WO2017015374A1 - Methods and compositions for chimeric antigen receptor targeting the glucose-regulated protein of 94 kda (grp94) - Google Patents

Abstract

The present invention provides a chimeric antigen receptor (CAR) that recognizes Grp94, as well as methods of use in the treatment of diseases and disorders.

Description

METHODS AND COMPOSITIONS FOR CHIMERIC ANTIGEN RECEPTOR TARGETING THE GLUCOSE-REGULATED PROTEIN OF 94 kDa (GRP94)

Statement of Priority

This application claims the benefit, under 35 U.S.C. § 1 19(e), of U.S.

Provisional Application Serial No. 62/ 194.765, filed July 20, 2015, the entire contents of which are incorporated herein by reference.

Statement Regarding Electronic Filing of a Sequence Listing A Sequence Listing in ASCII text format, submitted under 37 C.F.R. § 1.821 , entitled 5470-792WO__ST25.txt. 1 1 ,059 bytes in size, generated on July 19, 2016 and filed via EFS-Web, is provided in lieu of a paper copy. This Sequence Listing is hereby incorporated by reference into the specification for its disclosures.

Field of the Invention

This invention describes compositions and methods for a chimeric antigen receptor (CAR) that targets the glucose-regulated protein of 94 kDa (Grp94).

Background of the Invention

The glucose-regulated protein of 94 kDa (Grp94) is a member of the heat shock protein (HSP) 90 family. Grp94 is an essential endoplasmic reticulum chaperone, which is required for the conformational maturation of proteins destined for cell surface display or export. Grp94 regulates the activation of several signaling pathways that are associated with cell proliferation, survival and migration. This functional role of Grp94 in tumor cell biology provides a mechanism for the inhibition by Grp94 inhibitors of tumor cell proliferation and migration and for the induction of apoptosis.

The present invention overcomes previous shortcomings in the art by providing a chimeric antigen receptor (CAR) that targets Grp94 and methods of its use in treating cancer.

Summary of the Invention

The present invention concerns methods and compositions for the treatment of cancer, including treatment of cancer employing immunotherapy. In particular cases, the immunotherapy includes T lymphocytes engineered to target certain cancers. In specific embodiments, the cancer being treated has cancer cells with Grp94 as an antigen on the surface of and/or within the cancer cells. In particular cases, the cytotoxic T lymphocytes (CTLs) employed to target Grp94 on cancer cells comprise a receptor for Grp94 and, in specific cases, the receptor on the CTLs is chimeric, non- natural and engineered at least in part by the hand of man. In particular cases, the engineered chimeric antigen receptor (CAR) has one, two, three, four, or more components, and in some embodiments the one or more components facilitate targeting or binding of the T lymphocyte to the Grp94 antigen-comprising cancer cell, although in some cases one or more components are useful to promote T cell growth and maturity.

In certain embodiments, the present invention includes T lymphocytes engineered to comprise a chimeric receptor having an antibody for Grp94, part or all of a cytoplasmic signaling domain, and/or part or all of one or more costimulatory molecules, for example endodomains of costimulatory molecules. In specific embodiments, the antibody for Grp94 is a single-chain variable fragment (scFv), although in certain aspects the antibody is directed at other target antigens on the cell surface, such as HER2 or CD 19, for example. In certain embodiments, a cytoplasmic signaling domain, such as those derived from the T cell receptor .zeta. -chain, is employed as at least part of the chimeric receptor in order to produce stimulatory signals for T lymphocyte proliferation and effector function following engagement of the chimeric receptor with the target antigen. Examples would include, but are not limited to, endodomains from co-stimulatory molecules such as CD28, 4- IBB, and OX40 or the signaling components of cytokine receptors such as IL7 and IL15. In particular embodiments, costimulatory molecules are employed to enhance the activation, proliferation, and cytotoxicity of T cells produced by the CAR after antigen engagement. In specific embodiments, the costimulatory molecules are CD28, OX40, and 4- IBB and cytokine and the cytokine receptors are IL7 and 11.1 5.

Genetic engineering of human T lymphocytes to express tumor-directed chimeric antigen receptors (CAR) can produce antitumor effector cells that bypass tumor immune escape mechanisms that are due to abnormalities in protein-antigen processing and presentation.

In certain embodiments, the present invention provides chimeric T cells specific for the Grp94 antigen by joining an extracellular antigen-binding domain derived from the Grp94-specific antibody W9 to cytoplasmic signaling domains derived from the T-cell receptor zeta-chain, with the endodomains of the exemplary costimulatory molecules CD28 and OX40, for examples.

In certain embodiments, the present invention provides a method of targeting a cancer cell and/or a cancer initiating cell (CIC) having a glucose-regulated protein of 94 kl⁾a (Grp94) antigen, comprising providing to the cancer cell and/or CIC a cytotoxic T lymphocyte with a chimeric antigen receptor (CAR) that recognizes the Grp94 antigen. The cancer cell and/or CIC can be in vitro, ex vivo, and/or in vivo.

In further embodiments, the present invention provides a method of treating cancer in a subject, comprising administering the subject cytotoxic T lymphocytes having a chimeric antigen receptor that recognizes a Grp94 antigen present on and/or in cancer cells and/or cancer initiating cells (CICs) of the subject.

In some embodiments, the cancer cells and/or CICs can be contacted with LDE225, an inhibitor of the sonic hedgehog homolog (SHH) pathway.

Further embodiments of the invention provide related nucleic acids, recombinant expression vectors, host cells, populations of cells, antibodies, or antigen binding portions thereof, and pharmaceutical compositions relating to the CARs of the invention.

Brief Description of the Drawings

Fig. 1. Broad reactivity of the scFv W9 with a panel of human cancer cell lines.

Fig. 2. Surface expression o Grp94 in MM (panel A) and AML (panel B) cell lines.

Fig. 3. W9 defmed-Grp94 epitope expression on human TNBC CICs.

Fig. 4. W9 defined-Grp94 epitope expression on human breast carcinoma, pancreatic adenocarcinoma and melanoma lesion but not on human normal tissues.

Fig. 5. W9-CAR structure (panel A) and expression in activated human T lymphocytes (panel B).

Fig. 6. W9-CAR-T cells specifically kill MM cells Grp94+.

Fig. 7. W9-CAR-T cells kill AMI, (panel A) and PDAC (panel B) tumor cell lines Grp94+.

Fig. 8. LDE225 enhances growth inhibition of the CICs incubated with W9- CAR T cells in the PDAC2 and PDAC3 cell lines. Fig 9. CSPG4-specific CAR. Schematic representation of the retroviral vector encoding the CSPG4-specific CAR (panel A). Expression of the CSPG4- specific CAR in human T lymphocytes after retroviral transduction. The panels indicate the flow cytometry analysis of control and CAR-T cells (panel B). Cytotoxic activity of control and CAR-T cells measured by a ⁵¹Cr release assay. Target cells were CSPG4 tumor cells (melanoma), CSPG4^" cells (neuroblastoma) and K562 cells (eritroleukemia) (target for LAK cells) (panel C).

Detailed Description of the Invention

The present invention is explained in greater detail below. This description is not intended to be a detailed catalog of all the different ways in which the invention may be implemented, or all the features that may be added to the instant invention. For example, features illustrated with respect to one embodiment may be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from that embodiment. In addition, numerous variations and additions to the various embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure which do not depart from the instant invention. Hence, the following specification is intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations and variations thereof.

Unless the context indicates otherwise, it is specifically intended that the various features of the invention described herein can be used in any combination. Moreover, the present invention also contemplates that in some embodiments of the invention, any feature or combination of features set forth herein can be excluded or omitted.

In the following description, certain details are set forth such as specific quantities, sizes, etc. so as to provide a thorough understanding of the present embodiments disclosed herein. However, it will be obvious to those skilled in the art that the present disclosure may be practiced without such specific details. In many cases, details concerning such considerations and the like have been omitted inasmuch as such details are not necessary to obtain a complete understanding of the present disclosure and are within the skills of persons of ordinary skill in the relevant art.

The present invention is based on the discovery of a chimeric antigen receptor (CAR) generated from the single chain Fv (scFv) W9 that specifically targets an extracellular epitope of the intracellular Grp94 protein (W9-CAR). This epitope is expressed on differentiated cancer cells and on cancer initiating cells in various types of malignant tumors. W9-CAR can be stably expressed by human T lymphocytes upon gene transfer and W9-CAR-modified T cells can recognize and efficiently eliminate in vitro culture human tumor cell lines from head and neck, nasopharyngeal, esophageal, lung, breast, gastric, liver, colorectal cancer, pancreatic ductal

adenocarcinoma, osteosarcoma, multiple myeloma and acute leukemia. In view of the broad reactivity of scFv W9 with many types of solid and liquid tumors as

demonstrated in the present invention, the CAR derived from the scFv W9 can be used in the treatment of many types of solid and liquid human tumors.

Thus, in one embodiment, the present invention is based on the discovery of a chimeric receptor antigen (CAR) that targets cancer cells and/or cancer initiating cells (CICs) having a Grp94 antigen. Accordingly, the present invention provides a chimeric receptor antigen (CAR) that targets cancer cells and/or CICs having a Grp94 antigen, wherein the CAR comprises, consists essentially of and/or consists of the components described herein. Further provided herein is a cytotoxic T lymphocyte comprising a CAR that recognizes and binds Grp84 antigen. The cytotoxic T lymphocyte can be transduced with a viral vector or transfected with a plasmid or nucleic acid construct comprising a nucleotide sequence encoding the CAR of this invention and in some embodiments the nucleotide sequence can be SEQ ID NO: l .

In further embodiments, the present invention provides a method of targeting a cancer cell and/or a CIC having a glucose-regulated protein of 94 kDa (Grp94) antigen, comprising providing to the cell or contacting the cell with a cytotoxic T lymphocyte with a chimeric antigen receptor (CAR) that recognizes and binds the Grp94 antigen.

In some embodiments the cancer cell and/or CIC is in vitro, in some embodiments, the cancer cell and/or CIC is ex vivo and in some embodiments the cancer cell and/or CIC is in vivo.

Thus, in an additional embodiment of this invention, the present invention provides a method of treating cancer in a subject, comprising administering to the subject cytotoxic T lymphocytes having a chimeric antigen receptor that recognizes a

Grp94 antigen on the surface of cancer cells and/or cancer initiating cells (CICs). In some embodiments, the CAR comprises an antibody that binds Grp94 and in particular embodiments the antibody is a scFv antibody and in one embodiment, is a W9 scFv antibody.

