: 55.
In some embodiments, said immuno-responsive cell is an αβ T cell, γδ T cell, or a Natural Killer (NK) cell. In some embodiments, said T cell is an αβ T cell. In some embodiments, said T cell is a γδ T-cell.
In some embodiments, the polynucleotide or set of polynucleotides comprise: (a) a first nucleic acid encoding a CCR that binds to a B cell lineage antigen and; (b) a second nucleic acid encoding a CAR that binds to CD19. In some embodiments, said first nucleic acid and said second nucleic acid are in a single vector. In some embodiments, said first nucleic acid and said second nucleic acid are in two separate vectors.
In one aspect, the present invention provides a method of preparing the immuno-responsive cell, said method comprising transfecting or transducing the polynucleotide or set of polynucleotides provided herein into an immuno-responsive cell.
In another aspect, the present disclosure provides a method for directing a T cell-mediated immune response to a target cell in a patient in need thereof, said method comprising the administration to the patient of the immuno-responsive cell, wherein the target cell is a B cell.
In yet another aspect, the present disclosure provides a method of treating cancer, said method comprising the administration to the patient of an effective amount of the immuno-responsive cell. In some embodiments, the patient's cancer expresses CD19. In some embodiments, the patient has a cancer arising from the B cell lineage. In some embodiments, the patient has a cancer selected from the group consisting of acute or chronic B cell leukemia or B cell lymphoma.
In another aspect, the present disclosure provides the use of immuno-responsive cells for use in a therapy or as a medicament. The disclosure further provides immuno-responsive cells in the manufacture of a medicament for the treatment of a pathological disorder. In some embodiments, the pathological disorder is cancer.
The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the invention.
To enable bioluminescence and fluorescence imaging of cells and derived xenografts, tumor cell lines were transduced with the LT retroviral vector that encodes for both firefly luciferase enzyme and the red fluorescent protein (RFP), tandem dimer (td)Tomato. Expression of RFP was confirmed using flow cytometry, as indicated in
The CDR3 region of the VH domain within the FMC63 scFv was identified using www.abysis.org. To generate variants with an altered ability to bind CD19, an alanine (A) residue was substituted for the first or second glycine (G01, G02) or alternatively for the first, second, third, fourth or fifth tyrosine (Y01-Y05) within CDR3 of the said VH domain, as illustrated in
1-2 is a 2nd generation CAR in which targeting is achieved using the 1F5 scFv, as described in Budde et al., PLoS One 8(12): e82742 (2013) and incorporated herein by reference in its entirety. It comprises, from C-terminus to N-terminus (intracellular to extracellular), a CD3z signaling region, CD28 co-stimulatory and transmembrane domains, a CD28 hinge/spacer domain that contains an embedded myc epitope tag and a human CD20-targeting 1F5 single chain antibody (scFv) domain. Cells transduced with 1-2 alone are standard 2nd generation CAR-T cells and are used for comparative purposes.
R-2) is a 2nd generation CAR in which targeting is achieved using the RFB4 scFv, as described in James et al., J. Immunol. 180(10):7028-38 (2008) and incorporated herein by reference in its entirety. It comprises, from C-terminus to N-terminus (intracellular to extracellular), a CD3z signaling region, CD28 co-stimulatory and transmembrane domains, a CD28 hinge/spacer domain that contains an embedded myc epitope tag and a human CD22-targeting RFB4 single chain antibody (scFv) domain. Cells transduced with R-2 alone are standard 2nd generation CAR-T cells and are used for comparative purposes.
A series of B cell targeted pCARs (
The details of various embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and the drawings, and from the claims.
Unless otherwise defined herein, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. As used herein, the following terms have the meanings ascribed to them below.
As used herein, the term “variant” refers to a polypeptide sequence which is a naturally occurring polymorphic form of the basic sequence as well as synthetic variants, in which one or more amino acids within the chain are inserted, removed or replaced. However, the variant produces a biological effect which is similar to that of the basic sequence. For example, a variant of the intracellular domain of human CD3 zeta chain will act in a manner similar to that of the intracellular domain of human CD3 zeta chain. Amino acid substitutions may be regarded as “conservative” where an amino acid is replaced with a different amino acid in the same class with broadly similar properties. Non-conservative substitutions are where amino acids are replaced with amino acids of a different type or class.
As is well known to those skilled in the art, altering the primary structure of a peptide by a conservative substitution may not significantly alter the activity of that peptide because the side-chain of the amino acid which is inserted into the sequence may be able to form similar bonds and contacts as the side chain of the amino acid which has been substituted out. This is so even when the substitution is in a region which is critical in determining the peptide's conformation. Non-conservative substitutions may also be possible provided that these do not interrupt the function of the polypeptide as described above. Broadly speaking, fewer non-conservative substitutions will be possible without altering the biological activity of the polypeptides. In general, variants will have amino acid sequences that will be at least 70%, for instance at least 71%, 75%, 79%, 81%, 84%, 87%, 90%, 93%, 95%, 96% or 98% identical to the basic sequence, for example SEQ ID NO: 1 or SEQ ID NO: 2. Identity in this context may be determined using the BLASTP computer program with SEQ ID NO: 1, SEQ ID NO: 2, or a fragment thereof, in particular a fragment as described below, as the base sequence. The BLAST software is publicly available.
As used herein, the term “antigen” refers to any member of a specific binding pair that will bind to the binding elements. The term includes receptors on target cells.
