Early Results from a Phase II Study of Lenalidomide Monotherapy in Relapsed/Refractory Indolent 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 (NHL) as both monotherapy and in combination with rituximab.

Aim: To assess the safety and efficacy of lenalidomide monotherapy in subjects with relapsed/refractory indolent NHL.

Methods: Subjects with relapsed/refractory indolent 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, 23 subjects of a planned 40 have enrolled and received drug. Fifteen subjects are currently evaluable for tumor response. The median age of the 15 response-evaluable subjects is 64 (54–82) and 5 are female. Histology is small lymphocytic lymphoma [SLL] (n=8), follicular center lymphoma grades 1,2 [FL] (n=5) and nodal marginal B-cell lymphoma [NML] (n=2). Median time from diagnosis to lenalidomide monotherapy is 7.6 (3–14) years and median number of prior treatment regimens per subject is 3 (1–17). Two subjects (13%) exhibited an objective partial response (PR) at four months. Both responses, one FL and one NML, occurred in subjects with substantial tumor burden of 61.8 cm² and 80.3 cm², respectively. The 4-month time-to-response for these indolent NHL subjects is longer than the 2-month median time-to-response in aggressive NHL subjects (n=7) following lenalidomide monotherapy. Seven patients had stable disease (SD) for a tumor control rate (TCR) of 60% and 6 had progressive disease (PD). Grade 3 or 4 adverse events occurred in 9 (39%) subjects. These were predominantly Grade 3 hematological events (neutropenia, thrombocytopenia) with only 3 subjects (13%) experiencing a Grade 4 adverse reaction (all neutropenia).

Conclusion: Early results of lenalidomide monotherapy in indolent NHL show evidence of activity with a safety profile similar to that established previously in other hematological malignancies.