ATI-045 Versus Placebo in Patients With Moderate-to-Severe Atopic Dermatitis

Inclusion Criteria: * Diagnosis of chronic atopic dermatitis that has been present for ≥ 6 months before the screening visit and with no significant AD flares during the past 4 weeks before screening * Have active moderate to severe AD at screening and baseline visits * EASI score ≥ 16 and ≥10% BSA at the screening and baseline visits * History of inadequate response to treatment for AD with topical medications; or determination that topical treatments are otherwise medically inadvisable (e.g., because of important side effects or safety risks) * Patient applied a stable dose of non-medicated topical moisturizer (ideally once or twice daily) for ≥ 7 days prior to the baseline visit and agrees to continue use during study Exclusion Criteria: * Treatment with any of the following: 1. Intravenous immunoglobulin within 12 weeks prior to the baseline visit (W0D1) 2. Systemic antibiotics within 2 weeks prior to the baseline visit (W0D1) 3. Topical antibiotics within 1 week prior the baseline visit (W0D1) 4. Topical medicated treatment that could affect atopic dermatitis should be prohibited for at least 2 weeks prior to baseline visit. Example: topical corticosteroids, crisaborole, calcineurin inhibitors, ruxolitinib, roflumilast, tars, antimicrobials, medical devices, and bleach baths. 5. Topical products containing urea within 1 week prior to baseline visit (W0D1) 6. Doxepin, hydroxyzine, or diphenhydramine within 1 week prior to the baseline visit (W0D1) 7. Patient has used systemic treatments (other than biologics) that could affect AD less than 4 weeks or 5 half-lives (whichever is longer) prior to the baseline visit (W0D1), including, but not limited to, retinoids, calcineurin inhibitors, methotrexate, cyclosporine, hydroxycarbamide (hydroxyurea), azathioprine, oral/injectable corticosteroids, baricitinib, upadacitinib, and abrocitinib. 8. Biologics for AD treatments (such as dupilumab, tralokinumab, lebrikizumab, investigational biologics) within 5 half- lives or 12 weeks, whichever is longer prior to the baseline visit (W0D1) 9. An investigational drug (non-biologic) within 4 weeks or within 5 half-lives (if known), whichever is longer prior to the baseline visit (W0D1) 10. Phototherapy and photochemotherapy for AD within 4 weeks prior to the baseline visit (W0D1) 11. A live (attenuated) vaccine within 12 weeks prior to the baseline visit (W0D1) * History of anaphylaxis following biologic therapy. * History of allergy to corticosteroids, diphenhydramine, hydroxyzine, cetirizine, or fexofenadine.