Cevostamab (FcRH5×CD3 bispecific) + pom-dex drives ~86–88% ORR and high MRD-negativity in BCMA-naïve RRMM

Cevostamab is an FcRH5×CD3 T-cell–engaging bispecific antibody; here it was combined with pomalidomide (IMiD) plus dexamethasone to augment T-cell activity in the Phase Ib CAMMA 1 Arm B randomized dose-expansion (NCT04910568) in relapsed/refractory multiple myeloma (RRMM) after ≥1 IMiD and ≥1 proteasome inhibitor. As of September 6, 2025, BCMA-therapy–naïve patients (70 mg: n=29; 105 mg: n=25; median 2 prior lines; ~68–72% refractory to last line) achieved ORR 86.2% vs 88.0% and ≥VGPR 72.4% vs 76.0%, with ≥6-month DoR in 96.0% vs 90.9% and ongoing responses in 80.0% vs 81.8% at cutoff; soluble BCMA fell quickly (median −54.9% after first target dose, −83.0% by C1D15, −90.9% by C2D1) with no clear dose-dependent kinetic differences. Among CR+ patients evaluable for MRD (n=23), best MRD-negativity was 18/23 at 10⁻⁶ plus 3/23 at 10⁻⁵, and the CR+ MRD-negativity rate at 10⁻⁵ was similar for 70 mg vs 105 mg (90.9% vs 91.7%); importantly, this abstract does not provide detailed Grade ≥3 AE/CRS/ICANS rates, so tolerability vs other T-cell engagers can’t be judged here. By external benchmark, pom-dex alone in RRMM is typically ~31–33% ORR with median PFS ~4–5 months in later-line registrational-era studies, so the response depth/rate here looks well above what Pd delivers by itself (noting cross-trial limitations and that CAMMA 1 patients had a median of only 2 prior lines).