As used herein and with regard to the binding element to a target molecule, the terms “bind,” “specific binding,” “specifically binds to,” “specifically interacts with,” “specific for,” “selectively binds,” “selectively interacts with,” and “selective for” a particular antigen (e.g., a polypeptide target) or an epitope on a particular antigen mean binding that is measurably different from a non-specific or non-selective interaction (e.g., with a non-target molecule). Specific binding can be measured, for example, by measuring binding to a target molecule and comparing it to binding to a non-target molecule. Specific binding can also be determined by competition with a control molecule that mimics the epitope recognized on the target molecule.
The term “pCAR” as used herein refers to a parallel chimeric antigen receptor which comprises the combination of a 2nd generation chimeric antigen receptor (CAR) and, in parallel, a chimeric co-stimulatory receptor (CCR). pCAR has been described in WO2017/021701, which is incorporated by reference in its entirety herein.
In the claims, articles such as “a,” “an,” and “the” may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that include “or” between one or more members of a group are considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. The invention includes embodiments in which exactly one member of the group is present in, employed in, or otherwise relevant to a given product or process. The invention includes embodiments in which more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process.
It is also noted that the term “comprising” is intended to be open and permits but does not require the inclusion of additional elements or steps. When the term “comprising” is used herein, the term “consisting of” is thus also encompassed and disclosed.
Where ranges are given, endpoints are included. Furthermore, it is to be understood that unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or subrange within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise.
All cited sources, for example, references, publications, databases, database entries, and art cited herein, are incorporated into this application by reference, even if not expressly stated in the citation. In case of conflicting statements of a cited source and the instant application, the statement in the instant application shall control.
Section and table headings are not intended to be limiting.
In a first aspect, immuno-responsive cells are provided. The immuno-responsive cells express a pCAR which comprises the combination of a 2nd generation chimeric antigen receptor (CAR) and, in parallel, a chimeric co-stimulatory receptor (CCR).
The CAR comprises, from C-terminus to N-terminus (from intracellular to extracellular as expressed within the immuno-responsive cell), (a) a signaling region; (b) a first co-stimulatory signaling region; (c) a first transmembrane domain; and (d) a first binding element that specifically interacts with a first epitope on a CD19 target antigen.
The CCR comprises, from C-terminus to N-terminus (from intracellular to extracellular as expressed within the immuno-responsive cell), (e) a second co-stimulatory signaling region which is different from that of the first co-stimulatory signaling region of the CAR; (f) a second transmembrane domain; and (g) a second binding element that specifically interacts with a second epitope on a second antigen. The second epitope can be identical to or distinct from the first epitope. The second antigen can be CD19 or an alternative B cell lineage-specific antigen.
In typical embodiments, the immuno-responsive cells are T cells.
In certain embodiments, the immuno-responsive cells are αβ T cells. In particular embodiments, the immuno-responsive cells are cytotoxic αβ T cells. In particular embodiments, the immuno-responsive cells are αβ helper T cells. In particular embodiments, the immuno-responsive cells are regulatory αβ T cells (Tregs).
In certain embodiments, the immuno-responsive cells are γδ T cells. In particular embodiments, the immuno-responsive cells are Vδ2+ γδ T cells. In particular embodiments, the immuno-responsive cells are Vδ2− T cells. In specific embodiments, the Vδ2− T cells are Vδ1+ cells.
In certain embodiments, the immuno-responsive cells are Natural Killer (NK) cells.
In some embodiments, the immuno-responsive cell expresses no additional exogenous proteins. In other embodiments, the immuno-responsive cell is engineered to express additional exogenous proteins, such as a cytokine, receptor or derivative thereof.
In some embodiments, the immuno-responsive cells are obtained from peripheral blood mononuclear cells (PBMCs). In some embodiments, the immuno-responsive cells are obtained from tumors. In particular embodiments, the immuno-responsive cells obtained from tumors are tumor infiltrating lymphocytes (TILs). In specific embodiments, the TILs are αβ T cells. In other specific embodiments, the TILs are γδ T cells, and in particular, Vδ2+ or Vδ2− γδ T cells.
The CAR construct comprises a signaling region at its C-terminus. In some embodiments, the signaling region comprises an Immune-receptor-Tyrosine-based-Activation-Motif (ITAM), as reviewed for example by Love et al., Cold Spring Harbor Perspect. Biol. 2(6)1 a002485 (2010). In some embodiments, the signaling region comprises the intracellular domain of human CD3 zeta chain, as described for example in U.S. Pat. No. 7,446,190, incorporated by reference herein, or a variant thereof. In particular embodiments, the signaling region comprises the domain which spans amino acid residues 52-163 of the full-length human CD3 zeta chain. The CD3 zeta chain has a number of known polymorphic forms, (e.g. Sequence ID: gb|AAF34793.1 and gb|AAA60394.1), all of which are useful herein, and shown respectively as SEQ ID NO: 1 and 2:
Alternative signaling regions to the CD3 zeta domain include other ITAM containing units such as Fcεr1γ, CD3ε, DAP12 and multi-ITAM. See Eshhar Z et al., “Specific activation and targeting of cytotoxic lymphocytes through chimeric single chains consisting of antibody-binding domains and the gamma or zeta subunits of the immunoglobulin and T-cell receptors,” Proc Natl Acad Sci USA 90:720-724 (1993); Nolan et al., “Bypassing immunization: optimized design of “designer T cells” against carcinoembryonic antigen (CEA)-expressing tumors, and lack of suppression by soluble CEA,” Clin Cancer Res 5: 3928-3941 (1999); Zhao et al., “A herceptin-based chimeric antigen receptor with modified signaling domains leads to enhanced survival of transduced T lymphocytes and antitumor activity,” J Immunol 183: 5563-5574 (2009), Topfer et al. DAP12-based activating chimeric antigen receptor for NK cell tumor immunotherapy. J Immunol 194: 3201-3212 (2015); and James J R, “Tuning ITAM multiplicity on T cell receptors can control potency and selectivity to ligand density,” Sci Signal 11(531) eaan1088 (2018), the disclosures of which are incorporated herein by reference in their entireties.
