P-BCMA-101 clinical data as well as preclinical data from MUC1C and PSMA solid tumor programs and BCMA allogeneic program presented at the CAR-TCR Summit
SAN DIEGO, Sept. 05, 2018 (GLOBE NEWSWIRE) -- Poseida Therapeutics Inc. ("Poseida"), a clinical-stage biotechnology company translating best-in-class gene engineering technologies into lifesaving cell therapies, announced data results from the first eleven patients treated in its ongoing Phase 1 study of its P-BCMA-101 stem cell memory chimeric antigen receptor T-cell (CAR-T) product in relapsed/refractory multiple myeloma. All eleven patients remain on study with seven of ten patients evaluable by International Myeloma Working Group (IMWG) criteria achieving at least a partial response. The remaining patient also demonstrated a robust response, but has oligosecretory disease and was only evaluable by PET. Importantly, unlike previous CAR-T therapies, P-BCMA-101 is demonstrating exceptional safety, with only one instance of suspected cytokine release syndrome (9%) that was minimal and short-lived. No patients demonstrated neurotoxicity and no patients required admission to an intensive care unit or treatment with tociluzimab or steroids, interventions typically required during episodes of CRS elicited by other CAR-T therapies. Enrollment continues in the higher dose cohorts.
"The latest data results show that P-BCMA-101 induces deep responses in a heavily pretreated population with relapsed/refractory multiple myeloma, with some patients reaching VGPR and even stringent CR at early efficacy assessments," said Eric Ostertag, M.D., Ph.D., chief executive officer of Poseida Therapeutics. "We believe our advantages of a purified product, where all cells express the CAR molecule, and a product with high levels of stem cell memory T cells, producing a more gradual and prolonged immune response against tumor cells, provide a significantly better therapeutic index when compared with other CAR-T therapeutics. We are also encouraged that P-BCMA-101 is demonstrating significant efficacy even at doses that have been ineffective for other anti-BCMA CAR-T therapies and that our response rates continue to improve as the dose increases."
P-BCMA-101 Clinical Data Presented as Late Breaker Today at CAR-TCR Summit
As of August 10th, 2018, eleven patients had been treated across three doses groups with average CAR-T cell doses of 51x106 (n=3), 152x106 (n=7), and 430x106 (n=1). These patients were heavily pretreated with a median of 6 prior therapies. The median age was 60, with 73% considered high-risk, including those with high-risk cytogenetics. Peak T-cell expansion was observed between days 14 and 21, which is more gradual than the 5-14 day peak expansion seen with other CAR-T therapies and was associated with less acute cytokine release and other adverse effects.
A favorable safety profile continues to be observed. The single instance of suspected cytokine release syndrome occurred in a patient in the second cohort and rapidly resolved without treatment with tociluzimab or steroids. Consistent with the minimal evidence of CRS symptoms, patients' biomarkers of CRS, including IL-6 levels, are demonstrating peak levels lower than those seen in patients from other anti-BCMA CAR-T trials. Common adverse events were neutropenia and thrombocytopenia, which are typical for CAR-T and myeloma studies considering the disease, preconditioning chemotherapy and prior chemotherapy regimens. No dose limiting toxicities were observed at any dose. Enrollment requirements have been achieved in the third dose cohort and enrollment is expected to continue into the fourth and fifth dose cohorts per protocol.
This open-label, multicenter, single-ascending dose, Phase 1 study is designed to assess the safety of P-BCMA-101 in up to 40 subjects with relapsed and/or refractory multiple myeloma. The primary objective of this study is to determine the safety and maximum-tolerated dose of P-BCMA-101. Secondary objectives include anti-myeloma effect of P-BCMA-101.This study is funded in part by the California Institute for Regenerative Medicine. Additional information about the Phase 1 clinical study of P-BCMA-101 is available at www.clinicaltrials.gov using identifier: NCT03288493
Preclinical Presentations at CAR-TCR Summit
A Stem Cell Memory CAR-T Therapy for Epithelial-Derived (MUC1-C) Solid Tumors
Manufacture of Allogeneic "Universal Donor" CAR-T Therapies using piggyBac™ and Cas-CLOVER™ Gene Editing Technologies
How Can We Create An Allogeneic, Virus Free Manufacturing Process?
PSMA-specific CAR-T Memory Stem Cell Therapy Eliminates Solid Tumors in Multiple Prostate Cancer Models
P-BCMA-101 is a CAR-T immunotherapy designed to supercharge a patient's own T cells to safely and effectively eliminate tumor cells carrying B cell maturation antigen (BCMA), which is expressed on essentially all multiple myeloma tumor cells. P-BCMA-101 modifies a patient's T cells using piggyBac™, which enables several desirable features, including:
About Poseida Therapeutics, Inc.
Poseida Therapeutics is a clinical-stage biotechnology company translating best-in-class gene engineering technologies into lifesaving cell therapies. The company is developing CAR T-cell immunotherapies for multiple myeloma, prostate and other cancer types, as well as gene therapies for orphan diseases. P-BCMA-101 is Poseida's lead CAR-T therapy currently in Phase 1 clinical development for the treatment of multiple myeloma. Poseida has assembled a suite of industry-leading gene engineering technologies, including the piggyBac™ DNA Modification System, TAL-CLOVER™ and Cas-CLOVER™ site-specific nucleases, and Footprint-Free™ Gene Editing (FFGE). For more information, visit www.poseida.com.
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