BCMA CAR-T bb2121 Appears to Be Safe and Effective in Multiple Myeloma

An investigational BCMA-directed chimeric antigen receptor (CAR) T-cell (CAR-T) therapy, bb2121, appeared safe and effective for previously treated patients with relapsed or refractory multiple myeloma in a phase 1 trial (ClinicalTrials.gov identifier: NCT02658929). The trial results were published May 2, 2019, in the New England Journal of Medicine.¹

The phase 1 trial, ran by Celgene in collaboration with bluebird bio, Inc., included 33 patients with relapsed or refractory multiple myeloma who had received at least 3 prior lines of therapy. Patients received lymphodepletion with fludarabine and cyclophosphamide followed by a single infusion of bb2121, a BCMA-targeted CAR-T therapy. During the dose-escalation phase, patients received 50×10⁶, 150×10⁶, 450×10⁶, or 800×10⁶ CAR-positive (CAR+) T cells; the expansion phase used 150×10⁶ to 450×10⁶ CAR+ T cells.

Adverse events occurred in all patients, with 97% (32 of 33 patients) having a grade 3 event or higher. Approximately three-quarters of patients (76%) had cytokine release syndrome: 70% had grade 1 or grade 2, and 6% had grade 3. Neurologic toxicity was observed in 42% of patients: 39% had grade 1 or grade 2, and 3% (1 patient) had a reversible grade 4 event.

Overall, 85% of patients (95% CI, 68.1-94.9) responded to BCMA CAR-T therapy, with 45% (15 patients) achieving complete responses. Among the 15 patients with complete responses, 6 have relapsed. Complete responses occurred across all infusion doses, and responses were associated with CAR-T cell expansion. Negative minimal residual disease was detected for all 16 patients for whom response was achieved and minimal residual disease was evaluable. Patients had a median progression-free survival of 11.8 months (95% CI, 6.2-17.8).

A phase 2 trial (KarMMa-2) is under way (ClinicalTrials.gov identifier: NCT03601078).²

References

1. Raje N, Berdeja J, Lin Y, et al. Anti-BCMA CAR T-cell therapy bb2121 in relapsed or refractory multiple myeloma. N Engl J Med. 2019;380(18):1726-1737.
2. NEJM publishes bb2121 Phase 1 data in patients with multiple myeloma [news release]. Summit, NJ, and Cambridge, MA: Celgene Corporation and bluebird bio, Inc.; May 2, 2019. Accessed May 8, 2019.