A prospective, open-label, multicenter, observational study to evaluate the efficacy and safety of bortezomib-melphalan-prednisone as initial treatment for autologous stem cell transplantation-ineligible patients with multiple myeloma

Bortezomib-melphalan-prednisone (VMP) showed superior efficacy versus MP as first-line treatment for transplantation-ineligible multiple myeloma (MM). This study investigated the efficacy of VMP for Korean patients with MM. Overall, 177 MM patients received 9 cycles of VMP in this prospective, multicenter, observational study. The primary endpoint was 2-year progression-free survival (PFS). Thirty-nine (22%) patients were aged ≥ 75 years and 83 (47.4%) patients had International Staging System stage III. A median of 5 cycles were delivered. Overall response rate (ORR) was 72.9%, and complete response (CR) rate was 20.3%. With a median follow-up of 11.9 months, median PFS was 17 months. The 2-year PFS and overall survival (OS) rates were 29.2% and 80.0%, respectively. Median OS was not reached. PFS was significantly different depending on performance status (Eastern Cooperative Oncology Group < 2 vs. ≥ 2; p = 0.0002), β(2)-microglobulin level (< 5.5 vs. ≥ 5.5 mg/L; p = 0.0481), and cumulative dose of bortezomib (< 35.1 vs. ≥ 35.1 mg/m(2); p < 0001). The common adverse events (AEs) were in line with the well-known toxicity profiles associated with VMP. In conclusion, VMP is a feasible and effective front-line treatment for transplant-ineligible older patients with MM in Korea. Continuing therapy with prompt adjustment of treatment according to AEs may be important to improve outcomes of elderly patients.