Intermediate-dose cytosine arabinoside and amsacrine. An effective regimen with low toxicity in refractory acute nonlymphocytic leukemia.

Results of remission induction therapy in refractory acute nonlymphocytic leukemia (ANLL) has been improved since the introduction of high-dose cytosine arabinoside. However, the toxicity of these regimens attributes to an early death rate of about 20% to 30%. The authors treated 37 poor-risk patients with ANLL with intermediate-dose cytosine arabinoside and amsacrine for remission induction. One consolidation course and no maintenance therapy was given. Eleven of 19 patients with a first relapse entered complete remission (58%); ten of 15 patients in this group older than 50 years were complete responders (67%). Median duration of second remission was 8.2 months (range, 2-14). Three of 13 patients with primarily resistant disease had a complete remission (23%), but there was no response in five patients with a myeloid blastic phase of chronic myelogenous leukemia. Side effects of this remission induction regimen were mild; no cardiac, pulmonary, or central nervous system toxicity was observed. Five patients (14%) died during the remission induction phase, three from complications during aplasia and two from refractory leukemia.