Effect of Dupilumab (Anti-IL4Rα) on the Host-Microbe Interface in Atopic Dermatitis

This is a multi-center, randomized, double-masked, placebo-controlled trial investigating the effect of 6 weeks of dupilumab treatment on quantitative and qualitative measures of cutaneous microbial community structure, skin barrier biology, and circulating T cell profiles, in adults with chronic moderate-to-severe atopic dermatitis (AD). After obtaining informed consent, eligible participants will return to clinic for their Treatment Initiation Visit (Day 0) and will be randomized 2:1 active to placebo. Participants will receive three doses of dupilumab or placebo based on their randomization assignment. The first dose (600 mg loading dose of dupilumab or placebo) will be administered on Day 0 and the second and third doses (300 mg dupilumab or placebo) on Day 14 and Day 28, respectively. Participants will return to clinic on Days 3, 7, and 21 during the double-masked portion of the study. Participants will begin the open-label extension (OLE) at Day 42 and will receive dupilumab (600 mg loading dose \[two 300 mg injections\] for those initially randomized to the placebo group and a 300 mg dose plus placebo injection for those initially randomized to the dupilumab group). Participants will return to clinic on Days 77 and 112 during the OLE portion of the study. During all visits (Day 0-Day 112), Adverse Events (AEs), concomitant medications, and medical history will be assessed and physical exams including assessment of AD severity will be performed. Blood, urine, skin swabs, skin tape strips, and skin biopsies, as applicable, will be collected, and barrier assessments will be performed per the Schedule of Events, per protocol. Samples will be collected prior to dupilumab or placebo administration on Days 0, 14, 28, and 42. After Day 112, a follow-up call (Day 182) will be made to assess for pregnancy, current medications, and adverse events (AEs). If concerns arise between regularly scheduled visits, participants will be instructed to contact study personnel and may be asked to return to the study site for an "Unscheduled Visit." Participants may be asked to return for Unscheduled Visits, as needed for the duration of the study, to provide additional blood, skin swabs, skin tape strips, or skin biopsies,as applicable, for further mechanistic and functional studies, if biosamples are lost or destroyed, or if insufficient yields were obtained at a previous study visit.