Obinutuzumab (CD20) Induction+Maintenance Delivers 65% ORR in Relapsed Waldenström’s

Single-arm phase II (NCT03679455) tested obinutuzumab 1000 mg monotherapy (induction then q8wk maintenance ×2 yrs) in relapsed/refractory Waldenström macroglobulinaemia (n=23; median follow-up 3.8 yrs). Best overall response was 65% (higher when baseline IgM≥40 g/L: 75%); deep responses accrued on maintenance (VGPR+CR 30% at study end vs 4% post-induction). Estimated PFS and OS rates at last follow-up were 65% and 74%; grade≥3 AEs occurred in 65% (treatment-related 35%), dominated by neutropenia 58% and LFT elevations 17%—offering a time-limited, chemo-free option compared with continuous BTK inhibition, where ibrutinib monotherapy yields major responses ~70–80% and 4–5-yr PFS ~54–72%, while historical rituximab alone achieves ~50–60% responses with slower kinetics.