This is a Phase 1 first-in-human, 2-part adaptive study. Both Part A and Part B will be performed in a randomized, placebo-controlled, and double-blind manner.~Part A - Single Ascending Dose (SAD) Part A will be a SAD study investigating multiple dose levels of ATH 1020.~Part B - Multiple Ascending Dose (MAD) Part B will be a multiple ascending dose (MAD) study investigating multiple dose levels of ATH-1020.~Subjects in Cohort B5 (4 subjects) will additionally undergo CSF sampling pre-dose on Day 4 and up to 3 post dose timepoints to evaluate ATH-1020 blood-brain-barrier penetration
This Phase 1 randomized, placebo-controlled, double-blinded, first-in-human study will evaluate safety, tolerability, and pharmacokinetics of single and multiple ascending doses of ATH-1020 in healthy young and elderly subjects.