Efficacy Of Post-Transplant Cyclophosphamide As Graft-Versus-Host Disease Prophylaxis After Peripheral Blood Stem Cell Hla-Mismatched Unrelated Donor Hematopoietic Cell Transplantation; A Prospective Pilot Trial

Mismatched unrelated donors (MMUD) has improved access to hematopoietic cell transplantation (HCT) for underrepresented minority groups. However, MMUD HCT is historically associated with inferior outcomes primarily due to the increased risk of graft-versus-host disease (GvHD), when conventional calcineurin inhibitor-based GvHD prophylaxis is used. Post-transplant cyclophosphamide (PTCy) is an established and effective agent as part of GvHD prophylaxis post haploidentical HCT, which has been increasingly used in the matched donor HCT setting. To date, there have been no prospective studies reporting the efficacy of PTCy after peripheral blood stem cell (PBSC) MMUD HCT. Here, we conducted a pilot trial to estimate the GVHD-free relapse/progression-free survival (GRFS) at one-year post HCT and to evaluate the efficacy of PTCy as GvHD prophylaxis using either an ablative or reduced intensity conditioning regimen after PBSC MMUD HCT (NCT 03128359).