A Phase 1 trial of RD118, a novel fully human anti-GPRC5D CAR T-cell therapy, showed strong and durable responses in heavily pretreated patients with relapsed or refractory multiple myeloma. The study enrolled 18 patients, many with high-risk disease, including prior BCMA CAR T failure.
With a median follow-up of 17 months, the overall response rate reached 94.4%, while 72.2% achieved complete or stringent complete responses. Among patients previously treated with BCMA CAR T therapy, the response rate was 85.7%. All CAR T-naive patients responded. Patients with extramedullary disease and one patient with plasma cell leukemia also achieved ongoing stringent complete responses.
Median progression-free survival was 18.2 months, and the 12-month overall survival rate reached 93.3%.
Side effects were mostly manageable. Cytokine release syndrome was common but usually mild, and no cerebellar toxicities or treatment-related deaths were reported.