Non-Relapse Mortality in Acute Leukemia: Haploidentical Vs. Matched Related Donor - Experience at a Tertiary Hospital in Mexico -

Non-relapse mortality (NRM) is a critical outcome in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Since the early 2010s, haploidentical donors have become an alternative platform, particularly in the absence of an unrelated donor registry. Several groups have demonstrated comparable outcomes between haploidentical donor and matched related donor (MRD) in the context of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and acute lymphoblastic leukemia (ALL). This study aims to present our experience regarding NRM and compare it with previously published data. We conducted a retrospective review of all the patients with a diagnosis of AML, MDS and ALL who underwent a first allo-HSCT at our centre from January 2015 to December 2024. Descriptive analyses were performed using SPSS version 27, and Cox regression was conducted using R version 2023.09.1. A total of 73 patients were included. Notably, ALL was the primary indication for allo-SCT. Baseline characteristics were similar between both groups (Table 1), except for the source since we locally use mixed source (peripheral blood + bone marrow) in the haploidentical setting. Graft failure and cytomegalovirus reactivation were more frequent in the haploidentical group, while the incidence of acute and chronic graft versus host disease were no different. Regarding NRM, there was no significant difference between groups ( 1y- NRM 16.4% in the haploidentical vs. 17.8% in the MRD group, HR 1.47 95% CI 0.74-2.9, p=0.268). (Figure 1) Based on the preliminary data, there was no significant difference in NRM between haploidentical and MRD donors among patients with acute leukemia or MDS. These findings are consistent with prior reports, in which 1y -NRM in acute leukemia or MDS ranges from 12% to 25%.