Bendamustine Mitoxantrone and Rituximab (BMR): A New Effective Regimen for Refractory or Relapsed Indolent Lymphomas

Abstract

Bendamustine (B) and mitoxantrone (M) have been shown to be potent cytotoxic drugs for the treatment of relapsed or refractory indolent lymphomas. The anti-CD20 monoclonal antibody rituximab (R) has produced an overall response rate (ORR) of 50% as a single agent in relapsed or refractory indolent lymphomas. We posed the question whether a combination of the above agents (BMR) could improve these results. This study was an open label, single center pilot study for patients with relapsed or refractory, CD20-positive (indolent) lymphoma or chronic lymphocytic leukaemia. The therapy consisted of bendamustine (80 mg/m 2, day 1-3), mitoxantrone (10 mg/m 2, day 1), rituximab (375 mg/m 2, week 2-5). BM was repeated on day 36 or when the haematological parameters had recovered. The maximum therapy consisted of one BMR-cycle, followed by five BM courses. Treatment was stopped when the disease responded with PR/CR. During March 1999 and December 2000, 20 patients received the BMR-regimen (four secondary high grade lymphoma, 12 indolent lymphoma, four B-CLL). The median age of the patients was 67 years (range 36-82) and their performance status ranged from 0 to 3. Median number of previous treatment regimens was two (1-6). Of the lymphoma patients, 14 had stage IV disease, 1 stage III and 1 stage II. B-CLL patients were all Rai stage IV (Binet C). Overall response rate was 95% (19/20) with seven patients achieving a CR(35%) and 12 patients achieving a PR (60%). Median time to progression is 7 months (1-21) with a median observation time of 7 months (1-21). Response is still durable in 15/20 patients (75%) (1+ to 21+ months after therapy). Symptomatic, reversible grade three or four haematotoxicity occurred in 4/20 patients (20%). Non-symptomatic grade three or four haematotoxicity was seen in 9/20 patients (45%). No major non-haematological toxicity was observed. In conclusion, BMR is a well tolerated, very effective outpatient regimen of treatment for relapsed and refractory indolent lymphoid malignancies.