Compositions and methods for treating cancer with anti-CD123 immunotherapy
Inventors
Orentas, Rimas J. • Schneider, Dina • Dropulic , Boro • Dimitrov, Dimiter S. • Zhu, Zhongyu
Assignees
Lentigen Technology Inc • US Department of Health and Human Services
Publication Number
US-12037403-B2
Publication Date
2024-07-16
Expiration Date
2039-09-20
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Abstract
Chimeric antigen receptors containing CD123 antigen binding domains are disclosed. Nucleic acids, recombinant expression vectors, host cells, antigen binding fragments, and pharmaceutical compositions, relating to the chimeric antigen receptors are also disclosed. Methods of treating or preventing cancer in a subject, and methods of making chimeric antigen receptor T cells are also disclosed.
Core Innovation
The invention provides chimeric antigen receptors (CARs) containing CD123 antigen binding domains, which include novel human single chain variable fragment (hScFv) sequences distinct from murine-derived ScFvs previously used. These CARs exhibit high surface expression on transduced T cells, high cytolytic activity, and superior in vivo T cell expansion and persistence. Methods of making CAR T cells using nucleic acids encoding the CARs, comprising linked modules including an extracellular CD123 antigen binding domain, a transmembrane domain, and intracellular signaling domain(s), are also disclosed, along with therapeutic methods employing these CARs for treating or preventing cancer in a subject.
The background identifies the problem that cancers, including acute myeloid leukemia (AML) and related CD123+ malignancies, are challenging to treat effectively with existing therapies, due to toxicity, relapse, and limited survival improvements. Chemotherapy is associated with high toxicity and may fail to eliminate minimal residual disease (MRD), leading to relapse. Bone marrow transplantation eligibility is limited by tumor burden and MRD presence. Moreover, prior CAR therapies targeting CD123 often use murine-derived ScFvs, which pose immunogenicity risks resulting in CAR T cell elimination and dangerous allergic reactions. Hence, there is an urgent need for improved, safe, and effective immunotherapies targeting CD123 to overcome these limitations.
The invention addresses this need by providing fully human CD123 antigen binding domains incorporated into CAR constructs, thereby reducing immunogenicity and improving persistence and efficacy of CAR T cells against CD123+ malignancies. The CARs include design features such as CD8 hinge and transmembrane domains linked to co-stimulatory (e.g., 4-1BB) and CD3 zeta intracellular signaling domains, ensuring effective T cell activation. The disclosure includes the sequences of specific CD123-binding ScFvs, nucleic acids encoding CARs, vectors, and methods of transducing T cells. The CAR T cells generated exhibit potent and target-specific cytotoxic activity against CD123+ AML cell lines, strong cytokine secretion upon antigen engagement, and reduced cytokine release in the absence of tumor antigen, suggesting improved safety.
Claims Coverage
The patent includes multiple independent claims directed to isolated nucleic acid molecules encoding CARs with CD123 antigen binding domains, vectors comprising such nucleic acids, isolated cells and methods employing these vectors, and pharmaceutical compositions containing CAR-expressing T cells for cancer treatment.
Isolated nucleic acid encoding CD123-specific CARs
Nucleic acid molecules encode chimeric antigen receptors comprising at least one extracellular CD123 antigen binding domain. The nucleic acid sequences specifically include SEQ ID NOs: 3, 5, 9, 11, 19, 21, 25, 71, or 73.
CAR comprising encoded amino acid sequences with CD123 specificity
The CARs comprise amino acid sequences encoded by the nucleic acids corresponding to SEQ ID NOs: 4, 6, 10, 12, 20, 22, 26, 72, or 74, which include human CD123-specific antigen binding domains.
Vectors comprising nucleic acids encoding CD123 CARs
Expression vectors include nucleic acids encoding the CARs, capable of being DNA, RNA, plasmid, cosmid, herpes virus, measles virus, lentivirus, adenoviral, or retrovirus vectors.
Isolated cells containing vectors encoding CD123 CARs
Isolated cells, including T cells, comprising the above vectors that encode CARs targeting CD123.
Methods of making CAR-expressing cells
Methods of producing CAR-expressing T cells by transducing isolated T cells with vectors encoding the CD123-targeting CARs.
Pharmaceutical compositions with CAR-expressing T cells
Compositions comprising anti-tumor effective amounts of human T cells expressing the CD123-specific CARs encoded by nucleic acids of SEQ ID NOs: 3, 5, 9, 11, 19, 21, 25, 71, or 73, designed for treating cancers in humans.
The independent claims cover the isolated nucleic acid molecules encoding fully human CD123-binding CARs, vectors for their delivery, engineered cells expressing the CARs, methods of making such cells, and pharmaceutical compositions comprising these cells for cancer treatment, highlighting the humanized antigen binding domain sequences as core inventive features ensuring enhanced specificity, efficacy and safety.
Stated Advantages
Reduced immunogenicity compared to murine-derived ScFv CAR T cells, thereby preventing anti-CAR immune responses and CAR T cell elimination.
High surface expression on transduced T cells leading to potent and target-specific cytolytic activity against CD123-positive tumor cells.
Increased in vivo expansion and persistence of CAR-expressing T cells, which improves treatment longevity and efficacy.
Ability to tune CAR affinity allowing optimization between tumor specificity and reduced on-target off-tumor toxicity, potentially enhancing safety.
Potential to eliminate minimal residual disease more efficiently than chemotherapy, improving long-term treatment prognosis.
CAR T cells can be used as tumor debulking agents as a bridge to bone marrow transplant for patients with high tumor burden.
Documented Applications
Treatment or prevention of cancers associated with CD123 expression, including acute myeloid leukemia (AML), blastic plasmacytoid dendritic cell neoplasm (PBDCN), and other hematological malignancies.
Treatment of refractory cancers non-responsive to chemotherapy including leukemia, lymphoma, multiple myeloma, and various solid tumors such as lung, breast, ovarian, prostate, colon cancer, melanoma, and pediatric tumors.
Use of CAR T cells for immunotherapy to achieve specific anti-tumor effects with reduced toxicity.
Method of diagnosing diseases or conditions associated with CD123 expression using human anti-CD123 antibodies or fragments.
Application as cellular immunotherapy to generate persisting populations of genetically engineered T cells for at least one month or longer post administration.
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