Role of high-dose melphalan with autologous stem cell transplantation in multiple myeloma patients receiving botezomib-containing induction therapy.

To examine the role of high-dose melphalan therapy with autologous stem cell transplantation (HDM/ASCT) in the final outcomes of multiple myeloma (MM) patients receiving bortezomib-containing induction therapy (IT), we analyzed relationships between quality of response after IT including bortezomib or HDM/ASCT and survival. In total, 92 MM patients who received IT with bortezomib followed by HDM/ASCT were enrolled. The median follow-up was 28.0 months. Three-year progression-free survival (PFS) and overall survival (OS) were 41.1 and 72.0 %, respectively. A complete response (CR) after HDM/ASCT was a strong prognostic factor for PFS and OS (p = 0.002 and 0.001, respectively). Additionally, out of 67 patients who failed to achieve CR after IT, 36 (53.7 %) patients achieved CR after HDM/ASCT. PFS and OS in patients with CR after additional HDM/ASCT were similar to those in patients who had already achieved CR after IT. However, achievement of at least very good partial response following IT with bortezomib failed to improve PFS and OS (p = 0.35 and 0.11, respectively). Thus, we conclude that post-HDM/ASCT CR is the best prognostic factor for both PFS and OS regardless of response to bortezomib. Therefore, HDM/ASCT remains an important therapy in MM patients even after introduction of bortezomib IT.