In the CAR, the co-stimulatory signaling region is suitably located between the signaling region and transmembrane domain, and remote from the binding element.
In the CCR, the co-stimulatory signaling region is suitably located adjacent the transmembrane domain and remote from the binding element.
Suitable co-stimulatory signaling regions are well known in the art, and include the co-stimulatory signaling regions of members of the B7/CD28 family such as B7-1, B7-2, B7-H1, B7-H2, B7-H3, B7-H4, B7-H6, B7-H7, BTLA, CD28, CTLA-4, Gi24, ICOS, PD-1, PD-L2 or PDCD6; or ILT/CD85 family proteins such as LILRA3, LILRA4, LILRB1, LILRB2, LILRB3 or LILRB4; or tumor necrosis factor (TNF) superfamily members such as 4-1BB, BAFF, BAFF R, CD27, CD30, CD40, DR3, GITR, HVEM, LIGHT, Lymphotoxin-alpha, OX40, RELT, TACI, TL1A, TNF-alpha, or TNF RII; or members of the SLAM family such as 2B4, BLAME, CD2, CD2F-10, CD48, CD8, CD84, CD229, CRACC, NTB-A or SLAM; or members of the TIM family such as TIM-1, TIM-3 or TIM-4; or other co-stimulatory molecules such as CD7, CD96, CD160, CD200, CD300a, CRTAM, DAP12, Dectin-1, DPPIV, EphB6, Integrin alpha 4 beta 1, Integrin alpha 4 beta 7/LPAM-1, LAG-3 or TSLP R. See Mondino A et al., “Surface proteins involved in T cell costimulation,” J Leukoc Biol. 55:805-815 (1994); Thompson C B, “Distinct roles for the costimulatory ligands B7-1 and B7-2 in T helper cell differentiation?,” Cell. 81:979-982 (1995); Somoza C and Lanier L L, “T-cell costimulation via CD28-CD80/CD86 and CD40-CD40 ligand interactions,” Res Immunol. 146:171-176 (1995); Rhodes D A et al., “Regulation of immunity by butyrophilins,” Annu Rev Immunol. 34:151-172 (2016); Foell J et al., “T cell costimulatory and inhibitory receptors as therapeutic targets for inducing anti-tumor immunity”, Curr Cancer Drug Targets. 7:55-70 (2007); Greenwald R J et al., Annu Rev Immunol., “The B7 family revisited,” 23:515-548 (2005); Flem-Karlsen K et al., “B7-H3 in cancer—beyond immune regulation,” Trends Cancer. 4:401-404 (2018); Flies D B et al., “The new B7s: playing a pivotal role in tumor immunity,” J Immunother. 30:251-260 (2007); Gavrieli M et al., “BTLA and HVEM cross talk regulates inhibition and costimulation,” Adv Immunol. 92:157-185 (2006); Zhu Y et al., “B7-H5 costimulates human T cells via CD28H,” Nat Commun. 4:2043 (2013); Omar H A et al., “Tacking molecular targets beyond PD-1/PD-L1: Novel approaches to boost patients' response to cancer immunotherapy,” Crit Rev Oncol Hematol. 135:21-29 (2019); Hashemi M et al., “Association of PDCD6 polymorphisms with the risk of cancer: Evidence from a meta-analysis,” Oncotarget. 9:24857-24868 (2018); Kang X et al., “Inhibitory leukocyte immunoglobulin-like receptors: Immune checkpoint proteins and tumor sustaining factors,” Cell Cycle. 15:25-40 (2016); Watts T H, “TNF/TNFR family members in costimulation of T cell responses,” Annu Rev Immunol. 23:23-68 (2005); Bryceson Y T et al., “Activation, coactivation, and costimulation of resting human natural killer cells,” Immunol Rev. 214:73-91 (2006); Sharpe A H, “Analysis of lymphocyte costimulation in vivo using transgenic and ‘knockout’ mice,” Curr Opin Immunol. 7:389-395 (1995); Wingren A G et al., “T cell activation pathways: B7, LFA-3, and ICAM-1 shape unique T cell profiles,” Crit Rev Immunol. 15:235-253 (1995), the disclosures of which are incorporated herein by reference in their entireties.
The co-stimulatory signaling regions may be selected depending upon the particular use intended for the immuno-responsive cell. In particular, the co-stimulatory signaling regions can be selected to work additively or synergistically together. In some embodiments, the co-stimulatory signaling regions are selected from the co-stimulatory signaling regions of CD28, CD27, ICOS, 4-1BB, OX40, CD30, GITR, HVEM, DR3 and CD40.
In a particular embodiment, one co-stimulatory signaling region of the pCAR is the co-stimulatory signaling region of CD28 and the other is the co-stimulatory signaling region of 4-1BB. In a specific embodiment, the co-stimulatory signaling region of the CAR is the co-stimulatory signaling region of CD28 and the co-stimulatory signaling region of the CCR is the co-stimulatory signaling region of 4-1BB.
