A Study to Evaluate the Safety and Efficacy of ATx201 in Subjects With Moderate Atopic Dermatitis

Inclusion Criteria:

• clinically confirmed diagnosis of active atopic dermatitis

• at least a 6-month history of atopic dermatitis and had no significant flares inatopic dermatitis for at least 4 weeks before screening

• ≥2 areas of atopic dermatitis (excluding face, scalp, genitals, hands, and feet) of atleast 3 × 3 cm; with a lesional TSS of ≥5 at Day 1 for each treatment area

Exclusion Criteria:

• breastfeeding, pregnant, or is planning to become pregnant during the study.

• clinically infected atopic dermatitis

• Fitzpatrick's Skin Phototype ≥5

• Presence of any tattoos, scratches, open sores, excessive hair, or skin damages in thetarget lesion areas

• known to have immune deficiency or is immunocompromised.

• history of cancer or lymphoproliferative disease within 5 years prior to Day 1.

• major surgery within 8 weeks prior to Day 1 or has a major surgery planned during thestudy.

• clinically significant medical condition or physical/laboratory/vital signsabnormality that would, in the opinion of the investigator, put the subject at unduerisk or interfere with interpretation of study results.

• known history of chronic infectious disease (e.g., hepatitis B, hepatitis C, orinfection with human immunodeficiency virus).

• used hydroxyzine or diphenhydramine within 1 week prior to Day 1.

• used dupilumab within 12 weeks prior to Day 1.

• received any nonbiological investigational product or device within 4 weeks prior toDay 1

• used crisaborole and any other topical PDE-4 inhibitor within 4 weeks prior to Day 1.

• used doxepin within 1 week prior to Day 1.

• used topical products containing urea within 1 week prior to Day 1.

• used nonurea-containing emollient anywhere on the body from 1 day before Day 1.

• used systemic antibiotics or topical antibiotics on the treated areas within 2 weeksprior to Day 1.

• used any topical medicated treatment for atopic dermatitis within 2 weeks prior to Day 1, including, but not limited to, topical corticosteroids, calcineurin inhibitors,tars, bleach, antimicrobials, medical devices, and bleach baths.

• used systemic treatments (other than biologics) that could affect atopic dermatitisless than 4 weeks prior to Day 1 (e.g., retinoids, calcineurin inhibitors,methotrexate, cyclosporine, hydroxycarbamide [hydroxyurea], azathioprine,oral/injectable corticosteroids).

• received any marketed or investigational biological agent within 12 weeks or 5half-lives (whichever is longer) prior to Day 1.

• excessive sun exposure, is planning a trip to a sunny climate, has receivedultraviolet phototherapy, or has used tanning booths within 4 weeks prior to Day 1, oris not willing to minimize natural and artificial sunlight exposure during the study.Use of sunscreen products (excluding the treatment areas) and protective apparel arerecommended when exposure cannot be avoided.

• known or suspected allergy to ATx201 or any component of the investigational product.

• known history of clinically significant drug or alcohol abuse in the last year priorto Day 1.

• history of an allergic reaction or significant sensitivity to lidocaine or other localanesthetics.

• history of hypertrophic scarring or keloid formation in scars or suture sites.

• taking anticoagulant medication, such as heparin, low molecular weight-heparin,warfarin, or antiplatelets (nonsteroidal anti-inflammatory drugs and aspirin ≤81 mgwill not be considered antiplatelets) within 2 weeks prior to Day 1, or has acontraindication to skin biopsies.