Outcomes of elderly de novo acute myeloid leukemia treated by a risk-adapted approach based on age, comorbidity, and performance status

Several criteria to define fitness for induction chemotherapy in elderly acute myeloid leukemia (AML) have been proposed; however, no studies have reported outcomes according to the application of a risk-adapted approach. We treated 256 consecutive patients with elderly AML (≥60 years) with a risk-adapted approach based on age, comorbidity score (CS), and performance status (ECOG). Eighty-five low-risk patients (age≤65 years and ECOG 0-1 with CS<2), 86 intermediate-risk patients (age>65 years or ECOG=2 with CS<2), and 85 high-risk patients (ECOG>2 or CS≥2) were treated with induction chemotherapies, including standard intensive regimens, abbreviated-scheduled regimens, and modified low-dose cytarabine with oral etoposide (mLDAC), respectively. Overall response rates (ORR; complete response and complete response with incomplete recovery) for these three groups were 71.8%, 60.5%, and 41.2%, respectively, without a significant difference in early death rate (17.6%, 25.6%, 23.5%, P=0.415). Among three abbreviated-scheduled regimens, a gemtuzumab ozogamicin (GO)-containing regimen (n=43) showed a similar ORR rate (72.1%) to the intensive regimen. After achieving remission, 142 patients went on postremission treatments, including reduced-intensity allogeneic transplantation (RIC, n=41), standard consolidation (n=71), and repeated mLDAC (n=30) according to donor availability, age, ECOG, and CS. Multivariate analyses revealed that not only RIC, but also repeated mLDAC, resulted in significantly superior survival outcomes to standard consolidation independent of age, ECOG, and CS. Clinical benefits of mLDAC for high-risk patients and abbreviated induction with GO for intermediate-risk patients should be confirmed with further studies. Our results also suggest that RIC should be actively considered in elderly AML as a postremission treatment.