Preliminary Results from a Phase II Study of Lenalidomide Monotherapy in Relapsed/Refractory Aggressive Non-Hodgkin’s Lymphoma.

Background: Lenalidomide (Revlimid®), an immunomodulatory drug (IMiD®), was recently approved in the US for treatment of relapsed/refractory multiple myeloma and myelodysplastic syndromes associated with a deletion 5q[31] cytogenetic abnormality. Lenalidomide also has demonstrated activity in chronic lymphocytic leukemia and cutaneous T-cell lymphoma while thalidomide, a less potent IMiD®, has activity in non-Hodgkin’s lymphoma as both monotherapy and in combination with rituximab.

Aim: To assess the safety and activity of lenalidomide monotherapy in subjects with relapsed/refractory aggressive non-Hodgkin’s lymphoma (NHL).

Methods: Subjects with relapsed/refractory aggressive NHL following at least 1 prior treatment regimen with measurable disease are eligible. Subjects receive 25 mg lenalidomide orally once daily on Days 1–21 every 28 days and continue therapy for 52 weeks as tolerated or until disease progression. Response and progression are evaluated using the IWLRC methodology.

Results: As of July 25, 2006, 32 subjects of a planned 40 have enrolled and 31 have received drug. Twenty-two subjects are currently evaluable for tumor response. The median age of the 22 response-evaluable subjects is 65 (46–83) and 13 are female. Histology is diffuse large B-cell lymphoma [DLBCL] (n=12), follicular center lymphoma grade 3 [FL] (n=3), mantle cell lymphoma [MCL] (n=5) and transformed [TSF] (n=2). Median time from diagnosis to lenalidomide monotherapy is 2.3 (0.7–7) years and median number of prior treatment regimens per subject is 2 (1–6). Seven subjects (32%) exhibited an objective response (2 complete responses unconfirmed (CRu) and 5 partial responses (PR)), 6 had stable disease (SD) for a tumor control rate (TCR) of 59% and 9 progressive disease (PD). Responses were produced in each of the aggressive histologic subtypes studied: DLBCL (3/12), FL (1/3), MCL (2/5) and TSF (1/2). Five of 11 subjects (45%) with 1–2 prior treatment regimens had an objective response, as did 2 of 3 subjects (67%) who had received a prior stem cell transplant. Median time-to-response was 2 months. Grade 3 or 4 adverse events occurred in 18 of 31 (58%) subjects receiving drug. These were predominantly Grade 3 hematological events (neutropenia, thrombocytopenia) with only 4 subjects (13%) experiencing a Grade 4 adverse reaction.

Conclusion: Preliminary results indicate that lenalidomide monotherapy is active with manageable side effects in relapsed/refractory aggressive NHL.