In some embodiments, the CAR can comprise, consist essentially of and/or consist of the effector domain of the T cell receptor zeta chain or a related signal transduction endodomain derived from a T cell receptor. In some embodiments the chimeric antigen receptor is encoded by the nucleotide sequence of SEQ ID NO: l . Thus, the present invention further provides a vector (e.g., a viral vector) comprising the nucleotide sequence of SEQ ID NO: l and the T lymphocytes of this invention can be transduced with a viral vector comprising the nucleotide sequence of SEQ ID NO: 1 under conditions whereby the chimeric antigen receptor is produced in the T lymphocyte.

In some embodiments, the CAR can comprise one or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) costimulatory molecules, nonlimiting examples of which include CD28, OX40, 4- IBB, or a combination thereof.

In some embodiments, the cancer cells and/or CICs of this invention can be contacted with LDE225, an inhibitor of the sonic hedgehog homolog (SI II I ) pathway, before, during and/or after contacting with the CAR of this invention.

Nonlimiting examples of a cancer that can be treated according to the methods of this invention include B cell lymphoma, T cell lymphoma, myeloma, leukemia, hematopoietic neoplasias, thymoma, lymphoma, sarcoma, lung cancer, liver cancer, non-Hodgkins lymphoma, Hodgkins lymphoma, uterine cancer, cervical cancer, endometrial cancer, adenocarcinoma, breast cancer, pancreatic cancer, colon cancer, anal cancer, lung cancer, renal cancer, bladder cancer, liver cancer, prostate cancer, ovarian cancer, primary or metastatic melanoma, squamous cell carcinoma, basal cell carcinoma, brain cancer, angiosarcoma, hemangio sarcoma, head and neck carcinoma, thyroid carcinoma, soft tissue sarcoma, bone sarcoma, testicular cancer,

gastrointestinal cancer, and any other cancer now known or later identified (see, e.g., Rosenberg (1996) Ann. Rev. Med. 47:481-491 , the entire contents of which are incorporated by reference herein).

Definitions

As used herein, the term "costimulatory molecule" refers to a molecular component that promotes activation, proliferation and effector function of a T cell after engagement of an antigen specific receptor. As used herein, the term "cytoplasmic signaling domain" refers to the component of a co-stimulatory molecule or cytokine receptor that exists inside the cell and is responsible for transducing the external signal received to the internal metabolic processes of the cell, thereby altering its phenotype and function.

In embodiments of the present invention, the overexpression of Grp94 by cancer cells allows these cells to be targeted in vitro and in vivo by Grp94 CAR- expressing primary T cells, and in some embodiments, incorporation of endodomains from both CD28 and OX40 molecules mediates costimulation of the T lymphocytes, inducing T cell activation, proliferation, and cytotoxicity against Grp94-positive cancer and/or CIC cells.

In particular embodiments of the invention, there are methods for killing cancer cells using genetically manipulated T-cells that express a chimeric antigen receptor (CAR) directed against the antigen Grp94. In some embodiments, engagement (antigen binding) of this CAR leads to activation of the linked T-cell receptor C chain and the costimulatory molecules CD28 and OX40.

In particular embodiments of the invention, the CAR receptor comprises a single-chain variable fragment (scFv) that recognizes Grp4. The skilled artisan recognizes that scFv is a fusion protein of the variable regions of the heavy (VH) and light chains (VL) of immunoglobulins, connected with a short linker peptide of ten to about 25 amino acids. The linker may be rich in glycine for flexibility and/or it may have serine or threonine for solubility, in certain cases. In a particular embodiment, theW9 scFv antibody is used in the CAR. The scFv may be generated by methods known in the art.

In certain aspects, one can use cytokine exodomains or other ligand/receptor molecules as exodomains to provide targeting to the tumor cells.

The skilled artisan recognizes that T cells utilize co-stimulatory signals that are antigen non-specific to become fully activated. In particular cases they are provided by the interaction between co-stimulatory molecules expressed on the membrane of APC and the T cell. In specific embodiments, the one or more costimulatory molecules in the chimeric receptor come from the B7/CD28 family, TNF superfamily, or the signaling lymphocyte activation molecule (SLAM) family. Exemplary costimulatory molecules include one or more of the following in any combination: B7-1/CD80; CD28; B7-2/CD86; CTLA-4; B7-H1/PD-L1 ; ICOS; B7- H2; PD-1 ; B7-H3; PD-L2; B7-H4; PDCD6; BTLA; 4- 1 BB/TNFRSF9/CD 137; CD40 Ligand/TNFSF 4- I BB Ligand/TNFSF9; GITR/TNFRSF 18 ;

BAFF/BLyS/TNFSF13B; GITR Ligand/TNFSF18; BAFF R/TNFRSF13C;

HVEM/TNFRSF14; CD27/TNFRSF7; LIGHT/TNFSF14; CD27 Ligand/TNFSF7; OX40/TNFRSF4; CD30/TNFRSF8; OX40 Ligand/TNFSF4; CD30 Ligand/TNFSF8; TAC1/TNFRSF13B; CD40/TNFRSF5; 2B4/CD244/SLAMF4; CD84/SLAMF5; BLAME/SLAMF8; CD229/SLAMF3; CD2 CRACC/SLAMF7; CD2F-10/SLAMF9; NTB-A/SLAMF6; CD48/SLAMF2; SLAM/CD 150; CD58/LFA-3; CD2; Ikaros; CD53; Integrin alpha 4/CD49d; CD82/Kai-1 ; Integrin alpha 4 beta 1 ; CD90/Thyl ; Integrin alpha 4 beta 7/LPAM-l ; CD96; LAG-3; CD160; LMIR1/CD300A; CRTAM; TCL1A; DAP 12; TIM- 1 /KIM- 1 /HA VCR; Dectin-1/CLEC7A; TIM-4; DPPIV/CD26; TSLP; EphB6; TSLP R; and HLA-DR.

The CAR of the invention may employ one, two, three, four, or more costimulatory molecules in any combination.

The effector domain is a signaling domain that transduces the event of receptor ligand binding to an intracellular signal that partially activates the T lymphocyte. Absent appropriate co-stimulatory signals, this event is insufficient for useful T cell activation and proliferation. A nonlimiting example of an effector domain of this invention is the effector domain of the T cell receptor zeta chain.

In certain embodiments of the invention, methods of the present invention for clinical aspects are combined with other agents effective in the treatment of hyperproliferative disease, such as anti-cancer agents. An "anti-cancer" agent is capable of negatively affecting cancer in a subject, for example, by killing cancer cells, inducing apoptosis in cancer cells, reducing the growth rate of cancer cells, reducing the incidence or number of metastases, reducing tumor size, inhibiting tumor growth, reducing the blood supply to a tumor or cancer cells, promoting an immune response against cancer cells or a tumor, preventing or inhibiting the progression of cancer, and/or increasing the lifespan of a subject with cancer. More generally, these other compositions would be provided in a combined amount effective to kill or inhibit proliferation of the cancer cell. This process may involve contacting the cancer cells with the expression construct and the agent(s) or multiple factor(s) at the same time. This may be achieved by contacting the cell with a single composition or pharmacological formulation that includes both agents, or by contacting the cell with two distinct compositions or formulations, at the same time, wherein one composition includes the expression construct and the other includes the second agent(s). Tumor cell resistance to chemotherapy and radiotherapy agents represents a major problem in clinical oncology. One goal of current cancer research is to find ways to improve the efficacy of chemo- and radiotherapy by combining it with gene therapy. For example, the herpes simplex -thymidine kinase (HS-tK) gene, when delivered to brain tumors by a retroviral vector system, successfully induced susceptibility to the antiviral agent ganciclovir. In the context of the present invention, it is contemplated that cell therapy could be used similarly in conjunction with chemotherapeutic, radiotherapeutic, or immunotherapeutic intervention, in addition to other pro-apoptotic or cell cycle regulating agents.

Alternatively, the present inventive therapy may precede and/or follow the other agent treatment(s) by intervals ranging from minutes to weeks. In embodiments where the other agent and present invention are applied separately to the individual, one would generally ensure that a significant period of time did not expire between the time of each delivery, such that the agent and inventive therapy would still be able to exert an advantageously combined effect on the cell. In such instances, it is contemplated that one may contact the cell with the multiple modalities within about 12-24 h of each other and, more preferably, within about 6-12 h of each other. In some situations, it may be desirable to extend the time period for treatment significantly, however, where several d (2, 3, 4, 5, 6 or 7) to several wk (1 , 2, 3, 4, 5, 6, 7 or 8) lapse between the respective administrations.

It is expected that the treatment cycles would be repeated as necessary. It also is contemplated that various standard therapies, as well as surgical intervention, may be applied in combination with the inventive cell therapy.

Cancer therapies also include a variety of combination therapies with both chemical and radiation based treatments. Combination chemotherapies include, for example, abraxane, altretamine, docetaxel, herceptin, methotrexate, novantrone. zoladex, cisplatin (CDDP), carboplatin, procarbazine, mechlorethamine,

cyclophosphamide, camptothecin, ifosfamide, melphalan, chlorambucil, busulfan, nitrosurea, dactinomycin, daunorubicin, doxorubicin, bleomycin, plicomycin, mitomycin, etoposide (VP 16), tamoxifen, raloxifene, estrogen receptor binding agents, taxol, gemcitabien, navelbine, farnesyl-protein tansferase inhibitors, transplatinum, 5-fluorouracil, vincristin, vinblastin and methotrexate, or any analog or derivative variant of the foregoing. In specific embodiments, chemotherapy for Grp94 positive cancer is employed in conjunction with the invention, for example before, during and/or after

administration of the invention.

Other factors that cause DNA damage and have been used extensively include what are commonly known as .gamma. -rays, X-rays, and/or the directed delivery of radioisotopes to tumor cells. Other forms of DNA damaging factors are also contemplated such as microwaves and UV-irradiation. It is most likely that all of these factors affect a broad range of damage on DNA, on the precursors of DNA, on the replication and repair of DNA, and on the assembly and maintenance of chromosomes. Dosage ranges for X-rays range from daily doses of 50 to 200 roentgens for prolonged periods of time (3 to 4 wk), to single doses of 2000 to 6000 roentgens. Dosage ranges for radioisotopes vary widely, and depend on the half-life of the isotope, the strength and type of radiation emitted, and the uptake by the neoplastic cells.

The terms "contacted," "provided to" and "exposed," when applied to a cell, are used herein to describe the process by which a therapeutic agent (e.g., a CAR) is delivered to a target cell and/or are placed in direct juxtaposition with the target cell, e.g., under conditions that facilitate binding of the CAR to the target antigen in and/or on the target cell. In some embodiments, chemotherapy and/or radiation therapy can also be included before, after and/or during the contacting or exposing or providing to step to achieve cell killing or stasis, both agents are delivered to a cell in a combined amount effective to kill the cell or prevent it from dividing.

