High-dose, continuous-infusion cyclophosphamide, cytarabine, vincristine, and prednisone for remission induction in refractory adult acute leukemia.

Fifteen consecutive patients with refractory adult acute leukemia (RAAL) were treated with a combination of high-dose, continuous-infusion cyclophosphamide, cytarabine, vincristine, and prednisone (Hi-COAP). The initial nine patients received cyclophosphamide 350 mg/m2 as a 24-hour intravenous (IV) infusion over 5 days; cytarabine, 100 mg/m2 IV bolus every 12 hours for ten doses; vincristine, 2.0 mg IV bolus on day 1; and prednisone, 100 mg orally for 7 days. The last six patients had the cyclophosphamide infusion lengthened to 7 days, and the cytarabine increased to 14 doses. All patients were evaluable for toxicity and response. Seven patients (47%) obtained a complete remission and six patients (40%) a partial remission. Median duration of all remissions has been 7.0 months with a range of 1 to 32 months. Toxicity has been limited to primarily myelosuppression with no hemorrhagic cystitis, central nervous system (CNS), hepatic, or pulmonary toxicity noted. Gastrointestinal toxicity was mild, with no effect on nutritional status noted. Median duration of complete responders was 8.5 months. Thus, Hi-COAP demonstrates promising efficacy with minimal toxicity in RAAL and warrants further exploration in multiinstitutional trials.