Bortezomib Retreatment in Multiple Myeloma

• Determine best response to bortezomib re-treatment. Response will be evaluated according to the European Bone Marrow Transplant group's criteria at least every two treatment cycles (Cycle 1, Cycle 3, Cycle 5, Cycle 7, End of Treatment).
  

• Incidence of Serious Adverse Events, Grade 3 and 4 AEs,and all grades of neuropathy since signature of informed consent to at least 30 days last dose; best confirmed M-protein response (at least every 2 cycles); Duration Of Response; Time To Progression
  

For patients who have relapsed or are refractory to therapy, a standard of care is now bortezomib, based on the results of previous trials. However, there is currently no curative therapy for myeloma. When disease eventually recurs in patients who have received bortezomib for relapsed or refractory myeloma, there are few to no treatment options. It is critical to obtain data on the value of retreatment with bortezomib to determine response rates and duration in patients receiving it for the second time.The protocol is an open-label multicenter single arm study designed to determine the efficacy and safety of retreatment with bortezomib. Multiple myeloma patients should have relapsed or progressed after having responded to a bortezomib based chemotherapy (alone or in combination). Approximately 125 patients will be enrolled in the study. Patients will be treated with bortezomib alone or in combination with another drug (dexamethasone) for about half a year. There will be an initial screening period of up to 14 days to evaluate if the patient is suitable for the study (screening period), followed by up to 8 treatment cycles of 21 days each (treatment period). Response to treatment will be assessed according to the european group for blood and marrow transplant criteria. Disease burden will be monitored by measuring M-protein in serum and urine every 6 weeks until end of treatment, and every 8 weeks in the follow-up period. Safety will be assessed by monitoring of adverse events (AEs), vital signs, physical examination and clinical laboratory tests. After the treatment period, patients will be followed every two months (8 weeks) to check whether the disease might have returned. This long-term follow-up period might last at maximum 2 years period. Based on the last known tolerated dose, patients will receive treatment with bortezomib at 1.0 or 1.3 mg/m2 on day 1, 4, 8 and 11 of a 3-week cycle. There must be at least 72 hours between two doses. Treatment may be repeated for up to 8 cycles. At the investigator's discretion, dexamethasone can be added as per standard of care. Bortezomib at 1.0 mg/m2 or 1.3 mg/m2 will be administered as an intravenous (IV) bolus