AHEAD 3-45 (NCT04468659) is an ongoing Phase III study evaluating the efficacy and safety of lecanemab in the treatment of preclinical Alzheimer’s disease. Chad Swanson, PhD, Eisai Inc., explains that the study consists of two clinical trials – A3 and A45 – examining the use of lecanemab in preclinical AD populations with either intermediate or elevated brain amyloid levels respectively. Brain amyloid levels are assessed by PET Centiloid values. Dr Swanson describes the potential implications on the treatment of early and preclinical Alzheimer’s disease in clinical practice if positive results are obtained in the Clarity AD (NCT03887455) and AHEAD 3-45 studies. Dr Swanson explains how positive results would support the hypothesis that the clearing of amyloid plaques and soluble aggregate species can slow disease progression. It would also provide evidence for the tractability of AD, as well as supporting initiatives for early diagnosis and early identification of at-risk individuals. This interview took place during the Alzheimer’s Association International Conference (AAIC), 2021.