WO2020227595A1 - Clec4-targeted car-t-cells - Google Patents

Abstract

Disclosed are compositions and methods for targeted treatment of cancer, such as hepatocellular carcinoma. In particular, chimeric antigen receptor (CAR) T cells are disclosed that can be used with adoptive cell transfer to target and kill cancer cells with reduced antigen escape. Therefore, also disclosed are methods of providing an anti-tumor immunity in a subject with hepatocellular carcinoma that involves adoptive transfer of the disclosed CAR T cells.

Description

CLEC4-TARGETED CAR-T CELLS

RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Provisional Patent Application serial number 62/845,553, filed May 9, 2019, which is incorporated by reference in its entirety.

BACKGROUND

The liver is the largest solid organ in the body and though its primary functions are not traditionally classified as immunological, the liver performs essential immune tasks and maintains its own immune environment when compared to other organs. For example, the liver plays a role in the induction of immune tolerance, strong innate immunity, and less active adaptive immunity (or in some cases, over-reactive adaptive immunity, i.e., autoimmune liver disease). Relative to peripheral blood T cells, the proportion of gd- vs ab- T cells is higher in the liver, which also has the highest proportion of specialized macrophages (Kuppfer cells) in the body (Nemeth et al., (2009). "Microanatomy of the liver immune system." Semin. Immunopathol. 31(3): 333-343). Since bacterial products, environmental toxins, and food antigens constantly flow to the liver, it has evolved this immune environment through a dynamic network of specialized cell subsets that maintain a unique and redundant system of immune regulation that is biased towards hypo-response. For example, hepatocytes contribute to the liver’s inherent tolerogenicity by priming naive T cells in the absence of costimulation, resulting in defective cytotoxicity and clonal deletion. Such inherent tolerogenic factors may accumulate and be a contributing factor to the development of Hepatocellular Carcinoma (HCC), especially within the context of chronic liver inflammation.

Hepatocellular Carcinoma (HCC) is the third leading cause of cancer deaths worldwide, with over 500,000 people affected. The primary risk factors are cirrhosis, and chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). Though the incidence of HCC is highest in Asia and Africa, it is also the fastest growing cause of cancer-related death of US males. HBV infection is endemic in South-East Asia and Sub- Saharan Africa, and there is a global pandemic of hepatitis C virus (HCV) infection. In the United States, it is estimated that chronic HCV infection is attributed to 47% of HCC cases, with an additional 15% associated with HBV. Once diagnosed, HCC typically has poor prognosis. Current therapies include surgery (less than 20% of HCC patients are eligible for such procedures) and largely palliative local/regional therapies. HCC is known to be resistant to traditional chemotherapy and the 5-year survival is limited to 5-10% of patients, despite the advent of kinase inhibitor therapy (e.g., sorafenib (Llovet et ah, (2008).

"Sorafenib in advanced hepatocellular carcinoma." N Engl J Med 359(4): 378-390.)) improved overall survival from median 7.9 to 10.7 months. Only 2% of HCC patients achieved a radiographic partial response to kinase inhibitor therapy, and no patients had complete response. Moreover, since diabetes, obesity, and metabolic syndrome are also hypothesized risk factors, HCC is expected to become a progressively greater health problem and, thus, a major unmet medical need. Therefore, improved therapies for hepatocellular carcinoma are needed.

SUMMARY

The present invention is based, at least in part, on the discovery that CLEC4 (C-type lectin domain) can be used as a target for the targeted treatment of CLEC4-associated cancers. In some aspects, provided herein are immune cells that express a chimeric antigen receptor (CAR) polypeptide that targets C-type lectin (CLEC). In some embodiments, the CARs disclosed herein comprise a targeting domain such as a CLEC antigen-binding domain, a transmembrane domain, and an intracellular signaling domain. In certain preferred embodiments, the CLEC antigen-binding domain targets a C-type lectin domain family 4 (CLEC4) member (e.g., CLEC4 A, B, C, or D).

In certain aspects, provided herein are bi-specific chimeric antigen receptor (CAR)

T cells, said cells expressing a CAR polypeptide comprising a targeting domain that selectively binds a CLEC4 antigen (e.g., any one of the CLEC4 family members A, B, C,

D, or combinations thereof) and a CAR polypeptide comprising a targeting domain that selectively binds to another different tumor-associated antigen. In some such embodiments, the targeting domain of the chimeric antigen receptor (e.g., the CLEC antigen-binding domain and/or the other different tumor-associated antigen-binding domain) comprise a functional antibody fragment. Preferably, the antigen-binding domain of the chimeric antigen receptors comprise a single-chain variable fragment (scFv) that binds to the target of interest. In some embodiments, the transmembrane domain of the CARs disclosed herein comprise at least one transmembrane domain of any of CD28, 4 IBB, mutants thereof, or any combination thereof. In some preferred embodiments, the intracellular signaling domain of the CARs disclosed herein comprise at least one signaling domain of Oϋ3z, mutants thereof, or any combination thereof. In some embodiments, the CARs disclosed herein further comprise at least one co-stimulatory signaling region, such as a co

stimulatory signaling region comprising a signaling domain of any one of CD28 or a mutant thereof, CD 137 (4 IBB) or a mutant thereof, or any combination thereof. In some embodiments, the costimulatory signaling region contains 1, 2, 3, or 4 cytoplasmic domains of one or more intracellular signaling and/or costimulatory molecules. In some

embodiments, the costimulatory signaling region contains one or more mutations in the cytoplasmic domains of CD28 and/or 4- IBB that attenuate or preferably enhance signaling. In certain embodiments, the CAR-expressing immune cell no longer expresses one or more immune checkpoint molecules. In some such embodiments, the immune checkpoint molecules are blocked and/or suppressed by methods known in the art.

In some embodiments, the CAR polypeptide contains an incomplete endodomain. For example, the CAR polypeptide may contain either an intracellular signaling domain or a co-stimulatory domain, but not both. In these embodiments, the immune effector cell is not activated unless it and a second CAR polypeptide (or endogenous T-cell receptor) that contains the missing domain both bind their respective antigens. Therefore, in some embodiments, the CAR polypeptide contains a CD3 zeta (0"ϋ3z) signaling domain but does not contain a costimulatory signaling region (CSR). In other embodiments, the CAR polypeptide contains the cytoplasmic domain of CD28, 4- IBB, or a combination thereof, but does not contain a CD3 zeta ^ϋ3z) signaling domain (SD).

In some aspects, provided herein are methods of treating CLEC4-associated cancer in a subject, the method comprising administering an effective amount of an adoptive immunotherapy composition comprising CAR-expressing cells as disclosed herein. In some embodiments, the CAR-expressing cells of the adoptive immunotherapy composition are derived from the subject (e.g., autologous). Preferably, the CAR-expressing cells of the adoptive immunotherapy composition are derived from a donor sample, or from a bank or library comprising immune cells not derived from the patient (e.g., allogeneic). In some embodiments, the method further comprises administering at least one immune checkpoint inhibitor.

In some aspects, disclosed herein are isolated nucleic acids encoding the disclosed CAR polypeptides, as well as nucleic acid vectors containing said isolated nucleic acids operably linked to an expression control sequence. Additionally, disclosed herein are cells transfected with these vectors, or that otherwise comprise the disclosed nucleic acids, and the use of these cells to express and/or produce the disclosed CAR polypeptides. Without intending to be an exhaustive list, the cell may be an immune effector cell such as an alpha- beta T cell, a gamma-delta T cell, a Natural Killer (NK) cell, a Natural Killer T (NKT) cell, a B cell, an innate lymphoid cell (ILC), a cytokine induced killer (CIK) cell, a cytotoxic T lymphocyte (CTL), a lymphokine activated killer (LAK) cell, and a regulatory T cell. The cell expressing the herein described CAR polypeptides may alternatively be a pluripotent stem cell, such as an induced pluripotent stem cell (iPSC). In some embodiments, the cell exhibits an anti tumor immunity (e.g., mounts an immune response against a tumor) when the antigen binding domain of the CAR binds to a CLEC4 family member.

In further aspects of the invention, disclosed herein are pharmaceutical

compositions comprising the molecules disclosed herein in a pharmaceutically acceptable carrier. Also disclosed herein are methods for treating cancer in a subject that involve administering to the subject a therapeutically effective amount of the pharmaceutical compositions disclosed herein. In some embodiments, the cancer can be any CLEC4- expressing malignancy.

In some embodiments, the anti-CLEC4-binding agents disclosed herein comprise an antibody fragment that specifically binds CLEC4. For example, and without limitation, the antigen-binding domain can be a Fab or a single-chain variable fragment (scFv) of an antibody that specifically binds CLEC4. In some such embodiments, the anti-CLEC4 binding agent is an aptamer that specifically binds CLEC4. For example, in certain embodiments the anti-CLEC4-binding agent is, or otherwise comprises, a peptide aptamer selected from a random sequence pool based on its ability to bind CLEC4. In some embodiments, the anti-CLEC4-binding agents may also comprise a natural ligand of CLEC4, or a variant and/or fragment thereof, capable of binding CLEC4.

The CAR (or CAR-associated) polypeptides disclosed herein can also contain a transmembrane domain and an endodomain capable of activating an immune effector cell. For example, the endodomain can contain a signaling domain and one or more

costimulatory signaling regions.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DETAILED DESCRIPTION

Details

As disclosed herein, the present invention relates, at least in part, to immune cells which recombinantly express a chimeric antigen receptor (CAR) that targets C-type lectin (CLEC). The C-type lectin/C-type lectin-like domain (CTL/CTLD) superfamily of proteins share a common protein fold and have diverse functions, such as cell adhesion, cell-cell signaling, glycoprotein turnover, as well as roles in inflammation and the immune response. In some embodiments, the targeted CLEC is associated with the presence of a cancer cell and/or tumor. Preferably, the CLEC is expressed on the cell surface of a cancer cell (e.g., a tumor cell). In some preferred embodiments, the CLEC is a C-type lectin domain family 4 (CLEC4) member, including for example any of the CLEC4 family members A, B, C, or D. In some such embodiments, the CLEC4 is associated with hepatocellular carcinoma (HCC). In preferred embodiments, CLEC4 is targeted by an immune effector cell (i.e., T cells or Natural Killer (NK) cells) that are engineered to express a chimeric antigen receptor (CAR) polypeptide that selectively binds CLEC4.

A major advance for T cell therapy was the development of chimeric antigen receptors (CARs). First generation CARs were developed as an artificial receptor that, when expressed by T cells, could retarget them to a predetermined disease-associated antigen (e.g., tumor-associated antigens). Such CARs typically comprise a single chain variable fragment (scFv) derived from a target-specific antibody, fused to signaling domains from a T cell receptor (TCR), such as CD3z. Upon binding antigen, CARs trigger phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMS) and initiate the signal cascade required for cytolysis, cytokine secretion and proliferation, bypassing the endogenous antigen-processing pathway and MHC restriction. Second generation CAR designs include further signaling domains to enhance activation and co-stimulation, such as CD28 and/or 4-1BB. Compared to their earlier counterparts, second generation CARs were observed to induce more IL-2 secretion, increase T cell proliferation and persistence, mediate greater tumor rejection, and extend T cell survival. The third generation CARs are made by combining multiple signaling domains, such as 0ϋ3z-0ϋ28-0040 or Oϋ3z- CD28-41BB, to augment potency with stronger cytokine production and killing ability.

In some embodiments, the CAR T cells described herein are engineered so as to counteract any tolerogenic effects of the liver microenvironment by, for example and without limitation, suppressing or inhibiting PD-1 signaling. In certain embodiments, the CARs described herein may be sensitized to or selectively target a viral or non-viral antigen. An ideal target should not be expressed on any normal tissue/organ, or at least not in vital normal tissues (heart, liver, CNS, lung, and other tissues that may be particularly sensitive to transient damage) nor in closely related normal cellular counterparts, e.g., stem and/or progenitor cells. Searches for CAR targets have typically relied upon transcriptome analyses, assuming that there exists a direct correspondence between mRNA transcripts and protein expression. However, any such correlation is fraught with complexity and, in view of several confounding factors such as post-translational modifications, regulatory mechanisms, and variable half-lives, is likely unrepresentative of the cell proteome. Thus, integrated and comprehensive analysis of transcriptomic and proteomic data comparing malignant and normal cells is therefore necessary to capture all information thus far lacking from the indirect analyses of the transcriptome via mRNA or limited protein expression assays. Accordingly, in certain aspects disclosed herein, potential CAR targets (e.g., targets associated with or specific to HCC) are identified by integrating proteomic and genomic datasets from dysfunctional/ disease-state and normal cell populations. In certain embodiments, targets are identified using an algorithm together with analysis of paired tissue samples (i.e., from HCC & normal adjacent tissue). Such methodologies are further described in Pema et ah, (2017). "Integrating Proteomics and Transcriptomics for

Systematic Combinatorial Chimeric Antigen Receptor Therapy of AML." Cancer Cell 32(4): 506-519 e505., which is incorporated herein in its entirety. In certain preferred embodiments, CLEC4B and/or CLEC1B are identified as potential HCC-specific targets. In certain aspects of the invention disclosed herein, a dual signaling CAR T approach is used, providing a competitive advantage over current HCC CAR T programs in development. For example, Glypican-3, known to be expressed on normal hepatocytes at a lower level relative to HCCs, is associated with significant risk of toxicity when used alone as the target of CAR immunotherapy (Hoseini and Cheung (2017). "Immunotherapy of hepatocellular carcinoma using chimeric antigen receptors and bispecific antibodies." Cancer Lett 399: 44- 52). Also disclosed herein are immune effector cells, such as T cells or Natural Killer (NK) cells, that are engineered to express chimeric antigen receptor (CAR) polypeptides that selectively bind at least CLEC4 (e.g., one or more CLEC4 isoforms/family members, including CLEC4A, B, C or D). Therefore, also disclosed are methods for providing targeted immunity (e.g., anti -tumor immunity) in a subject with HCC that involves adoptive transfer of the disclosed immune effector cells engineered to express the disclosed CAR polypeptides.

In the tumor microenvironment cancer cells and host immune cells interact, potentially leading to promotion or inhibition of cancer progression. Ideally, the immune system would identify cancer cells and mobilize an immune response to eliminate the cancer. Unfortunately, at the T cell level, upregulation of inhibitory receptors, such as PD-1 and Tim-3, correlate with T cell dysfunction. This has been observed on both hepatitis C virus (HCV)-specific and HCV-nonspecific CD8⁺ T cells in the circulation and livers of patients with chronic HCV infection. Partial restoration of T cell proliferation and IFN-g secretion can be achieved ex vivo by inhibiting the binding of PD-1 and Tim-3 to their respective ligands (i.e., B7-H1, also known as PD-L1, and Galectin-9). What is more, recent reports have demonstrated that prolonged administration of IFN-a, a standard therapy for persistent HCV infection, promoted telomere loss in naive T cells. Given the correlation between shortened T cell telomeres and terminal differentiation (characterized by diminished proliferative potential), IFN-a-induced T cell“exhaustion” likely represents a significant barrier for immunotherapy in HCV-infected patients. In certain aspects disclosed herein, the invention employs checkpoint inhibition strategies. Checkpoint inhibitor therapies target key regulators of the immune system that either stimulate or inhibit the immune response. Such immune checkpoints can be exploited in the cancer disease state (e.g., by tumors) to evade attacks by the immune system. Checkpoint inhibitor studies have noted the activity of PD-1 inhibitor therapy (El-Khoueiry et ak, (2017).