Immunotherapeutics generally rely on the use of immune effector cells and molecules to target and destroy cancer cells. The immune effector may be, for example, an antibody specific for some marker on the surface of a tumor cell. The antibody alone may serve as an effector of therapy or it may recruit other cells to actually affect cell killing. The antibody also may be conjugated to a drug or toxin (chemotherapeutic, radionuclide, ricin A chain, cholera toxin, pertussis toxin, etc.) and serve merely as a targeting agent. Alternatively, the effector may be a lymphocyte carrying a surface molecule that interacts, either directly or indirectly, with a tumor cell target. Various effector cells include cytotoxic T cells and NK cells.

Immunotherapy could thus be used as part of a combined therapy, in conjunction with the present cell therapy. The general approach for combined therapy is discussed below. Generally, the tumor cell must bear some marker that is amenable to targeting, i.e., is not present on the majority of other cells. Many tumor markers exist and any of these may be suitable for targeting in the context of the present invention. Common tumor markers include carcinoembryonic antigen, prostate specific antigen, urinary tumor associated antigen, fetal antigen, tyrosinase (p97), gp68, TAG-72, HMFG, Sialyl Lewis Antigen, MucA, MucB. PLAP, estrogen receptor, laminin receptor, erb B and p 155.

Immunotherapy for a cancer of this invention may include interleukin-2 (11,-2 ) or interferon (IFN), for example.

In yet another embodiment, the secondary treatment can be a gene therapy in which a therapeutic polynucleotide is administered before, after, and/or at the same time as the present invention clinical embodiments. A variety of expression products are encompassed within the invention, including inducers of cellular proliferation, inhibitors of cellular proliferation, or regulators of programmed cell death.

Approximately 60% of persons with cancer will undergo surgery of some type, which includes preventative, diagnostic or staging, curative and palliative surgery. Curative surgery is a cancer treatment that may be used in conjunction with other therapies, such as the treatment of the present invention, chemotherapy, radiotherapy, hormonal therapy, gene therapy, immunotherapy and/or alternative therapies.

Curative surgery includes resection in which all or part of cancerous tissue is physically removed, excised, and/or destroyed. Tumor resection refers to physical removal of at least part of a tumor. In addition to tumor resection, treatment by surgery includes laser surgery, cryosurgery, electrosurgery, and microscopically controlled surgery (Mohs' surgery). It is further contemplated that the present invention may be used in conjunction with removal of superficial cancers, precancers, or incidental amounts of normal tissue.

Upon excision of part of all of cancerous cells, tissue, or tumor, a cavity may be formed in the body. Treatment may be accomplished by perfusion, direct injection or local application of the area with an additional anti-cancer therapy. Such treatment may be repeated, for example, every 1 , 2, 3, 4, 5, 6, or 7 days, or every 1 , 2, 3, 4, and 5 weeks or every 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , or 12 months. These treatments may be of varying dosages as well.

It is contemplated that other agents may be used in combination with the present invention to improve the therapeutic efficacy of treatment. These additional agents include immunomodulatory agents, agents that affect the upregulation of cell surface receptors and GAP junctions, cytostatic and differentiation agents, inhibitors of cell adhesion, or agents that increase the sensitivity of the hyperproliferative cells to apoptotic inducers. Immunomodulatory agents include tumor necrosis factor; interferon alpha, beta, and gamma; IL-2 and other cytokines; F42K and other cytokine analogs; or MlP-1 , MlP-lbeta, MCP-1 , RANTES, and other chemokines. It is further contemplated that the upregulation of cell surface receptors or their ligands such as Fas/Fas ligand, DR4 or DR5/TRAIL would potentiate the apoptotic inducing abilities of the present invention by establishment of an autocrine or paracrine effect on hyperproliferative cells. Increasing intercellular signaling by elevating the number of GAP junctions would increase the ant i -hyperpro 1 iferat i ve effects on the neighboring hyperproliferative cell population. In other embodiments, cytostatic or differentiation agents can be used in combination with the present invention to improve the anti- hyerproliferative efficacy of the treatments. Inhibitors of cell adhesion are contemplated to improve the efficacy of the present invention. Examples of cell adhesion inhibitors are focal adhesion kinase (FAKs) inhibitors and Lovastatin. It is further contemplated that other agents that increase the sensitivity of a

hyperproliferative cell to apoptosis, such as the antibody c225, could be used in combination with the present invention to improve the treatment efficacy.

As used herein, "a," "an" and "the" can mean one or more than one, depending on the context in which it is used. For example, "a" cell can mean one cell or multiple cells.

Also as used herein, "and/or" refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative ("or").

Furthermore, the term "about," as used herein when referring to a measurable value such as an amount of a compound or agent of this invention, dose, time, temperature, and the like, is meant to encompass variations of ± 20%, ± 10%, ± 5%, ± 1%, ± 0.5%, or even ± 0.1% of the specified amount.

As used herein, the transitional phrase "consisting essentially of means that the scope of a claim is to be interpreted to encompass the specified materials or steps recited in the claim, "and those that do not materially affect the basic and novel characteristic(s)" of the claimed invention. See, In re Herz, 537 F.2d 549, 551-52, 190 USPQ 461 , 463 (CCPA 1976) (emphasis in the original); see also MPEP § 21 1 1.03. Thus, the term "consisting essentially of when used in a claim of this invention is not intended to be interpreted to be equivalent to "comprising."

Also as used herein, "one or more" means one, two, three, four, five, six, seven, eight, nine, ten, 1 1, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.

Subjects that may be treated by the present invention include both human subjects for medical purposes and animal subjects for veterinary and drug screening and development purposes. Other suitable animal subjects are, in general, mammalian subjects such as primates, bovines, ovines, caprines, porcines, equines, felines, canines, lagomorphs, rodents (e.g. , rats and mice), etc. Human subjects are the most preferred. Human subjects include fetal, neonatal, infant, juvenile and adult subjects.

Amino acid as used herein refers to a compound having a free carboxyl group and a free unsubstituted amino group on the a carbon, which may be joined by peptide bonds to form a peptide active agent as described herein. Amino acids may be standard or non-standard, natural or synthetic, with examples (and their abbreviations) including but not limited to:

Asp D^r Aspartic Acid

Ala=A=Alanine

Arg==R=Arginine

Asn=N=Asparagine

Cys Cysteine

Gly=⁼G=Glycine

Glu^: lv Glutamic Acid

Gln=Q=Glutamine

Hi s=H=Hi stidine

lle^ l - Isoleucine

Leu=L=Leucine

Lys=K=Lysine

Met=M=Methionine

Phe P -Phenylalanine

Pro=P=Proline

Ser=S=Serine

Thr=T=Threonine

Trp- W ^Tryptophan Tyr=Y=Tyrosine

Val=V=Valine

Orrr Ornithine

Nal=2-napthylalanine

Nva=Norvaline

Nle=Norleucine

Thi=2-thienylalanine

Pcp=4-chlorophenylalanine

Bth=3-benzothienyalanine

Bip=4,4'-biphenylalanine

Tic=tetrahydroisoquinoline-3-carboxylic acid

Aib=aminoisobutyric acid

Anb=a-aminonormalbutyric acid

Dip=2,2-diphenylalanine

Thz=4-Thiazolylalanine

All peptide sequences mentioned herein are written according to the usual convention whereby the N-terminal amino acid is on the left and the C-terminal amino acid is on the right. A short line (or no line) between two amino acid residues indicates a peptide bond.

"Basic amino acid" refers to any amino acid that is positively charged at a pH of 6.0, including but not limited to R, K, and H.

"Aromatic amino acid" refers to any amino acid that has an aromatic group in the side-chain coupled to the alpha carbon, including but not limited to F, Y, W, and H.

"Hydrophobic amino acid" refers to any amino acid that has a hydrophobic side chain coupled to the alpha carbon, including but not limited to I, L, V, M, F, W and C, most preferably 1, L, and V.

"Neutral amino acid" refers to a non-charged amino acid, such as M, F, W, C and A.

"Treat" or "treating" as used herein refers to any type of treatment that imparts a benefit to a subject that has a disease or disorder or is at risk of having or developing the disease or disorder, including, for example, improvement in the condition of the subject (e.g., in one or more symptoms) and/or slowing of the progression of symptoms, etc. As used herein, "prevent," "preventing" or "prevention" includes prophylactic treatment of the subject to prevent the onset or advancement of a disorder, as determined, e.g., by the absence or delay in the manifestation of symptoms associated with the disorder. As used herein, "prevent," "preventing" or "prevention" is not necessarily meant to imply complete abolition of symptoms.

"Treatment effective amount," "effective amount," "amount effective to treat" or the like as used herein means an amount of the antibody or fragment thereof of this invention sufficient to produce a desirable effect upon a patient that has cancer, tumors, atherosclerosis, retinopathy, diabetic nephropathy, or any other undesirable medical condition in which IGF-l is inducing abnormal cellular growth. This includes improvement in the condition of the patient (e.g., in one or more symptoms), delay in the progression of the disease, etc.

"Pharmaceutically acceptable" as used herein means that the compound or composition is suitable for administration to a subject to achieve the treatments described herein, without unduly deleterious side effects in light of the severity of the disease and necessity of the treatment.

"Antibody" or "antibodies" as used herein refers to all types of

immunoglobulins, including IgG, IgM, IgA, IgD, and IgE. The term

"immunoglobulin" includes the subtypes of these immunoglobulins, such as IgGj, IgG₂, IgG₃, IgG₄, etc. The antibodies may be of any species of origin, including (for example) mouse, rat, rabbit, horse, or human, or may be chimeric or humanized antibodies. The term "antibody" as used herein includes antibody fragments which retain the capability of binding to a target antigen, for example, Fab, F(ab')₂, and Fv fragments, and the corresponding fragments obtained from antibodies other than IgG. Such fragments are also produced by known techniques. In some embodiments antibodies may be coupled to or conjugated to a detectable group or therapeutic group in accordance with known techniques.

Furthermore, the term "antibody" as used herein, is intended to refer to immunoglobulin molecules comprising four polypeptide chains, two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain comprises a heavy chain variable region (abbreviated herein as HCVR or VH) and a heavy chain constant region. The heavy chain constant region comprises three domains, CHI , CH2 and CH3. Each light chain comprises a light chain variable region (abbreviated herein as LCVR or VL) and a light chain constant region. The light chain constant region comprises one domain (CL1). The VH and VL regions can be further subdivided into regions of hypervariability, termed complementary determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). In various embodiments of the antibody or antigen binding fragment thereof of the invention, the FRs may be identical to the human germline sequences, or may be naturally or artificially modified. Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy- terminus in the following order: FR1 , CDR1. FR2, CDR2, FR3, CDR3, FR4.

