Treatment of acute nonlymphocytic leukemia in adults: response to 2,2-anhydro-1-B-D-arabinofuranosyl-5-fluorocytosine and thioguanine on the L-12 protocol.

Fifty-one adult patients with acute nonlymphocytic leukemia (excluding acute promyelocytic leukemia) were treated on the L-12 protocol. The L-12 differed from the preceding L-6 in that 2,2-anhydro-1-B-D-arabinofuranosyl-5-fluorocytosine (AAFC), replaced arabinosylcytosine (ara-C) together with 6-thioguanine (TG) for remission induction. Achievement of remission was followed by an extended 14-week multi-drug consolidation program. With this more intense regimen, an overall complete remission rate of 49% and a median remission duration of 23.7 months were achieved; these results were not significantly better than the 57% complete remission rate and 8.6 months median remission duration obtained with the L-6 regimen. Four year disease-free survival was 22% on the L-12 compared with 16% on the L-6 protocol. No relationship between prognosis and FAB classification was found on either the L-6 or the L-12 protocol.