Bicistronic chimeric antigen receptors and their uses
Inventors
Qin, Haiying • Mackall, Crystal L • Fry, Terry J.
Assignees
US Department of Health and Human Services
Publication Number
US-11980640-B2
Publication Date
2024-05-14
Expiration Date
2038-05-15
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Abstract
An embodiment of the invention provides bicistronic chimeric antigen receptor (CAR) amino acid constructs. Nucleic acids, recombinant expression vectors, host cells, populations of cells, and pharmaceutical compositions relating to the CAR constructs 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. Methods of making the CAR constructs are disclosed.
Core Innovation
The invention provides bicistronic chimeric antigen receptor (CAR) amino acid constructs comprising two CARs linked through one or more cleavable domains. Each CAR includes an antigen binding domain, a transmembrane domain, and an intracellular T cell signaling domain. The cleavable domain enables the release of each CAR from the construct so that each CAR can have antigenic specificity for its respective target and can elicit an antigen-specific immune response. Exemplary antigen binding domains include those derived from the m971 antibody with specificity to CD22 and from the FMC63 antibody with specificity to CD19.
The problem being solved addresses the unmet need for improved cancer treatments, particularly hematological malignancies such as acute lymphocytic leukemia and B cell lymphomas. Current advances, including chemotherapy and single antigen-targeting CAR therapies, often lead to poor prognosis or relapse due to antigen loss by cancer cells. The invention seeks to overcome cancer cell escape resulting from loss of a single antigen, heterogeneity of antigen expression, and to increase the patient population amenable to CAR therapy by simultaneously targeting both CD19 and CD22 antigens with bicistronic CAR constructs.
Claims Coverage
The patent claims cover multiple inventive features related to bicistronic CAR amino acid constructs comprising first and second CARs linked through two or more cleavable domains, nucleic acids encoding these constructs, recombinant expression vectors, host cells, pharmaceutical compositions, and methods of treating cancer.
Bicistronic CAR amino acid construct linked through cleavable domains
The construct comprises two or more cleavable domains linking a first CAR with an antigen binding domain specific for CD22 (heavy chain variable region CDRs SEQ ID NOS: 4, 6, 8; light chain variable regions SEQ ID NOS: 12, 14, 16) or CD19 (light chain variable region CDRs SEQ ID NOS: 24, 26, 28; heavy chain variable region CDRs SEQ ID NOS: 32, 34, 36), enabling each CAR to be separately present on the cell surface with antigenic specificity upon cleavage.
Use of CD8 transmembrane and hinge domains in CAR construct
At least one of the first or second transmembrane domains includes a CD8 transmembrane domain (amino acid sequence IYIWAPLAGTCGVLLLSLVITLYC) and a CD8 hinge domain (amino acid sequences represented by SEQ ID NOs: 18, 86, or closely related variants).
Intracellular T cell signaling domains comprising 4-1BB and CD3 zeta sequences
The first or second intracellular T cell signaling domain comprises a 4-1BB intracellular T cell signaling sequence (SEQ ID NO: 20) and a CD3 zeta intracellular T cell signaling sequence (SEQ ID NO: 21).
Cleavable domains comprising 2A and/or furin cleavage sites
The bicistronic CAR incorporates two or more cleavable domains selected from 2A self-cleaving peptides and furin cleavage sequences to permit separation of the CARs after expression.
Nucleic acids, recombinant vectors, host cells, populations, and pharmaceutical compositions
Nucleic acids encoding the bicistronic CAR constructs as defined above, recombinant expression vectors containing the nucleic acids, isolated host cells comprising the vectors, cell populations, and pharmaceutical compositions comprising these materials are claimed for use in cancer treatment.
The claims encompass bicistronic CAR constructs with defined antigen binding domains targeting CD19 and CD22 linked by cleavable domains, supporting expression of separated CARs on T cell surfaces that elicit antigen-specific responses, alongside related genetic materials, cell hosts, compositions, and therapeutic methods for treating cancers, especially hematological malignancies.
Stated Advantages
Reduction or prevention of cancer cell escape due to loss of expression of a single antigen by simultaneously targeting CD19 and CD22.
Increased effectiveness in treating cancers with heterogeneous expression levels of CD19 or CD22.
Potential to treat a broader patient population by addressing relapsed cancers that lose one antigen.
Equal or substantially equal expression of each CAR in each T cell using cleavable CAR constructs, overcoming inefficiencies observed in co-transduction with separate vectors.
Synergistic immune responses from targeting both antigens compared to therapies targeting a single antigen, enhancing anti-cancer efficacy.
Documented Applications
Detection of the presence of cancer in mammals using the CAR constructs, nucleic acids, recombinant vectors, host cells, or pharmaceutical compositions.
Treatment or prevention of cancer in mammals, particularly hematological malignancies such as acute lymphocytic leukemia, B cell lymphoma, and related disorders characterized by CD19 and/or CD22 expression.
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