<qa>  What is the aim of this multicenter randomised trial?The aim of this multicenter randomised trial in previously untreated patients with multiple myelome stage II, III DSis to assess the optimal timing of a second autologous stem-cell transplant.After a first-line therapy with thalidomide-dexamethasone followed by a PBSC collection, patients are randomly assigned to receive two autologous PBSC transplants arm Aor one autologous PBSC transplant followed by a consolidation therapy with thalidomide-dexamethasone arm B. Patients included in the arm B will receive a second transplant in case of disease progression on consolidation therapy, or in case of relapse in responders. 