PURPOSE: For several decades, the treatment of elderly patients with multiple myeloma (MM) has consisted of melphalan and prednisone (MP). The Dutch-Belgium Hemato-Oncology Cooperative Group (HOVON) investigated the efficacy of thalidomide added to MP (MP-T) in a randomized phase III trial. The objective of this study was to investigate the efficacy, toxicity, and effects on quality of life of MP-T. PATIENTS AND METHODS: A randomized phase III trial compared standard MP with MP-T (thalidomide 200 mg/d) in newly diagnosed patients with multiple myeloma older than age 65 years. Maintenance therapy with thalidomide 50 mg/d was administered to patients after MP-T until relapse. The primary end point was event-free survival (EFS); response rate, overall survival (OS), and progression-free survival (PFS) were secondary end points. RESULTS: An intent-to-treat analysis of 333 evaluable patients showed significantly higher response rates in MP-T-treated patients compared with MP-treated patients a response (> or = partial response: 66% v 45%, respectively; P <.001; and > or = very good partial response [VGPR]: 27% v 10%, respectively; P <.001). EFS was 13 months with MP-T versus 9 months with MP (P <.001). OS was 40 months with MP-T versus 31 months with MP (P = .05). CONCLUSION: This study demonstrates that thalidomide improves the response rate and VGPR in elderly patients with newly diagnosed MM. MP-T also results in a better EFS, PFS, and OS.