A Study of Single and Multiple Ascending Doses of H021 in Healthy Participants

This is a Phase 1 safety study of a new experimental drug called H021 in healthy volunteers. The study gives participants increasing doses — first in single doses, then in multiple doses over time — to understand how the body absorbs, processes, and tolerates the drug. **You may be eligible if...** - You are between 18 and 55 years old - You are a non-smoker (no tobacco or nicotine for at least 3 months) - You have a BMI between 18.5 and 32.0 - You are in good general health with no significant chronic illnesses - Women must be post-menopausal or using reliable contraception **You may NOT be eligible if...** - You have a history of significant neurological, heart, liver, kidney, or psychiatric disease - You have had a significant illness or surgery in the past 4 weeks - You are pregnant or breastfeeding - You are taking medications that could interfere with the study drug Talk to your doctor to see if this trial is right for you.