Phase II trial of cladribine and cytarabine in relapsed or refractory myeloid malignancies

To evaluate the efficacy of cladribine and cytarabine in children with relapsed or refractory myeloid malignancies, we administered cytarabine (200 mg/m2 per day) by continuous subcutaneous infusion and cladribine (8.9 mg/m2 per day) by continuous intravenous infusion concomitantly for 5 days to nine patients younger than 21 years. After one course, five patients had no response, two patients had partial responses, one had stable disease, and one had progressive disease. Two patients received a second course: one patient had stable disease after one course and progressive disease after the second; another patient had a partial response after one course and no response after the second. Despite the efficacy of the cladribine and cytarabine regimen in treating newly diagnosed acute myeloid leukemia (AML) in a previously reported study, the combination was not effective for relapsed or refractory childhood AML.