Salvage treatment for primary resistant acute myelogenous leukemia consisting of intermediate-dose cytosine arabinoside and interspaced continuous infusions of idarubicin: a phase-II study (no. 06901) of the EORTC Leukemia Cooperative Group.

Twenty-one patients with acute myeloid leukemia (AML) who failed to enter complete remission (CR) after first-line standard-dose remission-induction therapy with 7 days of cytarabine and 3 days of daunorubicin were treated with a salvage regimen containing intermediate-dose cytosine arabinoside (Ara-C) 2 x 500 mg/m2/day during 7 days in combination with continuous infusions of idarubicin 12 mg/m2/day on days 1, 3, and 5. Twenty patients were considered primary resistant, and one patient had a partial remission after two remission-induction courses. Overall, 11 patients (52%, 95% confidence interval: 30-74%) entered CR. Three patients died during hypoplasia and seven patients had resistant disease or a partial remission. The remission rate in this study compares favorably with the results obtained in similar patient categories. The toxicity of this salvage regimen was remarkably mild. No extramedullary toxicity was observed except for hepatic dysfunction in seven patients. The median duration of remission was 8.5 months, and ultimately, all complete remitters have relapsed except the patient who died from infectious complications after allogeneic bone marrow transplantation (BMT). This study shows that new intensive chemotherapy regimens may be effective after failure of primary treatment. Salvage regimens containing intermediate/high-dose Ara-C and/or alternative anthracyclines or anthracenes should be induced in the treatment of young patients with de novo AML.