Impact of post-transplant imatinib administration on Philadelphia chromosome-positive acute lymphoblastic leukaemia

To evaluate the effect of post-transplant imatinib administration, 34 Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph(+)ALL) patients were retrospectively analysed, with 7 receiving post-transplant imatinib administration. Overall survival was significantly better in patients with post-transplant administration (66.7% vs. 29.6% at 3 years, p=0.03), with no significant difference in leukaemia-free survival (0% vs. 29.6% at 3 years, p=0.29). The median duration of negative minimal residual disease (MRD) in patients with post-transplant imatinib administration was 6 months in the pre-emptive administration group, where imatinib was administered upon detecting MRD after allogeneic stem cell transplantation (allo-SCT). In the prophylactic administration group, imatinib was administered as soon as possible after allo-SCT, and the median duration of MRD was 12 months. In all patients whose observation periods were longer than one year, MRD became positive in both groups leading to haematological relapse. It is therefore concluded that post-transplant imatinib administration is not an ideal treatment for Ph(+)ALL patients whose MRD is positive at allo-SCT.