High dose cytarabine and mitoxantrone: an effective induction regimen for high-risk acute myeloid leukemia (AML).

Patients with high-risk AML, defined as those with advanced age, relapsed/refractory disease, unfavorable molecular and cytogenetic abnormalities, therapy-related myeloid neoplasm (t-MN) and multiple medical co-morbidities tend to respond poorly to standard cytarabine and daunorubicin induction therapy and have a poor prognosis. We performed a retrospective analysis of an alternative induction regimen using high dose cytarabine (HiDAC) and mitoxantrone (MITO) administered to 78 high-risk patients with AML at The University of Chicago from 2001 to 2008. The primary endpoints of the study were complete remission (CR) rate and death within 30 days of initiation of treatment. The median age was 63 years (range:23-85); 27% of these patients had a Charlson co-morbidity index (CCI) > 2. Forty-three (56%) patients had unfavorable cytogenetics, 28 (37%) had intermediate-risk cytogenetics and 5 (7%) had favorable cytogenetics. The CR rate was 45% and the CRi rate 10%; 7 patients (9%) died during induction. Notably, t-MN and relapsed/refractory patients had CR and induction death rates equivalent to de novo AML patients within this series. In this high risk AML population, HiDAC/MITO induction demonstrated an overall response rate of 55% with a low induction death rate of 9% and allowed 32 (41%) patients to proceed to allogeneic stem cell transplant.