Bendamustine + Rituximab (BR) Chemoimmunotherapy and Maintenance Lenalidomide in Relapsed/Refractory (R/R) Chronic Lymphocytic Leukemia (CLL) and Small Lymphocytic Lymphoma (SLL): A Wisconsin Oncology Network (WON) Study

Abstract 3647 Introduction: BR chemoimmunotherapy was shown to have an overall response rate (ORR) of 59%, a median progression-free survival (PFS) of 14.7 months, and an acceptable toxicity profile in R/R CLL (Fischer K, et al. J Clin Oncol 2011). Given the single-agent activity of lenalidomide in R/R CLL/SLL, we hypothesized that maintenance lenalidomide after BR induction could improve PFS. Methods: Thirty-four patients requiring therapy for R/R CLL/SLL were treated with bendamustine 90 mg/m2 IV on days 1 & 2 and rituximab 375 mg/m2 IV on day 1 every 28 days for a maximum of 6 cycles. Growth factor support was permitted. Patients achieving at least a minor response (objective improvement even if not meeting criteria for partial response) were eligible to proceed with 12 cycles of maintenance therapy with lenalidomide 5–10 mg/day orally given continuously in each 28-day cycle. Patients were eligible if they had histologically proven CLL/SLL and had received >1 but ≤5 prior cytotoxic chemotherapy regimens (retreatment with an identical regimen was not counted as a separate treatment). The primary endpoint was PFS. Results: Baseline characteristics include median age 67 (range 38–86), 25 men/9 women, 26 CLL/8 SLL, and median of 2 prior therapies (range 1–4). Cytogenetic profiling by FISH analysis was available in 22 patients (65%), with 11/22 demonstrating presence of 17p and/or 11q deletions. Twenty-five patients (74%) completed 6 cycles of induction BR. Two patients died from toxicities of pneumonia and heart failure during cycle 1; 7 patients received Conclusions: In our multicenter trial for patients with R/R CLL/SLL, the BR induction produced an ORR that is comparable to historical observations (65% vs 59%). However, the median PFS is longer (24.3 vs 14.7 months), suggesting maintenance lenalidomide may be contributing to an improved response duration. Based upon these promising results, we have initiated a successor study in which patients will receive lenalidomide plus rituximab maintenance after a BR induction. Disclosures: Chang: Celgene: Research Funding; Genentech: Research Funding. Off Label Use: Lenalidomide as maintenance therapy for CLL after induction rituximab + bendamustine chemoimmunotherapy. Fenske:Spectrum Pharmaceuticals: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Kahl:Millennium: Consultancy, Research Funding; Roche: Consultancy; Genentech: Consultancy, Research Funding.