GPRC5D-Directed CAR T-Cell Therapy BMS-986393 Shows Potential for R/R MM
The dose-escalation, first-in-human study of BMS-986393 enrolled patients with R/RMM who had three or more prior lines of therapy. Patients received BMS-986393 at doses of 25 (six patients), 75 (nine patients), 150 (12 patients), 300 (six patients), and 450 (three patients) x 106 CAR T cells. During the dose expansion portion, 12 additional patients received 150 x 106 CAR T cells; 11 patients received 300 x 106 CAR T cells; and eight patients received 450 x 106 CAR T cells.
The majority (83.6%) of patients had grade 3-4 treatment-emergent adverse events, most commonly neutropenia (59.7%), anemia (31.3%), and thrombocytopenia (29.9%). Risk for high-grade infection was only about 15%, Dr. Bal noted. No deaths from infection occurred.
Cytokine release syndrome (CRS) of any grade occurred in 86.6% of patients. One patient had grade 5 CRS related to the study drug, and this occurred at the highest dose level.
On-target, off-tumor adverse events included any-grade skin adverse events (20.9%), dysgeusia (17.9%), nail events (9.0%), and dysphagia (1.5%). Immune effector cell-associated neurotoxicity syndrome (ICANS)-type neurotoxicity was infrequent, with a total incidence of 10.4%. Non-ICANS neurotoxicity appeared to be dose related, was mostly low grade, and showed signs of reversibility in some patients, Dr. Bal said.
The overall response (OR) rate was 86.5% in the 52 efficacy evaluable patients. The complete response (CR) rate was 38.5%, with responses occurring at all dose levels. In patients with prior BCMA-directed therapy exposure (25 patients), including CAR T cells, the OR rate was 76.0% with CR occurring in 36.0% of the patients.
All six patients who were efficacy and measurable residual disease (MRD) evaluable and had CR or better were MRD-negative at month three.