Clinical efficacy of lenalidomide in patients with relapsed or refractory chronic lymphocytic leukemia: Results of a phase II study

Purpose Patients with relapsed or refractory chronic lymphocytic leukemia (CLL) have profound immune defects and limited treatment options. Given the dramatic activity of lenalidomide in other B-cell malignancies and its pleotropic immunomodulatory effects, we conducted a phase 11 trial of this agent in CLL. Patients and Methods Patients with relapsed or refractory B-cell CLL (B-CLL) were eligible if they required treatment as per the National Cancer Institute Working Group 1996 guidelines. Lenalidomide was administered orally at 25 mg on days 1 through 21 of a 28-day cycle. Response was assessed after each cycle. Patients were to continue treatment until disease progression, unacceptable toxicity, or complete remission. Rituximab was added to lenalidomide on disease progression. Results Forty-five patients were enrolled, with a median age of 64 years. Sixty-four percent of the patients had Rai stage III or IV disease, and 51 % were refractory to fludarabine. The overall response rate was 47%, with 9% of the patients attaining a complete remission. Fatigue, thrombocytopenia, and neutropenia were the most common adverse effects noted in 83%, 78%, and 78% of the patients, respectively. Conclusion Lenalidomide is clinically active in patients with relapsed or refractory B-CLL. These findings are encouraging and warrant further investigation of this agent in the treatment of this disorder.