A PHASE 3 MULTI-CENTER, LONG-TERM EXTENSION STUDY INVESTIGATING THE EFFICACY AND SAFETY OF ABROCITINIB, WITH OR WITHOUT TOPICAL MEDICATIONS, ADMINISTERED TO SUBJECTS AGED 12 YEARS AND OLDER WITH MODERATE TO SEVERE ATOPIC DERMATITIS

B7451015 is a Phase 3 study to evaluate Abrocitinib with or without Topical Medications in patients aged 12 years and older who have moderate to severe atopic dermatitis and have completed a qualifying parent study. The efficacy and safety of two dosage strengths of Abrocitinib, 100 mg and 200 mg taken orally once daily, will be evaluated over variable lengths of study participation. The study consists of a 92 week initial treatment period followed by a variable length secondary treatment period during which subjects will receive treatment with open-label abrocitinib until availability of commercial product in their country, or until the sponsor terminates the study in that country. The B7451015 study also includes a sub-study evaluating whether abrocitinib has any potential effects on adolescent bone with regard to abnormal bone findings in knee MRI. The sub-study will be conducted in selected countries at selected sites. Eligible subjects are those who were 12 to \<18 years of age at the screening visit of the qualifying parent study and who are currently participating in the main B7451015 study. The sub-study will include serial Magnetic Resonance Imaging (MRI) annually and continue until all enrolled subjects are 18 years of age and have been imaged at least once or have discontinued/withdrawn.