Bortezomib With High-dose Melphalan Conditioning Regimen in Newly Diagnosed Multiple Myeloma Patients: Long-term Follow-up.

BACKGROUND/AIM: Autologous stem cell transplantation (ASCT) is the standard strategy after induction therapy for newly diagnosed transplant-eligible multiple myeloma. High-dose melphalan (HDM) conditioning has been the recommended treatment regimen for a long time. No other conditioning regimen has been proven safer and more effective. Because bortezomib has a synergistic effect with melphalan, bortezomib with HDM (Bor-HDM) as a conditioning regimen has shown favorable outcomes, improved complete response rates after ASCT, and no prolonged hematological toxicities. However, few studies have reported long-term follow-up data. This study aimed to evaluate the long-term progression-free survival (PFS) and overall survival (OS) of patients receiving Bor-HDM conditioning, compared to those treated with HDM alone.

PATIENTS AND METHODS: This single-center retrospective study included 36 patients newly diagnosed with transplant-eligible myeloma from 2008 to 2020. In total, 15 patients received a Bor-HDM regimen, while 21 patients received HDM as a conditioning regimen. The probabilities of PFS and OS were plotted using the Kaplan-Meier method. All statistical analyses were performed using EZR software.

RESULTS: After a median follow up of 77 months, no severe hematological toxicities were observed. The PFS and OS rates in the Bor-HDM group as compared with the HDM group were 0.762 vs. 0.60 (p=0.409) and 0.80 vs. 0.904 (p=0.476) respectively. No significant differences were observed between the two groups.

CONCLUSION: These long-term results show that Bor-HDM is a safe and effective option for ASCT conditioning regimens.