[Clinical effects of low-dose Ara-C in acute nonlymphocytic leukemia and myelodysplastic syndromes]

Forty-eight patients with acute nonlymphocytic leukemia (ANLL) and myelodysplastic syndromes (MDS) were treated with low-dose Ara-C regimen (LDAC) (10 mg/m2 or 10 mg/body subcutaneously every 12 hours). Complete remission (CR) was obtained in sixteen patients (33%) and partial remission (PR) in six (16%). Seven of eight patients with hypoplastic leukemia entered CR. However, LDAC was not effective in MDS and ANLL developing from MDS. The rate of CR was 20% in relapsed or refractory ANLL. Relapse was occurred in thirteen patients until now. The median duration of remission was 7 months (range: 3-20 months). Seven of the sixteen patients who achieved CR were received LDAC at the same dose for 10 days every month as a maintenance therapy. The duration of CR of these patients was shown to be longer than that of the patients without any maintenance therapy. Myelosuppression was observed in nearly all of them and the other clinical findings including cytogenetic analysis indicated cytotoxicity rather than differentiation as the mechanism of LDAC. LDAC was effective especially in hypoplastic leukemia and the maintenance therapy was found to prolong the duration of CR.