Response and survival for primary therapy combination regimens and maintenance rituximab in Waldenstrom macroglobulinaemia

Waldenstrom macroglobulinaemia (WM) is a rare and incurable lymphoma. Comparative studies evaluating the efficacy of primary therapy in symptomatic WM patients have not been performed. In this study, we compared response and survival outcomes in WM patients who received primary therapy with cyclophosphamide-dexamethasone-rituximab (CDR), bortezomib-dexamethasone-rituximab (BDR) and bendamustine-rituximab (Benda-R), as well as maintenance rituximab following primary therapy. Analyses were adjusted for relevant clinical factors associated with response and survival. Maintenance rituximab was analysed as a time-varying covariate. Our study included 182 patients, of which 57 (31%) received Benda-R, 87 (48%) BDR and 38 (21%) CDR; 116 (64%) received maintenance rituximab. The median time to best response was shorter for Benda-R and BDR than CDR (18, 20 and 30 months, respectively). Benda-R and BDR were associated with better median progression-free survival (PFS) than CDR (5.5, 5.8 and 4.8 years, respectively), and better 10-year overall survival rates (OS; 95%, 96% and 81%, respectively). Maintenance rituximab was associated with higher rates of major response (97% vs. 68%), and better median PFS (6.8 years vs. 2.8 years) and 10-year OS rate (84% vs. 66%) when compared to not receiving maintenance. Benda-R, BDR and maintenance rituximab associate with higher response rates and longer survival in WM patients than CDR and no maintenance, respectively.