Comparison of the effects of early intensified induction chemotherapy and standard 3+7 chemotherapy in adult patients with acute myeloid leukemia.

BACKGROUND: Standard remission induction chemotherapy consisting of anthracycline plus cytarabine (3+7) is administered for adult acute myeloid leukemia (AML). However, the effects of intensified regimen on complete remission (CR), relapse and overall survival (OS) remain unknown.

METHODS: We analyzed 1195 patients treated with idarubicin plus cytarabine/BHAC (3+7) from 2002 to 2013. Among them, 731 received early intensification with 3-day cytarabine/BHAC (3+10, N=363) or 2-day idarubicin plus cytarabine/BHAC 3 days (5+10, N=368). The 3+10 and 5+10 strategies were applied to patients with bone marrow blast counts of 5-20% and >20% on day 7 of 3+7, respectively.

RESULTS: Early intensification correlated with a younger age (median: 40 vs. 45 yr) and higher t(8;21) frequency (20.4% vs. 7.1%), compared to 3+7. After early intensification, the early death rates were higher among the elderly (3+10 [15.7%], 5+10 [21.7%] vs. 3+7 [6.3%], P =0.038), while the post-induction CR rate was higher in young patients (3+10 [79.8%], 5+10 [75.1%] vs. 3+7 [65.1%], P <0.001). Early relapse rate was also decreased (3+10 [11.8%], 5+10 [11.7%] vs. 3+7 [22.0%], P <0.001). In multivariate analysis, early intensification correlated with an inferior 5-year OS among elderly patients (19.2% vs. 22.8%; hazard ratio [HR]=1.84, 95% confidence interval [CI]; 1.11-3.06, P =0.018) and lower overall relapse rate among young patients (33.0% vs. 41.4%, P =0.023; HR=0.71, 95% CI; 0.55-0.93, P =0.012).

CONCLUSION: Early intensification correlated with higher CR and lower relapse rates, but not OS in young AML patients. In elderly patients, early intensification correlated with a higher early death rate and poorer OS.