The effect of first-line imatinib interim therapy on the outcome of allogeneic stem cell transplantation in adults with newly diagnosed Philadelphia chromosome–positive acute lymphoblastic leukemia

Abstract

AbstractPreviously, we suggested that imatinib incorporation into conventional chemotherapy as an alternative (imatinib interim therapy) might be a useful strategy for bridging the time to allogeneic stem cell transplantation (SCT) for newly diagnosed Philadelphia chromosome–positive acute lymphoblastic leukemia (Ph+ ALL). Here, we provide an updated report on this strategy in 29 patients. At the time of enrollment, 23 patients (79.3%) achieved complete remission (CR). After the first imatinib cycle, the median breakpoint cluster region–Abelson oncogene locus (BCR-ABL)/ABL ratios decreased by 0.77 log in 25 (86.2%) responders, and their BCR-ABL/ABL ratios decreased further by 0.34 log after the second imatinib cycle, which included 7 molecular CR. One patient (4.3%) relapsed during the imatinib therapy. The remaining 3 patients were primarily refractory to both imatinib and chemotherapy. Twenty-five (86.2%) of the 29 patients received transplants in first CR. With a median follow-up duration of 25 months after SCT, the 3-year estimated probabilities of relapse, nonrelapse mortality, disease-free survival, and overall survival were 3.8%, 18.7%, 78.1%, and 78.1%, respectively. In comparison to our historical control data, first-line imatinib interim therapy appears to provide a good quality of CR and a survival advantage for patients with Ph+ ALL. Further long-term follow-up is needed to validate the results of this study.