Study to Evaluate the Efficacy and Safety of CTP-543 in Adults With Moderate to Severe Alopecia Areata (THRIVE-AA1)

Inclusion Criteria:

• Clinical presentation compatible with alopecia areata with a current episode lastingat least 6 months and not exceeding 10 years at the time of Screening. Total diseaseduration greater than 10 years is permitted.
• At least 50% scalp hair loss, as defined by a Severity of Alopecia Tool (SALT) score ≥50, at Screening and Baseline.
• Willing to comply with the study visits and requirements of the study protocol.

Exclusion Criteria:

• Treatment with other medications or agents within 1 month of Baseline or during thestudy that may affect hair regrowth or immune response.
• Active scalp inflammation, psoriasis, or seborrheic dermatitis requiring topicaltreatment to the scalp, significant trauma to the scalp, or other scalp condition thatmay interfere with the SALT assessment, or untreated actinic keratosis anywhere on thebody at Screening and/or Baseline.
• Treatment with systemic immunosuppressive medications within 3 months of Screening orduring the study, or biologics within 6 months of Screening or during the study.
• Females who are nursing, pregnant, or planning to become pregnant while in the study,and for 30 days after last dose of study drug.
• Clinically significant medical condition, psychiatric disease, or social condition, asdetermined by the Investigator, that may unfavorably alter the risk-benefit of studyparticipation, adversely affect study compliance, or confound interpretation of studyresults.