This study tests a new drug, LY3962681, on two groups: healthy people and Parkinson’s disease patients. The study has two parts:

• Single Ascending Dose (SAD): Healthy volunteers get one dose of LY3962681 or a placebo (a fake drug) into the spine.
• Multiple Ascending Dose (MAD): Parkinson’s patients get two doses of LY3962681 or placebo, spaced 12 to 24 weeks apart, also into the spine.

Key Points:

• SAD treatment lasts 1 day, MAD treatment involves 2 days over 12-24 weeks.
• Both studies include a follow-up period of up to 52 weeks.
• Participants must be healthy or stable with Parkinson’s and meet specific health criteria.

In the SAD study, participants must be healthy. For the MAD study, participants need a stable Parkinson’s diagnosis and must manage medications without changes for 6 months. Some conditions, like significant kidney problems or other serious illnesses, can exclude participants. Always consult a doctor to understand risks and benefits before joining a clinical trial.