Clinical Study on Induction of Remission Using Bortezomib (Vel), Cyclophosphamide (C), and Dexamethasone (D) in Patients Until 60 Years of Age With Untreated Multiple Myeloma and Planned for a High Dose Chemotherapy: (VelCD; Deutsche Studiengruppe Multiples Myelom [DSMM] XIa)

This is open-label (both the participant and the investigator know what treatment participants will receive), prospective (participants are identified and then followed forward in time for the outcome of the study), multi-centre, and non-randomized (participants are assigned to different treatment groups by the investigator) study. The study will be conducted into 2 parts (Part 1 and Part 2). Approximately 400 participants will be enrolled (30 in Part 1 and 370 in Part 2). In Part 1 the optimum dose of cyclophosphamide will be evaluated and in Part 2 the selected dose of cyclophosphamide from Part 1 will be administered. Part 2 will include a screening period of a maximum of 14 days followed by chemotherapy (bortezomib, cyclophosphamide, and dexamethasone) of a maximum of three 21-day cycles. Safety will be evaluated by the assessment of adverse events, vital signs, physical examination, electrocardiogram, and clinical laboratory tests which will be monitored throughout the study.