UC Irvine

The purine nucleoside analogues clofarabine and fludarabine are active in acute myeloid leukemia (AML). We conducted a phase I/II randomized study of idarubicin and cytarabine with either clofarabine (CIA) or fludarabine (FIA) for relapsed or refractory AML. Clofarabine 15 mg/m² was identified as the recommended phase II dose. Eighty-one patients were assigned using adaptive randomization to CIA (n = 48) or FIA (n = 33). The complete response (CR)/CR without platelet recovery rate did not differ between CIA and FIA (38% versus 30%, respectively; p = .50). In both arms, more than half of patients who had received only one prior line of therapy achieved remission. The median event-free survival for CIA and FIA was 2.0 and 1.9 months (p = .48), and the median overall survival was 6.3 and 4.7 months, respectively (p = .28). No significant differences in adverse events or early mortality rates were observed. Overall, CIA and FIA resulted in similar response rates and survival in patients with relapsed/refractory AML.