The effect of imatinib therapy on the outcome of allogeneic stem cell transplantation in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia.

Objective: To evaluate the efficacy of imatinib administration before and/or after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL).

Method: Patients with imatinib therapy time exceeding 30 days pre-/post-transplant were screened in our data. Imatinib was used in induced or consolidated chemotherapy pre-transplant, or maintenance therapy after 60 days post-transplant (therapy time was less than 180 days) regardless of the molecular status of the disease.

Results: Sixty-nine patients with Ph+ ALL were enrolled in the retrospective analysis. Forty-four patients received imatinib therapy, including 24 pre-transplant, 9 post-transplant, and 11 both pre- and post-transplant. With a median follow-up time of 395 days (range, 55-2762 days) post-transplant, 3-year estimated overall survival was 62.3 ± 16.6, 40.0 ± 21.9, 41.7 ± 22.2, and 25.9 ± 11.4%, respectively (P = 0.221), and disease-free survival (DFS) was 53.6 ± 17.9, 20.0 ± 17.9, 33.3 ± 25.5% and 23.6 ± 11.4%, respectively (P = 0.421), in patients with imatinib therapy pre-transplant, post-transplant, both pre- and post-transplant, neither pre- nor post-transplant. The incidence of relapse at 3 year for patients with imatinib therapy post-transplant (n = 20) was 63.6%, comparing with 24.2% (P = 0.018) in patients without imatinib therapy post-transplant (n = 49). The ratio of CD4+CD25+Foxp3+ cells in blood was significantly higher at 30 and 60 days after imatinib therapy than that at the time of pre-imatinib in 20 patients (P = 0.019 and 0.001, respectively).

Conclusions: Application of imatinib pre-transplant might have benefited for patients with Ph+ ALL. Whether administration of imatinib, regardless of the molecular status of the disease post-transplant increases relapse, is a worthy goal for further study.