Effect of donor characteristics on haploidentical transplantation with posttransplantation cyclophosphamide

We studied the association between non-HLA donor characteristics (age, sex, donor-recipient relationship, blood group [ABO] match, and cytomegalovirus [CMV] serostatus) and transplant outcomes after T-cell-replete HLA-haploidentical transplantation using posttransplantation cyclophosphamide (PT-Cy) in 928 adults with hematologic malignancy transplanted between 2008 and 2015. Siblings (n = 358) and offspring (n = 450) were the predominant donors, with only 120 patients having received grafts from parents. Although mortality risks were higher with donors aged 30 years or older (hazard ratio, 1.39; P < .0001), the introduction of patient age to the Cox regression model negated the effect of donor age. Two-year survival adjusted for CMV seropositivity, disease, and disease risk index was lower in patients aged 55 to 78 years after transplantation of grafts from donors younger than 30 years (53%) or aged at least 30 years (46%) compared with younger patients who received grafts from donors younger than 30 years (61%) and at least 30 years (60%; P < .0001). Similarly, 2-year survival in patients aged 55 to 78 years was lower after transplantation of grafts from siblings (45%) or offspring (48%) compared with patients aged 18 to 54 years after transplantation of grafts from siblings (62%), offspring (58%), and parents (61%; P < .0001). Graft failure was higher after transplantation of grafts from parents (14%) compared with siblings (6%) or offspring (7%; P = .02). Other non-HLA donor characteristics were not associated with survival or graft failure. The current analyses suggest patient and disease, rather than non-HLA donor characteristics, predominantly influence survival in adults.