Rituximab therapy in Waldenstrom's macroglobulinemia: Preliminary evidenceof clinical activity

To assess the preliminary efficacy of rituximab therapy in Waldenstrom's ma croglobulinemia (WM), we examined the clinical and laboratory data for all patients with WM treated on IDEC Pharmaceuticals sponsored trials and one p atient treated at Walter Reed Army Medical Center. Seven symptomatic patien ts with WM were treated with four (n = 6) or eight (n = 1) weekly infusions of rituximab (375 mg/m(2)). Patients had received a median of three prior therapies (range 1-4) which included alkylator therapy in all (five patient s refractory) and fludarabine in four (all refractory). Therapy was tolerat ed well in all patients without decrement in cellular immune function or si gnificant infectious morbidity. Partial responses were noted in three of th ese patients, including two with fludarabine-refractory disease. The median progression-free survival for these patients was 6.6 months (range 2.2-29 months). These data suggest that rituximab has clinical activity in heavil y pre-treated patients with Waldenstrom's macroglobulinemia. Based on these data, clinical studies of Rituximab in previously untreated and treated WM appear indicated.