bb2121 anti-BCMA CAR T-cell therapy in patients with relapsed/refractory multiple myeloma: Updated results from a multicenter phase I study.

8007Background: bb2121 is a second-generation chimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA) to redirect T cells to recognize and kill malignant myeloma cells. Initial data from the dose-escalation (DE) phase of CRB-401, a first-in-human study of bb2121 in relapsed/refractory multiple myeloma (RRMM), have shown promising efficacy and safety. We report updated safety and efficacy results on 43 patients (pts) enrolled in this ongoing study. Methods: CRB-401 (NCT02658929) is a 2-part, phase I study of bb2121 in pts with RRMM. DE pts had received ≥ 3 prior lines of therapy including a proteasome inhibitor and an immunomodulatory agent, or were double refractory, and had ≥ 50% BCMA expression on plasma cells. In the dose-expansion (Exp) phase, pts had to have received daratumumab and been refractory to last line of therapy; no BCMA expression was required. Following lymphodepletion with Flu (30 mg/m2)/Cy (300 mg/m2) given daily for 3 days, pts received 1 infusion of b...