In matched unrelated donor hematopoietic cell transplantation setting, the use of anti-thymocyte globulin is currently a standard of care. However, in acute lymphoblastic leukemia, we demonstrated in our retrospective analysis that the use of ATG was associated with increased risk of relapse. Now we have an alternative, which is post-transplant cyclophosphamide, more and more popular across European and worldwide centers, and this also used the context of MUD for ALL patients...
In matched unrelated donor hematopoietic cell transplantation setting, the use of anti-thymocyte globulin is currently a standard of care. However, in acute lymphoblastic leukemia, we demonstrated in our retrospective analysis that the use of ATG was associated with increased risk of relapse. Now we have an alternative, which is post-transplant cyclophosphamide, more and more popular across European and worldwide centers, and this also used the context of MUD for ALL patients. So in our study, we compare these two approaches, ATG versus post-transplant cyclophosphamide for ALL patients with good a MUD HCT. In the unified analysis, we found that the use of ATG was associated with an increased risk of relapse and a reduced probability of leukemia-free survival. In the multivariate model, adjusted for other prognostic factors, we confirmed the effect on leukemia risk, leukemia-free survival, which was reduced from patients who took ATG compared to PTCy.
So altogether, although the study was retrospective, we think it is justified to recommend PTCy as the backbone of immune suppression for patients treated with MUD HCT with ALL and first complete remission. Obviously, our findings require verification in prospective trials.