Safety and Efficacy of Upadacitinib in Combination With Topical Corticosteroids in Children From 2 to Less Than 12 Years of Age in Japan With Moderate to Severe Atopic Dermatitis

Inclusion Criteria: * A minimum weight of 10 kg and weight and height ≥ -2.0 SD for their age according to Japanese standard growth charts at the Baseline visit. * Atopic Dermatitis (AD), according to Hanifin and Rajka criteria, with onset of symptoms at least 6 months prior to Baseline. * Eczema Area and Severity Index (EASI) score ≥ 16; validated Investigator Global Assessment scale for Atopic Dermatitis (vIGA-AD) score ≥ 3; ≥ 10% body surface area (BSA) of AD involvement at the Baseline visit; and Baseline weekly average of daily WIS or WSI-NRS ≥ 4. * Participant has applied a topical, additive-free, bland emollient or moisturizer twice daily for at least 7 days before the Baseline visit. * Documented history (within 6 months of the Baseline visit) of inadequate response or intolerance to topical corticosteroids (TCS) and/or topical calcineurin inhibitors (TCI) or a systemic immunomodulating therapy, or medical inadvisability of available systemic therapy (e.g., because of important side effects or safety risks). Exclusion Criteria: * Participants that have current and/or history of other active skin diseases (e.g., psoriasis or Netherton syndrome or lupus erythematosus) or skin infections (bacterial, fungal, or viral) requiring systemic treatment within 4 weeks of the Baseline visit or that would interfere with the appropriate assessment of AD lesions. * Participants that have used topical treatments for AD (except for topical emollient or moisturizer treatments) including but not limited to TCS, TCI, or topical PDE-4 inhibitors, within 7 days of the Baseline visit or any the following prohibited AD treatments within the specified timeframes below prior to the Baseline visit: * Systemic therapy for AD, including but not limited to corticosteroids and cyclosporine, within 4 weeks; * Targeted biologic treatments within 5 half-lives (if known) or within 12 weeks, whichever is longer; * Phototherapy treatment, laser therapy, tanning booth use, or extended sun exposure that could affect disease severity or interfere with disease assessments within 4 weeks.