BACKGROUND: Thalidomide plus dexamethasone (TD) is a standard induction therapy for myeloma. We aimed to assess the efficacy and safety of addition of bortezomib to TD (VTD) versus TD alone as induction therapy before, and consolidation therapy after, double autologous stem-cell transplantation in newly diagnosed multiple myeloma. METHODS: Patients (aged 18-65 years) with previously untreated symptomatic myeloma were enrolled from 73 sites in Italy between May, 2006, and April, 2008, and data collection continued until June 30, 2010. Patients were randomly allocated (1:1 ratio) by a web-based system to receive three 21-day cycles of thalidomide (100 mg daily for the first 14 days and 200 mg daily thereafter) plus dexamethasone (40 mg daily on 8 of the first 12 days, but not consecutively; total of 320 mg per cycle), either alone or with bortezomib (1·3 mg/m(2) on days 1, 4, 8, and 11). The randomisation sequence was computer generated by the study coordinating team and was stratified by disease stage. After double autologous stem-cell transplantation, patients received two 35-day cycles of their assigned drug regimen, VTD or TD, as consolidation therapy. The primary endpoint was the rate of complete or near complete response to induction therapy. Analysis was by intention to treat. Patients and treating physicians were not masked to treatment allocation. This study is still underway but is not recruiting participants, and is registered with ClinicalTrials.gov, number NCT01134484, and with EudraCT, number 2005-003723-39. FINDINGS: 480 patients were enrolled and randomly assigned to receive VTD (n=241 patients) or TD (n=239). Six patients withdrew consent before start of treatment, and 236 on VTD and 238 on TD were included in the intention-to-treat analysis. After induction therapy, complete or near complete response was achieved in 73 patients (31%, 95% CI 25·0-36·8) receiving VTD, and 27 (11%, 7·3-15·4) on TD (p