Have severe Alopecia Areata (AA) that meets all of the following criteria:
* Hair loss encompassing ≥50% and ≤90% of the scalp, as measured by Severity of Alopecia Tool (SALT) score
* The duration of the current episode of severe AA is at least 6 months and does not exceed 4 years
* No significant spontaneous hair regrowth in the investigator's opinion for at least 6 months
* Agree not to use any AA treatments during the study
You may not be if
Primarily "diffuse" type of AA (characterized by diffuse hair shedding)
Are currently experiencing other forms of alopecia
Participants who, in the opinion of the investigator, are currently experiencing or have a history of unstable concomitant disease that requires frequent hospitalizations, and/or frequent use of systemic immunosuppressants that may interfere with participation in the study
Have received oral JAK Inhibitors in the past
Have had any major surgery within 8 weeks prior to screening or will require major surgery during the study
Have a history or presence of cardiovascular, respiratory, hepatic, gastrointestinal, endocrine, hematological, neurological, or neuropsychiatric disorders or any other serious and/or unstable illness
