The chimeric antigen receptor T-cell therapy P-BCMA-101 appeared safe among patients with relapsed/refractory multiple myeloma, according to the agent’s manufacturer.
P-BCMA-101 (Poseida Therapeutics) — a stem cell memory chimeric antigen receptor (CAR) T-cell product — is designed to enhance a patient’s own T cells to safely and effectively eliminate tumor cells carrying B-cell maturation antigen, which is found on essentially all multiple myeloma tumor cells.
Poseida Therapeutics released data from 11 patients in the ongoing phase 1 trial of P-BCMA-101. The analysis included patients who underwent a median of six prior therapies. Median age was 60 years, with many patients (73%) considered high risk.
Overall the agent appeared safe, with one instance (9%) of suspected cytokine release syndrome that appeared minimal and short-lived.
Researchers observed no patients with neurotoxicity and no ICU admissions. No patients required treatment with tocilizumab (Actemra, Genentech) or steroids.
At the time of reporting, all 11 patients remained in the study, with seven of 10 having achieved at least a partial response using the International Myeloma Working Group criteria.
“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 [very good partial response] and even stringent [complete response] at early efficacy assessments,” Eric Ostertag, MD, PhD, CEO of Poseida Therapeutics, said in company-issued press release.
Researchers presented full results at the CAR-TCR Summit.
“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,” Ostertag said. “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.”