Lenalidomide monotherapy in relapsed or refractory aggressive non-Hodgkin's lymphoma

Purpose: The major cause of death in aggressive lymphoma is relapse or nonresponse to initial therapy. Lenalidomide has activity in a variety of hematologic malignancies, including non-Hodgkin's lymphoma (NHL). We report the results of a phase II, single-arm, multicenter trial evaluating the safety and efficacy of lenalidomide oral monotherapy in patients with relapsed or refractory aggressive NHL. Patients and Methods: Patients were treated with oral lenalidomide 25 mg once daily on days 1 to 21, every 28 days, for 52 weeks, until disease progression or intolerance. The primary end point was response; secondary end points included duration of response, progression-free survival (PFS), and safety. Results: Forty-nine patients with a median age of 65 years received lenalidomide in this study. The most common histology was diffuse large B-cell lymphoma (53%), and patients had received a median of four prior treatment regimens for NHL. An objective response rate of 35% was observed in 49 treated patients, including a 12% rate of complete response/unconfirmed complete response. Responses were observed in each aggressive histologic subtype tested (diffuse large B-cell, follicular center grade 3, mantle cell, and transformed lymphomas). Of patients with stable disease or partial response at first assessment, 25% improved with continued treatment. Estimated median duration of response was 6.2 months, and median PFS was 4.0 months. The most common grade 4 adverse events were neutropenia (8.2%) and thrombocytopenia (8.2%); the most common grade 3 adverse events were neutropenia (24.5%), leukopenia (14.3%), and thrombocytopenia (12.2%). Conclusion: Oral lenalidomide monotherapy is active in relapsed or refractory aggressive NHL, with manageable side effects.