Abrocitinib Treatment of Atopic Dermatitis in Children 2 to Less Than 6 Years of Age

This is a 16-week, randomized, double-blind, placebo-controlled study to assess the efficacy and safety of abrocitinib compared to placebo in participants aged 2 to <6 years with moderate-to-severe AD. Participants will be screened within 28 days prior to the first dose of study intervention to confirm study eligibility. Participants who continue to meet eligibility criteria at baseline will be randomized 2:1 to abrocitinib oral suspension (at 100 mg adult equivalent dose level [AED] once daily [QD]) or matching placebo. Participants will be stratified by their baseline vIGA (score of 3 or 4). At the starting dose level of 100 mg QD AED, the dose volume (in mL of oral suspension) will depend on the participant's body weight.

Inclusion criteria

• Children aged 2 to <6 years at the time of informed consent /assent.

Disease Characteristics:

• All participants must meet all of the following criteria:
• A documented diagnosis of chronic AD for at least 1 year prior to screening and confirmed at screening and baseline visits according to the Hanifin and Rajka criteria;
• A diagnosis of moderate-to-severe AD at the baseline visit (must fulfill all of the following criteria: BSA ≥10%, vIGA ≥3, EASI ≥16 and WSI-NRS ≥4).

For countries outside the US:

Eligible participants must have:

• a documented history within 6 months before the screening visit of inadequate response to treatment with topical medicated therapy for AD (eg, TCS and TCI) for at least 4 weeks, or;
• required at least 1 systemic therapy for control of their disease.

For US only:

Eligible participants are those whose disease is not adequately controlled with at least 1 systemic therapy or when the use of systemic therapies is inadvisable.

• Prior systemic therapies may include biologics such as dupilumab, oral agents such as corticosteroids, cyclosporine, methotrexate Note that an inadequate response to topical treatments alone is not sufficient for eligibility in the US.

Other Inclusion Criteria:

• Body weight ≥10 kg.

Exclusion criteria

• Any medical or psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
• Skin infections that require treatment with systemic antimicrobials within 2 weeks prior to Day 1 (Baseline), or have non-typical pediatric superficial skin infections (excluding common self-limiting viral conditions such as verruca vulgaris and molluscum contagiosum) within 1 week of Day 1. History of systemic infection requiring hospitalization or parenteral antimicrobial therapy or as otherwise judged clinically significant by the investigator within 1 month prior to Day 1.
• Have a history (single episode) of disseminated herpes zoster or disseminated herpes simplex, or a recurrent localized, dermatomal herpes zoster.
• Infection with HIV, hepatitis B, and/or hepatitis C.
• Evidence of active TB or inadequately treated latent TB.
• Prior treatment with a systemic JAK inhibitor for AD.
• Live attenuated vaccination within 6 weeks prior to Day 1 or require vaccination with live attenuated vaccines during treatment or within 6 weeks after the last dose of study intervention.
• Concomitant use of strong inhibitors and inducers of CYP2C19 enzymes, strong inducers of CYP2C9 enzymes, sensitive P-gp substrates with narrow therapeutic index and sensitive CYP2C19 substrates with narrow therapeutic index are not allowed in the study.