High-dose ara-C and etoposide in refractory or relapsing acute leukemia

A total of 32 patients (15 men and 17 women) presenting with relapsing or refractory acute leukemia were treated with a 3-h infusion of 3 g/m2 cytosine arabinoside (ara-C) twice daily on days 1-6 and a 1-h infusion of 100 mg/m2 etoposide on days 1-5. In all, 6 subjects had acute lymphocytic leukemia (ALL); 25 had acute myeloid leukemia (AML) of types M1 (n = 6), M2 (n = 10), M4 (n = 5), and M5 (n = 4); and 1 had mixed-type leukemia. The median age was 35 years (ranges, 16-62 years). Of the patients presenting with AML, 11 were primarily refractory and 3 became refractory after their first relapse. Six subjects had an early first relapse following a complete remission (CR) that lasted less than 6 months and five, a second relapse. Another patient underwent a primary relapse after greater than 6 months but had been heavily pretreated. In all, 5 subjects with refractory AML achieved a CR (36%; 95% confidence interval (CI), 10%-62%) as did 7 patients exhibiting relapsing AML (58%; CI, 30%-86%). Three patients who had relapsing or resistant ALL achieved a CR. Side effects consisted of severe hematotoxicity associated with granulocytopenia of less than 500/mm3 that lasted for a mean of 23.6 days and thrombocytopenia of less than 20,000/mm3 whose mean duration was 20.8 days. Marked gastrointestinal toxicity and infections were also prevalent. Cutaneous and ocular toxicity as well as allergic, pulmonary and cerebellar side effects were observed in a few cases. We conclude that the combination of high-dose ara-C and etoposide is a powerful but toxic induction regimen for refractory or relapsed acute leukemia.