Plaque, Amyloid

The purpose of this study is to see how safe LY4560736 is and to see how much and how quickly LY4560736 gets into the bloodstream. For healthy participants, the study also looks at how much LY4560736 gets into the brain. This part of the study lasts up to 13 weeks which includes staying in the Clinical Research Unit (CRU) for at least 4 days. This group will include Japanese participants, and the Sponsor may choose to enroll Chinese participants. For participants with Alzheimer's Disease, the study will also look at levels of a specific Alzheimer's-related protein in the brain and will last up to 13 weeks which includes staying in the CRU twice, each lasts about 1 to 2 days. Japanese participants, and potentially Chinese participants, may also be enrolled in this group.

The purpose of this Master Protocol is to support multiple studies looking at safety and tolerability of different drugs in healthy participants and participants with Alzheimer's disease, and if they remove clumps of protein (amyloid plaque) in the brain in participants with Alzheimer's Disease. Participants will enroll into either A1D-MC-AT01 (NCT07787182) or A1D-MC-AT02 (upcoming).

The purpose of this study is to see how safe LY4405094 is and to see how much and how quickly LY4405094 gets into the bloodstream. For healthy participants, the study also looks at how much LY4405094 gets into the fluid around the brain and lasts up to 13 weeks and will include a 4-day stay in the Clinical Research Unit (CRU). For participants with Alzheimer's Disease, the study will also look at levels of a specific Alzheimer's-related protein in the brain and will last up to 25 weeks and will include a 3-day stay in the CRU.

The main purpose of this study is to determine if participants who previously took donanemab get clinical benefit when they receive annual doses. For each participant, the study will last up to 2.5 years and will include 6 visits.