Molecular response and prognostic factors of patients with Philadelphia chromosome/BCR-ABL-positive acute lymphoblastic leukemia treated by imatinib with chemotherapy

Abstract

To evaluate the molecular response and prognostic factors of patients with Philadelphia chromosome/BCR-ABL-positive acute lymphoblastic leukaemia (Ph⁺ ALL) treated by imatinib with chemotherapy. From May 2006 to July 2012, 82 adult Ph⁺ ALL patients were enrolled in the study. Forty-eight patients combined imatinib in, and 34 patients after induction therapy. Forty-nine patients underwent allogeneic hematopoietic stem cell transplant (allo-HSCT) after 3 to 5 cycles of consolidation therapy. The molecular response of BCR-ABL mRNA was evaluated by real-time quantitative PCR in every chemotherapy course ending. The complete remission (CR) rate after the first cycle of induction chemotherapy was 76.8% (63/82), with overall CR rate of 92.7% (76/82). The CR rate in the patients combined imatinib in was higher than of those combined imatinib after the first cycle of induction chemotherapy (93.8% vs 52.9%, P<0.001). 55.3% patients BCR-ABL decreased >1 log after induction therapy. Among 76 CR patients, cumulative incidence of relapse was 27.6%, the probabilities of disease-free survival (DFS) and overall survival (OS) at 3 years were 60.5% and 70.2%, respectively. allo-HSCT was an independent favorable factor for decrease of leukemia relapse (P<0.001). allo-HSCT, imatinib combined in the first cycle of induction therapy and female were independent favorable factors for DFS (P<0.01, 0.05 and 0.01, respectively), BCR-ABL mRNA reduction at least 1 log from baseline after the first induction therapy and allo-HSCT were independent favorable factors for OS (P=0.011 and 0.027, respectively). Imatinib combined in the first cycle of induction therapy, BCR-ABL mRNA reduction at least 1 log from baseline after the first induction therapy and allo-HSCT improved outcomes of Ph⁺ ALL patients.