"Nivolumab in patients with advanced hepatocellular carcinoma (CheckMate 040): an open-label, non-comparative, phase 1/2 dose escalation and expansion trial." Lancet 389 (10088): 2492-2502) and the FDA has approved Nivolumab for second line treatment of HCC with an objective response rate of 20%. Definitions

The term“antibody” refers to an immunoglobulin, derivatives thereof which maintain specific binding ability, and proteins having a binding domain which is homologous or largely homologous to an immunoglobulin binding domain. These proteins may be derived from natural sources, or partly or wholly synthetically produced.

An antibody may be monoclonal or polyclonal. The antibody may be a member of any immunoglobulin class from any species, including any of the human classes: IgG, IgM,

IgA, IgD, and IgE. In exemplary embodiments, antibodies used with the methods and compositions described herein are derivatives of the IgG class. In addition to intact immunoglobulin molecules, also included in the term“antibodies” are fragments or polymers of those immunoglobulin molecules, and human or humanized versions of immunoglobulin molecules that selectively bind the target antigen.

The term“antibody fragment” refers to any derivative of an antibody which is less than full-length. In exemplary embodiments, the antibody fragment retains at least a significant portion of the full-length antibody's specific binding ability. Examples of antibody fragments include, but are not limited to, Fab, Fab', F(ab')2, scFv, Fv, dsFv diabody, Fc, and Fd fragments. The antibody fragment may be produced by any means. For instance, the antibody fragment may be enzymatically or chemically produced by fragmentation of an intact antibody, it may be recombinantly produced from a gene encoding the partial antibody sequence, or it may be wholly or partially synthetically produced. The antibody fragment may optionally be a single chain antibody fragment. Alternatively, the fragment may comprise multiple chains which are linked together, for instance, by disulfide linkages. The fragment may also optionally be a multimolecular complex. A functional antibody fragment will typically comprise at least about 50 amino acids and more typically will comprise at least about 200 amino acids.

The term“antigen binding site” refers to a region of an antibody that specifically binds an epitope on an antigen.

The term“aptamer” refers to oligonucleic acid or peptide molecules that bind to a specific target molecule. These molecules are generally selected from a random sequence pool. The selected aptamers are capable of adapting unique tertiary structures and recognizing target molecules with high affinity and specificity. A“nucleic acid aptamer” is a DNA or RNA oligonucleic acid that binds to a target molecule via its conformation, and thereby inhibits or suppresses functions of such molecule. A nucleic acid aptamer may be constituted by DNA, RNA, or a combination thereof. A“peptide aptamer” is a

combinatorial protein molecule with a variable peptide sequence inserted within a constant scaffold protein. Identification of peptide aptamers is typically performed under stringent yeast dihybrid conditions, which enhances the probability for the selected peptide aptamers to be stably expressed and correctly folded in an intracellular context.

The term“carrier” means a compound, composition, substance, or structure that, when in combination with a compound or composition, aids or facilitates preparation, storage, administration, delivery, effectiveness, selectivity, or any other feature of the compound or composition for its intended use or purpose. For example, a carrier can be selected to minimize any degradation of the active ingredient and to minimize any adverse side effects in the subject.

The term“chimeric molecule” refers to a single molecule created by joining two or more molecules that exist separately in their native state. The single, chimeric molecule has the desired functionality of all of its constituent molecules. One type of chimeric molecules is a fusion protein.

The term“engineered antibody” refers to a recombinant molecule that comprises at least an antibody fragment comprising an antigen binding site derived from the variable domain of the heavy chain and/or light chain of an antibody and may optionally comprise the entire or part of the variable and/or constant domains of an antibody from any of the Ig classes (for example IgA, IgD, IgE, IgG, IgM and IgY).

The term“epitope” refers to the region of an antigen to which an antibody binds preferentially and specifically. A monoclonal antibody binds preferentially to a single specific epitope of a molecule that can be molecularly defined. In the present invention, multiple epitopes can be recognized by a multispecific antibody.

The term“fusion protein” refers to a polypeptide formed by the joining of two or more polypeptides through a peptide bond formed between the amino terminus of one polypeptide and the carboxyl terminus of another polypeptide. The fusion protein can be formed by the chemical coupling of the constituent polypeptides or it can be expressed as a single polypeptide from nucleic acid sequence encoding the single contiguous fusion protein. A single chain fusion protein is a fusion protein having a single contiguous polypeptide backbone. Fusion proteins can be prepared using conventional techniques in molecular biology to join the two genes in frame into a single nucleic acid, and then expressing the nucleic acid in an appropriate host cell under conditions in which the fusion protein is produced.

The term“Fab fragment” refers to a fragment of an antibody comprising an antigen binding site generated by cleavage of the antibody with the enzyme papain, which cuts at the hinge region N-terminally to the inter-H-chain disulfide bond and generates two Fab fragments from one antibody molecule.

The term“F(ab')2 fragment” refers to a fragment of an antibody containing two antigen-binding sites, generated by cleavage of the antibody molecule with the enzyme pepsin which cuts at the hinge region C-terminally to the inter-H-chain disulfide bond.

The term“Fc fragment” refers to the fragment of an antibody comprising the constant domain of its heavy chain.

The term“Fv fragment” refers to the fragment of an antibody comprising the variable domains of its heavy chain and light chain.

“Gene construct” refers to a nucleic acid, such as a vector, plasmid, viral genome or the like which includes a“coding sequence” for a polypeptide or which is otherwise transcribable to a biologically active RNA (e.g., antisense, decoy, ribozyme, etc), may be transfected into cells, e.g., mammalian cells, and may cause expression of the coding sequence in cells transfected with the construct. The gene construct may include one or more regulatory elements operably linked to the coding sequence, as well as intronic sequences, polyadenylation sites, origins of replication, marker genes, etc.

The term“identity” refers to sequence identity between two nucleic acid molecules or polypeptides. Identity can be determined by comparing a position in each sequence which may be aligned for purposes of comparison. When a position in the compared sequence is occupied by the same base, then the molecules are identical at that position. A degree of similarity or identity between nucleic acid or amino acid sequences is a function of the number of identical or matching nucleotides at positions shared by the nucleic acid sequences. Various alignment algorithms and/or programs may be used to calculate the identity between two sequences, including FASTA, or BLAST which are available as a part of the GCG sequence analysis package (University of Wisconsin, Madison, Wis.), and can be used with, e.g., default setting. For example, polypeptides having at least 70%, 85%, 90%, 95%, 98% or 99% identity to specific polypeptides described herein and preferably exhibiting substantially the same functions, as well as polynucleotide encoding such polypeptides, are contemplated. Unless otherwise indicated a similarity score will be based on use of BLOSUM62. When BLASTP is used, the percent similarity is based on the BLASTP positives score and the percent sequence identity is based on the BLASTP identities score. BLASTP“Identities” shows the number and fraction of total residues in the high scoring sequence pairs which are identical; and BLASTP“Positives” shows the number and fraction of residues for which the alignment scores have positive values and which are similar to each other. Amino acid sequences having these degrees of identity or similarity or any intermediate degree of identity of similarity to the amino acid sequences disclosed herein are contemplated and encompassed by this disclosure. The polynucleotide sequences of similar polypeptides are deduced using the genetic code and may be obtained by conventional means, in particular by reverse translating its amino acid sequence using the genetic code.

The term“linker” is art-recognized and refers to a molecule or group of molecules connecting two compounds, such as two polypeptides. The linker may be comprised of a single linking molecule or may comprise a linking molecule and a spacer molecule, intended to separate the linking molecule and a compound by a specific distance.

The term“multivalent antibody” refers to an antibody or

engineered antibody comprising more than one antigen recognition site. For example, a “bivalent” antibody has two antigen recognition sites, whereas a“tetravalent” antibody has four antigen recognition sites. The terms“monospecific”,“bispecific”,“trispecific”, “tetraspecific”, etc. refer to the number of different antigen recognition site specificities (as opposed to the number of antigen recognition sites) present in a multivalent antibody. For example, a“monospecific” antibody's antigen recognition sites all bind the same epitope. A “bispecific” antibody has at least one antigen recognition site that binds a first epitope and at least one antigen recognition site that binds a second epitope that is different from the first epitope. A“multivalent monospecific” antibody has multiple antigen recognition sites that all bind the same epitope. A“multivalent bispecific” antibody has multiple antigen recognition sites, some number of which bind a first epitope and some number of which bind a second epitope that is different from the first epitope.

The term“nucleic acid” refers to a natural or synthetic molecule comprising a single nucleotide or two or more nucleotides linked by a phosphate group at the 3’ position of one nucleotide to the 5’ end of another nucleotide. The nucleic acid is not limited by length, and thus the nucleic acid can include deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).

The term“operably linked to” refers to the functional relationship of a nucleic acid with another nucleic acid sequence. Promoters, enhancers, transcriptional and translational stop sites, and other signal sequences are examples of nucleic acid sequences operably linked to other sequences. For example, operable linkage of DNA to a transcriptional control element refers to the physical and functional relationship between the DNA and promoter such that the transcription of such DNA is initiated from the promoter by an RNA polymerase that specifically recognizes, binds to and transcribes the DNA.

The term“pharmaceutically acceptable” refers to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problems or complications commensurate with a reasonable benefit/risk ratio.

The terms“polypeptide fragment” or“fragment”, when used in reference to a particular polypeptide, refers to a polypeptide in which amino acid residues are deleted as compared to the reference polypeptide itself, but where the remaining amino acid sequence is usually identical to that of the reference polypeptide. Such deletions may occur at the amino-terminus or carboxy-terminus of the reference polypeptide, or alternatively both. Fragments typically are at least about 5, 6, 8 or 10 amino acids long, at least about 14 amino acids long, at least about 20, 30, 40 or 50 amino acids long, at least about 75 amino acids long, or at least about 100, 150, 200, 300, 500 or more amino acids long. A fragment can retain one or more of the biological activities of the reference polypeptide. In various embodiments, a fragment may comprise an enzymatic activity and/or an interaction site of the reference polypeptide. In other embodiments, a fragment may have immunogenic properties.

The term“single chain variable fragment" or "scFv” refers to an Fv fragment in which the heavy chain domain and the light chain domain are linked. One or more scFv fragments may be linked to other antibody fragments (such as the constant domain of a heavy chain or a light chain) to form antibody constructs having one or more antigen recognition sites. A“spacer” as used herein refers to a peptide that joins the proteins comprising a fusion protein. Generally, a spacer has no specific biological activity other than to join the proteins or to preserve some minimum distance or other spatial relationship between them. However, the constituent amino acids of a spacer may be selected to influence some property of the molecule such as the folding, net charge, or hydrophobicity of the molecule.

The term“specifically binds” or“specific binding”, as used herein, when referring to a polypeptide (including antibodies) or receptor, refers to a binding reaction which is determinative of the presence of the protein or polypeptide or receptor in a heterogeneous population of proteins and other biologies. Thus, under designated conditions (e.g.

immunoassay conditions in the case of an antibody), a specified ligand or antibody “specifically binds” to its particular“target” (e.g. an antibody specifically binds to an endothelial antigen) when it does not bind in a significant amount to other proteins present in the sample or to other proteins to which the ligand or antibody may come in contact in an organism. Generally, a first molecule that“specifically binds” a second molecule has an affinity constant (Ka) greater than about 10⁵ M^_1 (e.g., 10⁶ M^_1, 10⁷ M^_1, 10⁸ M^_1, 10⁹ M^_1, 10¹⁰ M^_1, 10¹¹ M^_1, and 10¹² M^_1 or more) with that second molecule. For example, in the case of the ability of a TCR to bind to a peptide presented on an MHC (e.g., class I MHC or class II MHC); typically, a TCR specifically binds to its peptide/MHC with an affinity of at least a KD of about 10-4 M or less, and binds to the predetermined antigen/binding partner with an affinity (as expressed by KD) that is at least 10 fold less, at least 100 fold less or at least 1000 fold less than its affinity for binding to a non-specific and unrelated

peptide/MHC complex (e.g., one comprising a BSA peptide or a casein peptide).

The term“subject” refers to any individual who is the target of administration or treatment. The subject can be a vertebrate, for example, a mammal. Thus, the subject can be a human or veterinary patient. The term“patient” refers to a subject under the treatment of a clinician, e.g., physician.

In certain embodiments, agents of the invention may be used alone or conjointly administered with another type of therapeutic agent. As used herein, the phrase“conjoint administration” or“administered conjointly” refers to any form of administration of two or more different therapeutic agents (e.g., a composition comprising a CAR T disclosed herein and an inhibitor of an immune checkpoint) such that the second agent is administered while the previously administered therapeutic agent is still effective in the body (e.g., the two agents are simultaneously effective in the subject, which may include synergistic effects of the two agents). For example, the different therapeutic agents can be administered either in the same formulation or in separate formulations, either concomitantly or sequentially. In some preferred embodiments, the CAR T cells express (e.g., present on the cell surface or secrete) further therapeutic agents. In certain embodiments, the different therapeutic agents (e.g., CAR T cells and immune checkpoint-blocking molecules) can be administered within about one hour, about 12 hours, about 24 hours, about 36 hours, about 48 hours, about 72 hours, or about a week of one another. Thus, a subject who receives such treatment can benefit from a combined effect of different therapeutic agents.

The terms“transformation” and“transfection” mean the introduction of a nucleic acid, e.g., an expression vector, into a recipient cell including introduction of a nucleic acid to the chromosomal DNA of said cell.

As used herein, the term“treatment” refers to clinical intervention designed to alter the natural course of the individual being treated during the course of clinical pathology. Desirable effects of treatment include decreasing the rate of progression, ameliorating or palliating the pathological state, and remission or improved prognosis of a particular disease, disorder, or condition. An individual is successfully“treated,” for example, if one or more symptoms associated with a particular disease, disorder, or condition are mitigated or eliminated.

The term“variant” refers to an amino acid or peptide sequence having conservative amino acid substitutions, non-conservative amino acid substitutions (e.g., a degenerate variant), substitutions within the wobble position of each codon (e.g., DNA and RNA) encoding an amino acid, amino acids added to the C-terminus of a peptide, or a peptide having 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% sequence identity to a reference sequence.

The term“vector” refers to a nucleic acid sequence capable of transporting into a cell another nucleic acid to which the vector sequence has been linked. The term “expression vector” includes any vector, (e.g., a plasmid, cosmid or phage chromosome) containing a gene construct in a form suitable for expression by a cell (e.g., linked to a transcriptional control element). The term“CLEC4” is intended to include fragments, variants (e.g., allelic variants), and derivatives of CLEC4 family members. In some embodiments, CLEC4 is CLEC4A, CLEC4B, CLEC4C, or CLEC4D.

