This is a randomized, double-blind, placebo-controlled study to assess the efficacy and safety of abrocitinib compared to a placebo in participants aged 6 to under 12 years with moderate-to-severe AD. Participants will be screened within 28 days before the first dose to confirm eligibility. Those who meet the criteria at baseline will be randomized 2:1 to receive either abrocitinib oral suspension (at a 100 mg adult equivalent dose once daily) or a matching placebo. Participants will be stratified by their baseline vIGA score (3 or 4). They will receive either abrocitinib or a matching placebo for 16 weeks. Additionally, participants must use emollients daily and follow standardized background medicated topical therapy (e.g., low to medium potency corticosteroids) according to protocol guidelines throughout the study's treatment period.

Ritlecitinib has been approved for treating severe alopecia areata (AA) in adults and adolescents aged 12 and older in the US, EU, and other countries, based on a positive benefit/risk assessment. However, there are no approved treatments for AA in children aged 6 to under 12. Study B7981027 is being conducted to evaluate the efficacy and safety of ritlecitinib in this younger group. This study is part of the EU Pediatric Investigation Plan (PIP) and fulfills a post-marketing requirement in the US.