In a particular embodiment, one co-stimulatory signaling region of the pCAR is the co-stimulatory signaling region of CD28 and the other is the co-stimulatory signaling region of CD27. In a specific embodiment, the co-stimulatory signaling region of the CAR is the co-stimulatory signaling region of CD28 and the co-stimulatory signaling region of the CCR is the co-stimulatory signaling region of CD27.
The transmembrane domains for the CAR and CCR constructs may be the same or different. In currently preferred embodiments, when the CAR and CCR constructs are expressed from a single vector, the transmembrane domains of the CAR and CCR are different, to ensure separation of the constructs on the surface of the cell. Selection of different transmembrane domains may also enhance stability of the expression vector since inclusion of a direct repeat nucleic acid sequence in the viral vector renders it prone to rearrangement, with deletion of sequences between the direct repeats. In embodiments in which the transmembrane domains of the CAR and CCR of the pCAR are chosen to be the same, this risk can be reduced by modifying or “wobbling” the codons selected to encode the same protein sequence.
Suitable transmembrane domains are known in the art and include for example, the transmembrane domains of CD8a, CD28, CD4 or CD3z. Selection of CD3z as transmembrane domain may lead to the association of the CAR or CCR with other elements of TCR/CD3 complex. This association may recruit more ITAMs but may also lead to the competition between the CAR/CCR and the endogenous TCR/CD3.
In certain embodiments, one transmembrane domain of the pCAR is the transmembrane domain of CD28 and the other is the transmembrane domain of CD8a. In a particular pCAR embodiment, the transmembrane domain of the CAR is the transmembrane domain of CD28 and the transmembrane domain of the CCR is the transmembrane domain of CD8a.
In embodiments in which the co-stimulatory signaling region of the CAR or CCR is, or comprises, the co-stimulatory signaling region of CD28, the CD28 transmembrane domain represents a suitable, often preferred, option for the transmembrane domain. The full length CD28 protein is a 220 amino acid protein of SEQ ID NO: 3, where the transmembrane domain is shown in bold type:
In some embodiments, one of the co-stimulatory signaling regions is based upon the hinge region and suitably also the transmembrane domain and endodomain of CD28. In some embodiments, the co-stimulatory signaling region comprises amino acids 114-220 of SEQ ID NO: 3, shown below as SEQ ID NO: 4:
In a particular embodiment, one of the co-stimulatory signaling regions is a modified form of SEQ ID NO: 4 which includes a c-myc tag of SEQ ID NO: 5:
The c-myc tag may be added to the co-stimulatory signaling region by insertion into the ectodomain or by replacement of a region in the ectodomain, which is therefore within the region of amino acids 1-152 of SEQ ID NO: 3.
In a particularly preferred embodiment, the c-myc tag replaces MYPPPY motif in the CD28 sequence. This motif represents a potentially hazardous sequence. It is responsible for interactions between CD28 and its natural ligands, CD80 and CD86, so that it provides potential for off-target toxicity when CAR-T cells or pCAR-T cells encounter a target cell that expresses either of these ligands. By replacement of this motif with a tag sequence as described above, the potential for unwanted side-effects is reduced. Thus, in a particular embodiment, the co-stimulatory signaling region of the CAR construct comprises SEQ ID NO: 6:
Furthermore, the inclusion of a c-myc epitope facilitates detection of the pCAR-T cells using a monoclonal antibody to the c-myc epitope. This is very useful since flow cytometric detection had proven unreliable when using some available antibodies.
In addition, the provision of a c-myc epitope tag could facilitate the antigen-independent expansion of targeted CAR-T cells, for example by cross-linking of the CAR using the appropriate monoclonal antibody, either in solution or immobilized onto a solid phase (e.g., a bag).
Moreover, expression of the epitope for the anti-human c-myc antibody, 9e10, within the variable region of a TCR has previously been shown to be sufficient to enable antibody-mediated and complement mediated cytotoxicity both in vitro and in vivo. See Kieback et al. Proc. Natl. Acad. Sci. USA, 105(2) 623-8 (2008). Thus, the provision of such epitope tags could also be used as a “suicide system,” whereby an antibody could be used to deplete pCAR-T cells in vivo in the event of toxicity.
In some embodiments, one of the co-stimulatory signaling regions is based upon the endodomain of 4-1BB. In some embodiments, the co-stimulatory signaling region comprises amino acids 214-255 of 4-1BB shown below as SEQ ID NO: 7:
In a particular embodiment, one of the co-stimulatory signaling regions is a modified form of SEQ ID NO: 7 which includes a FLAG epitope tag of SEQ ID NO: 8:
In a particularly preferred embodiment, the FLAG epitope tag is appended to the C-terminus of the 4-1BB endodomain. Thus, in a particular embodiment, the co-stimulatory signaling region of the CCR comprises SEQ ID NO: 9:
The binding elements of the CAR and CCR constructs of the pCAR respectively bind a first epitope and a second epitope which may be identical or distinct.
In some embodiments, the binding elements of the CAR and CCR constructs are identical. More commonly however, these binding elements are different from one another.
In various embodiments, the binding elements of the CAR and CCR specifically bind to a first epitope and second epitope of the same antigen. In certain of these embodiments, the binding elements of the CAR and CCR specifically bind to the same, overlapping, or different epitopes of the same antigen. In embodiments in which the first and second epitopes are the same or overlapping, the binding elements on the CAR and CCR can compete in their binding. In such embodiments, elements that bind with different affinity may be employed in order to achieve an optimal balance of signaling by the CAR and CCR components of the pCAR.
