The association of graft-versus-leukemia effect and graft-versus host disease in haploidentical transplantation with post-transplant cyclophosphamide for AML

The association of graft-versus-host disease (GVHD) and graft-versus-leukemia effect after stem-cell transplantation (SCT) is well established but with limited data in the setting of haploidentical SCT (haploSCT) with post-transplant cyclophosphamide (PTCy). We used a series of landmark analyses to investigate this association in 805 AML patients following haploSCT. On day +100, 707 patients were alive and leukemia-free, 500 had no prior acute GVHD, 137 had acute GVHD grade II and 70 had grade III-IV. Subsequent relapse rates were 20.3%, 23.2% and 15.0%, respectively (P = 0.52). Subsequent non-relapse mortality (NRM) was 8.6%, 17.8% and 38.6%, respectively (P < 0.0001). Leukemia-free survival (LFS) was 71.0%, 59.0% and 46.3%, respectively (P < 0.0001). Multivariate analysis showed that acute GVHD grade II and grade III-IV were not associated with relapse (HR 1.21, P = 0.37 and HR 1.03, P = 0.94), but were associated with increased NRM (HR 2.09, P = 0.005 and HR 6.41, P < 0.0001) and lower LFS (HR 1.47, P = 0.02 and HR 2.59, P = < 0.0001). Chronic GVHD was not associated with subsequent relapse. Extensive chronic GVHD was associated with higher NRM (HR 6.72, P < 0.0001) and inferior LFS (HR 3.29, P = < 0.0001). GVHD of any type or grade is not associated with lower relapse after haploSCT with PTCy. Severe forms are associated with higher NRM and lower survival.

Automated summary

In haploSCT patients, acute GVHD grades II and III-IV were not associated with relapse but were related to increased non-relapse mortality and lower leukemia-free survival. Chronic GVHD also had a significant impact on non-relapse mortality and survival rates.