Treatment of "poor risk" acute nonlymphocytic leukemia with continuously infused low-dose cytosine arabinoside.

There is currently little experience using a continuous intravenous infusion of low-dose cytosine arabinoside (LDARA-C) in the treatment of acute nonlymphocytic leukemia (ANLL). We report the results in 12 patients with ANLL described as either relapsed ANLL, ANLL with a preceding myelodysplastic phase, or ANLL in the elderly treated with 14 days of continuous intravenous LDARA-C (20 mg/m2/day). Complete responses (CR) were seen in five patients (42%) and partial responses (PR) in three patients (25%). Treatment resulted in overall and clonal cytoreduction, which was evident by serial bone marrow exams and bone marrow cytogenetic analysis. The ability to obtain a CR correlated with the finding of a low initial marrow cellularity (P less than .05). This study finds that continuous intravenous infusion of LDARA-C for ANLL can achieve response rates comparable to standard induction programs in a subset of patients traditionally defined as having a poor prognosis.