Study to Evaluate the Efficacy and Safety of Deuruxolitinib in Japanese Adults With Severe Alopecia Areata

This study evaluates the efficacy and safety of deuruxolitinib in Japanese Adults between 18 and 65 years of age who have 50% or greater scalp hair loss.

Inclusion Criteria: * Written informed consent has been obtained. * Japanese subjects with severe alopecia areata who are between 18 and 65 years of age, inclusive, at the time of informed consent. * Definitive diagnosis of alopecia areata with a current episode of scalp hair loss lasting at least 6 months. * SALT score of 50 or more at both Screening and Baseline. Exclusion Criteria: * Treatment with systemic immunosuppressive medications or agents, including Janus kinase inhibitors, within 4 months prior to randomization. * Treatment with biologics within 6 months prior to Screening. * Positive test results for hepatitis B virus, hepatitis C virus, or human immunodeficiency virus at Screening. * History of active tuberculosis, a positive interferon gamma release assay at Screening, or evidence of tuberculosis-related lesions on chest radiography. * Clinically significant hematologic abnormalities, hepatic impairment, or renal impairment at Screening.