Tyrosine kinase inhibitors improve long-term outcome of allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome positive acute lymphoblastic leukemia.

This study aimed to determine the impact of tyrosine-kinase inhibitors given pre- and post-allogeneic stem cell transplantation on long term outcome of patients allografted for Philadelphia chromosome-positive acute lymphoblastic leukemia. This retrospective analysis from the Acute Leukemia Working Party of EBMT included 473 de novo Philadelphia chromosome-positive acute lymphoblastic leukemia patients in first complete remission who underwent an allogeneic stem cell transplantation using an human leucocyte antigen-identical sibling or human leucocyte antigen-matched unrelated donor between 2000 and 2010. Three hundred ninety patients received tyrosine-kinase inhibitors before transplant, 329 at induction and 274 at consolidation. The Kaplan-Meier estimates of leukemia-free survival, overall survival, cumulative incidences of relapse incidence, and non-relapse mortality at 5 years were 38%, 46%, 36% and 26%, respectively. In multivariate analysis, tyrosine-kinase inhibitors given before allogeneic stem cell transplantation was associated with a better overall survival (HR=0.68; P=.04) and was associated with lower relapse incidence (HR=0.5; P=.01). In the post-transplant period, multivariate analysis identified prophylactic tyrosine-kinase inhibitors administration to be a significant factor for improved leukemia-free survival (HR=0.44; P=.002) and overall survival (HR=0.42; P=.004), and a lower relapse incidence (HR=0.40; P=.01). In conclusion, over the past decade, tyrosine-kinase inhibitors administration before allogeneic stem cell transplantation has significantly improved the long term allogeneic stem cell transplantation outcome of adult Philadelphia chromosome-positive acute lymphoblastic leukemia. Prospective studies will be of great interest to further confirm the potential benefit of the prophylactic use of tyrosine-kinase inhibitors in the post-transplant setting.