Lenalidomide in relapsed refractory myeloma patients: impact of previous response to bortezomib and thalidomide on treatment efficacy. Results of a medical need program in Belgium.

The prognosis of multiple myeloma patients has significantly improved since the introduction of the novel agents thalidomide, bortezomib and lenalidomide. We report the data of a medical need programme with lenalidomide plus dexamethasone, conducted in Belgium between August 2007 and March 2008, and including 98 relapsed refractory multiple myeloma patients. In addition to chemotherapy and steroids, all patients had received prior treatment with bortezomib, and 84% of them had been exposed to thalidomide. In 52 patients response data could be retrieved by post-hoc analysis. A partial remission or better was achieved in 52% (49% partial and 3% complete response) of patients, despite a median of 5 previous anti-myeloma treatment lines. Responses were rapid while the majority of patients received lenalidomide with once weekly (also called low-dose) dexamethasone. Treatment with lenalidomide plus dexamethasone did prolong overall survival by nearly half a year in this population with end-stage myeloma. Overall response and quality of response were independent of previous response to thalidomide and bortezomib, although the time to progression tended to be shorter in thalidomide- and bortezomib-refractory patients. It can be concluded that lenalidomide plus dexamethasone is an effective and safe treatment regimen in highly refractory multiple myeloma patients, and that these responses are irrespective of previous exposure or sensitivity to thalidomide and bortezomib.