Dr Auletta on the Impact of Post-Transplant Cyclophosphamide in Hematologic Malignancies

Jeffery Auletta, MD, physician, blood and marrow transplant (BMT), Hematology/Oncology/BMT, Infectious Diseases, Nationwide Children's Hospital; professor, pediatrics, The Ohio State University College of Medicine; member, the Leukemia Research Program, The Ohio State University Comprehensive Cancer Center; member, the Center for Regenerative Medicine and Cell-based Therapies, The Ohio State University, discusses the outcomes of comparing graft-versus-host disease (GVHD)–free, relapse-free survival (GRFS) and overall survival (OS) between 8/8 and 7/8 unrelated donor hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PTCy) in patients with acute leukemia or myelodysplastic syndromes (MDS).

PTCy has now become standard practice for preventing GVHD in both recipients of HLA-matched and -mismatched unrelated donor (URD) allografts, leading to successful HCT regardless of patient ancestry. The objective of this investigation was to discern disparities in OS and GRFS between 8/8 and 7/8 unrelated donor allografts when using PTCy compared with calcineurin-inhibitor (CNI)–based approaches, and to evaluate the impact of PTCy on remaining outcome differences due to HLA disparities.

Secondary objectives included comparing GRFS, OS, and other clinical outcomes among 8/8 and 7/8 URD recipients utilizing either PTCy- or CNI-based prophylaxis. The study involved adult patients undergoing initial URD HCT between January 2017 and June 2021.

The findings from this study demonstrate that using a mismatched URD yields similar outcomes to those observed when using a matched URD when employing PTCy as prophylaxis against GVHD, Auletta reports. Notably, although there was an outcome disparity in OS between 8/8 and 7/8 URD transplants with CNI-based GVHD prophylaxis, such a disparity was not observed when using PTCy, he explains.

Additionally, GRFS was comparable between 8/8 and 7/8 URD transplants with CNI-based GVHD prophylaxis but showed equivalence when using PTCy-based GVHD prophylaxis, with the latter demonstrating superior GRFS compared with URD transplants receiving CNI-based GVHD prophylaxis, Auletta concludes.