Lenalidomide and Vorinostat Maintenance after Autologous Transplantation in Multiple Myeloma: Long- Term Follow-Up

ABSTRACT Post-autologous stem cell transplantation (ASCT) maintenance therapy with lenalidomide is standard of care for patients with multiple myeloma (MM). Effective and tolerable drug combinations may further enhance the clinical response post-ASCT. Vorinostat, a histone deacetylase inhibitor, induces antiproliferative and proapoptotic effects in patients with MM. We hypothesized that combination maintenance therapy would further prolong the clinical response achieved from transplantation. We previously reported that the combination of lenalidomide and vorinostat as maintenance post-ASCT was tolerable in 16 patients with MM. We now present the long-term follow up of these patients. Progression-free survival (PFS) and overall survival (OS) outcomes were characterized using the Kaplan-Meier method. Five patients (31%) had high-risk disease, and the median number of lines of therapy before ASCT was 1 (range, 1 to 5). With a median follow-up of 89.8 months from ASCT, the median PFS was 64.3 months (range, 21.7 months to not reached [NR]), and OS was not reached (median, 53.0 months to NR). At the time of this report, 5 patients remained on the study. The combination of vorinostat and lenalidomide as maintenance post-ASCT is tolerable and induces a durable response. A phase III randomized study of lenalidomide versus a combination with vorinostat is warranted.