In various embodiments, the binding elements of the CAR and CCR components of the pCAR bind to different antigens. In certain embodiments, the antigens are different but may be associated with the same disease, such as the same specific cancer derived from the B cell lineage.
In a preferred embodiment, the CAR binds to CD19 while the CCR binds either to CD19 or to another B cell lineage-specific marker. Examples of the latter include, but are not restricted to CD20, CD22, CD23, CD79a and CD79b.
Thus, suitable binding elements may be any element which provides the pCAR with the ability to recognize a target of interest. The target to which the pCARs of the invention are directed can be any target of clinical interest to which it would be desirable to direct a T cell response.
In various embodiments, the binding elements used in the CARs and CCRs of the pCARs described herein are antigen binding sites (ABS) of antibodies. In typical embodiments, the ABS used as the binding element is formatted into an scFv or is a single domain antibody from a camelid, human or other species.
Alternatively, a binding element of a pCAR may comprise ligand(s) that bind to a surface protein of interest.
Alternatively, a binding element of a pCAR may comprise peptide(s) that bind to a surface protein of interest.
In some embodiments, the binding element is associated with a leader sequence which facilitates expression on the cell surface. Many leader sequences are known in the art, and these include the macrophage colony stimulating factor receptor (FMS) leader sequence, the CD8a leader sequence or the CD124 leader sequence.
In particular embodiments, the binding element of CAR or the binding element of CCR specifically interacts with an epitope on the CD19 target antigen. CD19 is a B-lymphocyte antigen encoded by the CD19 gene and is found on the surface of B cells. It is a known target for the treatment of B cell malignancies such as leukemia or non-Hodgkin's lymphoma. It has also been implicated in autoimmune diseases and so may be a target in the treatment of such conditions.
In some embodiments, the binding element of the CAR specifically interacts with an epitope on the CD19 antigen. In some embodiments, the binding element of the CCR specifically interacts with an epitope on the CD19 target antigen. In certain embodiments, the binding element of the CAR specifically interacts with an epitope on the CD19 antigen and the binding element of the CCR specifically interacts with the same, overlapping, or different epitope on the CD19 target antigen.
In currently preferred embodiments, the CAR and/or the CCR binding element specifically interacts with a first epitope on the CD19 target antigen. In some embodiments, the CAR or the CCR binding element comprises the antigen binding site of the FMC63 antibody. In certain embodiments, the CAR or the CCR binding element comprises the CDRs of the FMC63 antibody. The CDR sequences of the FMC63 antibody were determined using www.abysis.org and are shown as SEQ ID NO: 10-15 below.
In certain embodiments, the CAR or the CCR binding element comprises the VH and VL domains of the FMC63 antibody. The VH and VL domain sequences of the FMC63 antibody are shown below as SEQ ID NO: 16-17.
In particularly preferred embodiments, the CAR or the CCR binding element comprises the antigen binding site of the FMC63 antibody formatted as an scFv, either arranged as VH-linker-VL or as VL-linker-VH. These sequences are presented as SEQ ID NO: 18 and 19 below. In each case, the linker sequence between the VH and VL domains has been underlined and italicized.
In certain embodiments, the CAR or the CCR binding element comprises the amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99%, or 100% identical to the sequence of scFv of the FMC63 antibody, SEQ ID NO: 18 or 19.
In particularly preferred embodiments, the CAR or the CCR binding element comprises the CDR3 region of a variant of an FMC63 scFv. Specifically, the variant includes a mutation within the FMC VH domain (SEQ ID NO: 12) in order to modify affinity of the scFv for CD19. Particularly preferred embodiments contain a substitution of alanine (A) for either tyrosine (Y) or glycine (G) within CDR3 of the VH domain. These variants are shown below as SEQ ID NO: 20-26.
YYGGSYAMDY.
YGGSYAMDY.
GGSYAMDY.
GSYAMDY.
SYAMDY.
AMDY.
.
In some embodiments, the CAR or the CCR binding element specifically interacts with an epitope on the CD20 antigen. In some embodiments, the CAR or the CCR binding element comprises the 1F5 antibody, which binds to CD20. See Ledbetter and Clark, Hum. Immunol. 15(1):30-43 (1986), incorporated herein by reference in its entirety. CD20 is an integral membrane protein expressed on the surface of all B cells beginning at the pro-B phase and progressively increasing in concentration until maturity. In humans, CD20 is encoded by the MS4A1 gene. Antibodies which target CD20 are used in treatment of B cell lymphomas and leukemias, as well as in the treatment of autoimmune diseases such as arthritis, in particular rheumatoid arthritis, Multiple Sclerosis (MS) and systemic lupus erythematosus. In certain embodiments, the CCR binding element comprises the CDRs of the 1F5 antibody. The CDR sequences of the 1F5 antibody were determined using www.abysis.org and are shown below as SEQ ID NO: 27-32.
In certain embodiments, the CAR or the CCR binding element comprises the VH and VL domains of the 1F5 antibody. The VH and VL domain sequences of the 1F5 antibody are shown below as SEQ ID NO: 33-34.
In particularly preferred embodiments, the CAR or the CCR binding element comprises the antigen binding site of the 1F5 antibody formatted as a scFv, either arranged as VH-linker-VL or VL-linker-VH. These sequences are presented as SEQ ID NO: 35 and 36 below. In each case, the linker sequence between the VH and VL domains has been underlined and italicized.
In certain embodiments, the CAR or the CCR binding element comprises a variant of the scFv of the 1F5 antibody. The variant is 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99%, or 100% identical to SEQ ID NO: 35 or 36, as shown above.
