Relapsed/refractory WAldenström macroglobulinemia patients treated by VEnetoclax with or without anti-CD20 antibody: WAVE a retrospective study of the French CLL/WM group (FILO)

Abstract Recently venetoclax (Ven) monotherapy showed promising efficacy for relapsed/refractory (R/R) Waldenström macroglobulinemia (WM), a population with significant medical unmet need. We report the efficacy and safety of Ven associated or not with anti-CD20 therapy, in a real-word cohort of 46 patients with R/R WM treated at 17 French hospitals. The median number of prior lines of treatment was 3, including BTK inhibitor in 89%. Twenty-five patients (54%) received a combination of Ven + anti-CD20. At the time of best response, patients treated with Ven + anti-CD20 had a deep response rate (VGPR + uncertain CR) of 56% vs. 24% with Ven monotherapy ( p = 0.03). Anti-CD20 was the only factor associated with deep response rate in multivariate analysis (hazard ratio 4.07, p = 0.03). The 2-year PFS was 78% (95% CI, 54–90) for patients treated with Ven + anti-CD20 vs. 54% (95% CI, 27–74) with Ven monotherapy ( p = 0.25). AEs of grade ≥ 3 occurred in 17 patients (68%) with Ven + anti-CD20, vs. 7 patients (33%) with Ven ( p = 0.02), including 3 febrile aplasia ( p = 0.24). This is the first report of Ven +/- anti-CD20 in R/R WM, a strategy associated with deep responses and promising PFS, warranting further evaluation in prospective studies.