Vorinostat in Combination With Lenalidomide and Dexamethasone in Lenalidomide-Refractory Multiple Myeloma.

Background: This is a retrospective chart review to evaluate the efficacy of the addition of vorinostat to lenalidomide and dexamethasone in patients with multiple myeloma relapsed/refractory to lenalidomide and dexamethasone.

Methods: Charts from 26 consecutive patients able to obtain commercial vorinostat were analyzed for response and safety data.

Results: The overall response rate was 31%, and the clinical beneficial rate was 50%. The median duration of response was 3 months, and the median overall survival was 28.5 months. The most common grade 3 and 4 toxicities were hematologic and metabolic, including neutropenia (44%), thrombocytopenia (53%), and transaminase elevations (aspartate aminotransferase 9% and alanine aminotransferase 6%). No thromboembolic events or febrile neutropenia were observed.

Conclusion: These observations demonstrate that the addition of vorinostat to patients with lenalidomide- and dexamethasone-refractory multiple myeloma was associated with moderate response and was well-tolerated, warranting further assessment in a larger prospective study.