ATLANTA — Elderly patients undergoing consolidation therapy for acute myeloid leukemia (AML) using a modified regimen of high-dose cytarabine plus the anthracycline daunorubicin experienced prolonged disease-free survival (DFS) times, according to a study presented during the 54th American Society of Hematology Annual Meeting and Exposition.
“Older patients with intermediate-risk cytogenetics, who received a modified high-dose cytarabine-based consolidation regimen combined with anthracycline, had a superior DFS and a trend toward superior overall survival [OS], as compared to those who received conventional-dose consolidation therapy,” reported Mona Hassanein, MD, PhD, MSc, of the Medical Oncology and Hematology Department at Princess Margaret Hospital in Toronto, Ontario, Canada, and colleagues.
The authors studied 164 patients diagnosed during 1998-2002 with AML at age ≥60 years, who achieved complete remission after induction therapy with continuous-intravenous (IV) infusion of cytarabine (100mg/m2 per day) for 7 days, and daunorubicin (60mg/m2 IV daily x 3), or the 7+3 regimen).Participants then underwent 2 postremission consolidation therapy regimens in sequential cohorts: during 1998-2002, cohort 1 (n=55) received 2 consolidation cycles of cytarabine 1.5g/m2 every 12 hours over 3 hours x 6 doses on days 1, 3, and 5 plus daunorubicin 45mg/m2 twice daily. Cohort 2 consisted of 109 patients treated during 2003-2008; these patients received the 7+3 consolidation regimen followed by a second cycle consisting of mitoxantrone (10mg/m2 IV daily x 5) plus etoposide (100mg/m2 IV daily x 5).
Mean age of the patients was 68.4 years in the first cohort and 69.2 years in the second cohort.
Median DFS for the first cohort was 13.4 months (range, 10.1–25.5 months), versus 8.5 months (range, 7.9–11.7 months) for the second cohort (P=0.046). Two-year DFS was 37% and 28% for the first and second cohorts and 5-year DFS, 18% and 7%, respectively.
Median OS was 25.6 months (range, 17-35.7 months) for first-cohort patients and 14.8 months (range, 11–20.9 months) for second-cohort patients (P=0.087). Two-year OS was 53% and 37% for the first and second cohorts and 5-year OS, 27% and 17%, respectively.
“Among the entire cohort (n=164), and in the subgroup with adverse risk cytogenetics, there was no significant difference in OS or DFS between the two groups,” Dr. Hassanein noted. On multivariate analysis, presenting whole blood count, secondary AML, and consolidation regimen were independent predictors of DFS.
High-dose cytarabine 3g/m2 is a standard consolidation treatment for younger patients diagnosed with intermediate-risk AML, but the optimal postremission strategy for elderly patients is “unclear,” as this regimen is associated with high rates of severe toxicity and patient death among elderly patients, the authors reported. If the new findings are confirmed, however, they “suggest that older fit patients with intermediate-risk cytogenetics should receive more intensified postremission therapy with modified high-dose cytarabine,” Dr. Hassanein and colleagues concluded.