Long-Term Follow-Up of a "Donor" Versus "No Donor" Comparison in Multiple Myeloma Patients at First Relapse after Failing Autologous Transplantation.

•We present the long-term results of a donor versus no-donor comparison in patients with multiple myeloma in first relapse after autologous stem cell transplantation (SCT).•Significant benefits in progression-free survival and overall survival were seen in the donor group at a median follow-up of 110 months.•This study suggests that allogeneic SCT could be an option in young patients at high risk for relapse after first-line treatment.