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

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.