Alzheimer’s disease therapies are typically evaluated one drug at a time and too late in the disease course when substantial neurodegeneration has already occurred. Stand-alone prevention trials are slow, costly, and lack scalable blood-based screening mechanisms to efficiently evaluate interventions in individuals not yet showing signs of cognitive impairment. This project will establish and operate a national, biomarker-guided adaptive clinical trial platform to test 5 to 10 preventive combinations simultaneously in asymptomatic to very early-stage Alzheimer’s disease.