In some embodiments, the CAR or the CCR binding element specifically interacts with an epitope on the CD22 antigen. In some embodiments, the CAR or the CCR binding element is RFB4 antibody, which binds to CD22. See Campana et al., J. Immunol. 134(3):1524-30 (1985), incorporated herein by reference in its entirety. CD22 is a 135-kDa, B cell-specific adhesion molecule that is expressed on the cells of 60% to 90% of B cell malignancies. It is not expressed on hematopoietic stem cells or on any other non-lymphoid hematopoietic or nonhematopoietic cells. The CDR sequences of the RFB4 antibody were determined using www.abysis.org and are shown below as SEQ ID NO: 37-42.
In certain embodiments, the CAR or the CCR binding element comprises the VH and VL domains of the RFB4 antibody. The VH and VL domain sequences of the RFB4 antibody are shown below as SEQ ID NO: 43-44:
In particularly preferred embodiments, the CAR or the CCR binding element comprises the antigen binding site of the RFB4 antibody formatted as a scFv, either arranged as VH-linker-VL or VL-linker-VH. These sequences are presented as SEQ ID NO: 45 and 46 below. In each case, the linker sequence between the VH and VL domains has been underlined and italicized.
In certain embodiments, the CAR or the CCR binding element comprises a variant of the scFv of the RFB4 antibody. The variant is 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99%, or 100% identical to SEQ ID NO: 45 or 46, as shown above.
Combinations of the aforementioned B cell antigen-specific binding elements have been used to engineer pCARs in which the CAR and CCR elements bind to an identical epitope within CD19, or to different epitopes found on CD19 and a second lineage-specific B cell antigen. Many additional moieties that bind specifically to CD19 and to other lineage-specific B cell antigens are known in the art, meaning that a large number of B cell specific pCARs could be engineered using similar methodologies. Consequently, the following pCAR examples are offered for illustrative purposes only and are not intended to limit the scope of the present invention. Nomenclature of pCARs derives from the following order: CCR binder, CCR signaling domain/CAR binder.
The protein sequence of FBB/G01 pCAR is shown below as SEQ ID NO: 47. The FBB/G01 pCAR comprises:
GGGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of FBB/G02 pCAR is shown below as SEQ ID NO: 48. The FBB/G02 pCAR comprises:
GGGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of FBB/Y01 pCAR is shown below as SEQ ID NO: 49. The FBB/Y01 pCAR comprises:
The protein sequence of FBB/Y02 pCAR is shown below as SEQ ID NO: 50. The FBB/Y02 pCAR comprises:
GGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of FBB/Y03 pCAR is shown below as SEQ ID NO: 51. The FBB/Y03 pCAR comprises:
GGGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of FBB/Y04 pCAR is shown below as SEQ ID NO: 52. The FBB/Y04 pCAR comprises:
GGGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of FBB/Y05 pCAR is shown below as SEQ ID NO: 53. The FBB/Y05 pCAR comprises:
GGGGSGGGGSGGGGS
AAAPTTTPAPRPPTPAPTIASQP
GGGGSGGGGSGGGGS
AAAIEV
EQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYSLL
The protein sequence of 1BB/F pCAR is shown below as SEQ ID NO: 54. The 1BB/F pCAR comprises:
GSTSGSGKPGSGEGSTKG
AAAPTTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHT
GGGGSGGG
AAAIEVEQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLAC
The protein sequence of RBB/F pCAR is shown below as SEQ ID NO: 55. The RBB/F pCAR comprises:
GSTSGSGKPGSGEGSTKG
AAAAPTTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRG
AAAIEVEQKLISEEDLLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLACYS
Also provided herein is a combination of a first nucleic acid encoding a 2nd generation CAR as described above and a second nucleic acid encoding a CCR as described above. As indicated above, for convenience herein, the CAR and CCR combination is referred to in the singular as a pCAR, although the CAR and CCR are separate, co-expressed, proteins. Suitable sequences for the nucleic acids will be apparent to a skilled person based on the description of the CAR and CCR above. The sequences may be optimized for use in the required immuno-responsive cell. However, in some cases, as discussed above, codons may be varied from the optimum or “wobbled” in order to avoid repeat sequences. Particular examples of such nucleic acids will encode the preferred embodiments described above. In some embodiments, the B cell specific pCAR comprises the polypeptide of a sequence selected from SEQ ID NOs: 47-55. In some embodiments, the nucleic acid which encodes for the pCAR is selected from the group consisting of SEQ ID NOs: 109-117.
In some embodiments, the nucleic acid which encodes the CCR component of the pCAR is selected from the group consisting of SEQ ID NOs: 128, 129 and 130.
In some embodiments, the nucleic acid which encodes the CAR component of the pCAR is selected from the group consisting of SEQ ID NOs: 101-108.
In order to achieve transduction, the nucleic acids encoding the pCAR are suitably introduced into one or more vectors, such as a plasmid, a retroviral or lentiviral vector, or a non-viral vector. Such vectors, including plasmid vectors, or cell lines containing them, form a further aspect of the invention.
In typical embodiments, the immuno-responsive cells are subjected to genetic modification, for example by retroviral or lentiviral mediated transduction, to introduce CAR and CCR coding nucleic acids into the host T cell genome, thereby permitting stable pCAR expression. They may then be reintroduced into the patient, optionally after expansion, to provide a beneficial therapeutic effect, as described below.
The first and second nucleic acids encoding the CAR and CCR can be expressed from the same vector or from different vectors. The vector or vectors containing them can be combined in a kit, which is supplied with a view to generating immuno-responsive cells of the first aspect disclosed herein.
