These are the results of phase II study of bortezomib-melphalan-prednisolone (VMP) induction therapy followed by lenalidomide-dexamethasone (Rd) consolidation and lenalidomide maintenance in transplant-ineligible patients with newly diagnosed multiple myeloma (NDMM). The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), overall response rates (ORRs), and safety. Eighty-three eligible patients were enrolled between October 2012 and August 2014. The median PFS was 28.0 months (95% CI 19.6-36.7) and the median OS was 55.3 months (95% CI 51.6-NA). Among the patients who received lenalidomide maintenance therapy, median PFS was significantly improved in patients who had achieved a very good partial response (VGPR) or better (41.8 vs 20.7 months, p = 0.0070). As the best response, the rates of partial response or better were 85.5% comprising stringent complete response (sCR, 21.7%), complete response (CR, 10.8%), VGPR (18.1%), and partial response (PR, 34.9%). The most frequently observed grade 3 or higher adverse events during the VMP therapy were anemia (28.9%), neutropenia (15.6%), thrombocytopenia (6.0%), and peripheral neuropathy (2.4%). The most frequently observed grade 3 or higher adverse events during the Rd therapy were anemia (3.5%), neutropenia (1.8%), and skin rush (5.3%). The most frequently observed grade 3 or higher adverse events during lenalidomide maintenance therapy were anemia (7.4%) and neutropenia (24.1%). Thus, VMP induction therapy followed by Rd consolidation and lenalidomide maintenance is considered a well-tolerated and effective regimen in transplant-ineligible NDMM. This trial is registered with UMIN-CTR with the identification number UMIN000009042.
Keywords: Bortezomib; Dexamethasone; Lenalidomide; Multiple myeloma; Transplant ineligible.