AHEAD 3-4/5 Study: A Study to Evaluate Efficacy and Safety of Treatment With Lecanemab in Participants With Preclinical Alzheimer's Disease and Elevated Amyloid and Also in Participants With Early Preclinical Alzheimer's Disease and Intermediate Amyloid

Purpose of the Study

The primary purpose of this study is to determine whether treatment with lecanemab is superior to placebo on change from baseline of the Preclinical Alzheimer Cognitive Composite 5 (PACC5) at 216 weeks of treatment (A45 Trial) and to determine whether treatment with lecanemab is superior to placebo in reducing brain amyloid accumulation as measured by amyloid positron emission tomography (PET) at 216 weeks of treatment (A3 Trial).

What to Expect

Over the course of the 4 years you will:

• Be randomly assigned to a study group: Lecanemab (study drug) or placebo (saline solution, containing no active drug product). You do not get to pick your study group. You and your study doctor will not know if you are on the study drug or placebo.
• Come into the UCSF clinic for 22 study visits
• Have 55 intravenous (into the vein, or IV) infusions of lecanemab or placebo every 4 weeks for about 4 years
• Undergo brain scans (MRI and PET)
• Complete questionnaires and undergo tests of your memory and daily functioning, including computerized testing
• Undergo blood draws