| Contributors: |
Kharfan-Dabaja, M. A.; Labopin, M.; Ayala, E.; Bazarbachi, A.; Blaise, D.; Vydra, J.; Bramanti, S.; Itala-Remes, M.; Schmid, C.; Busca, A.; Forcade, E.; Rabitsch, W.; Zecca, M.; Kroger, N.; Bulabois, C. -E.; Grillo, G.; Rambaldi, A.; Fanin, R.; Zallio, F.; Di Renzo, N.; Koc, Y.; Novis, Y.; Mcdonald, A.; Herrera Arroyo, C.; Sanz, J.; Nagler, A.; Ciceri, F.; Mohty, M. |
| Description: |
Availability of haploidentical donors has broadened utilization of allogeneic hematopoietic cell transplantation (allo-HCT). Peripheral blood stem cells (PBSC) are being used with increased frequency in haploidentical allo-HCT. We evaluated extent of HLA disparity (2-3/8 versus 4/8 HLA antigen mismatches) on post-allograft outcomes when using T-cell replete PBSC from haploidentical donors for acute myeloid leukemia in first complete remission. Primary objectives entailed assessing cumulative incidence of grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD (any grade). A total of 645 patients received a haploidentical allo-HCT from a donor with either 2-3 of 8 HLA antigen mismatches (n = 180) or with 4 of 8 HLA antigen mismatches (n = 465). Presence of 2-3 of 8 versus 4 of 8 HLA mismatches did not affect the incidence of acute GVHD (grade 2-4) and chronic GVHD (any grade). Overall survival (OS), leukemia-free survival (LFS) relapse incidence (RI), nonrelapse mortality and the composite endpoint of GVHD-free relapse-free survival were also similar among the groups. Pertaining to HLA-B leader matching effect, our analysis did not discern any difference in aforementioned post-allograft outcomes for this variable. However, in univariate analysis, absence of an antigen mismatch in HLA-DPB1 showed a trend for better OS. Notwithstanding inherent limitations associated with registry data, our results did not show an advantage of selecting a haploidentical donor with 2-3 of 8 HLA antigen mismatches over one with 4 of 8 HLA antigen mismatches when using PBSC as the cell source. Adverse cytogenetics remains a major adverse determinant of inferior OS and LFS and a higher RI. Using reduced-intensity conditioning yielded worse OS and LFS. |