In general, the antibodies and antigen binding fragments thereof of the present invention possess very high affinities, typically possessing K_D values of from about 10^"8 through about 10^"12 M or higher, for example, at least 10^"8 M. at least 10^"9 M, at least 10^"10 M, at least 10^{"1 1} M, or at least 10^"12 M, when measured by binding to antigen presented on cell surface.

The antibodies and antigen binding fragments thereof of the present invention possess very high affinities, typically possessing EC50 values of from about 10^" through about 10^" M or higher, for example, at least 10^" M, at least 10^" M, at least 10^"10 M, at least 10^"" M, or at least 10^"12 M, when measured by binding to antigen presented on cell surface.

The term "antigen-binding portion" or" antigen-binding fragment" of an antibody (or simply "antibody portion" or "antibody fragment"), as used herein, refers to one or more fragments, portions or domains of an antibody that retain the ability to specifically bind to an antigen. It has been shown that fragments of a full-length antibody can perform the antigen-binding function of an antibody. Examples of binding fragments encompassed within the term "antigen-binding portion" of an antibody include (i) an Fab fragment, a monovalent fragment consisting of the VL, VH, CL1 and CHI domains; (ii) an F(ab')₂ fragment, a bivalent fragment comprising two F(ab)' fragments linked by a disulfide bridge at the hinge region; (iii) an Fd fragment consisting of the VH and CHI domains; (iv) an Fv fragment consisting of the VL and VH domains of a single arm of an antibody; (v) a dAb fragment (Ward et al. (1989) Nature 241 :544-546), which consists of a VH domain; and (vi) an isolated complementary determining region (CDR). Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single contiguous chain in which the VL and VH regions pair to form monovalent molecules (known as single chain Fv (scFv); see e.g., Bird et al. (1988) Science 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883). Such single chain antibodies are also intended to be encompassed within the term "antigen-binding portion" of an antibody. Other forms of single chain antibodies, such as diabodies, are also encompassed (see e.g., Holliger et al. (1993) Proc. Natl. Acad Sci. USA 90:6444-6448).

The term "epitope" refers to an antigenic determinant that interacts with a specific antigen binding site in the variable region of an antibody molecule known as a paratope. A single antigen may have more than one epitope. Epitopes may be either conformational or linear. A conformational epitope is produced by spatially juxtaposed amino acids from different segments of one (or more) linear polypeptide chain(s). A linear epitope is an epitope produced by adjacent amino acid residues in a polypeptide chain. In certain embodiments, an epitope may include other moieties, such as saccharides, phosphoryl groups, or sulfonyl groups on the antigen.

As applied to polypeptides, the term "substantial similarity" or "substantially similar" means that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 95% sequence identity, even more preferably at least 98% or 99% sequence identity. Preferably, residue positions, which are not identical, differ by conservative amino acid substitutions. A "conservative amino acid substitution" is one in which an amino acid residue is substituted by another amino acid residue having a side chain (R group) with similar chemical properties (e.g., charge or hydrophobicity). In general, a conservative amino acid substitution will not substantially change the functional properties of a protein. In cases where two or more amino acid sequences differ from each other by conservative substitutions, the percent or degree of similarity may be adjusted upwards to correct for the conservative nature of the substitution. Means for making this adjustment are well-known to those of skill in the art. See, e.g., Pearson (1994) Methods Mol. Biol. 24: 307-331 , herein incorporated by reference. Examples of groups of amino acids that have side chains with similar chemical properties include 1) aliphatic side chains: glycine, alanine, valine, leucine and isoleucine; 2) aliphatic-hydroxyl side chains: serine and threonine; 3) amide-containing side chains: asparagine and glutamine; 4) aromatic side chains: phenylalanine, tyrosine, and tryptophan; 5) basic side chains: lysine, arginine, and histidine; 6) acidic side chains: aspartate and glutamate, and 7) sulfur-containing side chains: cysteine and methionine. Preferred conservative amino acids substitution groups are: valine- leucine- lsoleucine, phenylalanine-tyrosine, lysine-arginine, alanine- valine, glutamate- aspartate, and asparagine-glutamine. Alternatively, a conservative replacement is any change having a positive value in the PAM250 log-likelihood matrix disclosed in Gonnet et al. (1992) Science 256: 1443 45, herein incorporated by reference. A "moderately conservative" replacement is any change having a nonnegative value in the PAM250 log-likelihood matrix.

Sequence similarity for polypeptides is typically measured using sequence analysis software. Protein analysis software matches similar sequences using measures of similarity assigned to various substitutions, deletions and other modifications, including conservative amino acid substitutions. For instance, GCG software contains programs such as GAP and BESTFIT which can be used with default parameters to determine sequence homology or sequence identity between closely related polypeptides, such as homologous polypeptides from different species of organisms or between a wild type protein and a mutein thereof. See, e.g., GCG Version 6.1. Polypeptide sequences also can be compared using FASTA with default or recommended parameters; a program in GCG Version 6.1. FASTA (e.g., FASTA2 and FASTA3) provides alignments and percent sequence identity of the regions of the best overlap between the query and search sequences (Pearson (2000) supra). Another preferred algorithm when comparing a sequence of the invention to a database containing a large number of sequences from different organisms is the computer program BLAST, especially BLASTP or TBLASTN, using default parameters. See, e.g., Altschul et al. (1990) J Mol. Biol. 215: 403 410 and Altschul et al. (1997) Nucleic Acids Res. 25:3389 402, each of which is herein incorporated by reference in its entirety.

"Therapeutic group" means any suitable therapeutic group, including but not limited to radionuclides, chemotherapeutic agents and cytotoxic agents.

"Radionuclide" as described herein may be any radionuclide suitable for delivering a therapeutic dosage of radiation to a tumor or cancer cell, including but not limited to ²²⁷Ac, ^2HAt, ¹³¹Ba, ⁷⁷Br, ¹⁰⁹Cd, ⁵¹Cr, ⁶⁷Cu, ^,65Dy, ^{l 55}Eu, ^,53Gd, ¹⁹⁸Au, ¹⁶⁶Ho, ^{I I3m}In, ^{! 15m}In, ¹²³I, ¹²⁵I, ¹³¹I, ¹⁸⁹Ir, ^{] 9,}Ir, ¹⁹²Ir, ¹⁹⁴Ir, ⁵²Fe, ⁵⁵Fe, ⁵⁹Fe, ¹⁷⁷Lu, ¹⁰⁹Pd, ³²P, ²²⁶Ra, ¹⁸⁶Re, ^,88Re, ¹⁵³Sm, ⁴⁶Sc, ⁴⁷Sc, ⁷²Se, .⁷⁵Se, ^,05Ag, ⁸⁹Sr, ³⁵S, ^,77Ta, ^{1 , 7}mSn, ¹²¹Sn, ¹⁶⁶Yb, ^,69Yb, ⁹⁰Y, ²¹²Bi, ^{1 !9}Sb, ¹⁹⁷l lg. ⁹⁷Ru, ¹⁰⁰Pd, ^10ImRh, and ²¹²Pb. "Cytotoxic agent" as used herein includes but is not limited to ricin (or more particularly the ricin A chain), aclacinomycin, diphtheria toxin. Monensin, Verrucarin A, Abrin, Vinca alkaloids, Tricothecenes, and Pseudomonas exotoxin A.

"Detectable group" as used herein includes any suitable detectable group, such

35 125 131

as radiolabels (e.g. S, I, I, etc.), enzyme labels (e.g. , horseradish peroxidase, alkaline phosphatase, etc.), fluorescence labels (e.g. , fluorescein, green fluorescent protein, etc.), etc., as are well known in the art and used in accordance with known techniques.

Formulations and administration

For administration in the methods of use described below, the active agent (e.g., the antibody or antigen-binding fragment thereof) will generally be mixed, prior to administration, with a non-toxic, pharmaceutically acceptable carrier substance (e.g. normal saline or phosphate-buffered saline), and will be administered using any medically appropriate procedure, e.g. , parenteral administration (e.g. , injection) such as by intravenous or intra-arterial injection.

The active agents described above may be formulated for administration in a pharmaceutical carrier in accordance with known techniques. See, e.g., Remington, The Science And Practice of Pharmacy (latest edition). In the manufacture of a pharmaceutical formulation according to the invention, the active compound

(including the physiologically acceptable salts thereof) is typically admixed with, inter alia, an acceptable carrier. The carrier must, of course, be acceptable in the sense of being compatible with any other ingredients in the formulation and must not be deleterious to the subject. The carrier may be a liquid and is preferably formulated with the compound as a unit-dose formulation which may contain from 0.01 or 0.5% to 95% or 99% by weight of the active compound. The carrier may be sterile or otherwise free from contaminants that would be undesirable to administer or deliver to a subject.

Formulations of the present invention suitable for parenteral administration comprise sterile aqueous and non-aqueous injection solutions of the active compound, which preparations are preferably isotonic with the blood of the intended subject. These preparations may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended subject. The active agents may be administered by any medically appropriate procedure, e.g. , normal intravenous or intra-arterial administration. In certain cases, direct administration to an atherosclerotic vessel may be desired.

Active agents may be provided in lyophylized form in a sterile aseptic container or may be provided in a pharmaceutical formulation in combination with a pharmaceutically acceptable carrier, such as sterile pyrogen-free water or sterile pyrogen-free physiological saline solution.

Dosage of the antibody or antigen binding fragment thereof of this invention for the methods of use described herein will depend, among other things, the condition of the subject, the particular disorder being treated, the route of

administration, the nature of the therapeutic agent employed, and the sensitivity of the subject to the particular therapeutic agent. For example, the dosage range can be from about 0.02 to about 500 micrograms per kilogram subject body weight. The specific dosage of the antibody or antigen binding fragment thereof is not critical, as long as it is effective to result in some beneficial effects in some individuals within an affected population. In general, the dosage may be as low as about 0.05, 0.1 , 0.5, 1 , 5, 10, 20 or 50 micrograms per kilogram subject body weight, or lower, and as high as about 60, 75, 90 or 100 micrograms per kilogram subject body weight, or even higher.

