Bortezomib for patients with previously untreated multiple myeloma: a systematic review and meta-analysis of randomized controlled trials.

Multiple myeloma (MM) is an incurable disease with a poor survival, which has not been affected even by high-dose chemotherapy. This systematic review was performed to assess the efficacy and safety of the novel agent bortezomib for patients with previously untreated MM. We systematically searched biomedical literature databases and identified randomized controlled trials (RCTs) comparing bortezomib with placebo, no bortezomib, or other active agents for patients with previously untreated MM. Overall survival (OS), reported as hazard ratio (HR) with 95% confidence interval (CI), was the primary outcome measure. The secondary outcomes included time to progression (TTP), progression-free survival (PFS), and response rates. Five RCTs involving 2,728 patients were included. Three trials compared bortezomib with no bortezomib, and two compared bortezomib with other active agents (vincristine ± adriamycin-based chemotherapy). All included RCTs had methodological shortcomings, including no or unclear allocation concealment and blinding. Compared with no bortezomib or vincristine-based chemotherapy, the bortezomib-based regimen significantly improved the OS of patients with previously untreated MM. HR was 0.71 (95% CI 0.55-0.93) and 0.77 (95% CI 0.60-0.99), respectively. However, when compared with the vincristine + adriamycin-based regimen, the OS was similar (HR = 0.87, 95% CI 0.57-1.33). TTP, PFS, and response rates were also improved in patients receiving bortezomib-based regimen. However, the risk of peripheral neuropathy was found to be significantly higher. In summary, bortezomib appears to improve survival and response rates of patients with previously untreated MM in spite of higher risk of peripheral neuropathy.