GvHD impact on haplo-HSCT with PTCy outcomes in ALL: A retrospective EBMT registry study

The graft-versus-leukemia (GVL) effect is associated with graft-versus-host disease (GvHD) after human leukocyte antigen-matched allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute lymphoblastic leukemia (ALL). There are limited data on GvHD and GVL association following haploidentical HSCT (haplo-HSCT) with post-transplant cyclophosphamide (PTCy). 

Shimoni et al. conducted a large retrospective European Society for Blood and Marrow Transplantation (EBMT) registry study to assess the impact of acute GvHD and chronic GvHD on haplo-HSCT with PTCy outcomes in patients with B-cell or T-cell ALL (N = 516). Results were published in the British Journal of Haematology. 

Key learnings

At Day 180 post-haplo-HSCT, the incidence of aGvHD Grade 2–4 and 3–4 was 33.3% and 11.7%, respectively, while 2 years post-haplo-HSCT cGvHD (all grades) occurred in 35.3% of patients. 

The 2-year OS, RI, and NRM post-haplo-HSCT were 64.4%, 27.1%, and 17.3%, respectively. The 2-year LFS and GvHD-free relapse-free survival were 55.7% and 43.7%, respectively.

Grade 3–4 aGvHD and extensive cGvHD were associated with significantly higher NRM (HR, 1.95; p = 0.024; and HR, 3.3; p = 0.006) and reduced OS (HR, 1.91; p = 0.028; and HR, 3.27; p = 0.006), respectively.

The findings show that post-haplo-HSCT with PTCy in ALL offers no survival benefit or reduction in the incidence of relapse. Future strategies should, therefore, focus on prevention of GvHD and reduction of relapse incidence.