Single-agent bortezomib or bortezomib-based regimens as consolidation therapy after autologous hematopoietic stem cell transplantation in multiple myeloma: a meta-analysis of randomized controlled trials.

The efficacy and safety of single-agent bortezomib or bortezomib-based regimens as consolidation therapy after autologous hematopoietic stem cell transplantation (ASCT) in patients with multiple myeloma (MM) has been in question. To address the issue, we conducted a meta-analysis of two randomized double-blind placebo-controlled studies involving a total of 691 patients. The primary outcomes of interest were progression-free survival (PFS) and response rate. Secondary outcomes included overall survival (OS) and adverse events. There was a marked benefit in 3-year PFS with bortezomib (Odds Ratio [OR] = 1.52, 95% confidence interval [CI] = 1.11 to 2.08), whereas there was no difference in 3-year overall survival (OS; OR = 0.91, 95% CI = 0.60 to 1.37). More bortezomib-treated paitents achieved at least a very good partial response (≥ VGPR) (OR = 1.73, 95% CI = 1.19 to 2.51). The rate of complete response or near-complete response (CR/nCR) was significantly higher with bortezomib consolidation therapy (OR = 1.62, 95% CI = 1.18 to 2.22). For adverse events, more patients in the bortezomib consolidation therapy arm experienced peripheral neuropathy (OR = 4.03, 95% CI = 2.72 to 5.96). Significant differences were also seen with those experiencing peripheral neuropathy greater than grade 2 (OR = 4.26, 95% CI = 1.06 to 17.11). Based on these results, we conclude that single-agent bortezomib or bortezomib-based regimens as consolidation therapy after ASCT in patients with MM was effective in the improvement of PFS and response rate. However, peripheral neuropathy must be closely monitored.