Comparing Reduced-Dose ATG and PTCy Versus Standard ATG

By Patrick Daly - Last Updated: October 14, 2022

According to a study published in the British Journal of Haematology, low-dose antithymocyte globulin (ATG) combined with reduced-dose posttransplant cyclophosphamide (PTCy) improved graft-versus-host disease (GVHD) prevention and survival in patients who received a haploidentical peripheral blood stem-cell transplantation (haplo-PBSCT) compared with a standard ATG regimen.

The study’s authors, led by Wenli Zhang, enrolled 122 patients from 4 transplant centers between 2018 and 2022. Participants were randomized 1:1 to either PTCy 40 mg/kg/d on days 3 and 4 plus ATG 2.5 mg/kg on day 8 or to ATG 10 mg/kg. The conditioning regimen was fludarabine, busulfan, and cytarabine (FBA), and the authors reported all patients achieved myeloid engraftment.

Reduced-Dose ATG and PTCy Improves Outcomes Versus Standard ATG

According to the report, the reduced-dose PTCy and ATG group had significantly lower cumulative incidences of grade II-IV (11.5% vs 39.3%; P=.001) and grade III-IV acute GVHD (6.6% vs 24.6%; P=.014) at day 100 compared with the standard ATG group.

Additionally, the reduced-dose group had significantly improved 2-year overall survival (75.4% vs 54.1%; P=.021), disease-free survival (72.7% vs 55.0%; P=.044), and GVHD-free/relapse-free survival (61.3% vs 42.3%; P=.022) compared with standard ATG, the authors stated.

Overall, the authors suggested their findings “demonstrate that the addition of low-dose ATG to reduced-dose PTCy with FBA conditioning is a promising strategy in haplo-PBSCT.”