The aim of this phase II trial was to investigate the efficacy of bortezomib plus dexamethasone (Vel-Dex) as induction therapy in patients with multiple myeloma (MM) and to define the role of intensification before transplantation. Fifty-seven patients were treated with four courses of Vel-Dex, two cycles of dexamethasone, cyclophosphamide, etoposide and cisplatin (DCEP), and a single autologous transplant. Fourteen patients (25%) went off-study: seven after Vel-Dex, seven after DCEP. All patients yielded high numbers of stem cells (median CD34+ cells 7.5 x 106/kg); 54 of the 57 patients (94%) collected > or =4 x 106/kg CD34+ cells, 60% with a single leukapheresis. The overall response rate (ORR) after Vel-Dex was 86% (70% had a very good partial response [VGPR] or better) regardless of cytogenetic abnormalities and International Staging System stage (ISS). The response at the end of the two DCEP cycles remained unchanged in 35 patients (70%), worsened in 15 (20%), and improved in 5 (10%). Because of the consistent drop-out, the ORR in intention-to-treat analysis decreased significantly from 86% after Vel-Dex to 76% after DCEP, and 73% after transplantation. However, when considering the subset of 43 patients who completed the program, the ORR was 96% (complete response 39%, VGPR 41%, partial response 16%). In conclusion, Vel-Dex produces high response rates, improves stem cell collection, and overcomes the need for intensification before autologous transplantation.