In the treatment of cancers or tumors the antibodies and antigen binding fragments thereof of the present invention may optionally be administered in conjunction with other, different, cytotoxic agents such as chemotherapeutic or antineoplastic compounds or radiation therapy useful in the treatment of the disorders or conditions described herein (e.g., chemotherapeutics or antineoplastic compounds). The other compounds may be administered prior to, concurrently and/or after administration of the antibodies or antigen binding fragments thereof of this invention. As used herein, the word "concurrently" means sufficiently close in time to produce a combined effect (that is, concurrently may be simultaneously, or it may be two or more administrations occurring before or after each other)

As used herein, the phrase "radiation therapy" includes, but is not limited to, x-rays or gamma rays which are delivered from either an externally applied source such as a beam or by implantation of small radioactive sources.

Nonlimiting examples of suitable chemotherapeutic agents which may be administered with the antibodies or antigen binding fragments as described herein include daunomycin, cisplatin, verapamil, cytosine arabinoside, aminopterin, democolcine, tamoxifen, Actinomycin D, Alkylating agents (including, without limitation, nitrogen mustards, ethylenimine derivatives, alkyl sulfonates, nitrosoureas and triazenes): Uracil mustard, Chlormethine, Cyclophosphamide (Cytoxan^®), Ifosfamide, Melphalan. Chlorambucil, Pipobroman, Triethylene-melamine,

Triethylenethiophosphoramine, Busulfan, Carmustine, Lomustine, Streptozocin, Dacarbazine, and Temozolomide; Antimetabolites (including, without limitation, folic acid antagonists, pyrimidine analogs, purine analogs and adenosine deaminase inhibitors): Methotrexate, 5-F!uorouracil, Floxuridine, Cytarabine, 6-Mercaptopurine, 6-Thioguanine, Fludarabine phosphate, Pentostatine, and Gemcitabine, Natural products and their derivatives (for example, vinca alkaloids, antitumor antibiotics, enzymes, lymphokines and epipodophyllotoxins): Vinblastine, Vincristine, Vindesine, Bleomycin, Dactinomycin, Daunorubicin, Doxorubicin, Epirubicin, Idarubicin, Ara- C, paclitaxel (paclitaxel is commercially available as Taxol®), Mithramycin,

Deoxyco-formycin, Mitomycin-C, L-Asparaginase, Interferons (especially IFN-a), Etoposide, and Teniposide; Other anti-proliferative cytotoxic agents are navelbene, CPT-1 1 , anastrazole, letrazole, capecitabine, reloxafine, cyclophosphamide, ifosamide, and droloxafme. Additional anti-proliferative cytotoxic agents include, but are not limited to, melphalan, hexamethyl melamine, thiotepa, cytarabin, idatrexate, trimetrexate, dacarbazine, L-asparaginase, camptothecin, topotecan, bicalutamide, flutamide, leuprolide, pyridobenzoindole derivatives, interferons, and interleukins. Preferred classes of antiproliferative cytotoxic agents are the EGFR inhibitors, Her-2 inhibitors, CDK inhibitors, and Herceptin® (trastuzumab). (see, e.g., US Patent No. 6,537,988; US Patent No. 6,420,377). Such compounds may be given in accordance with techniques currently known for the administration thereof.

Antibodies

Antibodies and the production thereof are known. See, e.g., US Patent No.

6,849,719; see also US Patents Nos. 6,838,282; 6,835,817; 6,824,989.

Antibodies of the invention include antibodies that are modified, i.e., by the covalent attachment of any type of molecule to the antibody such that covalent attachment does not prevent the antibody from specifically binding to its binding site. For example, antibodies of the invention may be modified, e.g., by glycosylation, acetylation, pegylation, phosphorylation, amidation, or with other protecting/blocking groups, proteolytic cleavage, linkage to a cellular ligand or other protein, etc. Any of numerous chemical modifications may be carried out by known techniques, including but not limited to specific chemical cleavage, acetylation, formylation, metabolic synthesis of tunicamycin, etc. Additionally, the antibodies may contain one or more non-classical amino acids.

Monoclonal antibodies can be prepared using a wide variety of techniques including the use of hybridoma, recombinant, and phage display technologies, or a combination thereof. For example, monoclonal antibodies can be produced using hybridoma techniques including those taught, for example, in Harlow et al.,

Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988); and Hammerling et al., Monoclonal Antibodies and 1 -Cell Hybridomas 563- 681 (Elsevier, N.Y., 1981). The term "monoclonal antibody" as used herein is not limited to antibodies produced through hybridoma technology. The term "monoclonal antibody" refers to an antibody that is derived from a single clone, including any eukaryotic, prokaryotic, or phage clone, and not the method by which it is produced.

Methods for producing and screening for specific antibodies using hybridoma technology are routine and known. Briefly, mice are immunized with an antigen or a cell expressing such antigen. Once an immune response is detected, e.g., antibodies specific for the antigen are detected in the mouse serum, the mouse spleen is harvested and splenocytes isolated. The splenocytes are then fused by known techniques to any suitable myeloma cells, for example cells from cell line SP20 available from the ATCC. Hybridomas are selected and cloned by limited dilution. The hybridoma clones are then assayed by methods known in the art for cells that secrete antibodies capable of binding a polypeptide or antigen of the invention.

Ascites fluid, which generally contains high levels of antibodies, can be generated by immunizing mice with positive hybridoma clones.

Examples of techniques which can be used to produce single-chain Fvs (scFv) and antibodies include those described in U.S. Patent Nos. 4,946,778 and

5,258,498; Huston et al. Methods in Enzymology 203:46-88 (1991); Shu et al. PNAS 90:7995-7999 (1993); and Skerra et al. Science 240: 1038-1040 (1988).

The term "humanized" as used herein refers to antibodies from non-human species whose amino acid sequences have been modified to increase their similarity to antibody variants produced naturally in humans. Thus, humanized antibodies are antibody molecules from a non-human species antibody that binds the desired antigen, having one or more complementarity determining regions (CDRs) from the non- human species and framework regions from a human immunoglobulin molecule. Often, framework residues in the human framework regions will be substituted with the corresponding residue from the donor antibody to alter, preferably to improve, antigen binding and/or reduce immunogenicity of the humanized antibody in a subject. These framework substitutions are identified by methods well known in the art, e.g., by modeling of the interactions of the CDR and framework residues to identify framework residues important for antigen binding and/or immunogenicity and sequence comparison to identify unusual framework residues at particular positions. (See, e.g., Queen et al. US Patent No. 5,585,089; Riechmann et al. Nature 332:323 (1988), which are incorporated herein by reference in their entireties.) Antibodies can be humanized using a variety of techniques known in the art including, for example, CDR-grafting {see, e.g., US Patent Nos. 5,225,539;

5,530,101 ; and 5,585,089), veneering or resurfacing {see, e.g., EP Patent No. 592,106; EP Patent No. 519,596; Padlan, Molecular Immunology 28(4/5):489-498 (1991); Studnicka et al, Protein Engineering 7(6):805-814 (1994); Roguska. et al., PNAS 91 :969-973 (1994)), and chain shuffling (US Patent No. 5,565,332). A detailed description of the production and characterization of the humanized monoclonal antibodies of the present invention is provided in the Examples section herein.

Completely human antibodies are desirable for therapeutic treatment, diagnosis, and/or detection of human subjects. Human antibodies can be made by a variety of methods known in the art including phage display methods described above using antibody libraries derived from human immunoglobulin sequences. See, e.g., US Patent Nos. 4,444,887 and 4,716,11 1.

Human antibodies can also be produced using transgenic mice which are incapable of expressing functional endogenous immunoglobulins, but which can express human immunoglobulin genes. For example, the human heavy and light chain immunoglobulin gene complexes may be introduced randomly or by

homologous recombination into mouse embryonic stem cells. Alternatively, the human variable region, constant region, and diversity region may be introduced into mouse embryonic stem cells in addition to the human heavy and light chain genes. The mouse heavy and light chain immunoglobulin genes may be rendered non- functional separately or simultaneously with the introduction of human

immunoglobulin loci by homologous recombination. In particular, homozygous deletion of the JH region prevents endogenous antibody production. The modified embryonic stem cells are expanded and microinjected into blastocysts to produce chimeric mice. The chimeric mice are then bred to produce homozygous offspring that express human antibodies. The transgenic mice are immunized in the normal fashion with a selected antigen, e.g., all or a portion of a polypeptide of the invention. Monoclonal antibodies directed against the antigen can be obtained from the immunized, transgenic mice using conventional hybridoma technology. The human immunoglobulin transgenes harbored by the transgenic mice rearrange during B cell differentiation, and subsequently undergo class switching and somatic mutation. Thus, using such a technique, it is possible to produce therapeutically useful IgG, IgA, IgM and IgE antibodies. For an overview of this technology for producing human antibodies, see Lonberg and Huszar (1995, Int. Rev. Immunol. 13:65-93). For a detailed discussion of this technology for producing human antibodies and human monoclonal antibodies and protocols for producing such antibodies, see, e.g., US Patent Nos. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661 ,016; 5,545,806;

5,814,318 and 5,939,598.

Completely human antibodies which recognize a selected epitope can be generated using a technique referred to as "guided selection." In this approach a selected non-human monoclonal antibody, e.g., a mouse antibody, is used to guide the selection of a completely human antibody recognizing the same epitope. (Jespers et al., Bio/technology 12:899-903 (1988)).

Further, antibodies to the polypeptides of the invention can, in turn, be utilized to generate anti- 1 diotype antibodies that "mimic" polypeptides of the invention using techniques well known to those skilled in the art. (See, e.g.,

Greenspan & Bona, FASEB J. 7(5):437-444; (1989) and Nissinoff, J Immunol.

147(8):2429-2438 (1991)). For example antibodies which bind to and competitively inhibit polypeptide multimerization and/or binding of a polypeptide of the invention to a ligand can be used to generate anti-ldiotypes that "mimic" the polypeptide multimerization and/or binding domain and, as a consequence, bind to and neutralize polypeptide and/or its ligand. Such neutralizing anti-ldiotypes or Fab fragments of such anti-ldiotypes can be used in therapeutic regimens to neutralize polypeptide ligand. For example, such anti- Idiotypic antibodies can be used to bind a polypeptide of the invention and/or to bind its ligands/receptors, and thereby block its biological activity.

The invention further provides polynucleotides comprising a nucleotide sequence encoding a chimeric antigen receptor of the invention as described above. The polynucleotides may be obtained, and the nucleotide sequence of the

polynucleotides determined, by any method known in the art. For example, if the nucleotide sequence of the components of the chimeric antigen receptor are known, a polynucleotide encoding the components may be assembled from chemically synthesized oligonucleotides, which involves the synthesis of overlapping

oligonucleotides containing portions of the sequence encoding the components of the chimeric antigen receptor, annealing and ligation of those oligonucleotides, and then amplification of the ligated oligonucleotides by PGR. Alternatively, a polynucleotide encoding a chimeric antigen receptor may be generated from nucleic acid from a suitable source. Amplified nucleic acids generated by PGR may then be cloned into replicable cloning vectors using any method well known in the art.

