This study tests if **sabirnetug**, a medicine given through an IV once every four weeks, can help slow down memory and thinking problems in people with early Alzheimer's disease. Alzheimer's is a disease that affects the brain, making it hard to remember things and think clearly. The study compares sabirnetug to a placebo, a treatment that doesn't contain active medicine. To join, participants must weigh between 66 and 352 pounds and meet other health conditions. They must also have a partner or caregiver who can help them throughout the study. Some people cannot join, like those with certain brain or mental health issues, or those with metal implants that make MRI scans unsafe.

• Duration: Participants receive treatment every four weeks.
• Visits: Regular clinic visits are required for infusions and tests.
• Eligibility: Certain health conditions and medications are required or not allowed.