Safety and Efficacy of Bendamustine and Rituximab (BR) Regimen in Indian Chronic Lymphocytic Leukaemia Patients.

Abstract

We investigated the safety and efficacy of bendamustine-rituximab (BR) in previously untreated symptomatic and advanced CLL patients, as there is no data available on BR from the Indian subcontinent.This retrospective study included 120 consecutive treatment naïve patients with CLL without del (17p), who were registered at the Department of Medical Oncology, AIIMS between January 2010 and July 2018. Bendamustine was given at a dose of 90mg/m2 on days 1 and 2, combined with rituximab 375mg/m2 rituximab on day 1, every 28days for up to 6 courses. Event-free survival (EFS) was defined as the date of treatment to date of relapse, disease progression, or death due to any cause.The median age was 57years (range: 30-75years). As per the clinical Rai stage, 30 (25%) patients were in stage II, 42 (35%) were in stage III and 48 (40%) were in stage IV. ZAP70 was positive (> 20%) in 50%, CD 38 was positive (> 30%) in 33%, and CD49d was positive (> 30%) in 49% of cases. Beta-2 microglobulin (B2M) was elevated (≥ 3.5mg/L) in 80% of cases. Fifty-five cases (50%, n = 110) were IGHV mutated. The mean number of cycles was 5 (1-6). The overall response rate (ORR) seen with BR was 90% and complete response was 45%. Median progression-free survival was 24months with a median follow-up period of 29months. Haemoglobin (< 10g/dL), elevated B2 M, unmutated IGHV had a statistically significant adverse impact on EFS on univariate analysis but on multivariate analysis, only IGHV mutation status was found to had significance on EFS. The median EFS was 27months in IGHV mutated versus 18months in IGHV unmutated-CLL patients (p = 0.001). Grade 3/4 neutropenia, thrombocytopenia, anemia, and infections were observed in 30.6%, 8%, and 12% respectively. The most common non-hematological toxicity was skin rash which was grade 1/2 in 24 (20%) cases and grade 3/4 in 12 (10%) cases. This is the largest study from India to demonstrate the safety and efficacy of BR in symptomatic CLL patients. BR is an effective and safe regimen in the first-line treatment of CLL. Unmutated-CLL patients have inferior EFS than mutated-CLL patients. Skin toxicity was the most common adverse effect seen in our population which was observed in around one-third of cases.