Severity and organ distribution of graft‐versus‐host disease with post‐transplant cyclophosphamide versus calcineurin inhibitor plus methotrexate/mycophenolate mofetil or sirolimus in allogenic HLA‐matched or single‐allele mismatched stem cell transplantation

Abstract Objective This retrospective single center study aims to describe changes in the severity and organ‐specific distribution of GvHD, by comparing the outcomes of 3 distinct GvHD prophylaxis approaches. Methods Between January 2012 and June 2022, 226 patients underwent allogeneic hematopoietic stem cell transplantation from HLA‐matched or 1‐allele mismatched related or unrelated donors. Fifty‐eight (26%) received prophylaxis with calcineurin inhibitor in combination with mycophenolate mofetil or a short course of methotrexate (Cohort‐1), 87 (38%) tacrolimus plus sirolimus (Cohort‐2), and 81 (36%) post‐transplant cyclophosphamide (PTCy) plus tacrolimus (Cohort‐3). Results The incidence of grade II‐IV aGvHD was 69% vs. 41.4% vs. 27.2%; p < .01. The most significant reduction with PTCy was observed in both stage 3–4 skin and lower gastrointestinal (GI) involvement ( p < .01). The incidence of moderate‐to‐severe cGvHD at 12 months was 34.5% vs. 34.5% vs. 6.2%; p < .01. Moderate‐to‐severe skin and GI cGvHD was less common after PTCy ( p < .01). The 1‐year GvHD‐free/relapse‐free survival was higher with PTCy ( p < .01). Conclusions Our study indicates that PTCy‐based GvHD prophylaxis reduces the frequency and severity of both acute and chronic GvHD, with a notable decrease in severe GI and cutaneous manifestations. The higher GRFS may result in lower GvHD‐related mortality, leading to an improved quality of life among survivors.