Bortezomib administered pre-auto-SCT and as maintenance therapy post transplant for multiple myeloma: A single institution phase II study

The appropriate induction therapy before and the role of maintenance therapy after auto-SCT for patients with multiple myeloma remain areas of active investigation. We conducted a study in 40 patients with bortezomib given sequentially pre-auto-SCT and as maintenance therapy post auto-SCT. Pre-transplant bortezomib was administered for two cycles followed by high-dose melphalan 200 mg/m² with auto-SCT of G-CSF-mobilized PBMCs. Post transplant bortezomib was administered weekly for 5 out of 6 weeks for six cycles. No adverse effects were observed on stem cell mobilization or engraftment. An overall response rate of 83% with a CR+very good partial remission (VGPR) of 50% was observed with this approach. Three-year Kaplan-Meier estimates of disease-free survival and overall survival (OS) were 38.2 and 63.1%, respectively. Bortezomib reduced CD8⁺ cytotoxic T cell and CD56⁺ natural killer cell PBL subsets and was clinically associated with high rates of viral reactivation to varicella zoster.