P-BCMA-101 gains FDA regenerative medicine designation


P-BCMA-101, an autologous chimeric antigen receptor (CAR) T-cell therapy being developed to treat patients with relapsed or refractory multiple myeloma (MM), has received the regenerative medicine advanced therapy (RMAT) designation from the Food and Drug Administration.

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P-BCMA-101 modifies patients’ T cells using a nonviral DNA modification system known as piggyBac. The modified T cells target cells expressing B-cell maturation antigen (BCMA), which is expressed on essentially all MM cells.

Early results from the phase 1 clinical trial of P-BCMA-101 were recently reported at the 2018 CAR-TCR Summit by Eric Ostertag, MD, PhD, chief executive officer of Poseida Therapeutics, the company developing P-BCMA-101.

Initial results of the trial (NCT03288493) included data on 11 patients with heavily pretreated MM. Patients were a median age of 60, and 73% were high risk. They had a median of six prior therapies.

Patients received conditioning treatment with fludarabine and cyclophosphamide for 3 days prior to receiving P-BCMA-101. They then received one of three doses of CAR T cells – 51×106 (n=3), 152×106 (n=7), or 430×106 (n=1).

The investigators observed no dose-limiting toxicities. Adverse events included neutropenia in eight patients and thrombocytopenia in five.

One patient may have had cytokine release syndrome, but the condition resolved without drug intervention. And investigators observed no neurotoxicity.

Seven of ten patients evaluable for response by International Myeloma Working Group criteria achieved at least a partial response, including very good partial responses and stringent complete response.

The eleventh patient has oligosecretory disease and was only evaluable by PET, which indicated a near-complete response.

Poseida expects to have additional data to report by the end of the year, according to Dr. Ostertag. The study is funded by the California Institute for Regenerative Medicine and Poseida Therapeutics.RMAT designation is intended to expedite development and review of regenerative medicines that are intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition.

Preliminary evidence must indicate that the therapy has the potential to address unmet medical needs for the disease or condition. RMAT designation includes all the benefits of fast track and breakthrough therapy designations, including early interactions with the FDA.

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