This is a global Phase 2 study to evaluate the safety and effectiveness of an investigational study drug (called SHR0302) in adults with moderate to severe alopecia areata.

The study is placebo-controlled, meaning that some patients entering the study will not receive active study drug but will receive tablets with no active ingredients (a placebo). This is a dose-ranging study, investigating 3 different dosing regimens. It will be double-blinded, meaning that the sponsor, the study doctors, the staff, and the patients will not know whether a patient is on active study drug (or the dose) or placebo.

Inclusion Criteria:

• Male or female subjects between 18-65 years of age (both inclusive), at the time of informed consent;
• Must have moderate to severe alopecia areata.

Exclusion Criteria:

• Other types of alopecia or other diseases that can cause hair loss
• Other scalp diseases that could interfere with assessment of hair loss/regrowth
• Any previous use of any Janus kinase (JAK) inhibitor