BDR in newly diagnosed patients with WM: final analysis of a phase 2 study after a minimum follow-up of 6 years.

In this phase 2 multicenter trial, we evaluated the efficacy of the combination of bortezomib, dexamethasone, and rituximab (BDR) in 59 previously untreated symptomatic patients with Waldenström macroglobulinemia (WM), most of which were of advanced age and with adverse prognostic factors. BDR consisted of a single 21-day cycle of bortezomib alone (1.3 mg/m2 IV on days 1, 4, 8, and 11), followed by weekly IV bortezomib (1.6 mg/m2 on days 1, 8, 15, and 22) for 4 additional 35-day cycles, with IV dexamethasone (40 mg) and IV rituximab (375 mg/m2) on cycles 2 and 5, for a total treatment duration of 23 weeks. On intent to treat, 85% responded (3% complete response, 7% very good partial response, 58% partial response). After a minimum follow-up of 6 years, median progression-free survival was 43 months and median duration of response for patients with at least partial response was 64.5 months. Overall survival at 7 years was 66%. No patient had developed secondary myelodysplasia, whereas transformation to high-grade lymphoma occurred in 3 patients who had received chemoimmunotherapy after BDR. Thus, BDR is a very active, fixed-duration, chemotherapy-free regimen, inducing durable responses and with a favorable long-term toxicity profile (www.ClinicalTrials.gov #NCT00981708).