CLEC4A or DCIR, also known as Lectin-like Immunoreceptor (LLIR), is a type II membrane protein belonging to the C-type lectin domain family (previously designated

CLECSF6). Four transcript variants encoding distinct isoforms have been identified. DCIR contains one carbohydrate recognition domain in its C-terminal extracellular domain and an immunoreceptor tyrosine-based inhibitory motif (ITIM) in its cytoplasmic domain. Besides dendritic cells (DC), DCIR is expressed on B cells, monocytes/macrophages and granulocytes. Representative human CLEC4 cDNA and human CLEC4 protein sequences are well-known in the art and are publicly available from the National Center for

Biotechnology Information (NCBI). Human CLEC4A variants include isoform 1

(NM_016184.3 and NP_057268.1, which represents the longest transcript, and encodes the longest isoform), isoform 2 (NM_194450.2 and NP_919432.1, which is also known as C- type lectin DDB27 short form, lacks an in-frame segment of the coding region, compared to variant 1, and encodes a shorter isoform, that is missing the transmembrane domain compared to isoform 1), isoform 3 (NM_194447.2 and NP_919429.2, which is also known as LLIRvl, lacks an in-frame segment of the coding region, compared to variant 1, and encodes a shorter isoform, that is missing the transmembrane domain compared to isoform 1), and isoform 4 (NM_194448.2 and NP_919430.1, which is also known as LLIRv2, lacks an in-frame segment of the coding region, compared to variant 1, and encodes the shortest isoform, that is missing a region thought to be responsible for oligomerization, compared to isoform 1). Nucleic acid and polypeptide sequences of CLEC4A orthologs in organisms other than humans are well-known and include, for example, Rhesus monkey CLEC4A (XM_001113483.3 and XP_001113483.1), dog CLEC4 (XM_014108320.2 and

XP_013963795.1), cattle CLEC4A (XM_024992216.1 and XP 024847984.1,

XM_015471278.2 and XP_015326764.1, XM_005207082.4 and XP_005207139.1, XM_005207083.4 and XP_005207140.1), mouse CLEC4A (NM_001170332.1 and

NP_001163803.1, NM_001170333.1 and NP_001163804.1 , NM_011999.4 and

NP_036129.1) and rat CLEC4A (NM_001005899.2 and NP_001005899.2).

Anti-CLEC4A antibodies suitable for binding CLEC4A and for deriving associated scFv fragments useful as target binding entities in CAR constructs are well-known in the art and include, for example, antibodies Cat #: 11476-R007, 11476-MM02, 11476-MM08, 11476-MM04, 11476-MM08-F, 11476-MM08-P, 11476-MM06, 11476-RPB01, 201490- T08, and 11476-RP02 (Sino Biological), antibodies MOR-0722, MOB-1856z-F(E), MOB- 1856z-S(P), BRD-0128MZ, and MOB-1112MZ (Creative Biolabs), antibodies MAB1748, AF1748, FAB26171P, MAB2617, BAF1748, FAB 1748 A, FAB 1748G, FAB1748R, FAB1748N, FAB1748S, FAB 1748T, FAB1748U, FAB1748V (R&D System), antibodies DDX0180P-100, MAB 1748, NBP2-12257, AF1748, NBP1-84446, MAB2617, NBP2- 15916, H00050856-B01P, and NBP2-12257UV (Novus Biologicals), antibody 355306, and 355302 (Biolegend), and antibodies PA5-82317, PA5-30888, 12-9875-42, MA5-29154, MA5-30241, MA5-30242, PA5-47195, MA5-23896, and MA5-24043 (ThermoFisher Scientific).

In certain embodiments, the CLEC4A target polypeptide against which the binding entity of the herein described CAR binds has the amino acid sequence:

MTSEITYAEVRFKNEFKSSGINTASSAASKERTAPHKSNTGFPKLLCASLLIFFLLLAISFFIAF VIFFQKYSQLLEKKTTKELVHTTLECVKKNMPVEETAW SCCPKNWKSFSSNCYFISTESAS WQDSEKDCARMEAHLLVINTQEEQDFIFQNLQEESAYFVGLSDPEGQRHWQWVDQTPYN ESSTFWHPREPSDPNERCVVLNFRKSPKRWGWNDVNCLGPQRSVCEMMKIHL (SEQ ID NO: 1).

It is to be noted that the term can further be used to refer to any combination of features described herein regarding CLEC4A molecules. For example, any combination of sequence composition, percentage identify, sequence length, domain structure, functional activity, etc. can be used to describe CLEC4A molecule of the present invention.

CLEC4B (DCAR) is a type II membrane protein belonging to the C-type lectin domain family. Two isoforms of DCAR, i.e., the 209 amino acid (aa) residue alpha isoform and a 176 aa form with a 33 aa deletion at the membrane proximal region of the

extracellular domain, exist. The DCAR extracellular domain contains a carbohydrate- recognition domain (CRD) that shares 91% amino acid sequence identity with the CRD of DCIR/CLEC4A. The DCAR intracellular domain is very short and lacks the ITIM motif found in DCIR. DCAR and DCIR are considered paired immunoregulatory receptors where DCAR activates through the ITAM of its associated adaptor molecule FcR gamma. Mouse CLEC4B variants include isoform 1 (NM_001190310.1 and NP_001177239.1, represents the longer transcript and encodes the longer isoform) and isoform 2 (NM 027218.3 and NP 081494.1, which lacks an in-frame exon in the coding region, compared to variant 1 resulting in a shorter protein, compared to isoform 1).

Anti-CLEC4B antibodies suitable for binding CLEC4B and for deriving associated scFv fragments useful as target binding entities in CAR constructs are well-known in the art and include, for example, antibodies Cat #: FAB2757G, FAB2757N, FAB2757R,

FAB2757S, FAB2757T, FAB2757U, FAB2757V, AF2757, and MAB2757 (R&D Systems), MA5-24089 and PA5-47387 (ThermoFisher Scientific), AF2757 and MAB2757 (Novus Biologicals). It is to be noted that the term can further be used to refer to any combination of features described herein regarding CLEC4B molecules. For example, any combination of sequence composition, percentage identify, sequence length, domain structure, functional activity, etc. can be used to describe CLEC4B molecule of the present invention.

CLEC4C or Dendritic cell lectin (DLEC), also known as BDCA-2, CD303, HECL, CLECSF11, and CLECSF7, is a 38 kDa type II transmembrane protein in the C-type lectin family. Mature human DLEC consists of a 21 amino acid (aa) cytoplasmic domain, a 23 aa transmembrane segment, and a 169 aa extracellular domain (ECD) that contains a juxtamembrane neck region and one carbohydrate recognition domain (CRD). Alternate splicing may generate multiple isoforms that lack the transmembrane segment and/or portions of the cytoplasmic, neck, and CRD regions. DLEC expression is restricted to plasmacytoid dendritic cells (pDC) and is downregulated during their maturation. pDC play a role in the innate immune response by producing IFN-alpha / beta following exposure to TLR7 and TLR9 agonists such as microbial CpG DNA. Antibody ligation of DLEC on pDC attenuates the CpG-stimulated production of interferons as well as a Thl biased response. DLEC interactions with HIV-1 gpl20 and hepatitis B virus soluble antigen may therefore limit the pDC antiviral response. Similar to other C-type lectins, DLEC can mediate antigen uptake for MHC loading and presentation to T cells. Crosslinking of DLEC on CpG-stimulated pDC inhibits pDC maturation and induces tyrosine phosphorylation on multiple proteins involved in B cell receptor signaling and endocytosis. These functions require the association of DLEC with the ITAM-containing Fc epsilon RI gamma chain. Human CLEC4C variants include isoform 1 (NM_130441.2 and NP_569708.1, which represents the longer transcript, and encodes the longer isoform) and isoform 2

(NM_203503.1 and NP_987099.1, which is also known as DLEC-beta, lacks an in-frame segment of the coding region, compared to variant 1, and encodes a shorter isoform, compared to isoform 1). Nucleic acid and polypeptide sequences of CLEC4C orthologs in organisms other than humans are well-known and include, for example, Chimpanzee CLEC4C (XM_001164809.2 and XP_001164809.2), Rhesus monkey CLEC4C

(XM_015150836.1 and XP_015006322.1), and mouse CLEC4C (NM_001190310.1 and NP_001177239.1, and NM_027218.3 and NP_081494.1).

Anti-CLEC4C antibodies suitable for binding CLEC4C and for deriving associated scFv fragments useful as target binding entities in CAR constructs are well-known in the art and include, for example, antibodies Cat #: AF 1376, MAB62991, and BAF1376 (R&D Systems), HPA029432, SAB2501252, and APREST72394 (Sigma Aldrich), PA5-56145, PA5-19123, OSD00005W, 46-9818-42, 11-9818-42, 25-9818-42, 17-9818-42, 48-9818-42, and 47-9818-42 (ThermoFisher Scientific), and AF 1376 (Novus Biologicals), and TAB- 1246CL, TAB-1244CL, TAB-1246CL-S(P), BDC3-12F5, TAB-174CL, AB-0461CL-S(P), MOB-217, TAB-0463CL, and TAB-0425CL (Creative Biolabs). It is to be noted that the term can further be used to refer to any combination of features described herein regarding CLEC4C molecules. For example, any combination of sequence composition, percentage identify, sequence length, domain structure, functional activity, etc. can be used to describe CLEC4C molecule of the present invention.

In certain embodiments, the CLEC4C target polypeptide against which the binding entity of the herein described CAR binds has the amino acid sequence:

MVPEEEPQDREKGLWWF QLKVW SMAVV SILLLS VCFT V S S VVPHNFMY SKTVKRL SKLRE Y Q Q YHP SLT C VMEGKDIED W S CCPTP WT SF Q S S C YFI STGMQ S WTK S QKN C SVMGADLVVINTREEQDFIIQNLKRNSSYFLGLSDPGGRRHWQWVDQTPYNENVT FWHSGEPNNLDERCAIINFRSSEEWGWNDIHCHVPQKSICKMKKIYI (SEQ ID NO: 2)·

CLEC4D is also known as C-type (calcium dependent, carbohydrate-recognition domain) lectin, superfamily member 8; C-type lectin domain family 4 member D; C-type lectin domain family 4, member D; C-type lectin receptor; C-type lectin superfamily member 8; C-type lectin-like receptor 6; CLEC-6; CLECSF8; macrophage C-type lectin; MCL. CD368 (CLEC4D), also known as CLEC6, is a 30 kD single pass type II

transmembrane protein and member of the C-type lectin-like domain (CTLD) superfamily. CLEC4D is an endocytic receptor, probably involved in antigen presentation, cell adhesion, and cell signaling. CLEC4D is expressed by macrophages, monocytes, neutrophils, and a subset of dendritic cells and is upregulated by IL-6, IL-10, TNF-a, and IFN-g. CLEC4D belongs to the CLR (C-type Lectin Receptor) family of molecules. It is synthesized as a 215 amino acid (aa) protein that contains a 17 aa N-terminal cytoplasmic domain, a 21 aa TM segment, and a 177 aa C-terminal extracellular region. The extracellular region shows a short stalk and a 118 aa CRD (carbohydrate recognition domain). CLEC4D is expressed in monocytes/macrophages and serves as an endocytic receptor. Homodimers and

homotrimers form on the cell surface. The human CLEC4D extracellular region shares 63% aa sequence identity with the mouse extracellular region. Human CLEC4D variants include NM_080387.5 and NP_525126.2. Nucleic acid and polypeptide sequences of CLEC4D orthologs in organisms other than humans are well-known and include, for example, Chimpanzee CLEC4D (XM_001134875.4 and XP_001134875.2), Rhesus monkey

CLEC4D (XM_001113566.3 and XP_001113566.1), dog CLEC4D (XM_849215.5 and XP_854308.3, XM_014108700.2 and XP_013964175.1, XM_022411515.1 and

XP_022267223.1 , XM_022411518.1 and XP_022267226.1, XM_005637197.2 and

XP_005637254.1, XM_022411520.1 and XP_022267228.1, XM_022411516.1 and

XP_022267224.1, and XM_022411519.1 and XP_022267227.1), cattle CLEC4D

(NM_001193117.1 and NP_001180046.1), mouse CLEC4D (NM_001163161.1 and NP_001156633.1, NM_010819.4 and NP_034949.3), and rat CLEC4D (NM_001003707.1 and NP_001003707.1).

Anti-CLEC4D antibodies suitable for binding CLEC4D and for deriving associated scFv fragments useful as target binding entities in CAR constructs are well-known in the art and include, for example, antibodies Cat #: PA5-52131, PA5-49700, PA5-47403, MAS- 24152, and MA5-30245 (ThermoFisher Scientific), 360205, 360206, 360204, and 360202 (BioLegend), abl75021, and abl66246 (abeam), MAB2806, AF2806, NBP1-84445, and H00338339-B01P (Novus Biologicals), and MAB2806, AF2806, and FAB2806A (R&D Systems).

In certain embodiments, the CLEC4D target polypeptide against which the binding entity of the herein described CAR binds has the amino acid sequence:

MGLEKPQ SKLEGGMHPQLIPS VI AVVFILLL S V CFI ASCL VTHHNF SRCKRGT GVHK LEHHAKLKCIKEK SELK S AEGS TWNCCPID WRAF Q SN C YFPLTDNKT W AE SERN C S GMGAHLMTISTEAEQNFIIQFLDRRLSYFLGLRDENAKGQWRWVDQTPFNPRRVF

WHKNEPDNSQGENCVVLVYNQDKWAWNDVPCNFEASRICKIPGTTLN (SEQ ID NO: 3). Chimeric Antigen Receptors (CAR)

Disclosed herein are chimeric antigen receptor (CAR) polypeptides that can be expressed in immune effector cells to enhance activity against specific targets (e.g., antitumor activity against hepatocellular carcinoma).

In some aspects, the CARs disclosed herein are made up of three domains: an ectodomain, a transmembrane domain, and an endodomain.

In certain embodiments, the ectodomain comprises a CLEC4-binding region and is responsible for antigen recognition. CLEC4 may be CLEC4A, CLEC4B, CLEC4C, or CLEC4D. It also optionally contains a signal peptide (SP) so that the CAR can be glycosylated and anchored in the cell membrane of the immune effector cell.

In some embodiments, the transmembrane domain (TD) connects the ectodomain (i.e., the extracellular domain) to the endodomain (i.e., the intracellular domain) and resides within the cell membrane when expressed by a cell.

In some embodiments, the endodomain transmits an activation signal to the immune effector cell after antigen recognition. In some such embodiments, the endodomain can contain an intracellular signaling domain (ISD) and, optionally, a co-stimulatory signaling region (CSR). A“signaling domain (SD)”, such as an ISD, generally contains

immunoreceptor tyrosine-based activation motifs (IT AMs) that activate a signaling cascade when the IT AM is phosphorylated. The term“co-stimulatory signaling region (CSR)” refers to intracellular signaling domains from costimulatory protein receptors, such as CD28, 41BB, and ICOS, that are able to enhance T-cell activation by T-cell receptors.

In some embodiments, the endodomain contains an SD or a CSR, but not both. In these embodiments, an immune effector cell containing the disclosed CAR is only activated if another CAR (or a T-cell receptor) containing the missing domain also binds its respective antigen.

In some embodiments, the disclosed CAR is defined by the formula:

SP-CLEC4-HG-TM-C SR-SD ; or

SP-CLEC4-HG-TM-SD-C SR;

wherein“SP” represents an optional signal peptide,

wherein“CLEC4” represents a CLEC4 antigen binding region,

wherein“HG” represents an optional hinge domain (spacer domain),

wherein“TM” represents a transmembrane domain, wherein“CSR” represents one or more co- stimulatory signaling regions, wherein“SD” represents a signaling domain, and

wherein represents a peptide bond or linker.

Additional CAR constructs are described, for example, in Fresnak, et al. Engineered T cells: the promise and challenges of cancer immunotherapy. Nat Rev Cancer. 2016 Aug 23; 16(9): 566-81, which is incorporated by reference in its entirety for the teaching of these CAR models.

