Despite the good response of stem cell transplant (SCT) in the treatment of multiple myeloma (MM), most patients relapse or do not achieve complete remission, suggesting that additional treatment is needed. We assessed the impact of thalidomide in maintenance after SCT in untreated patients with MM. A hundred and eight patients (<70 years old) were randomized to receive maintenance with dexamethasone (arm A; n = 52) or dexamethasone with thalidomide (arm B; n = 56; 200 mg daily) for 12 months or until disease progression. After a median follow-up of 27 months, an intention to treat analysis showed a 2-year progression-free survival (PFS) of 30% in arm A (95% CI 22-38) and 64% in arm B (95% CI 57-71; P = 0.002), with median PFS of 19 months and 36 months, respectively. In patients who did not achieve at least a very good partial response, the PFS at 2 years was significantly higher when in use of thalidomide (19 vs. 59%; P = 0.002). Overall survival at 2 years was not significantly improved (70 vs. 85% in arm A and arm B, respectively; P = 0.27). The addition of thalidomide to dexamethasone as maintenance improved the PFS mainly in patients who did not respond to treatment after SCT. © 2012 Wiley Periodicals, Inc.8710948952Attal, M., Harousseau, J.L., Stoppa, A.M., A prospective, randomized trial of autologous bone marrow transplantation and chemotherapy in multiple myeloma. Intergroupe Francais du Myelome (1996) N Engl J Med, 335, pp. 91-97Child, J.A., Morgan, G.J., Davies, F.E., High-dose chemotherapy with hematopoietic stem-cell rescue for multiple myeloma (2003) N Engl J Med, 348, pp. 1875-1883Attal, M., Harousseau, J.L., Leyvraz, S., Maintenance therapy with thalidomide improves survival in patients with multiple myeloma (2006) Blood, 108, pp. 3289-3294Spencer, A., Prince, H.M., Roberts, A.W., Consolidation therapy with low-dose thalidomide and prednisolone prolongs the survival of multiple myeloma patients undergoing a single autologous stem-cell transplantation procedure (2009) J Clin Oncol, 27, pp. 1788-1793Barlogie, B., Desikan, R., Eddlemon, P., Extended survival in advanced and refractory multiple myeloma after single-agent thalidomide: Identification of prognostic factors in a phase 2 study of 169 patients (2001) Blood, 98, pp. 492-494Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: A report of the International Myeloma Working Group (2003) Br J Haematol, 121, pp. 749-757Blade, J., Samson, D., Reece, D., Criteria for evaluating disease response and progression in patients with multiple myeloma treated by high-dose therapy and haemopoietic stem cell transplantation. Myeloma Subcommittee of the EBMT. European Group for Blood and Marrow Transplant (1998) Br J Haematol, 102, pp. 1115-1123Attal, M., Harousseau, J.L., Facon, T., Single versus double autologous stem-cell transplantation for multiple myeloma (2003) N Engl J Med, 349, pp. 2495-2502Spencer, A., Seldon, M., Deveridge, S., Induction with oral chemotherapy (CID) followed by early autologous stem cell transplantation for de novo multiple myeloma patients (2004) Hematol J, 5, pp. 216-221Barlogie, B., Tricot, G., Anaissie, E., Thalidomide and hematopoietic-cell transplantation for multiple myeloma (2006) N Engl J Med, 354, pp. 1021-1030Lokhorst, H.M., van der Holt, B., Zweegman, S., A randomized phase 3 study on the effect of thalidomide combined with adriamycin, dexamethasone, and high-dose melphalan, followed by thalidomide maintenance in patients with multiple myeloma (2010) Blood, 115, pp. 1113-1120Morgan, G.J., Davies, F.E., Gregory, W.M., The role of maintenance thalidomide therapy in multiple myeloma: MRC Myeloma IX results and meta-analysis (2012) Blood, 119, pp. 7-15Stewart, A.K., Trudel, S., Bahlis, N.J., A randomized phase III trial of thalidomide and prednisone as maintenance therapy following autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM): The NCIC CTG MY.10 Trial (2010) ASH Annu Meeting Abstr, 116, p. 39Singhal, S., Mehta, J., Desikan, R., Antitumor activity of thalidomide in refractory multiple myeloma (1999) N Engl J Med, 341, pp. 1565-1571Rajkumar, S.V., Hayman, S., Gertz, M.A., Combination therapy with thalidomide plus dexamethasone for newly diagnosed myeloma (2002) J Clin Oncol, 20, pp. 4319-4323Barlogie, B., Attal, M., Crowley, J., Long-term follow-up of autotransplantation trials for multiple myeloma: Update of protocols conducted by the intergroupe francophone du myelome, southwest oncology group, and university of arkansas for medical sciences (2010) J Clin Oncol, 28, pp. 1209-1214Ludwig, H., Adam, Z., Tóthová, E., Thalidomide maintenance treatment increases progression-free but not overall survival in elderly patients with myeloma (2010) Haematologica, 95, pp. 1548-1554Richardson, P., Jagannath, S., Hussein, M., Safety and efficacy of single-agent lenalidomide in patients with relapsed and refractory multiple myeloma (2009) Blood, 114, pp. 772-778Attal, M., Lauwers-Cances, V., Marit, G., Lenalidomide maintenance after stem-cell transplantation for multiple myeloma (2012), 366, pp. 1782-1791. , N Engl J MedMcCarthy, P.L., Owzar, K., Hofmeister, C.C., Hurd, D.D., Lenalidomide after stem-cell transplantation for multiple myeloma (2012) N Engl J Med, 366, pp. 1770-1781Hungria, V.T., Maiolino, A., Martinez, G., Confirmation of the utility of the International Staging System and identification of a unique pattern of disease in Brazilian patients with multiple myeloma (2008) Haematologica, 93, pp. 791-792