Low-dose ARA-C fails to enhance differentiation of leukaemic cells.

Nine patients with acute myelogenous leukaemia were treated with low-dose ARA-C (10 mg/m2, q 12h) for a planned 21 d. Complete remission was attained in only one patient (11.1%). Definite cytoreductive effect was seen in four additional patients. There was one treatment-related death. Haematologic toxicity occurred in all nine patients with sever thrombocytopenia most prominent. Severe hepatotoxicity precluded further ARA-C treatment in one patient. Because of toxicity only two patients were able to complete their scheduled 3 week courses of low-dose ARA-C. No evidence of ARA-C induced differentiation of leukaemic cells was noted on follow-up bone marrow examination during or shortly after the treatment course. The utility and indication for low-dose ARA-C therapy of AML remains to be determined.