This is a randomised, placebo controlled, phase II study evaluating toxicity and safety of fludarabine added to CyDex (cyclophosphamide+dexamethasone) as induction therapy in younger patients with untreated and treatment demanding multiple myeloma. The treatment regimen Patients will be randomised at diagnosis either to CyDex + Placebo (control Arm A) or CyDex + Fludarabine (Experimental Arm B).