Influence of alternative donor type on early survival after hematopoietic stem cell transplantation for acute myeloid leukemia lacking a sibling donor.

Allogeneic hematopoietic stem cell transplantation is the only potentially curative therapy for acute myeloid leukemia. In the absence of an HLA-matched related or unrelated donor (MRD or MUD), the best alternative donor source remains controversial. Umbilical cord blood and haploidentical donors offer a shorter delay from indication to transplantation. This retrospective multicentre study of a French registry compares overall survival in the 18 months following registration in the absence of a MRD between four types of donors. Between 2012 and 2016, 1302 patients were transplanted using MUD (control, n = 803), mismatched MUD (n = 219), umbilical cord blood (n = 153) and haploidentical (n = 127) donors. Multivariate analyses were conducted for overall survival after registration, after transplant, and transplant-related mortality. After adjustment for variables, the type of donor did not influence any of the three end points. Our results confirmed the significant negative impact of longer time between registration and transplant: HR = 1.04 [1.02-1.06] (p < 0.0001). This indicates a positive correlation between better survival and shorter registration-to-transplantation wait time. In the absence of a sibling donor, the alternative stem cell source does not impact early survival in acute myeloid leukemia patients. The minimization of registration-to-transplantation time should be considered when weighing the alternative donor options.