Multiple Myeloma Treated With Thalidomide Before Autotransplant or With Conventional Chemotherapy and as Consolidation/Maintenance Treatment in Young and Elderly Patients : 3 Randomized Studies.

Inclusion Criteria: * for MY-TAG(auto-transplant): age 18-65, multiple myeloma Salmon-Durie stage II, stage III and symptomatic stage I (lytic bone lesion or a 25 % increase of monoclonal protein) * for MY-DECT (conventional chemotherapy) : qge 66-80, multiple myeloma Salmon-Durie stage II, stage III and symptomatic stage I (lytic bone lesion or a 25 % increase of monoclonal protein) * for MY-PLAT (maintenance at plateau-phase): patients treated in MY-TAG or MY-DECt with at least a minimal response (25 % decrease of M protein)3-6 months after autotransplant or last chemotherapy Exclusion Criteria: * for MY-TAG : age 66 or more, smoldering stage I multiple myeloma, previous therapy, plasma cell leukemia,creatinine \> 300 micromol/L, liver failure, anthracycline contra-indicated, thalidomide contra-indicated, corticosteroid contra-indicated * for MY-DECT : age \< 66 or \> 80, smoldering stage I multiple myeloma, previous therapy, plasma cell leukemia,creatinine \> 300 micromol/L, liver failure, thalidomide contra-indicated, corticosteroid contra-indicated * for MY-PLAT : no response or progressive disease, randomization \> 6 m since autotransplant or last chemotherapy, creatinine \> 300 micromol/L, liver failure, thalidomide contra-indicated, corticosteroid contra-indicated