Post-Transplantation Cyclophosphamide vs ATG for GVHD Prophylaxis Among Patients Undergoing Allogeneic Stem Cell Transplant From Mismatched Unrelated Donors

Results of a retrospective multicenter analysis demonstrated that post-transplantation cyclophosphamide (PTCy) yielded survival and non-relapse mortality (NRM) benefit compared to rabbit anti-thymocyte globulin (rATG) treatment for graft-versus-host disease (GVHD) prophylaxis among patients undergoing peripheral blood allogeneic stem cell transplantation (alloSCT) from mismatched unrelated donors (MMUD).

“In Europe, it is standard practice to use rabbit anti-thymocyte globulin to reduce the high NRM and GVHD risks after MMUD alloSCT,” wrote Olaf Penack, MD, PhD, Charité Universitätsmedizin Berlin, Berlin, Germany. “As an alternative to rATG, post-transplantation cyclophosphamide is in increasing clinical use.”

Investigators analyzed the outcome of rATG vs PTCy prophylaxis among adult patients with hematologic malignancies undergoing first peripheral blood alloSCT from MMUD (9 out of 10 antigen match) between January 2018 and June 2021 from the European Society for Blood and Marrow Transplantation (EBMT) database. Additionally, multivariate analyses were performed using the Cox proportional-hazards regression model. In the final analyses, 2,123 patients were included, with 583 treated with PTCy and 1540 treates with rATD. It was noted that 2 years after alloSCT, a lower NRM was demonstrated in the PTCy group of 18% vs 24.9% in the rATG group (P = 0.028, hazard ratio [HR] 0.74.)

Analyses results demonstrated that overall survival (OS) in the PTCy cohort was higher at 65.7%, vs 55.7% in the rATG cohort (P < 0.001, HR 0.77.) Additionally, progression-free survival (PFS) measured better among patients in the PTCy cohort, with 59.1% vs. 48.8% with rATG (P = 0.001, HR 0.78.) The incidences of chronic GVHD and acute GVHD were not significantly different between the groups.

Penack and colleagues concluded, “We found significantly lower NRM as well as higher survival in recipients of peripheral blood alloSCTs from MMUD receiving PTCy as compared to rATG. The results of this analysis suggest an added value of PTCy as GVHD prophylaxis in MMUD alloSCT.”

Source:

Penack O, Abouqateb M, Peczynski C, et al. PTCy versus ATG as graft-versus-host disease prophylaxis in mismatched unrelated stem cell transplantation. Published online 15 March 2024. doi: 10.1038/s41408-024-01032-8