Lower Risk Of Graft Versus Host Disease After Exposure To Checkpoint Inhibitors With The Use Of Post-Transplant Cyclophosphamide Prophylaxis

Background: Allogeneic hematopoietic stem cell transplantation (alloHCT) remains a curative approach for patients with AML/MDS. Still, up to 50 % of patients relapse after alloHCT. Immune checkpoint inhibitors (ICI) are being used in the post-transplant setting to reverse the immune dysfunction that contributes to AML/MDS relapse. However, a major concern with using ICI post alloHCT is the increased risk of graft versus host disease (GVHD). A variety of pre- and post- transplant factors can play a crucial role in exacerbating GVHD. We performed a retrospective analysis to report our experience with ICIs used after alloHCT in AML/MDS patients with a focus on the impact of post-transplant cyclophosphamide (PTCy).