Poseida Provides Update on Phase 1 Study of P-BCMA-101 CAR-T Stem Cell Memory Product in Patients with Relapsed/Refractory Multiple Myeloma

SAN DIEGO – September 5, 2018 – 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.