In certain embodiments, the CAR can be, for example (and without limitation), a TRUCK, a Universal CAR, a Self-driving CAR, an Armored CAR, a Self-destruct CAR, a Conditional CAR, a Marked CAR, a TenCAR, a Dual CAR, or a sCAR.

TRUCKS (T cells redirected for universal cytokine killing) co-express a chimeric antigen receptor (CAR) and an antitumor cytokine. Cytokine expression may be

constitutive or induced by T cell activation. Targeted by CAR specificity, localized production of pro-inflammatory cytokines recruits endogenous immune cells to tumor sites and may potentiate an antitumor response.

Universal, allogeneic CAR T cells are engineered to no longer express endogenous T cell receptor (TCR) and/or major histocompatibility complex (MHC) molecules, thereby preventing graft-versus-host disease (GVHD) or rejection, respectively.

Self-driving CARs co-express a CAR and a chemokine receptor, which binds to a tumor ligand, thereby enhancing tumor homing.

CAR T cells engineered to be resistant to immunosuppression (Armored CARs) may be genetically modified to no longer express various immune checkpoint molecules (e.g., cytotoxic T lymphocyte-associated antigen 4 (CTLA4) or programmed cell death protein 1 (PD-1)). Exemplary“Knockdown” and“Knockout” techniques include, but are not limited to, RNA interference (RNAi) (e.g., asRNA, miRNA, shRNA, siRNA, etc.) and CRISPR interference (CRISPRi) (e.g., CRISPR-Cas9). In certain embodiments, CAR T cells are engineered to express a dominant-negative form of a checkpoint molecule. In some such embodiments, the extracellular ligand-binding domain (i.e., ectodomain) of the immune checkpoint molecule is fused to a transmembrane membrane in order to compete for ligand binding. For example, the extracellular ligand-binding domain of PD-1 may be fused to a CD8 transmembrane domain, thus competing for PD-1 ligand from the target cell. In some embodiments, CAR T cells are engineered to express an immune checkpoint switch receptor to exploit the inhibitory immune checkpoint ligand present on a target cell. In such embodiments, the extracellular ligand-binding domain of the immune checkpoint molecule is fused to a signaling, stimulatory, and/or co-stimulatory domain. For example, the extracellular ligand-binding domain of PD-1 may be fused to a CD28 domain, thus providing CD28 costimulation while blocking PD-1 signaling. In further embodiments, the CAR T cells may be administered with an aptamer or a monoclonal antibody that blocks immune checkpoint signaling. In some such embodiments, the CAR T cells (e.g., CAR T cell therapy) are combined with a PD-1 blockade method, such as administration with PD- 1/PD-Ll antagonistic aptamers or anti-PD-l/PD-Ll antibodies. In preferred embodiments, the CAR T cells and PD-1 pathway -blocking antibodies are administered conjointly. In further embodiments, the CAR T cells are engineered to express or express and secrete an immune checkpoint-blocking antibody, such as anti -PD-1 or anti-PD-Ll, or fragments thereof. In yet further embodiments, the CAR T cells are administered with a vector (e.g., an engineered virus) that expresses an immune checkpoint-blocking molecule described herein.

A self-destruct CAR may be designed using RNA delivered by electroporation to encode the CAR. Alternatively, inducible apoptosis of the T cell may be achieved based on ganciclovir binding to thymidine kinase in gene-modified lymphocytes or the more recently described system of activation of human caspase 9 by a small-molecule dimerizer.

A conditional CAR T cell is by default unresponsive, or switched‘off, until the addition of a small molecule to complete the“circuit” (e.g., molecular pathway), enabling full transduction of both signal 1 and signal 2, thereby activating the CAR T cell.

Alternatively, T cells may be engineered to express an adaptor-specific receptor with affinity for subsequently administered secondary antibodies directed at target antigen.

Marked CAR T cells express a CAR plus a tumor epitope to which an existing monoclonal antibody agent binds. In the setting of intolerable adverse effects,

administration of the monoclonal antibody clears the CAR T cells and alleviates symptoms with no additional off-tumor effects.

A tandem CAR (TanCAR) T cell expresses a single CAR consisting of two linked single-chain variable fragments (scFvs) that have different affinities fused to intracellular co-stimulatory domain(s) and a CD3z domain. TanCAR T cell activation is achieved only when target cells co-express both targets. A dual CAR T cell expresses two separate CARs with different ligand binding targets. By way of non-limiting example, one CAR may include only the CD3z domain while the other CAR includes only the co- stimulatory domain(s). In some such

embodiments, the dual CAR T cell is activated when both targets are expressed on the tumor.

A safety CAR (sCAR) consists of an extracellular scFv fused to an intracellular inhibitory domain. sCAR T cells co-expressing a standard CAR become activated only when encountering target cells that possess the standard CAR target but lack the sCAR target.

In some embodiments, the antigen recognition domain of the disclosed CAR is an scFv. In further embodiments, the antigen recognition domain is from native T-cell receptor (TCR) alpha and beta single chains as have been described herein. Preferably, such antigen recognition domains have simple ectodomains (e.g., a CD4 ectodomain to recognize HIV infected cells). Alternatively, such antigen recognition domains comprise exotic recognition components such as a linked cytokine (which can lead to recognition of cells bearing the cytokine receptor). Generally, with respect to the methods disclosed herein, almost anything that binds a given target with high affinity can be used as an antigen recognition region.

The intracellular endodomain transmits a signal to the immune effector cell expressing the CAR after antigen recognition, activating at least one of the normal effector functions of said immune effector cell. In certain embodiments, the effector function of a T cell, for example, may be cytolytic activity or helper activity, including the secretion of cytokines. Therefore, the endodomain may comprise the“intracellular signaling domain” of a T cell receptor (TCR) and optional co-receptors. While usually the entire intracellular signaling domain can be employed, in many cases it is not necessary to use the entire chain. To the extent that a truncated portion of the intracellular signaling domain is used, such truncated portion may be used in place of the intact chain as long as it transduces the effector function signal.

Cytoplasmic signaling sequences that regulate primary activation of the TCR complex that act in a stimulatory manner may contain signaling motifs which are known as immunoreceptor tyrosine-based activation motifs (IT AMs). Examples of ITAM-containing cytoplasmic signaling sequences include those derived from CD8, CD3^ CD35, CD3y, CD3e, CD32 (Fc gamma Rlla), DAP10, DAP 12, CD79a, CD79b, FcyRIy, FcyRIIIy,

FceRip (FCERIB), and FceRIy (FCERIG).

In particular embodiments, the intracellular signaling domain is derived from CD3 zeta (Oϋ3z) (TCR zeta, GenBank acc no. BAG36664.1). T-cell surface glycoprotein CD3 zeta (Oϋ3z) chain, also known as T-cell receptor T3 zeta chain or CD247 (Cluster of Differentiation 247), is a protein that in humans is encoded by the CD247 gene. The intracellular tails of the CD3 molecules contain a single IT AM, which is essential for the signaling capacity of the TCR. The intracellular tail of the z chain ^ϋ3z) contains 3 ITAMs. In some embodiments, the z chain is a mutant z chain. For example, the mutant z chain comprises a mutation, such as a point mutation, in at least one IT AM so as to render said ITAM non-functional. In some such embodiments, either the membrane-proximal ITAM (ITAM1), the membrane-distal ITAM (C-terminal third ITAM, ITAM3), or both are non-functional. In further embodiments, either two membrane-proximal ITAMS (IT AMI and ITAM2) or two membrane-distal ITAMS (ITAM2 and ITAM3) are non-functional. In yet further embodiments, only ITAM2 is non-functional. In some embodiments, the mutant z chain comprises a deletion (e.g., truncation) mutation such that at least one ITAM is missing. In some such embodiments, the z chain is missing the membrane-proximal ITAM (IT AMI), the membrane-distal ITAM (ITAM3), or both. In other embodiments, the z chain is missing either two membrane-proximal ITAMS (IT AMI and ITAM2) or two membrane- distal ITAMS (ITAM2 and ITAM3). In further embodiments, the z chain is missing ITAM2. Methods to produce mutant CD3z is known to those skilled in the art (WO

2019/133969). Removing at least one ITAM from the introduced CAR may reduce CD3z- mediated apoptosis. Alternatively, removing at least one ITAM from the introduced CAR can reduce its size without loss of function. CARs comprising such altered CD3z domains are contemplated by the present invention.

Also contemplated are CARs comprising an altered CD28 domain that imparts desired functional properties to the CAR. In this regard, the native CD28 domain comprises three intracellular subdomains consisting of the amino acid sequences YMNM, PRRP, and PYAP that regulate signaling pathways post stimulation (see, e.g., WO

2019/010383, incorporated herein by reference for this teaching). The CAR constructs described herein may comprise a modified CD28 domain wherein one or more of the YMNM, PRRP, and/or PYAP subdomains are mutated or deleted, so as to amplify, attenuate, or inactivate said subdomain(s), thereby modulating CAR-T function. In certain preferred embodiments, the altered CD28 domain employed is Mut06 as described in WO 2019/010383.

First-generation CARs typically had the intracellular domain from the Oϋ3z chain, which is the primary transmitter of signals from endogenous TCRs. Second-generation CARs add intracellular signaling domains from various costimulatory protein receptors (e.g., CD28, 41BB, ICOS) to the endodomain of the CAR to provide additional signals to the T cell. For example, a target-specific ScFv fused to the extracellular, transmembrane and intracellular signaling domains of the co-stimulatory receptor CD28 and the

cytoplasmic signaling domain of the T cell receptor-associated CD3 z chain. Preclinical studies have indicated that the second generation of CAR designs improves the antitumor activity of T cells. More recent, third-generation CARs combine multiple signaling domains to further augment potency. T cells grafted with these CARs have demonstrated improved expansion, activation, persistence, and tumor-eradicating efficiency independent of costimulatory receptor/ligand interaction (Imai C, et al. Leukemia 2004 18:676-84; Maher J, et al. Nat Biotechnol 2002 20:70-5).

For example, the endodomain of the CAR can be designed to comprise the CD3z signaling domain by itself or combined with any other desired cytoplasmic domain(s) useful in the context of the CAR of the invention. For example, the cytoplasmic domain of the CAR can comprise a CD3z chain portion and a costimulatory signaling region. The costimulatory signaling region refers to a portion of the CAR comprising the intracellular domain of a costimulatory molecule. A costimulatory molecule is a cell surface molecule other than an antigen receptor or their ligands that is required for an efficient response of lymphocytes to an antigen. Examples of such molecules include CD27, CD28, 4- IBB (CD137), 0X40, CD30, CD40, ICOS, lymphocyte function-associated antigen-1 (LFA-1), CD2, CD7, LIGHT, NKG2C, B7-H3, and a ligand that specifically binds with CD83, CD8, CD4, b2c, CD80, CD86, DAP10, DAP 12, MyD88, BTNL3, NKG2D, and mutants thereof. Thus, while the CAR is exemplified primarily with CD28 as the co-stimulatory signaling element, other costimulatory elements can be used alone or in combination with other co stimulatory signaling elements.

In some embodiments, the CAR comprises a hinge sequence. A hinge sequence is a short sequence of amino acids that facilitates antibody flexibility (see, e.g., Woof et al., Nat. Rev. Immunol., 4(2): 89-99 (2004)). The hinge sequence may be positioned between the antigen recognition moiety (e.g., -CLEC4 scFv) and the transmembrane domain. The hinge sequence can be any suitable sequence derived or obtained from any suitable molecule. In some embodiments, for example, the hinge sequence is derived from a CD8a molecule or a CD28 molecule.

The transmembrane domain may be derived either from a natural or from a synthetic source. Where the source is natural, the domain may be derived from any membrane-bound or transmembrane protein. For example, the transmembrane region may be derived from (i.e., comprise at least the transmembrane region(s) of) the alpha, beta or zeta chain of the T-cell receptor, CD28, CD3 epsilon, CD45, CD4, CD5, CD8 (e.g., CD8 alpha, CD8 beta), CD9, CD16, CD22, CD33, CD37, CD64, CD80, CD86, CD134, CD137, or CD 154, KIRDS2, 0X40, CD2, CD27, LFA-1 (CD 11 a, CD 18) , ICOS (CD278) , 4- IBB (CD 137) , GITR, CD40, BAFFR, HVEM (LIGHTR) , SLAMF7, NKp80 (KLRFl) ,

CD 160, CD 19, IL2R beta, IL2R gamma, IL7R a, ITGA1, VLA1, CD49a, ITGA4, IA4, CD49D, ITGA6, VLA-6, CD49f, ITGAD, CD l id, ITGAE, CD 103, ITGAL, CD 11 a, LFA- 1, ITGAM, CDl lb, ITGAX, CDl lc, ITGB1, CD29, ITGB2, CD18, LFA-1, ITGB7, TNFR2, DNAM1 (CD226) , SLAMF4 (CD244, 2B4) , CD84, CD96 (Tactile) ,

CEACAM1, CRTAM, Ly9 (CD229) , CD160 (BY55) , PSGL1, CD100 (SEMA4D) , SLAMF6 (NTB-A, Lyl08) , SLAM (SLAMFl, CD 150, IPO-3) , BLAME (SLAMF8) , SELPLG (CD 162) , LTBR, and PAG/Cbp. Alternatively, the transmembrane domain may be synthetic, in which case it will comprise predominantly hydrophobic residues such as leucine and valine. In some embodiments, a triplet of phenylalanine, tryptophan and valine will be found at each end of a synthetic transmembrane domain. A short oligo- or polypeptide linker, such as between 2 and 10 amino acids in length, may form the linkage between the transmembrane domain and the endoplasmic domain of the CAR.

In some embodiments, the CAR has more than one transmembrane domain, which can be a repeat of the same transmembrane domain, or can be different transmembrane domains.

In some embodiments, the CAR is a multi-chain CAR, as described in

WO2015/039523, which is incorporated by reference for this teaching. A multi-chain CAR can comprise separate extracellular ligand binding and signaling domains in different transmembrane polypeptides. The signaling domains can be designed to assemble in juxtamembrane position, which forms flexible architecture closer to natural receptors, that confers optimal signal transduction. For example, the multi-chain CAR can comprise a part of an FCERI alpha chain and a part of an FCERI beta chain such that the FCERI chains spontaneously dimerize together to form a CAR.

In some embodiments, the CAR contains one signaling domain. In other embodiments, the CAR contains one or more signaling domain (co-stimulatory signaling domain). The one or more signaling domain may be a polypeptide selected from: CD8, CD3C, CD 35, CD3y, CD3e, FcyRI-y, FcyRIII-y, FceRIp, FceRIy, DAP10, DAP 12, CD32, CD79a, CD79b, CD28, CD3C, CD4, b2c, CD137 (41BB), ICOS, CD27, CD285, CD80, NKp30, 0X40, and mutants thereof.

Tables 1, 2, and 3 below provide some example combinations of target-binding domains, co-stimulatory signaling domains, and intracellular signaling domains. Such examples are for the purpose of illustration and are not meant to be an exhaustive list of combinations that can occur in the CARs disclosed herein.

In some embodiments, the anti-CLEC4 binding agent is single chain variable fragment (scFv) antibody. The affinity/specificity of an anti-CLEC4 scFv is driven in large part by specific sequences within complementarity determining regions (CDRs) in the heavy (VH) and light (VL) chain. Each VH and VL sequence will have three CDRs (CDR1, CDR2, CDR3).

