APOE and Alzheimer disease: There were 1653 and 1638 people with early Alzheimer’s disease [MCI attributable to Alzheimer’s disease (80%) or moderate Alzheimer’s disease (20%)] in two identically planned 18-month randomized, double-blind, placebo-controlled, parallel-group investigations (ENGAGE and EMERGE), respectively.31 Patients were randomly assigned (in a 1:1:1 ratio) to receive placebo or low-dose aducanumab (3 mg/kg for carrier of APOE-ε4 allele and 6 mg/kg otherwise) and high-dose aducanumab (6 mg/kg for carrier of APOE-ε4 allele and 10 mg/kg otherwise).