High anti-lymphoma activity of bendamustine/mitoxantrone/rituximab in rituximab pretreated relapsed or refractory indolent lymphomas and mantle cell lymphomas. A multicenter phase II study of the German Low Grade Lymphoma Study Group (GLSG)

On the basis of a preceding phase I study, the current trial explored bendamustine in combination with mitoxantrone and rituximab (BMR) in patients with stage III/IV relapsed or refractory indolent lymphomas and mantle cell lymphoma (MCL) with or without prior rituximab containing chemo-immunotherapy (R-chemo) treatment. Therapy consisted of bendamustine 90 mg/m2 days 1 + 2, mitoxantrone 10 mg/m2 day 1, rituximab 375 mg/m2 day 8. Treatment was repeated on day 29 for a total of four cycles. Between 3 April and 04 July, 57 patients were recruited from 24 participating institutions, 39% of whom had received prior R-chemo therapy. Median age was 66 years (40 – 83). Lymphoma subtypes were 29 follicular (FL), 18 MCL, and 10 other indolent lymphomas. The overall response rate (ORR) was 89% with 35% CR and 54% PR. ORR in R-chemo pretreated patients was 76% (38% CR, 38% PR). After a median observation time of 27 months (1 – 43), the estimated median progression free survival is 19 months. The 2 year overall survival is 60% for patients with FL and MCL. Treatment related toxicities of grade 3/4 comprised a reversible myelosuppression (10% anemia, 78% leukocytopenia, 46% granulocytopenia, 16% thrombocytopenia). However, unexpected hospitalisations were necessary after 4% of BMR-application only. BMR is a very effective new outpatient immuno-chemotherapy with low toxicity for patients with relapsed/refractory FL, MCL and other indolent lymphomas.