Previous thalidomide therapy may not affect lenalidomide response and outcome in relapse or refractory multiple myeloma patients.

INTRODUCTION: Lenalidomide is a thalidomide analogue, designed to have improved efficacy and tolerability over the parent drug. The aim of this retrospective analysis is to evaluate the impact of thalidomide therapy on lenalidomide response and outcome in relapse or refractory multiple myeloma patients. PATIENTS AND METHODS: A total of 106 relapsed or refractory multiple myeloma patients received lenalidomide 25mg plus dexamethasone as salvage therapy; 80 patients progressed on thalidomide treatment (thalidomide-resistant) and 26 patients discontinued thalidomide in at least partial remission (thalidomide-sensitive). Median time from diagnosis to lenalidomide treatment was 57 months. Median prior lines of therapies were 3, range 1-6. 62% of patients were previously treated with autologous stem cell transplantation, and 71% with bortezomib-based regimens.
RESULTS: In the thalidomide-resistant and -sensitive groups, the at least partial response rates were 56.2% and 61.5% (P = .45), including at least VGPR rates of 16.2% and 11.5%; the median progression free survival was 10 and 12 months (P=.12) and the median overall survival was 17 and 18.5 months (P = .50), respectively.
CONCLUSION: Lenalidomide may be equally effective in heavily pre-treated multiple myeloma patients who are thalidomide-resistant or thalidomide-sensitive to a previous therapy.