Poseida Awarded $19.8M Grant to Continue Developing P-BCMA-101 for Multiple Myeloma

The California Institute for Regenerative Medicine (CIRM) awarded a $19.8 million grant to Poseida Therapeutics to support the clinical development of their P-BCMA-101 investigational immunotherapy for relapsed and refractory multiple myeloma.

P-BCMA-101 is undergoing testing in a Phase 1 clinical trial (NCT03288493) for multiple myeloma that is currently recruiting participants.

“Poseida is developing a promising next generation CAR-T cell therapy which includes many of the desirable attributes of emerging CAR-T cell therapies into a single treatment,” Maria Millan, MD, president and chief executive officer of CIRM, said in a press release. “CIRM is pleased to support Poseida in the development of this novel CAR-T therapy which represents a much-needed solution for multiple myeloma.”

P-BCMA-101 is a chimeric antigen receptor (CAR) T-cell therapy. This is a tailored approach to fight cancer in which researchers use a patient’s own T-cells, which are vital cells of the immune system. These cells are collected from the patient’s blood and taken to the lab, where they are engineered to express, at their surface, special receptors called CARs.

CARs allow T-cells to recognize a specific protein (antigen) that is highly produced by tumor cells. The re-engineered T-cells are then expanded in the lab into the billions and injected back into the patient, where they will attack tumor cells more efficiently.

P-BCMA-101 targets a specific antigen called B-cell maturation antigen (BCMA) that is expressed by all multiple myeloma cells. But unlike many other CAR T-cell therapies, P-BCMA-101 delivers the CAR gene to the T-cells using a non-viral gene delivery system. This system has a number of advantages, including the production of T-cells with stem cell memory, the selection of engineered cells, and safety.

Because P-BCMA-101 contains a high number of stem cell memory T-cells, patients have sustained responses and do not require additional infusions of the therapy, as shown in multiple preclinical studies.

In CAR T-cell therapies, only 5% to 30% of the reinfused T-cells were actually genetically modified. But with the positive selection tool included in Poseida’s gene delivery system, researchers can select only the modified cells, ensuring that their cell therapy is 100% pure. Also, P-BCMA-101’s safety is ensured by a backup mechanism — T-cells are rapidly shut down if significant side effects occur.

“We are honored that CIRM has recognized the promise of P-BCMA-101 as an immunotherapy for patients with multiple myeloma and is contributing to the advancement of this program in Phase 1 clinical development,” said Eric Ostertag, MD, PhD, Poseida’s chief executive officer. “P-BCMA-101 is elegantly designed with several key characteristics, including an exceptionally high concentration of stem cell memory T-cells which has the potential to significantly improve durability of response to treatment.”