Efficacy and safety of bendamustine (BDM) in patients (pts) with mantle cell lymphoma (MCL).

Abstract

e18562 Background: BDM is approved in the United States for relapsed indolent lymphoma. However, the prospective study establishing the BDM monotherapy indication did not include any MCL pts (Friedberg, JCO 2008). Another study of rituximab plus BDM for relapsed indolent lymphomas included only 12 MCL pts (Robinson, JCO 2008). Herein we report our experience with BDM specifically in MCL pts. Methods: We retrospectively reviewed the records of all MCL pts who were treated with BDM at 3 centers. Demographic, clinical, toxicity, response and survival data were collected. The primary endpoint was overall response rate (ORR) and secondary endpoints were overall survival (OS), event-free survival (EFS) and safety. Results: Between 11/2008 and 12/2010, 21 MCL pts received BDM, 4 as frontline treatment and 16 for relapsed disease. The median age was 57 years (range 42-86) and 95% had stage IV disease. The most common regimen was rituximab 375mg/m2 on day 1 and BDM 100mg/m2 on days 1 and 2, every 28 days. A median of 5 cycles were given per patient (range 1-6). There were 10 complete responses (CR) and 6 partial responses (PR) with an ORR of 76% (95%CI 58-94%). After a median follow-up of 5.7 months (range 0.3 – 24 months), the median EFS and OS were not reached. The Kaplan-Meier estimated 2-year EFS and OS was 63% (95%CI 48-77%) and 72% (95%CI 60-85%) respectively. Grade 3 or 4 neutropenia, anemia, thrombocytopenia and neutropenic fever occurred in 29%, 5%, 24% and 10% respectively. Severe non-hematological toxicities included one case of herpes zoster during therapy and one case of progressive multifocal leukoencephalopathy (PML) occurring 10 months after completion of therapy. Conclusions: BDM in combination with rituximab had a high response rate, with 48% CR’s, in this study of predominantly relapsed/refractory MCL pts. The hematological toxicities were expected and manageable. There was one case of PML, which has not previously been described with BDM, but this patient was also treated with rituximab which is associated with PML. BDM appears to be a good salvage agent for MCL.