The present invention is explained in greater detail in the following non- limiting examples.

EXAMPLES

The following examples are presented in order to more fully illustrate the preferred embodiments of the invention. They should in no way, however, be construed as limiting the broad scope of the invention.

EXAMPLE 1. Chimeric antigen receptor targeting the glucose-regulated protein of 94 kDa (Grp94)

The glucose-regulated proteins (GRPs) belong to the heat shock protein (HSP) family,- while HSPs are mostly located in the cytosol and nucleus, GRPs are located in the endoplasmic reticulum or mitochondria and can be actively translocated to other cellular sites including cell surface membrane and secreted. GRPs are stress-inducible chaperones that facilitate protein folding and assembling and the export of misfolded proteins for degradation. In their chaperon role, GRPs are involved in controlling multiple biological functions including cell proliferation, invasion and apoptosis. It is becoming evident that GRPs have also relevant biological functions in cancer development as GRP overexpression has been reported in several types of tumors and is associated with their aggressive phenotype.

The Grp94 also known as GP96 and HSP90B1 is overexpressed in several cancers including head and neck, nasopharyngeal, esophageal, lung, breast, gastric, liver, colorectal cancer, pancreatic ductal adenocarcinoma, osteosarcoma, multiple myeloma and acute leukemia . The critical role of Grp94 in cancer development relies on its involvement in several biological pathways. Grp94 is involved in cell proliferation since it controls the maturation and secretion of mitogenic factors such as insulin-like growth factors and the WNT signaling through the processes of the low-density lipoprotein receptor-related protein 6 (FRP6). GRPs generally suppress apoptosis, and Grp94 protects cancer cells from apoptosis by maintaining the Ca²⁺ homeostasis of the endoplasmic reticulum. GRP96 silencing in breast cancer tumor cell lines reduces tumor cell invasion and metastasis.

The surface expression of stress proteins including Grp94 on tumor cells, but not on normal cells, offers the opportunity to develop therapeutic monoclonal antibodies for the treatment of malignancies. We have isolated the single chain Fv (scFv) W9 by panning the synthetic phage scFv library (#1 ) with WM1 158 human melanoma cells. ScFv W9 is specific for Grp94, since mass spectrometry analysis of the peptides generated from the 100 kDa molecule immunoprecipitated by the scFv W9 from 1 melanoma and 3 carcinoma cell lines has identified the two peptides ELISNASDALDK (SEQ ID NO:2) and GVVDSDDLPLNVSR (SEQ ID NO:3) that are derived uniquely from Grp94. This conclusion is corroborated by the lack of reactivity of scFv W9 mAb W9 with FO-1 melanoma cells in which Grp94 expression was knocked down by Grp94-specific shRNA. ScFv W9 has the unique specificity to recognize an extracellular epitope of the intracellular Grp94, since scFv W9 stains viable human tumor cell lines. (Sabbatino et al. "Grp94-specific monoclonal antibody to counteract BRAF inhibitor resistance in BRAF^V600E melanoma" Journal of

Translational Medicine 13(Suppl 1): K12 (2015); Wang et al. "Intracellular antigens as targets for antibody based immunotherapy of malignant diseases" Molecular Oncology 9: 1982-1993 (2015); US Patent No. 8,771 ,687 to Ferrone et al.; US Patent No. 9,340,608 to Ferrone et al., each of which is incorporated by reference herein). They include head and neck, nasopharyngeal, esophageal, lung, breast, gastric, liver, colorectal cancer, pancreatic ductal adenocarcinoma, osteosarcoma, multiple myeloma and acute leukemia. Representative examples of scFv W9 stains are shown in Figures 1 and 2.

It is noteworthy that scFv W9 stains not only differentiated cancer cells, but also cancer initiating cells in many types of cell lines. Representative examples are . shown in Figure 3. Furthermore immunohistochemical staining of surgically removed tumors with scFv W9 shows that the staining is mostly, if not exclusively restricted to the cell membrane of malignant cells. Representative results are shown in Figure 4. The latter results also indicate that the scFv W9 defined Grp94 epitope is expressed in vivo.

In order to couple the antigen specificity of the W9 scFv with the cytotoxic activity of human T lymphocytes the W9 scFv sequence was cloned in frame with the human CD8a stalk and the intracytoplamis domains of CD28 and the -chain of the TCR/CD3 complex to generate the Grp94-specific chimeric antigen receptor (W9- CAR). The cassette was inserted into the SFG retroviral backbone (Figure 5). To produce the retroviral supernatant, 293 T cells were cotransfected with retroviral vectors, Peg-Pam-e plasmid containing the sequence for MoMLV gag-pol, and the DRF plasmid containing the sequence for the RD1 14 envelope. Supernatant containing the retrovirus was collected following 48 and 72 hrs incubation at 37°C. For transduction, 0.5 x 10⁶/mL peripheral blood mononuclear cells (PBMCs) activated with anti-CD3 and anti-CD28 antibodies and recombinant human interleukin-7 and recombinant human interleukin- 15 were plated in complete media in 24-well plates precoated with a recombinant fibronectin fragment. CAR expression on T-lymphocytes was measured following 48 and 72 hrs. incubation at 37°C. Cells were maintained in culture in complete media supplemented with i ll. -7 and II . - 1 5 every 3 days.

To assess their antitumor activity, W9-CAR transduced T cells were cultured with MM, AML and PDAC tumor cells lines. After 5-7 days of co-culture, cells were collected, stained with monoclonal antibodies to detect both T-lymphocytes (anti-CD3 mAb) and tumor cells (anti-CD 138 for MM. anti-CD33 for AML and GEP for PDAC as these last cells were labeled stably transduced with a GFP vector for detection purposes) and then analyzed by flow cytometry (Figures 6 and 7). We have found that W9-CAR T cells can efficiently control the in vitro growth of Grp94+ MM, AML and PDAC tumor cells.

Since tumor eradication requires not only the elimination of differentiated tumor cells but also that of CICs, human PDAC2 or PDAC3 cells (2.5x 1 oVwell in a 6 -we 11 plate) were incubated with LDE225 (10 μΜ), a small molecule inhibitor of hedgehog sonic pathway, for 48 hrs at 37°C in RPMI 1640 medium supplemented with 10% FCS. Then W9-CAR T cells were added to tumor cells using an effector to target ratio as 1 : 1, and the incubation was continued for an additional 24 hrs. in RPMI 1640 medium supplemented with LDE225. PDAC cells co-cultured with control T cells were used as a control. Cells were stained for PDAC CICs, defined as aldehyde dehydrogenases (ALDH)^bright cells, with ALDEFLUOR with or without the DF.AB inhibitor. PDAC CICs are identified as ALDH^bright cells, since this cell population has been shown to display the characteristics of CICs. Specifically, they form

mammospheres in vitro and are tumorigenic in immunodeficient mice. Tumor cells were gated according to size (forward scatter) and granularity (side scatter). These results indicate that LDE225 enhances the ability of W9-CAR T cells to suppress the growth of PDAC CICs (Figure 8).

The invention regards the first CAR that targets Grp94. Taking in

consideration the broad expression of Grp94 in human cancer malignancies this CAR can have an enormous impact in the treatment of human cancers.

EXAMPLE 2. Chondroitin sulfate proteoglycan 4 (CSPG4) as a target for CAR- based T cell immunotherapy of solid tumors

Proteoglycans (PGs) are critical molecules involved in multiple physiological cell functions, but also key players in cancer development and progression. In particular, chondroitin sulfate proteoglycan 4 (CSPG4) is overexpressed in several human malignancies and generally recognized as a tumor-associated antigen (TAA) suitable to be targeted by immune-based approaches.

Adoptive transfer of genetically modified T lymphocytes is emerging as a powerful therapeutic approach in cancer patients. In this regard the selection of the appropriate antigen to be targeted in solid tumors becomes a critical aspect in promoting potent antitumor effects whilst preventing toxicities.

T lymphocytes expressing a CSPG4-specific chimeric antigen receptor (CAR) offer the possibility to target a broad spectrum of solid tumors for which no curative treatments are currently available. In addition, since CSPG4 is also expressed by tumor-associated pericytes, targeting this antigen may also contribute to tumor regression via inhibition of neoangiogenesis. Preclinical experiments to date justify the clinical translation of CSPG4-specific CAR-T cells.

Cancer immunotherapy in the form of administration of monoclonal antibodies (mAbs) recognizing tumor associated antigens (TAAs) or check point inhibitors, and adoptive transfer of tumor-specific T lymphocytes are the most rapidly developing approaches for cancer targeted therapy. In particular, the striking clinical responses observed in recent years after the infusion of T lymphocytes genetically engineered to express a CD19-specific chimeric antigen receptor (CAR) may significantly change the current clinical practice for some B cell malignancies. The application of CAR-T cells for the treatment of solid tumors may represent the most innovative therapeutic approach for many tumors for which no effective therapy is available. However, the clinical experience with CD 19-specific CAR-T cells has shown that profound B cell aplasia occurs in patients in whom long term persistence of CAR-T cells is achieved. Therefore the selection of the TAA to be targeted by engineered T cells in solid tumors is crucial to prevent deleterious side effects potentially caused by targeting the same TAA expressed in normal tissues. There is a limited number of TAAs that meet these criteria. This study analyzes the

characteristics of the TAA chondroitin sulfate proteoglycan 4 (CSPG4) and why

CSPG4 represents an attractive target to implement immunotherapy with CAR-T cells for the treatment of various types of solid tumors.

Cell-surface proteoglycans. Cell-surface proteoglycans (PGs) are macromolecules that can be detected intracellularly, at the cell-surface or in the extracellular matrix (ECM). They are composed of a protein core with one or more glycosaminoglycan (GAG) chains that are linear carbohydrate chains of repeating disaccharide units of an JV-acetylated hexose sugar linked to a hexuronic acid. The synthesis of the protein core as well as the addition of GAG chains and sulfate residues occur in the Golgi apparatus, but the mechanism regulating these processes still remains poorly understood. Cell-surface PGs are critical in mediating cell to cell interactions and with a wide variety of ECM components. In addition, cell-surface PGs can themselves be shed from the membrane to form functional soluble PGs. The most important cell-surface PGs are cell-surface heparan-sulfate PGs and chondroitin sulfate PGs (CSPG). In this analysis, we will only consider the chondroitin sulfate proteoglycan 4 (CSPG4) that belongs to the CSPG family.