In some embodiments, the anti-CLEC4 binding agent is derived from natural antibodies, such as monoclonal antibodies. In some cases, the antibody is human. In some cases, the antibody has undergone an alteration to render it less immunogenic when administered to humans. For example, the alteration comprises one or more techniques selected from chimerization, humanization, CDR-grafting, deimmunization, and mutation of framework amino acids to correspond to the closest human germline sequence.

Also disclosed are bi-specific CARs that target a CLEC4 and at least one additional cancer-associated antigen (e.g., a tumor antigen). Also disclosed are CARs designed to work only in conjunction with another CAR that binds a different antigen, such as a cancer- associated antigen. For example, in these embodiments, the endodomain of the disclosed CAR can contain only an signaling domain (SD) or a co-stimulatory signaling region (CSR), but not both. The second CAR (or endogenous T-cell) provides the missing signal if it is activated. For example, if the disclosed CAR contains an SD but not a CSR, then the immune effector cell containing this CAR is only activated if another CAR (or T-cell) containing a CSR binds its respective antigen. Likewise, if the disclosed CAR contains a CSR but not a SD, then the immune effector cell containing this CAR is only activated if another CAR (or T-cell) containing an SD binds its respective antigen.

Tumor antigens are proteins that are produced by tumor cells that elicit an immune response, particularly T-cell mediated immune responses. The additional antigen binding domain can be an antibody or a natural ligand of the tumor antigen. The selection of the additional antigen binding domain will depend on the particular type of cancer to be treated. Tumor antigens are well known in the art and include, for example, a glioma-associated antigen, carcinoembryonic antigen (CEA), EGFRvIII, IL-llRa, IL-13Ra, EGFR, FAP, B7H3, Kit, CA LX, CS-1, MUC1, BCMA, bcr-abl, HER2, b-human chorionic

gonadotropin, alphafetoprotein (AFP), ALK, CD19, TIM3, cyclin Bl, lectin-reactive AFP, Fos-related antigen 1, ADRB3, thyroglobulin, EphA2, RAGE-1, RU1, RU2, SSX2, AKAP- 4, LCK, OY-TES1, PAX5, SART3, CLL-1, fucosyl GM1, GloboH, MN-CA IX, EPCAM, EVT6-AML, TGS5, human telomerase reverse transcriptase, plysialic acid, PLAC1, RU1, RU2 (AS), intestinal carboxyl esterase, lewisY, sLe, LY6K, HSP70, HSP27, mut hsp70-2, M-CSF, MYCN, RhoC, TRP-2, CYPIBI, BORIS, prostase, prostate-specific antigen (PSA), PAX3, PAP, NY-ESO-1, LAGE-la, LMP2, NCAM, p53, p53 mutant, Ras mutant, gplOO, prostein, OR51E2, PANX3, PSMA, PSCA, Her2/neu, hTERT, HMWMAA, HAVCR1, VEGFR2, PDGFR-beta, survivin and telomerase, legumain, HPV E6,E7, sperm protein 17, S SEA-4, tyrosinase, TARP, WT1, prostate-carcinoma tumor antigen- 1 (PCTA-1), ML-IAP, MAGE, MAGE-A1, MAGE-A2, MAGE-C1, MAGE-C2, Annexin-A2, MAD-CT-1, MAD- CT-2, Mel an A/M ART 1, XAGE1 , ELF2M, ERG (TMPRSS2 ETS fusion gene), NA17, neutrophil elastase, sarcoma translocation breakpoints, NY-BR-1, ephnnB2, CD20, CD22, CD24, CD30, TIM3, CD38, CD44v6, CD97, CD171, CD 179a, androgen receptor, FAP, insulin growth factor (IGF)-I, IGFII, IGF-I receptor, GD2, o-acetyl-GD2, GD3, GM3, GPRC5D, GPR20, CXORF61, folate receptor (FRa), folate receptor beta, ROR1, Flt3, TAG72, TN Ag, Tie 2, TEM1, TEM7R, CLDN6, TSHR, UPK2, and mesothelin. In certain preferred embodiments, the tumor antigen is selected from folate receptor (FRa), mesothelin, EGFRvIII, IL-13Ra, CD 123, CD 19, TIM3, BCMA, GD2, CLL-1, CA-IX, MUC1, HER2, and any combination thereof.

Further non-limiting examples of tumor antigens include the following:

Differentiation antigens such as tyrosinase, TRP-1, TRP-2 and tumor-specific multilineage antigens such as MAGE-1, MAGE-3, BAGE, GAGE-1, GAGE-2, pi 5; overexpressed embryonic antigens such as CEA; overexpressed oncogenes and mutated tumor-suppressor genes such as p53, Ras, HER-2/neu; unique tumor antigens resulting from chromosomal translocations; such as BCR-ABL, E2A-PRL, H4-RET, IGH-IGK, MYL-RAR; and viral antigens, such as the Epstein Barr virus antigens EB VA and the human papillomavirus (HPV) antigens E6 and E7. Other large, protein-based antigens include SCCA, GP73, FC- GP73, TSP-180, MAGE-4, MAGE-5, MAGE-6, RAGE, NY-ESO, pl85erbB2, pl80erbB-3, c-met, nm- 23H1, PSA, CA 19-9, CA 72-4, CAM 17.1, NuMa, K-ras, beta-Catenin, CDK4, Mum-1, p 15, p 16, 43-9F, 5T4, 791Tgp72, alpha-fetoprotein, beta-HCG, BCA225, BTAA, CA 125, CA 15-3\CA 27.29\BCAA, CA 195, CA 242, CA-50, CAM43, CD68\P1, CO-029, FGF-5, G250, Ga733\EpCAM, HTgp-175, M344, MA-50, MG7-Ag, MOV18, NB/70K, NY-CO-1, RCAS1, SDCCAG1 6, TA-90\Mac-2 binding protein\cyclophilm C-associated protein, TAAL6, TAG72, TLP, TPS, GPC3, MUC16, TAG-72, LMP1, EBMA-1, BARF-1, CS1, CD319, FIERI, B7H6, LI CAM, IL6, and MET.

CAR Ligand-Binding Domains

The extracellular domain of the CARs disclosed herein generally comprise an antigen recognition domain that binds a target antigen. Such antigen-specific binding domains are typically derived from an antibody. In some embodiments, the antigen-binding domain is a functional antibody fragment or derivative thereof (e.g., an scFv or a Fab, or any suitable antigen binding fragment of an antibody). In preferred embodiments, the antigen binding domain is a single-chain variable fragment (scFv). In some such embodiments, the scFv is from a monoclonal antibody (mAh). In certain preferred embodiments, the antigen- specific binding domain (e.g., the scFv) is fused to the transmembrane and/or signaling motifs involved in lymphocyte activation as disclosed in Sadelain, et al. Nat Rev Cancer 2003 3:35-45, incorporated herein by reference in its entirety.

Anti-CLEC4 scFv

In some embodiments, the anti-CLEC4 scFv can comprise a variable heavy (VH) domain having CDR1, CDR2 and CDR3 sequences and a variable light (VL) domain having CDR1, CDR2 and CDR3 sequences.

PCT application WO2016/156450 describes antibodies directed against CLEC4C. This PCT publication is hereby incorporated by reference in its entirety, and in particular for the antibodies described therein and scFv fragments thereof that may be produced therefrom.

Nucleic Acids and Vectors

Also disclosed are polynucleotides and polynucleotide vectors encoding the disclosed CLEC4-specific CARs that allow expression of the CLEC-specific CARs in the disclosed immune effector cells.

Nucleic acid sequences encoding the disclosed CARs, and regions thereof, can be obtained using recombinant methods known in the art, such as, for example by screening libraries from cells expressing the gene, by deriving the gene from a vector known to include the same, or by isolating directly from cells and tissues containing the same, using standard techniques. Alternatively, the gene of interest can be produced synthetically, rather than cloned.

Expression of nucleic acids encoding CARs is typically achieved by operably linking a nucleic acid encoding the CAR polypeptide to a promoter, and incorporating the construct into an expression vector. Typical cloning vectors contain transcription and translation terminators, initiation sequences, and promoters useful for regulation of the expression of the desired nucleic acid sequence.

The disclosed nucleic acid can be cloned into a number of types of vectors. For example, the nucleic acid can be cloned into a vector including, but not limited to a plasmid, a phagemid, a phage derivative, an animal virus, and a cosmid. Vectors of particular interest include expression vectors, replication vectors, probe generation vectors, and sequencing vectors.

Further, the expression vector may be provided to a cell in the form of a viral vector. Viral vector technology is well known in the art and is described, for example, in Sambrook et al. (2001, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York), and in other virology and molecular biology manuals. Viruses, which are useful as vectors include, but are not limited to, retroviruses, adenoviruses, adeno-associated viruses, herpes viruses, and lentiviruses. In general, a suitable vector contains an origin of replication functional in at least one organism, a promoter sequence, convenient restriction endonuclease sites, and one or more selectable markers. In some embodiments, the polynucleotide vectors are lentiviral or retroviral vectors. A number of viral based systems have been developed for gene transfer into mammalian cells. For example, retroviruses provide a convenient platform for gene delivery systems. A selected gene can be inserted into a vector and packaged in retroviral particles using techniques known in the art. The recombinant virus can then be isolated and delivered to cells of the subject either in vivo or ex vivo.

One example of a suitable promoter is the immediate early cytomegalovirus (CMV) promoter sequence. This promoter sequence is a strong constitutive promoter sequence capable of driving high levels of expression of any polynucleotide sequence operatively linked thereto. Another example of a suitable promoter is Elongation Growth Factor- la (EF-la). However, other constitutive promoter sequences may also be used, including, but not limited to the simian virus 40 (SV40) early promoter, MND (myeloproliferative sarcoma virus) promoter, mouse mammary tumor virus (MMTV), human

immunodeficiency virus (HIV) long terminal repeat (LTR) promoter, MoMuLV promoter, an avian leukemia virus promoter, an Epstein-Barr virus immediate early promoter, a Rous sarcoma virus promoter, as well as human gene promoters such as, but not limited to, the actin promoter, the myosin promoter, the hemoglobin promoter, and the creatine kinase promoter. The promoter can alternatively be an inducible promoter. Examples of inducible promoters include, but are not limited to a metallothionine promoter, a glucocorticoid promoter, a progesterone promoter, and a tetracycline promoter.

Additional promoter elements, e.g., enhancers, regulate the frequency of transcriptional initiation. Typically, these are located in the region 30-110 bp upstream of the start site, although a number of promoters have recently been shown to contain functional elements downstream of the start site as well. The spacing between promoter elements frequently is flexible, so that promoter function is preserved when elements are inverted or moved relative to one another.

In order to assess the expression of a CAR polypeptide or portions thereof, the expression vector to be introduced into a cell can also contain either a selectable marker gene or a reporter gene or both to facilitate identification and selection of expressing cells from the population of cells sought to be transfected or infected through viral vectors. In other aspects, the selectable marker may be carried on a separate piece of DNA and used in a co-transfection procedure. Both selectable markers and reporter genes may be flanked with appropriate regulatory sequences to enable expression in the host cells. Useful selectable markers include, for example, antibiotic-resistance genes.

Reporter genes are used for identifying potentially transfected cells and for evaluating the functionality of regulatory sequences. In general, a reporter gene is a gene that is not present in or expressed by the recipient organism or tissue and that encodes a polypeptide whose expression is manifested by some easily detectable property, e.g., enzymatic activity. Expression of the reporter gene is assayed at a suitable time after the DNA has been introduced into the recipient cells. Suitable reporter genes may include genes encoding luciferase, beta-galactosidase, chloramphenicol acetyl transferase, secreted alkaline phosphatase, or the green fluorescent protein gene. Suitable expression systems are well known and may be prepared using known techniques or obtained commercially. In general, the construct with the minimal 5' flanking region showing the highest level of expression of reporter gene is identified as the promoter. Such promoter regions may be linked to a reporter gene and used to evaluate agents for the ability to modulate promoter- driven transcription.

Methods of introducing and expressing genes into a cell are known in the art. In the context of an expression vector, the vector can be readily introduced into a host cell, e.g., mammalian, bacterial, yeast, or insect cell by any method in the art. For example, the expression vector can be transferred into a host cell by physical, chemical, or biological means.

Physical methods for introducing a polynucleotide into a host cell include calcium phosphate precipitation, lipofection, particle bombardment, microinjection, electroporation, and the like. Methods for producing cells comprising vectors and/or exogenous nucleic acids are well-known in the art. See, for example, Sambrook et al. (2001, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, New York).

Biological methods for introducing a polynucleotide of interest into a host cell include the use of DNA and RNA vectors. Viral vectors, and especially retroviral vectors, have become the most widely used method for inserting genes into mammalian, e.g., human cells.

Chemical means for introducing a polynucleotide into a host cell include colloidal dispersion systems, such as macromolecule complexes, nanocapsules, microspheres, beads, and lipid-based systems including oil-in-water emulsions, micelles, mixed micelles, and liposomes. An exemplary colloidal system for use as a delivery vehicle in vitro and in vivo is a liposome (e.g., an artificial membrane vesicle).

In the case where a non-viral delivery system is utilized, an exemplary delivery vehicle is a liposome. In another aspect, the nucleic acid may be associated with a lipid. The nucleic acid associated with a lipid may be encapsulated in the aqueous interior of a liposome, interspersed within the lipid bilayer of a liposome, attached to a liposome via a linking molecule that is associated with both the liposome and the oligonucleotide, entrapped in a liposome, complexed with a liposome, dispersed in a solution containing a lipid, mixed with a lipid, combined with a lipid, contained as a suspension in a lipid, contained or complexed with a micelle, or otherwise associated with a lipid. Lipid, lipid/DNA or lipid/expression vector associated compositions are not limited to any particular structure in solution. For example, they may be present in a bilayer structure, as micelles, or with a“collapsed” structure. They may also simply be interspersed in a solution, possibly forming aggregates that are not uniform in size or shape. Lipids are fatty substances which may be naturally occurring or synthetic lipids. For example, lipids include the fatty droplets that naturally occur in the cytoplasm as well as the class of compounds which contain long-chain aliphatic hydrocarbons and their derivatives, such as fatty acids, alcohols, amines, amino alcohols, and aldehydes. Lipids suitable for use can be obtained from commercial sources. For example, dimyristyl phosphatidylcholine (“DMPC”) can be obtained from Sigma, St. Louis, Mo.; dicetyl phosphate (“DCP”) can be obtained from K & K Laboratories (Plainview, N. Y); cholesterol (“Choi”) can be obtained from Calbiochem- Behring; dimyristyl phosphatidylglycerol (“DMPG”) and other lipids may be obtained from Avanti Polar Lipids, Inc, (Birmingham, Ala.).

