Objective: Patients with multiple myeloma (MM) achieving high-quality responses, defined as a complete response (CR) and a very good partial response (VGPR) after transplant, benefit from high-dose therapy followed by autologous stem cell transplantation (ASCT). Induction pre-transplantation treatment with vincristine, doxorubicin and dexamethasone (VAD) is currently being replaced by new targeted agents with high anti-myeloma activity. The use of these novel agents may increase the CR + VGPR rate before ASCT, which may improve post-transplantation responses and survival.
Methods: We performed a retrospective analysis of 69 patients with MM who received bortezomib-containing regimens (n = 30) or VAD (n = 39) before collection of peripheral blood stem cells and ASCT.
Results: Objective response rate (at least a partial response) prior to ASCT was documented in 27 (90%) of 30 and 31 (81.6%) of evaluable 38 patients with bortezomib-containing regimens and VAD, respectively. The difference between the two groups was not significant (P = 0.494). However, the high-quality response rate with VGPR or more in the bortezomib group was significantly higher compared with the VAD group (66.7% vs. 34.2%, respectively, P = 0.006). The superiority of bortezomib-containing regimens in the high-quality response rate remained significant for only the newly diagnosed patients (n = 16, P = 0.008). The engraftment data as well as stem cell harvesting were comparable between the two groups. The major bortezomib-related toxicities were thrombocytopenias and peripheral neuropathies; toxicities of VAD were hematologic and infectious. After ASCT, the difference between the two groups did not reach the level of statistical significance with respect to progression-free survival and overall survival (P = 0.498 and 0.835, respectively).
Conclusions: The results of this retrospective comparison of bortezomib-containing regimens with the VAD as induction treatment prior to ASCT for MM provided a demonstration of the superiority of bortezomib therapy in terms of achieving a high-quality response. However, survivals following ASCT did not differ according to the induction regimens.