Multicenter Phase II Study of Bendamustine Plus Rituximab in Patients With Relapsed or Refractory Diffuse Large B-Cell Lymphoma

PURPOSE: Effective and less aggressive therapies are required for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) who are not eligible for or have undergone autologous stem-cell transplantation (ASCT). The present phase II study assessed the efficacy and safety of bendamustine plus rituximab (BR) in this population. PATIENTS AND METHODS: Patients with relapsed or refractory DLBCL treated with one to three prior chemotherapy regimens received rituximab 375 mg/m(2) intravenous (IV) infusion on day 1 and bendamustine 120 mg/m(2) by IV infusion on days 2 and 3 of each 21-day cycle for up to six cycles. The primary end point was overall response rate (ORR), and the secondary end points were complete response (CR) rate, progression-free survival (PFS), and safety. RESULTS: Sixty-three patients were enrolled, and 59 received BR. The median age was 67 years (range, 36 to 75 years), and 62.7% of patients were 65 years of age or older. Fifty-seven patients (96.6%) were previously treated with rituximab-containing chemotherapy. The ORR was 62.7% (95% CI, 49.1% to 75.0%), with a CR rate of 37.3% (95% CI, 25.0% to 50.9%). The ORRs were comparable between patients ≥ 65 years of age and less than 65 years (62.2% and 63.6%, respectively). The median PFS was 6.7 months (95% CI, 3.6 to 13.7 months). The most frequently observed grade 3 or 4 adverse events were hematologic: lymphopenia (78.0%), neutropenia (76.3%), leukopenia (72.9%), CD4 lymphopenia (66.1%), and thrombocytopenia (22.0%). CONCLUSION: BR is a promising salvage regimen for patients with relapsed or refractory DLBCL after rituximab-containing chemotherapy, warranting further investigation.