Allogeneic hematopoietic cell transplantation (allogeneic HCT) for treatment of pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL)

Background. Allogeneic hematopoietic cell transplant (HCT) with best available donor for children with Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) has previously been considered standard practice. Since the introduction of imatinib into the treatment of this disease, the role of allogeneic HCT is more uncertain. Procedure. We investigated the impact of remission status, graft source, and imatinib use on transplant outcomes for 37 children with Ph+ ALL who received an allogeneic HCT at the University of Minnesota between 1990 and 2006. The median age at HCT was 7.47 (range; 1.4-16.4) years. Thirteen patients received imatinib therapy pre- and/or post-HCT (imatinib group) and 24 patients, received either no imatinib (n = 23) or only post-HCT relapse (n = 1) (non-imatinib group). Results. There was no difference in disease-free survival (DFS) or relapse between the imatinib and non-imatinib groups at 3 years (62%/15% vs. 53%/26%; P = 0.99; 0.81, respectively). There was no significant difference in transplant outcomes between matched related donor or unrelated donor (umbilical cord blood or matched unrelated marrow) recipients whereas patients receiving allogeneic HCT in first remission (CR1) had superior DFS and less relapse compared to patients transplanted in ≥CR2 (71%/16% vs. 29%/36%; P = 0.01; P = 0.05). Conclusions. Based on this retrospective analysis at a single institution, the use of imatinib either pre- and/or post-transplant does not appear to significantly impact outcomes for children with Ph+ ALL and allogeneic HCT with the best available donor should be encouraged in CR1.