Inclusion Criteria:

• Male and female adults aged ≥ 18 years (at the screening visit) with capacity to consent.
• Diagnosis of moderate-to-severe Atopic Dermatitis (AD) as defined by the Hanifin and Rajka (1980) criteria.
• AD duration of at least 3 months.
• IGA score of 2 to 3 at the screening visit.
• Treatment naïve and/or willing to pursue 30-day wash-out period if they are using topical medications, oral medications, or injectable medications.
• For participants who sign photography consent, at least 1 target lesion that measures at least 5 cm2 at the screening visit. The target lesion must be representative of the participant's disease state but not located on the hands, feet, genitalia, face, scalp, or intertriginous areas.

Exclusion Criteria:

• Unstable history of atopic dermatitis (spontaneously improving or rapidly deteriorating) as determined by the investigator over the previous 4 weeks before baseline/visit 0.
• Disease history concerns, i.e., lymphoma, immunodeficiency, chronic infections such as HIV, hepatitis, or tuberculosis, dialysis, and/or history of skin cancer within 5 years.
• Chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungals within 2 weeks before the baseline/visit 0.
• Active acute bacterial, fungal, or viral skin infection (e.g., herpes simplex, herpes zoster, chicken pox, clinically infected AD, impetigo) within 1 week before the baseline/visit 0.
• Insufficient area of uninvolved (control) skin.
• Relative contraindications to skin biopsy (e.g., serum platelets < 10; allergy to lidocaine).
• Atopic dermatitis exclusive to areas of the hands, feet, face, scalp, intertriginous areas, or genitalia.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 1/10/23. Questions regarding updates should be directed to the study team contact.