Alzheimer's disease (AD) is a chronic neurodegenerative disease leading to cognitive decline, dementia, and ultimately death. Despite extensive R&D efforts, there are no diseases modifying treatments for AD available. The stage in which patients receive a clinical diagnosis of probable AD may be too late for disease modifying pharmacotherapy. Prevention strategies may be required to successfully tackle AD. Preclinical AD applies to over half of all healthy elderly subjects and manifests by signs of amyloid deposition and/or neuronal injury in the brain, preceding the stage in which symptoms of dementia, cognitive and functional impairment become observable. Prevention trials in preclinical AD require longer and larger clinical trials using biomarkers and cognitive endpoints, which requires collaboration across academia, government and industry.