[Tyrosine kinase inhibitor maintenance therapy following allogenic hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia]

There have been many reports regarding tyrosine kinase inhibitor (TKI) administration to prevent relapse following allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). However, there are no commonly accepted standards for the choice of TKIs. We retrospectively analyzed the clinical features of Ph+ALL patients who received TKIs after allo-HSCT at our institution. The prophylactic administration of TKIs (pro) occurred in eight patients, and six patients received preemptive TKI administration (pre). The median follow-up period after allo-HSCT was 1,427 (range, 161-2,428) days in the pro group and 773.5 (range, 156-2,243) days in the pre group. Only one patient with non-hematological complete remission before allo-HSCT relapsed among the patients in the pro group. In the pre group, four patients treated with only TKIs achieved negativity of minimal residual disease. The 2-year overall survival rate after allo-HSCT was 85.7% in the pro group and 100% in the pre group. We used lower doses of TKIs compared with previous reports and this analysis shows that the dose is safe and effective as the treatment.