Background:Eligible patients with multiple myeloma (MM) are offered autologous hematopoietic cell transplantation (auto-HCT) in their first remission. The usual conditioning regimen consists of melphalan (Alkeran) 200 mg/m 2infused over ~ 30 minutes due to its limited stability. Evomela is a newer formulation of melphalan, which is stable at room temperature for ~ 24 hours. The current trial studied the dose escalation and compared the short versus extended infusion time of evomela used as a conditioning regimen before auto-HCT.