CSPG4 expression and function in normal cells. CSPG4 is a member of the CSPG family. The rat orthologue of CSPG4 is known as nerve/glial antigen 2 (NG2). CSPG4 and NG2 are highly conserved although it still remains to be conclusively determined whether human CSPG4 and rat NG2 share completely overlapping functions. CSPG4 is a unique PG complex consisting of a 250 kDa N-linked glycoprotein and a 450 kDa proteoglycan component. The two components were initially reported to be non-covalently associated. Subsequent studies have then convincingly shown that they are independently expressed on the membrane of malignant cells. CSPG4, like NG2, is a cell surface type I transmembrane protein in which three major structural domains can be identified: the extracellular (consisting of 3 subdomains), the transmembrane and the cytoplasmic C-terminal domains. As with other PGs, decoration of CSPG4 with ehondroitin sulfate occurs in the Golgi compartment.

CSPC4/NG2 involvement in organ development and vessel formation, in mouse models, CSPG4/NG2 is expressed by several immature cells such as oligodendrocyte progenitor cells, chondroblasts, skeletal muscle myoblasts, vascular smooth muscle cells and brain capillary endothelial cells, while being down-regulated in most differentiated cells. During embryonic development, CSPG4/NG2 is expressed in the embryonic heart by day 9 and in the microvasculature of the central nervous system by day 12. While the expression pattern of CSPG4/NG2 may suggest a critical role in organogenesis, the knockout mouse NG2^-/" does not show a specific phenotype as these mice are morphologically and functionally comparable to wild- type mice. CSPG4/NG2 is however involved in angiogenesis and wound repair. In mice NG2 is expressed by angiogenesis-associated pericytes in both normal and pathologic conditions. NG2 interacts with the galectin-3/a3pi integrin complex expressed by endothelial cells. Activation of βΐ integrin signaling promotes endothelial cell motility and endothelial tube formation in in vitro assays and blood vessel development in vivo. In addition, CSPG4 also associates with platelet-derived growth factor receptor (PDGFR)-a, integrins α3β1 and α4β 1. STAT5A may be involved in regulating CSPG4 expression since there are potential binding sites of STAT5A located in CSPG4 promoter region.

CSPG4 expression in normal adult tissues. The interest in using CS G4 as a target of immunotherapy in the clinical setting has emphasized the need to characterize its expression in normal adult tissues. Potential side effects caused by its expression in "crucial" normal cells would be a major contraindication to the clinical use of CSPG4 as a target for immunotherapy. The Cancer Genome Atlas of proteins and RNAs report that CSPG4 protein and especially CSPG4 mRNA has a broad distribution in normal tissues. However, the experimental evidence supporting these conclusions is only partially presented, and therefore it is difficult to determine the validity of the statement that CSGP4 is broadly expressed in normal tissues, although with different levels. In contrast, immunohistochemistry staining and mRNA expression profiling have shown that CSPG4 has a restricted distribution in normal tissues. Whether the conflicting results reflect the different specificity of the Abs and/or sensitivity of the methods used is not known. Some of the commercially available CSPG4-specific polyclonal xeno-Abs display a broader reactivity with normal tissues than our own mAbs. Lastly in view of the likely lower sensitivity of binding assays with mAbs than of lytic assays performed with CAR-redirected T cells as effectors, it is noteworthy that T cells transduced with CSPG4-specific CARs did not lyse in vitro a variety of normal cells which do not express CSPG4 on the basis of the results obtained with binding assays with mAbs.

Differential CSPG4 expression on pericytes in different anatomic sites. In view of the potential implications for the therapeutic efficacy of CSPG4-targeted therapies, it is noteworthy that CSPG4 displays a differential distribution on pericytes in different anatomic sites. It is up-regulated on tumor associated pericytes in the tumor m i c roe n v i ro n m e n t , but it is not or barely detectable on pericytes in anatomic sites distant from tumor sites. CSPG4 up-regulation on tumor associated pericytes may be due to the hypoxic conditions which are frequently present in the tumor microenvironment. CSPG4 expression is upregulated on triple negative breast cancer (TNBC) cells incubated under hypoxic conditions. Immunotargeting of CSPG4 is likely to decrease pericyte/endothelial cell interactions, leading to deficits in basal lamina assembly and endothelial junction formation, increased vessel leakiness and increased intratumoral hypoxia. As a result, neoangiogenesis and growth of tumor cells, even those which do not express CSPG4, may be inhibited. This possibility has been experimentally proven in a mouse model. We have shown that immunization of mice with hysteria monocytogenes based vaccines expressing distinct CSPG4 fragments induced CSPG4-specific T cell immunity that cross reacted with the mouse counterpart of human CSPG4. The induced T cell immunity markedly delayed the growth of tumors, even those that do not express CSPG4 or its homologue NG2. The anti-tumor activity of the induced CSPG4-specific T cells was associated with infiltration of the tumor stroma by CDS ' T cells and a significant reduction in the pericyte coverage in the tumor vasculature. Interestingly and importantly for the clinical translation, the induced CSPG4-specific T cell immunity did not cause toxicity due to the inhibition of normal vessel formation. Specifically no effects were detected within the time required for wound closure, fertility, gestation length, and pup mass at birth in mice. The lack of systemic effects one would expect because of the targeting of pericytes by the induced CSPG4-specific T cell immunity is likely to reflect the low or lack of CSPG4 expression on pericytes in anatomic sites different and distant from the tumor microenvironment.

CSPG4 expression and function in malignant cells. We initially identified CSPG4 expression on melanoma cells utilizing monoclonal antibodies generated by immunizing mice with human melanoma cells. CSPG4, also known as High

Molecular Weight-Melanoma Associated Antigen (HMW-MAA) and Melanoma Chondroitin Sulphate Proteoglycan (MCSP) attracted our attention, because of its unusual structural profile and its restricted distribution in normal tissues.

CSPG4 overexpression in human malignancies. Initial studies focused on the expression of CSPG4 by melanoma cells, since it was assumed that the expression of this TAA was restricted to this type of malignancy. Analysis of about 2000 surgically removed melanoma tumors showed that CSPG4 is expressed in more than 70% of melanoma lesions. In subsequent years flow cytometry analysis of established cancer cell lines and immunohistochemistry staining of surgically excised tumors from patients has shown that CSPG4 is expressed on several types of malignancies besides melanoma. They include glioblastoma, squamous cell carcinoma of the head and neck (SCCHN), TNBC, mesothelioma, renal cell carcinoma, chondrosarcoma, osteosarcoma, soft tissue sarcomas, and subsets of acute leukemia. In most malignancies CSPG4 has a high expression on malignant cells with limited intra- and inter-lesion heterogeneity. It is noteworthy that in various types of cancer such as SCCHN, TNBC and melanoma, CSPG4 has been shown to be expressed not only by differentiated malignant cells, but also by cancer initiating cells (CICs). However, this expression pattern is present in many types of cancers but does not appear to be a general phenomenon, since CSPG4 was not detected on CICs, identified on the basis of CD133 expression, in glioma tumors.

CSPG4 overexpression and oncogenesis. Several lines of experimental evidence indicate that even if CSPG4/NG2 is not an oncogene per se, it can be directly involved in melanoma progression by promoting tumor cell motility and metastasis. In particular, the cytoplasmic domains of NG2 contains multiple amino acid residues that can be phosphorylated and then promote sustained activation of survival and growth pathways such as the integrin-regulated focal adhesion kinase

(FAK), ERK 1,2, and PI3K/AKT pathways. This implicates CSPG4/NG2 as playing a crucial role in tumor progression by controlling cell adhesion processes, and may also accounts for the association between CSPG4 expression and poor clinical outcome as found in acral lentiginous melanoma, high grade glioma. HNSCC and breast cancer.

CSPG4 as a target of immunotherapy. CSPG4 and its homologous NG2 have been targeted with mAbs and T cell-based immunotherapy both in animal models and clinical settings. The malignancy that has been mostly targeted in these studies is malignant melanoma, in general, targeting CSPG4 has been found to be associated with a survival prolongation and only occasionally with a marked reduction of tumor volume. Both in animal models and patients induction of CSPG4- T cell and humoral immunity has not been associated with major toxicity.

CSPG4-specific antibody based immunotherapy. CSPG4 and its homo!ogs in other animal species are self-antigens and therefore are generally not immunogenic when expressed by tumor cells. Unresponsiveness to self-CSPG4 can be overcome by immunization with CSPG4 mimics. CSPG4 immune responses have been indeed elicited both in humans and dogs with melanoma and also in rat models. CSPG4 mimics were represented by anti-idiotype mAbs which bear the internal image of the nominal antigen in human subjects and in rats and by DNA encoding the human CSPG4 in dogs. In the latter case the high degree of homology, but not complete identity between human CSPG4 and its dog counterpart, provides the DNA encoding human CSPG4 with the ability to overcome unresponsiveness to self-CSPG4 in xenogeneic hosts. The induced humoral immunity was associated with a survival prolongation. None of the described experiments formally proved a cause effect relationship between CSPG4-specific humoral immunity and clinical responses and also excludes a therapeutic role of T cell-mediated responses. Nevertheless the antitumor effects of the in vivo induced humoral responses is supported by the ability of CSPG4-specific Abs to inhibit tumor growth, and more importantly disease recurrence and metastatic spread in immunodeficient mice grafted with human melanoma, TNBC, mesothelioma cells and glioblastoma. In support of the critical tumorigenic role of CSPG4 signaling pathways, inhibition of CSPG4-related pathways and tumor regression can also be achieved by local delivery of shRNA as demonstrated by local injection of lentivirus carrying CSPG4-specific shRNA in melanoma models. This approach may become clinically applicable considering the possibility to use oncolytic viruses as a delivery system for shRNA infused either intratumoral or systemically. To further exploit the specificity of CSPG4-specific Abs, an anti-CSPG4 scFv Ab fragment was fused with human TNF-related apoptosis- inducing ligand (TRAIL) in an attempt to locally deliver a pro-apoptotic molecule to CSPG4 expressing tumors. Finally, the specificity of CSPG4 Abs has also been exploited to engage the cellular component of the immune system. A humanized bi- specific BiTE Ab (bi-specific T-cell engaging) that binds CSPG4 and CD3 molecules was created, and when T lymphocytes were co-cultured with melanoma cells in the presence of the specific BITE, CSPG4-expressing melanoma cells were lysed. Taking into consideration that a similar molecule has been recently approved by the FDA to treat CD 19-exprcssing B cell malignancies, BITE-CSPG4-specific Abs will be tested in clinical trials.