In some embodiments, the T cells may also be engineered to co-express a chimeric cytokine receptor such as 4αβ, which comprises a fusion of the ectodomain of IL-4 receptor-α and the transmembrane and endodomain of the shared IL-2/15 receptor-β chain. In this case, the expansion step may include an ex vivo culture step in a medium which comprises the cytokine, such as a medium comprising IL-4 as the sole cytokine support in the case of 4αβ. Alternatively, the chimeric cytokine receptor may comprise the ectodomain of the IL-4 receptor-α chain joined to the receptor endodomain used by a common 7 cytokine with distinct properties, such as IL-7. Expansion of the cells in IL-4 may result in less cell differentiation under these circumstances. In this way, selective expansion and enrichment of genetically engineered T cells with the desired state of differentiation can be ensured.
As discussed above, the immuno-responsive pCAR cells are useful in therapy to direct a T cell-mediated immune response to a target cell. Thus, in another aspect, methods for directing a T cell-mediated immune response to a target cell in a patient in need thereof are provided. The method comprises the administration to the patient a population of immuno-responsive cells as described above, wherein the binding elements are specific for the target cell. In some embodiments, the target cell expresses CD19 and/or other B cell antigens.
In another aspect, methods for treating cancer in a patient in need thereof are provided. The method comprises administering to the patient a population of immuno-responsive cells as described above, wherein the binding elements are specific for the target cell. In some embodiments, the target cell expresses CD19 and/or other B cell antigens. In some embodiments, the patient has acute or chronic B cell leukemia or B cell lymphoma.
In various embodiments, a therapeutically effective number of the immuno-responsive cells is administered to the patient. In certain embodiments, the immuno-responsive cells are administered by intravenous infusion. In certain embodiments, the immuno-responsive cells are administered by intratumoral injection. In certain embodiments, the immuno-responsive cells are administered by peritumoral injection. In certain embodiments, the immuno-responsive cells are administered by a plurality of routes selected from intravenous infusion, intratumoral injection, and peritumoral injection.
Below are examples of specific embodiments for carrying out the present invention. The examples are offered for illustrative purposes only and are not intended to limit the scope of the present invention in any way. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperatures, etc.), but some experimental error and deviation should, of course, be allowed for.
All tumor cells and 293T cells were grown in DMEM supplemented with L-Glutamine and 10% FBS. Where indicated, tumor cells were transduced to express a firefly luciferase and tandem dimer Tomato red fluorescent protein (LT) SFG vector, followed by flow sorting for red fluorescent protein expression. LO68 CD19+ cells and LO68 CD19+/CD20+ cells were generated by transduction of LO68-LT cells with an SFG retroviral vector that encodes for human CD19 and/or human CD20.
293T cells were triple transfected in Genejuice (MilliporeSigma, Merck KGaA, Darmstadt, Germany) with (i) SFG retroviral vectors encoding the indicated CAR/pCAR, (ii) RDF plasmid encoding the RD 114 envelope and (iii) Peq-Pam plasmid encoding gag-pol, as recommended by the manufacturers. For transfection of 1.5×106 293T cells in a 100 mm plate, 4.6875 μg SFG retroviral vector, 4.6875 μg Peq-Pam plasmid, and 3.125 μg RDF plasmid were used. Viral vector containing medium was collected 48 and 72 h post-transfection, snap-frozen and stored at −80° C. In some cases, stable packaging cell lines were then created by transduction of 293 VEC GALV cells with retrovirus. Virus prepared from either source was used interchangeably for transduction of target cells.
Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donor peripheral blood samples by density gradient centrifugation using Ficoll-Paque (Ethical approval no. 18/WS/0047). T cells were cultured in RPMI with GlutaMax supplemented with 5% human AB serum. Activation of T cells was achieved by culture in the presence of 5 g/mL phytohemagglutinin leucoagglutinin (PHA-L) for 24-48 h after which the cells were grown in IL-2 (100 U/mL) for a further 24 h prior to gene transfer. T cell transduction was achieved using RetroNectin (Takara Bio) coated-plates according to the Manufacturer's protocol. Activated PBMCs (1×106 cells) were added per well of a RetroNectin coated 6-well plate. Retrovirus-containing medium (3 mL) was then added per well with 100 U/mL IL2.
Tumor cells were seeded at 2×104 or 1×105 cells/well in a 24 or 96 well plate and were incubated with T cells at specified target to effector ratios. In some cases, destruction of tumor cells by T cells was quantified using an MTT assay. To achieve this, MTT (Sigma) was added at 500 μg/ml in D10 medium for 2 hours at 37° C. and 5% CO2. After removal of the supernatant, formazan crystals were re-suspended in 100 μL DMSO. Absorbance was measured at 560 nm. Alternatively, tumor cell viability was monitored by luciferase assays. D-luciferin (PerkinElmer, Waltham Mass.) was added at 150 mg/mL immediately prior to luminescence reading. In either case, tumor cell viability was calculated as follows: (absorbance or luminescence of tumor cells cultured with T cells/absorbance or luminescence of untreated monolayer alone)×100%.
Expression of CARs was detected using 9e10 antibody, which binds to a myc epitope tag (EQKLISEEDL), followed by PE-conjugated goat anti-mouse antibody. Expression of the CCR component of pCARs was detected by intracellular staining using a PE-conjugated antibody, which binds to a FLAG epitope tag (DYKDDDDK).
