Trial Studying Maintenance Treatment With Lenalidomide and Dexamethasone Versus Lenalidomide, Dexamethasone and MLN9708 After Autologous Hematopoietic Stem Cell Transplantation in Patients With Newly-diagnosed Symptomatic Multiple Myeloma

This protocol is a randomized, open-label, national, multicenter trial studying maintenance treatment with lenalidomide and dexamethasone versus lenalidomide, dexamethasone and MLN9708 after autologous hematopoietic stem cell transplantation in patients with newly-diagnosed symptomatic multiple myeloma. A total of 316 patients, from the study GEM2012MENOS65, will be enrolled in the study. The pre-treatment period includes the screening visit in which participants provide informed consent in writing in order to take part in the study. The patient is then assessed to determine his/her eligibility. The selection process will begin 21 days before the first dose of medication is administered (days -21 to 0). All procedures during the pre-treatment period will be carried out after completion of the two cycles of post-transplant consolidation with VRD which coincide with the end-of-study visit of clinical trial GEM2012MENOS65. During the treatment period, eligible patients will be included in the study and receive maintenance treatment with lenalidomide/dexamethasone versus lenalidomide/dexamethasone/MLN9708. Each cycle will last 28 days. Treatment arm A will consist of oral administration of 15 mg/day of oral lenalidomide on days 1-21, and 20 mg/day of dexamethasone administered orally on days 1-4 and 9-12 for a period of two years. Arm B of the maintenance treatment will be the same as arm A, with the addition of MLN9708 during the two year maintenance period, at a dose of 4 mg/day on days 1, 8 and 15 of the cycle. At two years, patients with negative MRD will finish maintenance treatment. Patients with positive MRD will continue treatment with lenalidomide/dexamethasone until they have completed five years of maintenance treatment. In this case, 20 mg/day of dexamethasone will only be administered on days 1-4 of the cycle. The dose of lenalidomide will not be adjusted. (unless necessary to treat adverse events) Once this phase of active treatment is complete, patie