Immune effector cells

Also disclosed are immune effector cells that are engineered to express the disclosed CARs (also referred to herein as“CAR-T cells”). These cells are preferably obtained from the subject to be treated (i.e., are autologous). However, in some embodiments, immune effector cell lines or donor effector cells (allogeneic) are used. Immune effector cells can be obtained from a number of sources, including peripheral blood mononuclear cells, bone marrow, lymph node tissue, cord blood, thymus tissue, tissue from a site of infection, ascites, pleural effusion, spleen tissue, and tumors. Immune effector cells can be obtained from blood collected from a subject using any number of techniques known to the skilled artisan, such as Ficoll™ separation. For example, cells from the circulating blood of an individual may be obtained by apheresis. In some embodiments, immune effector cells are isolated from peripheral blood lymphocytes by lysing the red blood cells and depleting the monocytes, for example, by centrifugation through a PERCOLL™ gradient or by counterflow centrifugal elutriation. A specific subpopulation of immune effector cells can be further isolated by positive or negative selection techniques. For example, immune effector cells can be isolated using a combination of antibodies directed to surface markers unique to the positively selected cells, e.g., by incubation with antibody-conjugated beads for a time period sufficient for positive selection of the desired immune effector cells.

Alternatively, enrichment of immune effector cells population can be accomplished by negative selection using a combination of antibodies directed to surface markers unique to the negatively selected cells.

In some embodiments, the immune effector cells comprise any leukocyte involved in defending the body against infectious disease and foreign materials. For example, the immune effector cells can comprise lymphocytes, monocytes, macrophages, dendritic cells, mast cells, neutrophils, basophils, eosinophils, or any combinations thereof. For example, the immune effector cells can comprise T lymphocytes, preferably cytotoxic T lymphocytes (CTLs).

T cells or T lymphocytes can be distinguished from other lymphocytes, such as B cells and natural killer cells (NK cells), by the presence of a T-cell receptor (TCR) on the cell surface. They are called T cells because they mature in the thymus (although some also mature in the tonsils). There are several subsets of T cells, each with a distinct function.

T helper cells (TH cells) assist other white blood cells in immunologic processes, including maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages. These cells are also known as CD4⁺ T cells because they express the CD4 glycoprotein on their surface. Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete small proteins called cytokines that regulate or assist in the active immune response. These cells can differentiate into one of several subtypes, including THI , TH2, TH3, TH17, TH9, or TFH, which secrete different cytokines to facilitate a different type of immune response. Cytotoxic T cells (Tc cells, or CTLs) destroy virally infected cells and tumor cells, and are also implicated in transplant rejection. These cells are also known as CD8⁺ T cells since they express the CD8 glycoprotein at their surface. These cells recognize their targets by binding to antigen associated with MHC class I molecules, which are present on the surface of all nucleated cells. Through IL-10, adenosine and other molecules secreted by regulatory T cells, the CD8⁺ cells can be inactivated to an anergic state, which prevents autoimmune diseases.

In some embodiments, the immune effector cells that comprise a CAR as described herein are pluripotent stem cells capable of differentiating into a cell of the immune system, for example, a cytotoxic T cell. In certain preferred embodiments, the immune effector cells of the present invention are CAR-expressing induced pluripotent stem cells (iPSCs).

Memory T cells are a subset of antigen-specific T cells that persist long-term after an infection has resolved. They quickly expand to large numbers of effector T cells upon re exposure to their cognate antigen, thus providing the immune system with“memory” against past infections. Memory cells may be either CD4⁺ or CD8⁺. Memory T cells typically express the cell surface protein CD45RO.

Regulatory T cells (Treg cells), formerly known as suppressor T cells, are crucial for the maintenance of immunological tolerance. Their major role is to shut down T cell- mediated immunity toward the end of an immune reaction and to suppress auto-reactive T cells that escaped the process of negative selection in the thymus. Two major classes of CD4⁺ Treg cells have been described— naturally occurring Treg cells and adaptive Treg cells.

Natural killer T (NKT) cells (not to be confused with natural killer (NK) cells) bridge the adaptive immune system with the innate immune system. Unlike conventional T cells that recognize peptide antigens presented by major histocompatibility complex (MHC) molecules, NKT cells recognize gly colipid antigen presented by a molecule called CD Id.

In some embodiments, the T cells comprise a mixture of CD4⁺ cells. In other embodiments, the T cells are enriched for one or more subsets based on cell surface expression. For example, in some cases, the T comprise are cytotoxic CD8⁺ T lymphocytes. In some embodiments, the T cells comprise gd T cells, which possess a distinct T-cell receptor (TCR) having one g chain and one d chain instead of a and b chains.

Natural-killer (NK) cells are CD56⁺CD3 large granular lymphocytes that can kill virally infected and transformed cells, and constitute a critical cellular subset of the innate immune system (Godfrey J, et al. Leuk Lymphoma 2012 53: 1666-1676). Unlike cytotoxic CD8⁺ T lymphocytes, NK cells launch cytotoxicity against tumor cells without the requirement for prior sensitization, and can also eradicate MHC-I-negative cells (Nami- Mancinelli E, et al. Int Immunol 2011 23:427-431). NK cells are safer effector cells, as they may avoid the potentially lethal complications of cytokine storms (Morgan RA, et al. Mol Ther 2010 18:843-851), tumor lysis syndrome (Porter DL, et al. N Engl J Med 2011 365:725-733), and on-target, off-tumor effects. Although NK cells have a well-known role as killers of cancer cells, and NK cell impairment has been extensively documented as crucial for progression of Multiple myeloma (MM) (Godfrey J, et al. Leuk Lymphoma 2012 53:1666-1676; Fauriat C, et al. Leukemia 2006 20:732-733), the means by which one might enhance NK cell-mediated anti-MM activity has been largely unexplored prior to the disclosed CARs.

Epstein-Barr virus (EBV)-induced lymphoproliferative diseases (EBV-LPDs) and other EBV-associated cancers are a significant cause of morbidity and mortality for recipients of allogeneic hematopoietic cell transplantation (HCT) or solid organ transplants (SOT), particularly in those who have received certain T-cell reactive Abs to prevent or treat Graft versus host disease (GVHD). Prophylaxis and treatment by the adoptive transfer of autologous or allogeneic EBV-specific cytotoxic T cells and the subsequent long-term restoration of immunity against EBV-associated lymphoproliferation have provided positive outcomes in the management of these uniformly fatal complications of allogeneic tissue transfer. Therefore, in some embodiments, the disclosed immune effector cells that comprise one or more of the CAR polypeptides of the present invention are allogeneic or autologous EBV-specific cytotoxic T lymphocytes (CTLs). For example, generation of EBV-specific cytotoxic T cells may involve isolating PBMCs from of an EBV-seropositive autologous or allogenic donor and enriching them for T cells by depletion of monocytes and NK cells. EBV-specific cytotoxic T cells may also be produced by contacting donor PBMCs or purified donor T cells with a "stimulator" cell that expresses one or more EBV antigen(s) and presents the EBV antigen(s) to unstimulated T cells, thereby causing stimulation and expansion of EBV-specific CTLs. EBV antigens include, for example, latent membrane protein (LMP) and EBV nuclear antigen (EBNA) proteins, such as LMP- 1, LMP-2A, and LMP-2B and EBNA-1, EBNA-2, EBNA-3A, EBNA-3B, EBNA-3C and EBNA-LP. Cytotoxic T cells that comprise T cell receptor(s) which recognize one or more EBV-specific antigens are deemed to have been "sensitized" to those EBV antigen(s) and are therefore termed "EBV-sensitized cytotoxic T cells" herein. Known methods for generating allogeneic or autologous EBV-specific cytotoxic T cell populations that may comprise one or more of the CAR polypeptides of the present invention are described, for example, in Barker et al., Blood 2010 116(23):5045-49; Doubrovina, et al., Blood 2012 119(11):2644-56; Koehne, et al. Blood 2002 99(5): 1730-40; and Smith et al. Cancer Res 2012 72(5): 1116-25, which are incorporated by reference for these teachings. Similarly, cytotoxic T cells may be "sensitized" to other viral antigens, including cytomegalovirus (CMV), papillomavirus (e.g., HPV), adenovirus, polyomavirus (e.g., BKV, JCV, and Merkel cell virus), retrovirus (e.g., HTLV-I, also including lentivirus such as HIV), picornavirus (e.g., Hepatitis A virus), hepadnavirus (e.g., Hepatitis B virus), hepacivirus (e.g., Hepatitis C virus), deltavirus (e.g., Hepatitis D virus), hepevirus (e.g., Hepatitis E virus), and the like. In some preferred embodiments, the target antigen is from an oncovirus. In some such embodiments, the T cells used for generating the CAR-T cells of the invention are polyfunctional T-cells, i.e., those T cells that are capable of inducing multiple immune effector functions, that provide a more effective immune response to a pathogen than do cells that produce, for example, only a single immune effector (e.g. a single biomarker such as a cytokine or CD 107a). Less-polyfunctional, monofunctional, or even“exhausted” T cells may dominate immune responses during chronic infections, thus negatively impacting protection against virus-associated complications. In further preferred embodiments, the CAR-T cells of the invention are polyfunctional. In certain embodiments, at least 50% of the T cells used for generating the CAR-T cells of the invention are CD4+ T cells. In some such embodiments, said T cells are less than 50% CD4+ T cells. In still further embodiments, said T cells are predominantly CD4+ T cells. In some embodiments, at least 50% of the T cells used for generating the CAR-T cells of the invention are CD8+ T cells. In some such embodiments, said T cells are less than 50% CD8+ T cells. In still further embodiments, said T cells are predominantly CD8+ T cells. Such polyfunctional T cells are described, for example, in WO 2017/203356, which is herein incorporated by reference. In some embodiments, the T cells (e.g., the sensitized T cells and/or CAR-T cells described herein) are stored in a cell library or bank before they are administered to the subject. In some embodiments, the engineered CAR-T cells expressing the disclosed CARs further express a dominant-negative mutation that effects immune checkpoint blockade (e.g., express a dominant-negative form of an immune checkpoint molecule such as PD-1). Without intending to be an exhaustive list, the immune checkpoint molecule is selected from programmed death 1 (PD-1), cytotoxic T lymphocyte antigen-4 (CTLA-4), B- and T- lymphocyte attenuator (BTLA), T cell immunoglobulin mucin-3 (TIM-3), lymphocyte- activation protein 3 (LAG-3), T cell immunoreceptor with Ig and ITIM domains (TIGIT), leukocyte-associated immunoglobulin- like receptor 1 (LAIR1), natural killer cell receptor 2B4 (2B4), and CD 160. The immune checkpoint molecule may also be transforming growth factor b (TGF-b) receptor. Preferably, the immune checkpoint molecule is CTLA-4. Most preferably, the immune checkpoint molecule is PD-1.

PCT application WO2017/040945 describes methods of engineering CAR-T cells, which in addition to the a CAR polypeptide as described herein, also express a dominant negative form of an inhibitor of a cell-mediated immune response. The WO2017/040945 application is hereby incorporated by reference.

Therapeutic Methods

Immune effector cells expressing the disclosed CARs can elicit an anti-tumor immune response against CLEC4-expressing cancer cells. The anti-tumor immune response elicited by the disclosed CAR-modified immune effector cells may be an active or a passive immune response. In addition, the CAR-mediated immune response may be part of an adoptive immunotherapy approach in which CAR-modified immune effector cells induce an immune response specific to CLEC4.

Adoptive transfer of immune effector cells expressing chimeric antigen receptors is a promising anti-cancer therapeutic. Following the collection of a patient’s immune effector cells, the cells may be genetically engineered to express the disclosed CLEC4-specific CARs, then infused back into the patient. Moreover, immune effector cells obtained from a donor other than the patient (i.e., allogeneic to the patient) may be genetically engineered to express the disclosed CLEC4-specific CARs, then the CAR-containing cells infused into the patient. In certain specific embodiments, the immune effector cells which comprise an anti-CLEC4 CAR polypeptide are allogeneic EBV-specific cytotoxic T cells. The disclosed CAR-modified immune effector cells may be administered either alone, or as a pharmaceutical composition in combination with diluents and/or with other components such as IL-2, IL-15, or other cytokines or cell populations. Briefly, pharmaceutical compositions may comprise a target cell population as described herein, in combination with one or more pharmaceutically or physiologically acceptable carriers, diluents or excipients. Such compositions may comprise buffers such as neutral buffered saline, phosphate buffered saline and the like; carbohydrates such as glucose, mannose, sucrose or dextrans, mannitol; proteins; polypeptides or amino acids such as glycine; antioxidants; chelating agents such as EDTA or glutathione; adjuvants (e.g., aluminum hydroxide); and preservatives. Compositions for use in the disclosed methods are in some embodiments formulated for intravenous administration. Pharmaceutical compositions may be administered in any manner appropriate treat MM. The quantity and frequency of administration will be determined by such factors as the condition of the patient, and the severity of the patient's disease, although appropriate dosages may be determined by clinical trials.

When“an immunologically effective amount”,“an anti-tumor effective amount”, “an tumor-inhibiting effective amount”, or“therapeutic amount” is indicated, the precise amount of the compositions of the present invention to be administered can be determined by a physician with consideration of individual differences in age, weight, tumor size, extent of infection or metastasis, and condition of the patient (subject). It can generally be stated that a pharmaceutical composition comprising the T cells described herein may be administered at a dosage of 10⁴ to 10⁹ cells/kg body weight, such as 10⁵ to 10⁶ cells/kg body weight, including all integer values within those ranges. T cell compositions may also be administered multiple times at these dosages. The cells can be administered by using infusion techniques that are commonly known in immunotherapy (see, e.g., Rosenberg et ah, New Eng. J. of Med. 319: 1676, 1988). The optimal dosage and treatment regime for a particular patient can readily be determined by one skilled in the art of medicine by monitoring the patient for signs of disease and adjusting the treatment accordingly.

In certain embodiments, it may be desired to administer activated T cells to a subject and then subsequently re-draw blood (or have an apheresis performed), activate T cells therefrom according to the disclosed methods, and reinfuse the patient with these activated and expanded T cells. This process can be carried out multiple times every few weeks. In certain embodiments, T cells can be activated from blood draws of from 10 cc to 400 cc. In certain embodiments, T cells are activated from blood draws of 20 cc, 30 cc, 40 cc, 50 cc, 60 cc, 70 cc, 80 cc, 90 cc, or 100 cc. Using this multiple blood draw/multiple reinfusion protocol may serve to select out certain populations of T cells.

The administration of the disclosed compositions may be carried out in any convenient manner, including by injection, transfusion, or implantation. The compositions described herein may be administered to a patient subcutaneously, intradermally, intratumorally, intranodally, intramedullary, intramuscularly, by intravenous (i.v.) injection, or intraperitoneally. In some embodiments, the disclosed compositions are administered to a patient by intradermal or subcutaneous injection. In some embodiments, the disclosed compositions are administered by i.v. injection. The compositions may also be injected directly into a tumor, lymph node, or site of infection.

