Parkinson Disease Psychosis

This clinical trial will test whether AGB101 (low-dose levetiracetam, 220 mg, extended release tablet) can improve symptoms of psychosis in Parkinson's disease. Participants will be asked to complete up to 5 in-person study visits over approximately 20 weeks. Participants will receive both AGB101 and a placebo to take once a day for 6 weeks, with a 4-week washout in between. Participation will also involve physical/neurological exams, questionnaires, paper and pencil tests, providing blood and urine samples, and completing two MRI exams.

It is hypothesize that patients with clinically diagnosed neurodegenerative diseases will have significantly different receptor occupancy of 5HT2A receptors compared to a healthy age/sex-matched control group. This will be tested by measuring 5HT2A receptor density using the PET radioligand (R)-\[18F\]MH.MZ in both populations.

This study consists of 2 parts. Part A is a randomized, open-label, 2-period, crossover study to evaluate the food effect of LY03017 in healthy adults. Part B is a single-arm study to evaluate the safety and pharmacokinetics of LY03017 in elderly volunteers.

The purpose of this study is to evaluate the safety, tolerability and pharmacokinetics and pharmacodynamics of oral doses of FB418 in healthy adult subjects and healthy elderly subjects.