M971 chimeric antigen receptors
Inventors
Orentas, Rimas J. • Pastan, Ira H. • Dimitrov, Dimiter S. • Mackall, Crystal L.
Assignees
US Department of Health and Human Services
Publication Number
US-10703816-B2
Publication Date
2020-07-07
Expiration Date
2033-09-18
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Abstract
The invention provides a chimeric antigen receptor (CAR) comprising an antigen binding domain comprising SEQ ID NOs: 1-6, a transmembrane domain, and an intracellular T cell signaling domain. Nucleic acids, recombinant expression vectors, host cells, populations of cells, antibodies, or antigen binding portions thereof, and pharmaceutical compositions relating to the CARs are disclosed. Methods of detecting the presence of cancer in a mammal and methods of treating or preventing cancer in a mammal are also disclosed.
Core Innovation
The invention provides a chimeric antigen receptor (CAR) comprising an antigen binding domain including sequences SEQ ID NOs: 1-6, a transmembrane domain, and an intracellular T cell signaling domain. These CARs specifically target the CD22 antigen expressed on the surface of certain B cell malignancies, leveraging the antigen specificity to detect, treat, or prevent cancer in a mammal. The CAR includes domains derived from the m971 antibody which binds CD22 with improved specificity and affinity by recognizing a distinct CD22 epitope. The CARs can include variants and functional portions retaining biological activity, and combinations of transmembrane and intracellular signaling domains such as CD8 or CD28 transmembrane domains and CD28, CD137, and CD3 zeta intracellular domains.
The problem addressed by the invention arises from the high mortality associated with various cancers, particularly hematological malignancies like leukemias and lymphomas, where existing treatments such as chemotherapy often have poor prognoses. There is a recognized unmet need for additional effective treatments to target and eliminate cancer cells while avoiding damage to early B cell development stages and stem cells.
By incorporating the antigen binding specificity toward CD22, expressed in a majority of B cell lymphomas and leukemias but absent in early B cell or stem cells, the CARs enable targeted immune responses from engineered T cells toward malignant cells, thus providing a therapeutic strategy that improves upon previous antibody and immunotoxin approaches. The CARs do not rely on MHC presentation and are designed to increase T cell efficacy and persistence in lysing tumor cells, evidenced by in vitro cytotoxicity assays and murine models showing tumor regression and improved survival.
Claims Coverage
The patent includes one independent claim that encompasses multiple inventive features related to a nucleic acid encoding a CAR with specific domains and sequences.
Nucleic acid encoding a CD22-specific CAR with defined antigen binding domains
A nucleic acid comprising a nucleotide sequence encoding a CAR having an antigen binding domain which binds CD22 and comprises amino acid sequences for heavy chain CDR1 (SEQ ID NO: 1), CDR2 (SEQ ID NO: 2), CDR3 (SEQ ID NO: 3), and light chain CDR1 (SEQ ID NO: 4), CDR2 (SEQ ID NO: 5), and CDR3 (SEQ ID NO: 6).
Nucleic acids comprising specific sequence identifiers
Nucleic acids comprising SEQ ID NO: 25 and optionally selected from SEQ ID NOs: 26, 27, or 28 encoding various transmembrane and intracellular signaling domains.
Recombinant expression vector containing the nucleic acid encoding the CAR
A recombinant expression vector engineered to comprise the nucleic acid encoding the CAR with the defined antigen binding, transmembrane, and intracellular T cell signaling domains.
Host cell and populations comprising the expression vector
An isolated host cell, including T cells, harboring the recombinant expression vector, and populations of isolated cells comprising such host cells.
Antigen binding domain variable region inclusion
Nucleic acids encoding antigen binding domains comprising the light chain variable region (SEQ ID NO: 7), the heavy chain variable region (SEQ ID NO: 8), or the combined sequence (SEQ ID NO: 9).
Transmembrane and intracellular signaling domains
Nucleic acids encoding transmembrane domains comprising SEQ ID NO: 12 or 18 and/or SEQ ID NO: 15; intracellular T cell signaling domains comprising SEQ ID NOs: 13 or 20; 16 or 19; 14, 17 or 21.
Pharmaceutical composition comprising engineered T cells
A pharmaceutical composition containing the host cells, particularly T cells, or populations thereof transformed with the recombinant vectors encoding the CAR.
Method for treating hematological cancer
A method of treating hematological cancer in a human subject by administering an effective amount of the host cells transduced with the nucleic acid encoding the CAR.
The claim covers a nucleic acid encoding a CAR targeting CD22 with specified CDR sequences, transmembrane and intracellular domains, recombinant expression vectors containing it, host cells including T cells comprising the vectors, pharmaceutical compositions, and methods of treating hematological cancers with these engineered cells.
Stated Advantages
The inventive CARs provide antigen-specific targeting and destruction of CD22-expressing cancer cells while substantially avoiding destruction of stem cells and early stage B cells due to CD22's expression pattern.
The CARs demonstrate superior binding affinity and antigen recognition compared to previous constructs such as HA22, targeting a distinct CD22 epitope.
Second generation CAR constructs exhibit enhanced surface expression, increased cytokine secretion, and superior cytotoxic activity compared to third generation CARs.
Treatment with cells transduced with the m971 CAR results in tumor burden reduction, slower disease progression, and increased survival in vivo in murine models compared to controls.
Documented Applications
Methods of detecting the presence of cancer in mammals by contacting a sample with the CAR or related antibodies and detecting bound complexes.
Methods of treating or preventing cancer, particularly hematological malignancies such as leukemias and lymphomas, in mammals by administration of pharmaceutical compositions comprising CAR-expressing host cells.
Use of recombinant expression vectors and host cells expressing CARs for adoptive immunotherapy against CD22-expressing cancer cells.
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