B-cell numbers evaluated in patients (pivotal R2PD and cohort C) at baseline. Patients receiving prior anti-BCMA therapies at any point during treatment did not have lower B-cell numbers at baseline. These findings for patients in cohort C (n = 24) are similar to those observed for the pivotal RP2D population (anti-BCMA therapy–naive population; n = 76). RP2D, recommended phase 2 dose.