R-Bendamustine Vs R-CHOP As Initial Treatment for Advanced Stage Low Grade Follicular Lymphoma: A Matched-Pair Analysis

Introduction: In the randomized phase 3 clinical trial performed by the Study group indolent Lymphoma (STiL) in patients with indolent and mantle cell lymphoma, the complete response (CR) rates and progression-free survival (PFS) were superior with first-line bendamustine plus rituximab (BR) therapy compared with CHOP plus rituximab (R-CHOP) therapy. However, in a second randomized phase 3 clinical trial (the BRIGHT study) also performed in patients with indolent and mantle cell lymphoma, the CR rates were similar between BR and R-CHOP groups and PFS data has not been reported. In both trials, the toxicity profile was better for BR compared with R-CHOP. Here, we report the results of a matched-pair analysis of advanced stage low-grade follicular lymphoma patients treated with first-line BR or R-CHOP at MD Anderson Cancer Center, Houston, Texas.

Methods: We reviewed the medical records of all patients (n=74) with stage III or IV grade 1 or 2 follicular lymphoma treated at MD Anderson Cancer Center with first-line BR between January 2009 and December 2013. Each BR patient was paired with a grade 1 or 2 follicular lymphoma patient treated with first-line R-CHOP matched by age, gender, and stage. Patients with histological diagnosis of concurrent diffuse large B-cell lymphoma were excluded.

Results: There were no significant differences in most baseline patient characteristics including age, gender, stage, FLIPI 1 and FLIPI 2 risk groups, Ki-67 score, absolute monocyte count, and absolute lymphocyte count (p>0.05). However, more patients in R-CHOP group met GELF criteria compared with BR group (69% vs 47%, p=0.012). Also, more patients in R-CHOP group had SUVmax >10 on baseline FDG PET scan compared with BR group (74% vs 49%, p=0.011). Median number of chemotherapy cycles was 6 for both groups (range, 2-6 for BR and 4-8 for R-CHOP). The CR rates were comparable between the two groups (93% for BR and 91% for R-CHOP, p=0.142). The median follow-up was 24.4 months (range, 2.8-63.2 months) for BR patients and 68.1 months (range, 4.4-149.4 months) for R-CHOP patients. At 24 months, the PFS and overall survival (OS) were comparable between the two groups (PFS and OS of 85% and 94% for BR and 82% and 99% for R-CHOP; log rank p=0.654 for PFS and 0.158 for OS).

Conclusions: In this 1:1 matched pair analysis of advanced stage low-grade follicular lymphoma patients treated with first-line BR or R-CHOP, the CR rates, PFS and OS were comparable between the two therapies. However, longer follow-up is required for better comparison of PFS, OS, and long-term toxicities between the two regimens.