This clinical trial is focused on studying Early Alzheimer’s Disease, a condition that affects memory and thinking skills. The study will evaluate a treatment called JNJ-63733657, which is an anti-tau monoclonal antibody. Monoclonal antibodies are special proteins made in a lab that can attach to specific substances in the body. In this case, the treatment targets tau, a protein that can form tangles in the brain of people with Alzheimer’s Disease.

The purpose of the study is to assess the effectiveness and safety of JNJ-63733657 compared to a placebo. Participants will receive the treatment as a solution for infusion, which means it will be given through a vein. The study will follow a randomized, double-blind, placebo-controlled design. This means that participants will be randomly assigned to receive either the treatment or a placebo, and neither the participants nor the researchers will know who is receiving which until the study is completed. The study will also include a long-term extension period to gather more information about the treatment’s effects over time.

Throughout the study, participants will be monitored for changes in their condition using a tool called the iADRS, which measures both cognitive abilities and daily functioning. The study aims to observe any changes from the start of the trial to the end, which is planned to last for several years. This research hopes to provide valuable insights into the potential benefits of JNJ-63733657 for individuals with Early Alzheimer’s Disease.