In certain embodiments, the disclosed CAR-modified immune effector cells are administered to a patient in conjunction with (e.g., before, simultaneously or following) any number of relevant treatment modalities, including but not limited to thalidomide, dexamethasone, bortezomib, and lenalidomide. In further embodiments, the CAR-modified immune effector cells may be used in combination with chemotherapy, radiation, immunosuppressive agents, such as cyclosporin, azathioprine, methotrexate,

mycophenolate, and FK506, antibodies, or other immunoablative agents such as CAM PATH, anti-CD3 antibodies or other antibody therapies, cytoxin, fludaribine, cyclosporin, FK506, rapamycin, mycophenolic acid, steroids, FR901228, cytokines, and irradiation. In some embodiments, the CAR-modified immune effector cells are administered to a patient in conjunction with (e.g., before, simultaneously or following) bone marrow

transplantation, T cell ablative therapy using either chemotherapy agents such as, fludarabine, external-beam radiation therapy (XRT), cyclophosphamide, or antibodies such as OKT3 or CAMPATH. In other embodiments, the cell compositions of the present invention are administered following B-cell ablative therapy such as agents that react with CD20, e.g., Rituxan. For example, in some embodiments, subjects may undergo standard treatment with high dose chemotherapy followed by peripheral blood stem cell

transplantation. In certain embodiments, following the transplant, subjects receive an infusion of the expanded immune cells of the present invention. In additional embodiments, expanded cells are administered before or following surgery. The cancer of the disclosed methods can be any CLEC4-expressing cell in a subject undergoing unregulated growth, invasion, or metastasis. Cancers that express CLEC4 include both solid and liquid tumors including, for example, glioblastoma, tenosynovial giant cell tumors (TSGCTs), melanoma, mesothelioma, uterine cancer, prostate cancer, ovarian cancer, adenocarcinoma of the lung, thyroid cancer, bladder cancer, breast cancer, esophageal cancer, endometrial cancer, gastric cancer, renal cancer, colorectal cancer, pancreatic cancer, liver cancers including hepatocellular carcinoma, AML, DLBCL, lymphomas, multiple myelomas, and the like. CLEC4 has also been found on Jurkat cells. In some embodiments, the cancer is a gallbladder cancer, exocrine adenocarcinoma, or apocrine adenocarcinomas.

In some embodiments, the cancer can be any neoplasm or tumor for which radiotherapy is currently used. Alternatively, the cancer can be a neoplasm or tumor that is not sufficiently sensitive to radiotherapy using standard methods. Thus, the cancer can be a sarcoma, lymphoma, leukemia, carcinoma, blastoma, or germ cell tumor. A representative but non-limiting list of cancers that the disclosed compositions can be used to treat include hepatocellular carcinoma, lymphoma, B cell lymphoma, T cell lymphoma, mycosis fungoides, Hodgkin’s Disease, myeloid leukemia, bladder cancer, brain cancer, nervous system cancer, head and neck cancer, squamous cell carcinoma of head and neck, kidney cancer, lung cancers such as small cell lung cancer and non-small cell lung cancer, neuroblastoma/glioblastoma, ovarian cancer, pancreatic cancer, prostate cancer, skin cancer, liver cancer, melanoma, squamous cell carcinomas of the mouth, throat, larynx, and lung, endometrial cancer, cervical cancer, cervical carcinoma, breast cancer, epithelial cancer, renal cancer, genitourinary cancer, pulmonary cancer, esophageal carcinoma, head and neck carcinoma, large bowel cancer, hematopoietic cancers; testicular cancer; colon and rectal cancers, renal cancer, prostatic cancer, and pancreatic cancer.

The disclosed CARs can be used in combination with any compound, moiety or group which has a cytotoxic or cytostatic effect. Drug moieties include chemotherapeutic agents, which may function as microtubulin inhibitors, mitosis inhibitors, topoisomerase inhibitors, or DNA intercalators, and particularly those which are used for cancer therapy.

The disclosed CARs can be used in combination with an immune checkpoint inhibitor. Two known immune checkpoint pathways involve signaling through the cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed-death 1 (PD-1) receptors. These proteins are members of the CD28-B7 family of co-signaling molecules that play important roles throughout all stages of T cell function. The PD-1 receptor (also known as CD279) is expressed on the surface of activated T cells. Its ligands, PD-L1 (B7-H1;

CD274) and PD-L2 (B7-DC; CD273), are expressed on the surface of APCs such as dendritic cells or macrophages. PD-L1 is the predominant ligand, while PD-L2 has a much more restricted expression pattern. When the ligands bind to PD-1, an inhibitory signal is transmitted into the T cell, which reduces cytokine production and suppresses T-cell proliferation. Checkpoint inhibitors include, but are not limited to aptamers and antibodies that block PD-1 (Nivolumab (BMS-936558 or MDX1106), CT-011, MK-3475), PD-L1 (MDX-1105 (BMS-936559), MPDL3280A, MSB0010718C), PD-L2 (rHIgM12B7), CTLA-4 (Ipilimumab (MDX-010), Tremelimumab (CP-675,206)), IDO, B7-H3

(MGA271), B7-H4, TIM3, LAG-3 (BMS-986016). Techniques for combining CARs with checkpoint inhibitors in immune effector cells and use thereof for the treatment of various disorders are described, for example, in WO 2017/040945, which is incorporated by reference herein.

Human monoclonal antibodies to programmed death 1 (PD-1) and methods for treating cancer using anti -PD-1 antibodies alone or in combination with other

immunotherapeutics are described in U.S. Patent No. 8,008,449, which is incorporated by reference for these antibodies. Anti-PD-Ll antibodies and uses therefor are described in U.S. Patent No. 8,552,154, which is incorporated by reference for these antibodies.

Anticancer agent comprising anti-PD-1 antibody or anti-PD-Ll antibody are described in U.S. Patent No. 8,617,546, which is incorporated by reference for these antibodies.

In some embodiments, the PDL1 inhibitor comprises an antibody that specifically binds PDL1, such as BMS-936559 (Bristol-Myers Squibb) or MPDL3280A (Roche). In some embodiments, the PD-1 inhibitor comprises an antibody that specifically binds PD-1, such as lambrolizumab (Merck), nivolumab (Bristol-Myers Squibb), or MEDI4736 (AstraZeneca). Human monoclonal antibodies to PD-1 and methods for treating cancer using anti-PD-1 antibodies alone or in combination with other immunotherapeutics are described in U.S. Patent No. 8,008,449, which is incorporated by reference for these antibodies. Anti-PD-Ll antibodies and uses therefor are described in U.S. Patent No. 8,552,154, which is incorporated by reference for these antibodies. Anticancer agent comprising anti-PD-1 antibody or anti-PD-Ll antibody are described in U.S. Patent No. 8,617,546, which is incorporated by reference for these antibodies.

The disclosed CARs can be used in combination with other cancer

immunotherapies. There are two distinct types of immunotherapy: passive immunotherapy uses components of the immune system to direct targeted cytotoxic activity against cancer cells, without necessarily initiating an immune response in the patient, while active immunotherapy actively triggers an endogenous immune response. Passive strategies include the use of the monoclonal antibodies (mAbs) produced by B cells in response to a specific antigen. The development of hybridoma technology in the 1970s and the identification of tumor-specific antigens permitted the pharmaceutical development of mAbs that could specifically target tumor cells for destruction by the immune system. Among them is rituximab (Rituxan, Genentech), which binds to the CD20 protein that is highly expressed on the surface of B cell malignancies such as non-Hodgkin’s lymphoma (NHL). Rituximab is approved by the FDA for the treatment of NHL and chronic lymphocytic leukemia (CLL) in combination with chemotherapy. Another important mAb is trastuzumab (Herceptin; Genentech), which revolutionized the treatment of HER2 (human epidermal growth factor receptor 2)-positive breast cancer by targeting the expression of HER2.

Generating optimal“killer” CD8 T cell responses also requires T cell receptor activation plus co-stimulation, which can be provided through ligation of tumor necrosis factor receptor family members, including 0X40 (CD134) and 4-1BB (CD137). 0X40 is of particular interest as treatment with an activating (agonist) anti-OX40 mAb augments T cell differentiation and cytolytic function leading to enhanced anti-tumor immunity against a variety of tumors.

In some embodiments, such an additional therapeutic agent may be selected from an antimetabolite, such as methotrexate, 6-mercaptopurine, 6-thioguanine, cytarabine, fludarabine, 5-fluorouracil, decarbazine, hydroxyurea, asparaginase, gemcitabine or cladribine.

In some embodiments, such an additional therapeutic agent may be selected from an alkylating agent, such as mechlorethamine, thioepa, chlorambucil, melphalan, carmustine (BSNU), lomustine (CCNU), cyclophosphamide, busulfan, dibromomannitol, streptozotocin, dacarbazine (DTIC), procarbazine, mitomycin C, cisplatin and other platinum derivatives, such as carboplatin.

In some embodiments, such an additional therapeutic agent may be selected from an anti-mitotic agent, such as taxanes, for instance docetaxel, and paclitaxel, and vinca alkaloids, for instance vindesine, vincristine, vinblastine, and vinorelbine.

In some embodiments, such an additional therapeutic agent may be selected from a topoisomerase inhibitor, such as topotecan or irinotecan, or a cytostatic drug, such as etoposide and teniposide.

In some embodiments, such an additional therapeutic agent may be selected from a growth factor inhibitor, such as an inhibitor of ErbBl (EGFR) (such as an EGFR antibody, e.g. zalutumumab, cetuximab, panitumumab or nimotuzumab or other EGFR inhibitors, such as gefitinib or erlotinib), another inhibitor of ErbB2 (HER2/neu) (such as a HER2 antibody, e.g. trastuzumab, trastuzumab-DM 1 or pertuzumab) or an inhibitor of both EGFR and HER2, such as lapatinib).

In some embodiments, such an additional therapeutic agent may be selected from a tyrosine kinase inhibitor, such as imatinib (Glivec, Gleevec STI571) or lapatinib.

Therefore, in some embodiments, a disclosed antibody is used in combination with ofatumumab, zanolimumab, daratumumab, ranibizumab, nimotuzumab, panitumumab, hu806, daclizumab (Zenapax), basiliximab (Simulect), infliximab (Remicade), adalimumab (Humira), natalizumab (Tysabri), omalizumab (Xolair), efalizumab (Raptiva), and/or rituximab.

In some embodiments, a therapeutic agent for use in combination with a CARs for treating the disorders as described above may be an anti-cancer cytokine, chemokine, or combination thereof. Examples of suitable cytokines and growth factors include IFNy, IL-2, IL-4, IL-6, IL-7, IL-10, IL-12, IL-13, IL-15, IL-18, IL-23, IL-24, IL-27, IL-28a, IL-28b, IL- 29, KGF, IFNa (e.g., INFa2b), IFN , GM-CSF, CD40L, Flt3 ligand, stem cell factor, ancestim, and TNFa. Suitable chemokines may include Glu-Leu-Arg (ELR)-negative chemokines such as IP- 10, MCP-3, MIG, and SDF-la from the human CXC and C-C chemokine families. Suitable cytokines include cytokine derivatives, cytokine variants, cytokine fragments, and cytokine fusion proteins.

In some embodiments, a therapeutic agent for use in combination with a CARs for treating the disorders as described above may be a cell cycle control/apoptosis regulator (or "regulating agent"). A cell cycle control/apoptosis regulator may include molecules that target and modulate cell cycle control/apoptosis regulators such as (i) cdc-25 (such as NSC 663284), (ii) cyclin-dependent kinases that overstimulate the cell cycle (such as flavopiridol (L868275, HMR1275), 7-hydroxystaurosporine (UCN-01, KW-2401), and roscovitine (R- roscovitine, CYC202)), and (iii) telomerase modulators (such as BIBR1532, SOT-095, GRN163 and compositions described in for instance US 6,440,735 and US 6,713,055) . Non-limiting examples of molecules that interfere with apoptotic pathways include TNF- related apoptosis-inducing ligand (TRAIL)/apoptosis-2 ligand (Apo-2L), antibodies that activate TRAIL receptors, IFNs, and anti-sense Bcl-2.

In some embodiments, a therapeutic agent for use in combination with a CARs for treating the disorders as described above may be a hormonal regulating agent, such as agents useful for anti-androgen and anti-estrogen therapy. Examples of such hormonal regulating agents are tamoxifen, idoxifene, fulvestrant, droloxifene, toremifene, raloxifene, diethylstilbestrol, ethinyl estradiol/estinyl, an antiandrogene (such as flutaminde/eulexin), a progestin (such as such as hydroxyprogesterone caproate, medroxy- progesterone/provera, megestrol acepate/megace), an adrenocorticosteroid (such as hydrocortisone, prednisone), luteinizing hormone-releasing hormone (and analogs thereof and other LHRH agonists such as buserelin and goserelin), an aromatase inhibitor (such as anastrazole/arimidex, aminoglutethimide/cytraden, exemestane) or a hormone inhibitor (such as

octreotide/ sandostatin).

In some embodiments, a therapeutic agent for use in combination with CARs for treating the disorders as described above may be an anti-cancer nucleic acid or an anti cancer inhibitory RNA molecule.

Combined administration, as described above, may be simultaneous, separate, or sequential. For simultaneous administration the agents may be administered as one composition or as separate compositions, as appropriate.

In some embodiments, the disclosed CARs is administered in combination with radiotherapy. Radiotherapy may comprise radiation or associated administration of radiopharmaceuticals to a patient is provided. The source of radiation may be either external or internal to the patient being treated (radiation treatment may, for example, be in the form of external beam radiation therapy (EBRT) or brachytherapy (BT)). Radioactive elements that may be used in practicing such methods include, e.g., radium, cesium-137, iridium-192, americium-241, gold-198, cobalt-57, copper-67, technetium-99, iodide-123, iodide-131, and indium-111.

In some embodiments, the disclosed CARs is administered in combination with surgery.

CAR-T cells may be designed in several ways that enhance tumor cytotoxicity and specificity, evade tumor immunosuppression, avoid host rejection, and prolong their therapeutic half-life. TRUCK (T-cells Redirected for Universal Cytokine Killing) T cells for example, possess a CAR but are also engineered to release cytokines such as IL-12 that promote tumor killing. Because these cells are designed to release a molecular payload upon activation of the CAR once localized to the tumor environment, these CAR-T cells are sometimes also referred to as‘armored CARs’. Several cytokines as cancer therapies are being investigated both pre-clinically and clinically, and may also prove useful when similarly incorporated into a TRUCK form of CAR-T therapy. Among these include IL-2, IL-3. IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, IL-13, IL-15, IL-18, M-CSF, GM-CSF, IFN-a, IFN-g, TNF-a, TRAIL, FLT3 ligand, Lymphotactin, and TGF-b (Dranoff 2004).“Self driving” or“homing” CAR-T cells are engineered to express a chemokine receptor in addition to their CAR. As certain chemokines can be upregulated in tumors, incorporation of a chemokine receptor aids in tumor trafficking to and infiltration by the adoptive T-cell, thereby enhancing both specificity and functionality of the CAR-T (Moon 2011). Universal CAR-T cells also possess a CAR, but are engineered such that they do not express endogenous TCR (T-cell receptor) or MHC (major histocompatibility complex) proteins. Removal of these two proteins from the signaling repertoire of the adoptive T-cell therapy prevents graft-versus-host-disease and rejection, respectively. Armored CAR-T cells are additionally so named for their ability to evade tumor immunosuppression and tumor- induced CAR-T hypofunction. These particular CAR-Ts possess a CAR, and may be engineered to not express checkpoint inhibitors. Alternatively, these CAR-Ts can be co administered with a monoclonal antibody (mAb) that blocks checkpoint signaling.

Administration of an anti-PDLl antibody significantly restored the killing ability of CAR TILs (tumor infiltrating lymphocytes). While PD-1-PD-L1 and CTLA-4-CD80/CD86 signaling pathways have been investigated, it is possible to target other immune checkpoint signaling molecules in the design of an armored CAR-T including LAG-3, Tim-3, IDO-1, 2B4, and KIR. Other intracellular inhibitors of TILs include phosphatases (SHP1), ubiquitin-ligases (i.e., cbl-b), and kinases (i.e., diacylglycerol kinase) . Armored CAR-Ts may also be engineered to express proteins or receptors that protect them against or make them resistant to the effects of tumor-secreted cytokines. For example, CTLs (cytotoxic T lymphocytes) transduced with the double negative form of the TGF-b receptor are resistant to the immunosuppression by lymphoma secreted TGF-b. These transduced cells showed notably increased antitumor activity in vivo when compared to their control counterparts.

