ATG and PTCy: Monotherapy vs combination therapy for aGvHD prophylaxis

An analysis of the European Society for Blood and Marrow Transplantation (EBMT) registry comparing post-transplant cyclophosphamide (PTCy), anti-thymocyte globulin (ATG) monotherapy, and both combined for acute graft-versus-host disease (aGvHD) prophylaxis has been published in Cancer by Bazarbacji et al.¹Overall, 3,649 patients with acute myeloid leukemia (AML) receiving a haplo-identical transplant were included in the study.¹

The analysis highlighted that PTCy monotherapy is generally used as the standard of care for aGvHD prophylaxis, while ATG is an alternative, especially in Europe and Asia.

Multivariate analysis demonstrated that:

• ATG was associated with worse outcomes than PTYc across all transplant outcomes.
• PTCy and ATG combination treatment significantly reduced the incidence of Grade 2–4 (p = 0.0003) and Grade 3–4 (p = 0.018) aGvHD, without negatively impacting transplant outcomes, compared with either agent alone. 
• PTCy and ATG combination treatment did not impact rates of cGvHD compared with either agent alone.

These findings suggest that using a combined PTCy and ATG regimen could improve patient outcomes, reducing the incidence of aGvHD following transplant; prospective randomized trials are needed to confirm these results.

Clinicians might consider adopting a PTCy-ATG combination approach to enhance the effectiveness of haplo-stem cell transplant in adult AML patients lacking fully matched donors.