Administration of imatinib after allogeneic hematopoietic stem cell transplantation may improve disease-free survival for patients with Philadelphia chromosome-positive acute lymphobla stic leukemia

Patients with Ph？+？ALL that received allo-HCT were enrolled in the study. Real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was used to detect BCR-ABL transcript levels. Imatinib therapy was initiated if patient neutrophil counts were？>？1.0？×？109/L and platelet counts were？>？50.0？×？109/L, or if they displayed either elevated BCR-ABL transcript levels in two consecutive tests, or a BCR-ABL transcript level？≥？10-2 after initial engraftment. Patients receiving imatinib after relapse were assigned to the non-imatinib group. The imatinib treatment was scheduled for 3–12？months, until BCR-ABL transcript levels were negative at least for three consecutive tests or complete molecular remission was sustained for at least 3？months.A total of 82 patients were enrolled. Sixty-two patients initiated imatinib therapy post-HCT. Imatinib therapy was initiated at a median time of 70？days post-HCT. Grade 3–4 adverse events (AEs) occurred in 17.7% of patients. Ten patients (16.1%) terminated imatinib therapy owing to AEs. Among the patients in imatinib and non-imatinib groups, the estimated 5-year relapse rate was 10.2% and 33.1% (p？=？0.016), and the 5-year probability of DFS was 81.5% and 33.5% (p？=？0.000) with the median follow-up of 31？months (range, 2.5-76？months) and 24.5？months (range, 4–72？months), respectively. Multivariate analysis identified imatinib maintenance therapy post-HCT as an independent prognostic factor for DFS (p？=？0.000, hazard ratio [HR] =4.8) and OS (p？=？0.000, HR？=？6.2).These results indicate that relapse rate can be reduced and DFS may be improved in Ph？+？ALL patients with imatinib maintenance therapy after HCT. BCR-ABLmonitoring by qRT-PCR can guide maintenance therapy with imatinib including initiation time and treatment duration after allo-HCT.