Improved Response Rates with Bortezomib in Relapsed or Refractory Multiple Myeloma: An Observational Study in Chinese Patients

INTRODUCTION Bortezomib, a novel proteasome inhibitor, is approved for the treatment of relapsed multiple myeloma (MM). Efficacy and safety of bortezomib is well known; however, it was necessary to validate the data in patients with different ethnic backgrounds. The efficacy and safety of bortezomib was assessed in patients from China with relapsed/refractory MM in a real-world scenario. METHODS This prospective, non-interventional, observational study enrolled both male and female Chinese patients, aged ≥18 years and diagnosed with relapsed or refractory MM. Administration of intravenous bortezomib at 1.3 mg/m2 was recommended twice a week for 2 weeks (days 1, 4, 8 and 11), followed by a 10-day rest period (maximum of 8 cycles) and a follow-up every 12 weeks for 3 years. Efficacy assessments included best response, objective response rate (ORR), time to response, duration of response, and overall survival. Safety was also assessed. RESULTS A total of 517 patients were enrolled with a median age of 58.7 years. Patients predominantly had immunoglobulin G type (46.2%) and stage III (47.8%) myeloma. Overall, 202 (42.3%) patients had partial response as best response, ORR was 88.9% and the proportion of patients exhibiting complete response was 24.7%. The median time to response observed was 27 (21-40) days. Median time to progression was 415 days and median overall survival was 475 days. Thrombocytopenia (14.4%) was the most common adverse event. CONCLUSION Bortezomib demonstrated clinical response in majority of patients and was well tolerated in this observational study in Chinese patients with relapsed/refractory MM.