Hangzhou Yuhong Pharmaceutical Technology Co., Ltd.

Primary objective: To evaluate the efficacy of YH001 capsule in subjects with severe alopecia areata. Secondary objective: To evaluate the efficacy, safety and pharmacokinetic (PK) characteristics of YH001 capsule in subjects with severe alopecia areata. Exploratory objective: To explore the pharmacodynamic (PD) characteristics of YH001 capsule in subjects with severe alopecia areata.

The main purpose of the study is to evaluate the safety and tolerability of single and multiple doses of YH001 capsules in healthy Chinese adult subjects. Secondary objectives of the study are: 1. Evaluate the pharmacokinetic characteristics of single and multiple doses of YH001 capsules in healthy Chinese adult subjects; 2. Determine the maximum tolerated dose; 3. Determine the recommended dose for Phase II; 4. Evaluate the safety, tolerability and food effects on PK parameters of single doses of YH001 capsules in healthy Chinese adult subjects under fasting and high-fat meal conditions; 5. Explore the possible metabolites and metabolic pathways of YH001 capsules after oral administration.