Bendamustine is effective in relapsed or refractory aggressive non-Hodgkin's lymphoma

Background: Bendamustine, an alkylating agent with a nitrogen mustard group and a purine-like benzimidazol group, has been shown to be effective in several solid tumors and indolent non-Hodgkin's lymphomas, but has not yet been studied for efficacy in aggressive lymphomas. Patients and methods: We conducted a phase II study in patients with relapsed or refractory high-grade non-Hodgkin's lymphomas, using bendamustine at a dose of 120 mg/m(2) on days 1 and 2, every 3 weeks for up to six cycles. Twenty-one patients were enrolled; 18 were evaluable for response and toxicity, 10 of whom were refractory to previous chemotherapy. Results: With three patients achieving a complete response (at 6, greater than or equal to8 and greater than or equal to22 months) and five a partial response (three at 2 months, one at 3 months and one at 10 months), the total response rate of the evaluable patients was 44% (eight out of 18; 38% of all patients). Two complete and two partial responders were refractory to prior treatment. In 10 patients, treatment had to be stopped after one to three cycles due to progressive disease or hematological toxicity (n=2). Non-hematological side effects were mild. Eight (13%0) WHO grade 3 and no grade 4 events were observed in 60 evaluable treatment cycles. Hematologic toxicity was moderate (grade 3 and 4): anemia in five cycles (8%), leukopenia in seven (12%) and thrombocytopenia in eight (13%). Conclusions: Bendamustine as a single agent is effective against aggressive lymphoma, even in cases of refractory disease. Further studies are warranted to determine the significance of bendamustine in the treatment of aggressive lymphomas.