Flexible low-intensity combination chemotherapy for elderly patients with acute myeloid leukemia.

Twenty-five patients aged 57 to 88 years (median, 70 years) with acute myeloid leukemia were treated with a flexible low-intensity treatment regimen comprising mitozantrone (mitoxantrone) 6 mg/m2 administered by intravenous infusion x3 days, cytarabine 10 mg/m2 subcutaneously every 12 hours x7 to 14 days, and etoposide 100 mg orally x7 to 14 days. Seventeen of these patients had a preexisting myelodysplastic syndrome. The clinical response was correlated to the results of cytogenetic studies (23 patients) and of viability studies of leukemic blasts (7 patients). Eleven of the 25 patients achieved complete remission (CR), 8 achieved partial remission (PR), and 4 showed no response. There was 1 toxic death, and 1 patient died soon (1 week) after presentation. Treatment was well tolerated. Although myelotoxicity occurred regularly, the recovery time was < or = 3 weeks for most of the responding patients. Duration of survival for patients who had CR has ranged from 4+ to 43+ months and for patients who had PR, 3 to 16 months. Irrespective of the remission status (CR or PR), responding patients with favorable (n = 1) or intermediate (n = 10) cytogenetic findings had a significantly better survival time (median, 14 months) than did those with unfavorable (n = 7) cytogenetic findings (median, 5 months). In vitro studies showed a progressive reduction in the number of circulating blasts. The number of viable blasts 3 days after initiation of therapy appeared to give an early indication of clinical response. Treatment with a flexible low-intensity protocol seems to achieve results comparable with those reported for intensive antileukemia therapy and has much less toxicity.