Lenalidomide Monotherapy in Relapsed or Refractory Aggressive Non-Hodgkin's Lymphoma

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 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. 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%). Oral lenalidomide monotherapy is active in relapsed or refractory aggressive NHL, with manageable side effects.