Results of a phase II study of lenalidomide and rituximab for refractory/relapsed chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is an incurable disease in need of new therapeutic strategies. The immunomodulatory agent, lenalidomide, has shown activity as salvage therapy for CLL. In this phase II trial, we combined lenalidomide with rituximab in 25 patients (range, 41–79) with refractory/relapsed CLL. Lenalidomide was administered orally on escalating doses, with cycle 1 doses of 2.5 mg daily on days 1–7, 5 mg on days 8–14, and 10 mg on days 15–21 followed by 7 days off. On cycle 2 and beyond, lenalidomide was administered at 20 mg daily on days 1–21. Rituximab was administered at 375 mg/m 2 intravenously on a weekly basis for the first cycle starting on day 15 for 4 doses, with each cycle being 28 days. Treatment was continued until disease progression or toxicity. Overall response rate was 45.8% on intent-to-treat and 61.1% in evaluable patients (all partial responses). Median time to treatment failure was 14.3 months for evaluable patients, and median overall survival was not reached. The most common grade 3/4 toxicity was neutropenia (72% of patients). The most common nonhematologic toxicity was infection (29% of patients). Lenalidomide combined with rituximab showed activity in heavily treated refractory CLL with an acceptable toxicity profile. [ABSTRACT FROM AUTHOR]