FDA Grants Poseida’s P-BCMA-101 RMAT Status for Treatment of Multiple Myeloma

The U.S. Food and Drug Administration (FDA) has granted P-BCMA-101, Poseida Therapeutics’ CAR T-cell therapy and lead product candidate, the Regenerative Medicine Advanced Therapy (RMAT) designation for the treatment of relapsed or refractory multiple myeloma.

Preliminary results from a Phase 1 trial (NCT03288493) suggest the candidate is safe and may have superior effectiveness compared with other CAR T-cell therapies.

The RMAT designation is granted to regenerative therapies intended to treat, modify, reverse, or cure a serious condition, and for which preliminary clinical data evidences the therapy’s potential to address unmet medical needs for a condition.

The statute grants all the benefits of a Fast Track and Breakthrough Therapy designation, including early interactions with sponsors and the FDA, which may be used to discuss intermediate or surrogate clinical trial endpoints and support accelerated approval of the therapy.

P-BCMA-101 is designed to target the B cell maturation antigen (BCMA), a protein highly expressed at the surface of virtually all multiple myeloma cells.

The therapy is based on the patient’s own T-cells, which are taken from the blood and genetically engineered to recognize BCMA and destroy cells producing this factor.

The patient’s T-cells are genetically modified through a molecular system owned by Poseida called piggyBac. This approach has the benefit of being virus-free and allowing the production of a highly pure population of stem cell memory T cells — proliferative cells capable of sustaining the therapy’s effect after its administration.

The high purity of P-BCMA-101 may reduce its toxicity compared with other CAR-T approaches, Poseida states. Also, P-BCMA-101 contains a “switch” so that the therapy can be rapidly reduced or eliminated in case of dangerous side effects.

The safety, dose tolerability and cancer response to the therapy is being tested in a Phase 1 clinical trial (NCT03288493) in patients with multiple myeloma whose cancer has returned after treatment (relapsed) or failed to respond to prior therapies (refractory).

 Preliminary results from the study suggest that P-BCMA-101 may lead to superior response rates compared to other CAR-T therapies at similar doses, while presenting a positive safety profile.  

“P-BCMA-101 is the first anti-BCMA CAR-T therapy to receive RMAT designation from the FDA and underscores the urgent need for new treatment options for multiple myeloma,” Eric Ostertag, MD, PhD, chief executive officer of Poseida Therapeutics, said in a press release.

He added that “initial Phase 1 data presented at the CAR-TCR Summit earlier this year included encouraging response rates and safety data, including meaningful responses in a heavily pretreated population, with some patients reaching VGPR [very good partial response] and stringent CR [complete response].”

Updated results on the trial are expected by the end of 2018, said Ostertag, who added that Poseida is looking forward to working with the FDA to speed development of P-BCMA-101.