Immunosuppression-Free Status at 1 Year after Haploidentical Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide.

The development of chronic graft-versus-host disease (GVHD) in 1-year survivors after matched related or unrelated hematopoietic cell transplantation was shown to be associated with higher nonrelapse mortality (NRM) and worse overall survival (OS). The impact of chronic GVHD requiring immunosuppression (IS) for recipients of haploidentical transplantation (HIDT) with post-transplantation cyclophosphamide (PTCy) who have survived to 1 year post-transplantation has not been studied previously and was investigated for this analysis. A total of 322 adult patients who underwent HIDT at our center were included in this study. The effect of IS-free status on post-transplantation outcomes was assessed. The median follow-up for survivors was 63.9 months (range, 18.3 to 165 months). A total of 163 patients (65%) were IS-free at 1 year post-HIDT. Baseline characteristics of this group were similar to those of patients still requiring IS, except for higher percentages of female donor-male recipient pairs (28% versus 15%; P =.03) and female donors (48% versus 30%; P =.008). Logistic regression to identify patients more likely to be on IS at 1 year post-HIDT identified the use of a female donor as a significant risk factor (odds ratio, 2.11; P = .009). In a Cox regression analysis, patients requiring IS at 1 year post-transplantation had higher NRM (hazard ratio [HR], 4.18; 95% confidence interval [CI], 1.80 to 6.72; P < .001) and showed a trend toward worse disease-free survival (DFS) (HR, 1.59; 95% CI, .95 to 2.66; P =.08), with no impact on OS (HR, 1.44; 95% CI, .90 to 2.31; P = .13) or relapse (HR, .77; 95% CI, .37 to 1.61; P = .49). These results indicate that use of a female donor is a significant risk factor for requiring IS at 1 year post-HIDT. Additionally, chronic GVHD requiring IS at 1-year post-HIDT no significant effect on relapse but is associated with higher NRM and a trend toward worse DFS.
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