Tandem and dual CAR-T cells are unique in that they possess two distinct antigen binding domains. A tandem CAR contains two sequential antigen binding domains facing the extracellular environment connected to the intracellular costimulatory and stimulatory domains. A dual CAR is engineered such that one extracellular antigen binding domain is connected to the intracellular costimulatory domain and a second, distinct extracellular antigen binding domain is connected to the intracellular stimulatory domain. Because the stimulatory and costimulatory domains are split between two separate antigen binding domains, dual CARs are also referred to as“split CARs”. In both tandem and dual CAR designs, binding of both antigen binding domains is necessary to allow signaling of the CAR circuit in the T-cell. Because these two CAR designs have binding affinities for different, distinct antigens, they are also referred to as“bi-specific” CARs.

One primary concern with CAR-T cells as a form of“living therapeutic” is their manipulability in vivo and their potential immune-stimulating side effects. To better control CAR-T therapy and prevent against unwanted side effects, a variety of features have been engineered including off-switches, safety mechanisms, and conditional control mechanisms. Both self-destruct and marked/tagged CAR-T cells for example, are engineered to have an“off-switch” that promotes clearance of the CAR-expressing T-cell.

A self-destruct CAR-T contains a CAR, but is also engineered to express a pro-apoptotic suicide gene or“elimination gene” inducible upon administration of an exogenous molecule. A variety of suicide genes may be employed for this purpose, including HSV- TK (herpes simplex virus thymidine kinase), Fas, iCasp9 (inducible caspase 9), CD20,

MYC TAG, and truncated EGFR (endothelial growth factor receptor). HSK for example, will convert the prodrug ganciclovir (GCV) into GCV-triphosphate that incorporates itself into replicating DNA, ultimately leading to cell death. iCasp9 is a chimeric protein containing components of FK506-binding protein that binds the small molecule AP1903, leading to caspase 9 dimerization and apoptosis. A marked/ tagged CAR-T cell however, is one that possesses a CAR but also is engineered to express a selection marker.

Administration of a mAb against this selection marker will promote clearance of the CAR- T cell. Truncated EGFR is one such targetable antigen by the anti-EGFR mAb, and administration of cetuximab works to promotes elimination of the CAR-T cell. CARs created to have these features are also referred to as sCARs for‘switchable CARs’, and RCARs for‘regulatable CARs’. A“safety CAR”, also known as an“inhibitory CAR” (iCAR), is engineered to express two antigen binding domains. One of these ectodomains is directed against a tumor related antigen and bound to an intracellular costimulatory and stimulatory domain. The second extracellular antigen binding domain however is specific for normal tissue and bound to an intracellular checkpoint domain such as CTLA4, PD-1, or CD45. Incorporation of multiple intracellular inhibitory domains to the iCAR is also possible. Some inhibitory molecules that may provide these inhibitory domains include B7- Hl, B7-1, CD 160, PIH, 2B4, CEACAM (CEACAM-1. CEACAM-3, and/or CEACAM-5), LAG-3, TIGIT, BTLA, LAIR1, and TGFP-R. In the presence of normal tissue, stimulation of this second antigen binding domain will work to inhibit the CAR. It should be noted that due to this dual antigen specificity, iCARs are also a form of bi-specific CAR-T cells. The safety CAR-T engineering enhances specificity of the CAR-T cell for tumor tissue, and is advantageous in situations where certain normal tissues may express very low levels of a tumor associated antigen that would lead to off target effects with a standard CAR (Morgan 2010). A conditional CAR-T cell expresses an extracellular antigen binding domain connected to an intracellular costimulatory domain and a separate, intracellular

costimulator. The costimulatory and stimulatory domain sequences are engineered in such a way that upon administration of an exogenous molecule the resultant proteins will come together intracellularly to complete the CAR circuit. In this way, CAR-T activation can be modulated, and possibly even‘fine-tuned’ or personalized to a specific patient. Similar to a dual CAR design, the stimulatory and costimulatory domains are physically separated when inactive in the conditional CAR; for this reason, these too are also referred to as a“split CAR”.

In some embodiments, two or more of these engineered features may be combined to create an enhanced, multifunctional CAR-T. For example, it is possible to create a CAR- T cell with either dual- or conditional-CAR design that also releases cytokines like a TRUCK. In some embodiments, a dual-conditional CAR-T cell could be made such that it expresses two CARs with two separate antigen binding domains against two distinct cancer antigens, each bound to their respective costimulatory domains. The costimulatory domain would only become functional with the stimulatory domain after the activating molecule is administered. For this CAR-T cell to be effective the cancer must express both cancer antigens and the activating molecule must be administered to the patient; this design thereby incorporating features of both dual and conditional CAR-T cells.

Typically, CAR-T cells are created using a-b T cells, however g-d T cells may also be used. In some embodiments, the described CAR constructs, domains, and engineered features used to generate CAR-T cells could similarly be employed in the generation of other types of CAR-expressing immune cells including NK (natural killer) cells, B cells, mast cells, myeloid-derived phagocytes, and NKT cells. Alternatively, a CAR-expressing cell may be created to have properties of both T-cell and NK cells. In additional embodiments, the cells transduced with CARs may be autologous or allogeneic to a patient to which they are administered.

Several different methods for CAR expression may be used including retroviral transduction (including g-retroviral), lentiviral transduction, transposon/transposases (Sleeping Beauty and PiggyBac systems), and messenger RNA transfer-mediated gene expression. Gene editing (gene insertion or gene deletion/disruption) has become of increasing importance with respect to the possibility for engineering CAR-T cells as well. CRISPR-Cas9, ZFN (zinc finger nuclease), and TALEN (transcription activator like effector nuclease) systems are three potential methods through which CAR-T cells may be generated.

Exemplification

Example 1 : Bioinformatics and proteomics screen to identify therapeutic targets for hepatocellular cancers.

Public transcriptome data is combined with proteomic data generated from 5 Hepatitis B, 5 Hepatitis C, 5 Non-Alcoholic Steato-Hepatitis (NASH) and 5 fibrolamellar subtypes of hepatocellular carcinoma (HCC) using computational biology and

bioinformatics approaches to identify targets suitable for CAR-T binding domains and selective targeting to hepatocellular carcinoma. The results of these analyses demonstrated that CLEC4A, CLEC4B, CLEC4C and CLEC4D cell surface expression is associated with certain types of cancer in humans, including hepatocellular carcinoma. Therefore, it is recognized herein that the various CLEC4 proteins are suitable targets for designing and administering autologous or allogeneic CAR-T therapies for the treatment of hepatocellular carcinoma in humans.

Expression of CLEC4 proteins as well as HCC-subtype targets suitable for CAR T binding domains are characterized on tissue microarrays. In addition, CLEC4 protein expression on HCC, hepatocytes and a panel of normal tissue are evaluated using mouse anti-human CLEC4 antibodies.

Example 2: CLEC4-CAR design

Cytotoxic T-cells (CTLS), previously sensitized to one or EBV antigen(s), are used to engineer CAR T cells that selectively target at least one of the identified and evaluated HCC-associated CLEC4 family members (i.e., CLEC4 A-D). The CAR polypeptide is specifically designed to reduce CAR T cell exhaustion and enhance CAR T cell persistence in the subject. CAR signaling domains are optimized through a combination of co stimulatory domains (i.e., CD28) and signal domain mutants (i.e., CD3z-lXX). Moreover, the CAR T cells are capable of expressing an inhibitor of an immune checkpoint molecule (i.e., a dominant-negative PD-1 polypeptide), thus overcoming the immunosuppressive microenvironment found among many tumors.

A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A chimeric antigen receptor (CAR) polypeptide that binds to a CLEC4 antigen, comprising a CLEC4 antigen-binding domain, a transmembrane domain, and an intracellular signaling domain.

2. The CAR polypeptide of claim 1, wherein the CLEC4 antigen is a CLEC4A antigen, CLEC4B antigen, CLEC4C antigen, or CLEC4D antigen.

3. The CAR polypeptide of claim 1 or 2, wherein the CLEC4 antigen-binding domain is a functional antibody fragment.

4. The CAR polypeptide of any one of claims 1 to 3, wherein the CLEC4 antigen-binding domain is a single-chain variable fragment (scFv).

5. The CAR polypeptide of any one of claims 1 to 4, wherein the transmembrane domain is derived from a transmembrane or membrane-bound polypeptide.

6. The CAR polypeptide of any one of claims 1 to 5, wherein the transmembrane domain comprises at least one transmembrane domain of any one of the polypeptides CD28, NKp30, CDS, DAPIO, 41BB, DAP 12, CD3C, CD3e, CD45, CD4, CD5, CD8, CD9, CD 16, CD22, CD33, CD37, CD64, CD80, CD86, CD134, CD137, CD154, KIRDS2, 0X40, CD2, CD27, LFA-1, ICOS (CD278) , 4-1BB (CD137) , GITR, CD40, BAFFR, HVEM (LIGHTR) , SLAMF7, NKp80 (KLRFl) , CD 160, CD 19, IL2R beta, IL2R gamma, IL7R a, ITGA1, VLA1, CD49a, ITGA4, IA4, CD49D, ITGA6, VLA-6, CD49f, IT GAD, CD l id, ITGAE, CD 103, ITGAL, CD1 la, LFA-1, ITGAM, CDl lb, ITGAX, CDl lc, ITGB 1, CD29, ITGB2, CD18, LFA-1, ITGB7, TNFR2, DNAM1 (CD226) , SLAMF4 (CD244, 2B4) , CD84, CD96 (Tactile) , CEACAM1, CRT AM, Ly9 (CD229) , CD160 (BY55) , PSGL1, CD100 (SEMA4D) , SLAMF6 (NTB-A, Lyl08) , SLAM (SLAMFl, CD 150, IPO-3) , BLAME (SLAMF8) , SELPLG (CD 162) , LTBR, PAG/Cbp, mutants thereof, or any combination thereof.

7. The CAR polypeptide of any one of claims 1 to 6, wherein the transmembrane domain comprises the transmembrane domain of CD28 and/or 4 IBB.

8. The CAR polypeptide of any one of claims 1 to 7, wherein the signaling domain comprises at least one signaling domain of any one of the polypeptides CD8, CD3C, CD 35, CD3y, CD3e, FcyRI-y, FcyRIII-y, FceRIp, FceRIy, DAP 10, DAP 12, CD32, CD79a, CD79b, CD28, CD3C, CD4, b2c, CD137 (41BB), ICOS, CD27, CD285, CD80, NKp30, 0X40, mutants thereof, or any combination thereof.

9. The CAR polypeptide of any one of claims 1 to 8, further comprising at least one co-stimulatory signaling region.

10. The CAR polypeptide of claim 9, wherein the co-stimulatory signaling region comprises a signaling domain of any one of the polypeptides CD8, CD3^ CD35, CD3y, CD3e, FcyRI-y, FcyRIII-y, FceRIp, FceRIy, DAP10, DAP 12, CD32, CD79a, CD79b, CD28, CD3C, CD4, b2c, CD137 (41BB), ICOS, CD27, CD285, CD80, NKp30, 0X40, mutants thereof, or any combination thereof.

11. The CAR polypeptide of claim 9 or 10, wherein the co-stimulatory signaling region comprises a signaling domain of CD28 or a mutant thereof.

12. The CAR polypeptide of claim 11, wherein the CD28 signaling domain comprises at least one mutation or deletion of any one of subdomains YMNM, PRRP, PYAP, or any combination thereof.

13. The CAR polypeptide of claim 11 or 12, wherein the CD28 signaling domain lacks activity of at least one of the subdomains selected from YMNM, PRRP, or PYAP.

14. The CAR polypeptide of any one of claims 11 to 13, wherein the CD28 signaling domain lacks activity of any two of the subdomains selected from YMNM, PRRP, or PYAP.

15. The CAR polypeptide of claim 9 or 10, wherein the co-stimulatory signaling region comprises a signaling domain of CD137 (41BB) or a mutant thereof.

16. The CAR polypeptide of any one of claims 1 to 14, wherein the at least one signaling domain comprises a native CD3z or a mutant thereof.

17. The CAR polypeptide of claim 16, wherein the mutant Oϋ3z lacks a C- terminal immunoreceptor tyrosine-based activation motif (IT AM).

18. The CAR polypeptide of claim 16, wherein the mutant CD3z lacks two C- terminal immunoreceptor tyrosine-based activation motifs (ITAMs).

19. The CAR polypeptide of claim 16, wherein the mutant CD3z comprises only one immunoreceptor tyrosine-based activation motif (IT AM).

20. The CAR polypeptide of any one of claims 1 to 19, further comprising a hinge sequence.

21. The CAR polypeptide of claim 20, wherein the hinge sequence is derived from a CD8a molecule or a CD28 molecule.

22. A nucleic acid encoding the CAR polypeptide of any one of claims 1 to 21.

23. A vector comprising the nucleic acid of claim 22.

24. An immune cell comprising the nucleic acid of claim 22.

25. An immune cell comprising the vector of claim 23.

26. An immune cell expressing the CAR polypeptide of any one of claims 1 to 21.

27. The immune cell of any one of claims 24 to 26, wherein the immune cell is a leukocyte.

28. The immune cell of any one of claims 24 to 27 wherein the immune cell is a lymphocyte, a monocyte, a macrophage, a dendritic cell, a mast cell, a neutrophil, a basophil, or an eosinophil.

29. The immune cell of any one of claims 24 to 28 wherein the immune cell is a lymphocyte selected from an abT cell, gdT cell, a Natural Killer (NK) cell, a Natural Killer T (NKT) cell, a B cell, an innate lymphoid cell (ILC), a cytokine induced killer (CIK) cell, a cytotoxic T lymphocyte (CTL), a lymphokine activated killer (LAK) cell, a regulatory T cell, an induced pluripotent stem cell (iPSC), or any combination thereof.

30. The immune cell of claim 29, wherein the immune cell is a cytotoxic T lymphocyte (CTL).

31. The immune cell of claim 29 or 30, wherein the immune cell is a viral antigen- sensitized CTL.

32. The immune cell of any one of claims 29 to 31, wherein the immune cell is a CTL sensitized to a viral antigen from any one of Epstein-Barr virus (EBV), cytomegalovirus (CMV), B.K. virus (BKV), John Cunningham virus (JCV), picornavirus (e.g., Hepatitis A virus), hepadnavirus (e.g., Hepatitis B virus), hepacivirus (e.g., Hepatitis C virus), deltavirus (e.g., Hepatitis D virus), hepevirus (e.g., Hepatitis E virus), or any combination thereof.

33. The immune cell of any one of claims 29 to 32, wherein the immune cell is an EBV-sensitized CTL.

34. A bi-specific chimeric antigen receptor (CAR) T cell expressing

(a) a CAR polypeptide that selectively binds a CLEC4 antigen and

(b) a CAR polypeptide that selectively binds a tumor-associated antigen that is not a CLEC4 antigen.

35. A method of treating a CLEC4-associated cancer in a subject, the method comprising administering to said subject an effective amount of the immune cells of any one of claims 24 to 33.

36. The method of claim 35, wherein said cancer is hepatocellular carcinoma.