Supernatant was collected at 24 hours from co-cultures of tumor cells with CAR T cells. Cytokine levels were quantified using a human IFN-γ (Bio-Techne) or human IL-2 ELISA kit (Invitrogen) according to the Manufacturer's protocol.
Suspension tumor cells were co-cultured with CAR-T/pCAR-T cells at an initial effector:target (E:T) ratio of 1:1 for 72-96 h. Residual tumor cell viability was then assessed by luciferase assay. D-luciferin (PerkinElmer) was added at 150 mg/mL immediately prior to luminescence reading. Fresh tumor cells (105 cells) were then added and this procedure was repeated until T cell cultures failed to expand.
Alternatively, adherent LO68 tumor cell lines were plated in triplicate at 1×105 cells per well in a 24-well culture plate 24 h prior to addition of T cells. CAR-T/pCAR-T cells were added at a 1:1 effector:target ratio. Tumor cell killing was measured after 48-72 h using an MTT assay, performed as described above. T cells were then collected and restimulated by addition to a new tumor cell monolayer provided that >20% tumor cells were killed compared to untreated cells. Tumor cell viability was calculated as described in section 5.1.4.
PBMCs from healthy donors were engineered to express the indicated CARs/pCARs or were untransduced. After 11 days of expansion in IL-2 (100 U/mL, added every 2-3 days), cells were analyzed by flow cytometry for expression of the CAR and CCR as described above. Female NSG mice were injected i.v. with 5×105 cells Nalm-6 LT cells. After 4 days, 5×105 CAR* (or untransduced) T cells were injected i.v. in 200 μl of PBS, making comparison with PBS as control. Tumor status was monitored by bioluminescence imaging (BLI), performed under isoflurane anaesthesia 20 minutes after injection of StayBrite™ D-Luciferin, Potassium Salt in 200 μl PBS (150 mg/kg). Image acquisition was performed at the indicated time points using an IVIS® Lumina III (PerkinElmer) with Living Image software (PerkinElmer) set for automatically optimized exposure time, binning and F/stop. Animals were humanely killed when experimental endpoints had been reached.
CD19-engineered LO68 tumor cells were seeded in a z-Movi microfluidic chip and cultured for 16 hours. The next day, flow sorted CAR-T cells were serially flowed in the chips and incubated with the target cells for 5 minutes prior to initializing a 3-minute linear force ramp. Cell detachment was determined using post-experiment using image analysis techniques.
T cells were engineered by retroviral transduction to express a CD28-containing 2nd generation CAR designated F-2, or VH CDR3 mutated derivatives designated Y01, Y02, Y03, Y04, Y05, G01 or G02, or were untransduced (
To test binding to CD19, transduced T cells were incubated with CD19-Fc at two different concentrations, 0.5 μg (
To further test the relative CD19 binding capacity of the 2G CAR, F-2, and its mutated derivatives, the engineered CAR-T cells were incubated on a monolayer of CD19+ LO68 tumor cells in a z-Movi microfluidic chip. Increasing fluidic force was applied and the percentage of bound T-cells was determined (median, n=3). T cells expressing the VH CDR3 mutated CARs presented a spectrum of binding activities for CD19. Most of the VH CDR3 mutated derivatives exhibited reduced binding activity for CD19 as compared with the 2G CAR F. Data from representative experiments are shown in
To evaluate anti-tumor activity, transduced T cells were co-cultivated in vitro with Nalm-6 LT or Raji LT cells, both of which naturally express CD19 (
To further evaluate cytotoxic activity, 2×104 transduced T cells were co-cultivated in duplicate with an equal number of Nalm-6 (
Transduced T cells were co-cultivated in vitro with Nalm-6 LT (
Following the co-cultivation experiments described above (data shown in
Transduced T cells were subjected to successive rounds of antigen (Ag) stimulation in the absence of exogenous cytokine IL-2. Triplicate cultures containing 105 engineered T cells were re-stimulated twice weekly by addition of 105 Nalm-6 tumor cells.
The anti-tumor activity of the CD19-specific CAR-T and pCAR-T cells was assessed in vivo in NSG mice bearing established Nalm-6 leukemic xenografts.
RFP/ffLuc+ Nalm6 cells (5×105 cells) were injected i.v. in NSG mice. On day 5, animals were arranged into groups of 5-10 mice with equal disease burden (according to BLI). Mice were then treated with 5×105 of the indicated CAR or pCAR T-cells, administered i.v. Comparison was made with PBS. Pooled bioluminescence emission (“total flux”) from leukemic xenografts was measured for each treatment from day 8 (
These results indicate that the CD19-specific pCAR-T cells have superior anti-tumor activity in vivo compared to the 2G CAR-T cells in NSG mice with established leukemic burden.
T cells were engineered to express the CD19- or CD20-specific 2nd generation CAR T cells (F-2 and 1-2, respectively) or the 1BB/F pCAR. 1×105 transduced CAR or pCAR T cells were co-cultivated in triplicate with an equal number of LO68-CD19+CD20+ tumor cells. After 72 hours, T cells were transferred to a fresh monolayer of LO68-CD19+CD20+ cells. Data plotted in
In
CAR or pCAR T cells were co-cultivated with LO68-CD19+CD20+ tumor cells at an effector:target (T cell:tumor cell) ratio of 1:1 and 1:4. Supernatants were collected after 24 hours of co-cultivations and were analyzed for IFN-7 (
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments in accordance with the invention described herein. The scope of the present invention is not intended to be limited to the above Description, but rather is as set forth in the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/074071 | 8/28/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62892936 | Aug 2019 | US | |
| 62983451 | Feb 2020 | US |
