A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Operationally Seamless, Adaptive Phase 2/3 Study to Evaluate the Efficacy and Safety of Baricitinib in Adult Patients With Severe or Very Severe Alopecia Areata

• Are at least 18 years and ≤60 years for males (≤70 years of age for females) at the time of informed consent.

• Must self-identify as either Black or African American in race in the open label addenda.

• Have severe or very severe AA, as determined by all of the following:

‣ Current AA episode of more than 6 months' duration and hair loss encompassing ≥50% of the scalp, as measured by SALT Alopecia Areata Investigator Global Assessment (AA-IGA) of 3 or 4) at screening and baseline.

⁃ No spontaneous improvement over the past 6 months.

⁃ Current episode of severe or very severe AA of less than 8 years.

• Male or nonpregnant, nonbreastfeeding female participants.