Allogeneic Hematopoietic Cell Transplantation (Allo-HCT) for Treatment of Pediatric Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (ALL).

Allo-HCT with best available donor for children with Philadelphia positive (Ph+) ALL has previously been considered standard practice. Since the introduction of imatinib into the treatment of this disease, the role of allo-HCT is more uncertain.

We investigated the impact of remission status, graft source, and imatinib use on transplant outcomes for thirty-seven children with Ph+ ALL who received an allo-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 after post-HCT relapse (n=1) (non-imatinib group).

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 allo-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).

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 allo-HCT with the best available donor should be encouraged in CR1.

No relevant conflicts of interest to declare.