NEW YORK – Bellicum Pharmaceuticals on Wednesday said it will discontinue two ongoing Phase I/II trials of its GoCAR-T products BPX-601 and BPX-603 with rimiducid following serious immune-related adverse events including cytokine release syndrome in a prostate cancer patient.
BPX-601 is made by modifying patients' T cells to recognize and target the prostate stem cell antigen (PSCA). In the BPX-601 clinical trial, investigators are evaluating safety and activity of the therapy in patients with previously treated prostate cancers expressing high levels of PSCA. The first phase of the trial is a dose escalation study, in which patients receive an infusion of the CAR T cells followed by intravenous infusions of rimiducid. The grade four adverse event was the second dose-limiting toxicity in that patient cohort during dose escalation.
Although five out of nine patients in the BPX-601 trial had a pSA50 response to treatment, and four had a PSA90 response, indicating clinically meaningful efficacy, Bellicum does not have the resources to optimize the clinical dose and schedule of the combined therapies or the design of the BPX-601 construct to achieve a favorable risk/benefit profile.
As such, it has decided to stop not only the BPX-601 trial, but also another similarly designed trial of its HER-specific CAR T-product BPX-603 with rimiducid in patients with HER2-positive solid tumors. Bellicum is evaluating its strategic alternatives and communicating with regulatory agencies about the decision to discontinue the trials.