US intergroup study of chemotherapy plus dasatinib and allogeneic stem cell transplant in Philadelphia chromosome positive ALL

Abstract

Abstract: This multicenter trial was conducted to determine whether the addition of dasatinib to chemotherapy followed by an allogeneic hematopoietic cell transplant (HCT) in patients with Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) was feasible. Patients ≥18 and ≤60 years of age with newly diagnosed Ph+ ALL received up to 8 cycles of alternating hyperfractionated cyclophosphamide, vincristine, Adriamycin, and dexamethasone and high-dose cytarabine and methotrexate with dasatinib. Patients with an available matched sibling or unrelated donor underwent an allogeneic HCT in first complete remission (CR1), followed by daily dasatinib starting from day 100. Others received maintenance therapy with vincristine and prednisone for 2 years and dasatinib indefinitely. Ninety-seven patients (94 evaluable) with a median age of 44 years (range, 20-60 years) and median white blood cells at presentation of 10 × 109/L (range, 1-410 × 109/L) were accrued. Eighty-three patients (88%) achieved CR or CR with incomplete count recovery (CRi), and 41 underwent allogeneic stem cell transplant in CR1. Median follow-up is 36 months (range, 9-63). For the overall population, overall survival (OS), event-free survival, and relapse-free survival (RFS) at 3 years were 69%, 55%, and 62%, respectively. The 12-month RFS and OS after transplant were 71% and 87%, respectively. Landmark analysis at 175 days from the time of CR/CRi (longest time to HCT) showed statistically superior advantages for RFS and OS (P = .038 and P = .037, respectively) for the transplanted patients. Addition of dasatinib to chemotherapy and HCT for younger patients with Ph+ ALL is feasible and warrants further testing.