CSPG4-specific T cell based immunotherapy. While for many years T cell therapies were mostly based on the ex vivo expansion of tumor-specific T cell precursors circulating in the peripheral blood or isolated from tumor biopsies, most recent T cell therapies rely on an engineering process of circulating T lymphocytes. Polyclonal T cells are genetically modified using viral vectors to express either a HLA class I restricted T cell receptor ( P^'T^'CR) specific for TAA derived peptides or CARs.

In sharp contrast with apTCRs, CARs are chimeric proteins in which the antigen-binding moieties of Abs are coupled with signaling molecules of T lymphocytes. In general, the variable regions of the heavy and light chains, in the form of a single-chain Ab, are joined with the intracellular signaling domains derived from the 0)3ζ chain of the T-cell receptor, in tandem to costimulatory endodomains such as CD28, 4- IBB or OX40. When expressed by T lymphocytes these molecules redirect the antigen-specificity of engrafted T cells towards the Ab moiety, and promote the effector function and co-stimulation of T lymphocytes.

The different structures of api CRs and CARs lead to fundamental differences in antigen recognition of T cells engineered to express these molecules. PTCR-T cell based strategies require that the TAA is processed by the HLA class I antigen processing machinery (APM), so that peptides are generated and presented by the restricting HLA class I allele to the cognate a(3TCR. Specifically, peptides generated by the proteasome from mostly, although not exclusively, endogenous proteins are transported by the heterodimer transporter associated with antigen processing (TAP) to the endoplasmic reticulum. 1 1 ere peptides are loaded on P2-microglobulin- associated HLA class I heavy chain dimers with the help of the chaperone molecules ERp57, calnexin, calreticulin and tapasin. The trimolecular complex then travels to the cell membrane where it is presented to the cognate αβ CR.

In sharp contrast to conventional a(3TCR recognition, CAR-redirected T cells do not require any processing of the targeted TAA since the antigen-binding moiety is derived from Abs, but requires that TAAs be expressed on tumor cell membrane. The CAR-based strategy has several advantages over the apTCR-based strategy. First, not being HLA class I restricted, CAR-T cell are applicable to all patients independently of their HLA type. Furthermore the recognition of targeted tumor cells by CAR-T cells does not require processing and presentation of the targeted TAA by the HLA class I APM. As a result, the anti-tumor activity of CAR-T cells is not affected by abnormalities in APM, which are frequently present in malignant cells, although with marked differences among various types of cancers. Through multiple mechanisms these abnormalities provide tumor cells with an escape from T cell recognition and destruction.

From a practical point of view, it is noteworthy that the frequency of HLA class I APM defects may be as high as 60% in some types of cancers such as breast, pancreas and prostate cancer. In addition, while some of the APM defects can be corrected with cytokines and/or demethylating agents, others caused by structural mutations require gene therapy to restore the function of the HL A class I APM.

Therefore, while tumors with deficits in APM may not be good candidates for adoptive immunotherapy with apTCR-transduced T cells, they remain targets for

CAR-T cells if they express a TAA on the cell surface. It is also important to note that while the analysis of the expression in normal tissues of the TAA targeted by CAR-T cells can be easily assessed by immunohistochemistry using the same Ab from which the CAR was derived, the analysis of the expression in normal tissues of the HLA class I antigen-TAA derived peptide complex to be targeted with apTCR-transduced T cells remains a challenge.

The majority of the mAbs reported to recognize HLA class I antigen-TAA derived peptide complexes have a questionable specificity. Furthermore most, if not all these mAbs have a low association constant and as a result the sensitivity of the binding assay with tissues, whether normal or malignant, is not sufficient to detect the expression of these complexes. Therefore one cannot determine whether the lack of binding of Abs to normal tissues reflects lack of expression of the corresponding HLA class I antigen-TAA derived peptide complex or insufficient sensitivity of the binding assay used to detect target antigens expressed at low level.

CSPG4 seems a suitable target for CAR-T cells. CARs specific for CSPG4 have been generated from several mAbs (Fig. 9). Specifically, we have generated a CSPG4-specific CAR using the 763.67 mouse Ab and CD28^ as signaling molecules (CAR.CSPG4). Our in vitro and in vivo experiments demonstrated that polyclonal activated human T lymphocytes engineered with a gamma retroviral vector to express the CAR.CSPG4 showed antitumor activity against a variety of CSPG4 positive solid tumors including melanoma, breast carcinoma, HNSCC and mesothelioma. Thus this preclinical assessment paves the rationale for the clinical translation of CAR-T cell based therapy in solid tumors that express CSPG4.

The data we have summarized indicate that because of its high expression on malignant cells in various types of cancers with limited intra- and inter-lesional heterogeneity and its restricted distribution in normal tissues, CSPG4 appears to be an attractive target for immunotherapy with CAR-T cells. The malignancies that express CSPG4 share the characteristics that no effective therapy is available for their treatment and do not appear to express other known TAAs. Therefore CSPG4 as a target of immunotherapy with CAR- T cells meets an unmet need. Two characteristics of the cellular expression of CSPG4 are noteworthy because of their potential role in the outcome of immunotherapy with CAR-T cells. First, CSPG4 is expressed not only on differentiated cancer cells, but also on CICs in most, although not all the tumor types analyzed. Therefore targeting of CSPG4 may eliminate not only differentiated cancer cells, but also CICs. The cancer stem cell theory describes CICs has having chemo- and radio-resistance, and high tumorigenicity in immunodeficient mice. These characteristics contribute to tumor recurrence and metastatic spread, the two major causes of patients' morbidity and mortality. Therefore therapeutic strategies must eliminate not only differentiated cancer cells, but also CICs. CSPG4-specific immunity has been shown to mediate destruction of target cells, especially if combined with small molecules which inhibit signaling pathways with an important functional role in differentiated cancer cells and in CICs.

Second, CSPG4 has a differential expression on pericytes in different anatomic sites. The selective upregulation of CSPG4 on activated pericytes in the tumor microenvironment provides a target for antiangiogenic therapy which is not associated with the side effects caused by systemic antiangiogenic therapy. Furthermore the inhibition of angiogenesis in the tumor microenvironment caused by CSPG4 targeted immunotherapy may contribute in preventing tumor escape due to the loss of the targeted antigen.

It still remains to be defined if the robust clinical responses obtained in acute lymphoid leukemia with CAR-T cells can be also achieved in solid tumors even i the appropriate TAA such as CSPG4 is targeted. The clinical experience with CAR-T cells in solid tumors is still very limited, but encouraging results have been reported in neuroblastoma. In solid tumors several biological aspects may in principle reduce the clinical efficacy of adoptively transferred tumor-specific T cells even if these cells are equipped to efficiently kill tumor cells. For example, T cell trafficking and tumor invasion through the extracellular matrix should be ensured in solid tumors. It has been shown in preclinical models that optimizing the expression of chemokine receptors in CAR-T cells to engage the chemokines produced by tumor cells or stroma helps the appropriate migration of CAR-T cells. Vice versa tumor cells can be infected in vivo with biological agents such as oncolytic viruses to release chemokines such as RANTES and T cell growth factors such as IL-15 to create a favorable tumor environment for the recruitment and survival of CAR-T cells. T lymphocytes have the physiologic capacity to extravasate, and travel within tissues as they can actively use chemokine gradients and release proteolytic enzymes to degrade components of the extracellular matrix. However some of these proteolytic enzymes such as heparanase that degrade heparan sulfate proteoglycans PGs can be defective in CAR- T cells. Transgenic expression of heparanase in CAR-T cells including CSGP4- specific CAR-T cells seems to increase the capacity of these cells to infiltrate the ECM of solid tumors.

Finally, several inhibitory mechanisms are present in the tumor

microenvironment to block tumor specific T lymphocytes. In particular the PD- 1/PDL-l pathway has emerged as a critical blocking mechanism of T cell specific tumor responses. Antibodies that block the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and the Programmed Death (PD)-l receptor or its PD-L1 ligand have produced encouraging results as single agents in human malignancies. It is thus anticipated that the combination of these antibodies with CAR-T cells may enhance the rate of antitumor activity in several solid tumors.

All publications, patent applications, patents, patent publications and other references cited herein are incorporated by reference in their entireties for the teachings relevant to the sentence and/or paragraph in which the reference is presented.

Claims

THAT WHICH IS CLAIMED IS:

1. A method of targeting a cancer cell and/or a cancer initiating cell (CIC) having a glucose-regulated protein of 94 kDa (Grp94) antigen, comprising providing to the cancer cell and/or the CIC a cytotoxic T lymphocyte with a chimeric antigen receptor (CAR) that recognizes the Grp94 antigen.

2. The method of claim 1 , wherein the cancer cell and/or CIC is in vitro or in vivo.

3. The method of claim 1 , wherein the chimeric antigen receptor comprises an antibody that binds Grp94.

4. The method of claim 2, wherein the antibody is a scFv antibody.

5. The method of claim 4, wherein the antibody is a W9 scFv antibody.

6. The method of claim 1 wherein the chimeric antigen receptor is encoded by the nucleotide sequence of SEQ ID NO: 1.

7. The method of claim 1 , wherein the chimeric antigen receptor comprises the effector domain of the T-cell receptor zeta chain or related signal transduction endodomains derived from the T cell receptor.

8. The method of claim 1 , wherein the chimeric antigen receptor comprises one or more costimulatory molecules.

9. The method of claim 8, wherein the costimulatory molecules comprise CD28, OX40, 4-1 BB, or a combination thereof.

10. A method of treating cancer in a subject, comprising administering the subject cytotoxic T lymphocytes having a chimeric antigen receptor that recognizes a Grp94 antigen present on and/or in cancer cells and/or cancer initiating cells of the subject.

1 1. The method of claim 10, wherein the chimeric antigen receptor comprises an antibody that binds Grp94.

12. The method of claim 1 1 , wherein the antibody is a scFv antibody.

13. The method of claim 1 1 , wherein the antibody is a W9 scFv antibody.

14. The method of claim 10, wherein the chimeric antigen receptor is encoded by the nucleotide sequence of SEQ ID NO: 1.

15. The method of claim 10, wherein the chimeric antigen receptor comprises the effector domain of the T-cell receptor zeta chain.

16. The method of claim 10, wherein the chimeric antigen receptor comprises one or more costimulatory molecules.

17. The method of claim 16, wherein the costimulatory molecules comprise CD28, OX40, 4- IBB, or a combination thereof.

18. The method of claim 10, wherein the subject has had and/or is having an additional cancer therapy for cancer.

19. The method of any preceding claim, further comprising the step of contacting the cancer cells and/or CICs with LDE225.