A Study Evaluating APG777 in Atopic Dermatitis

Inclusion Criteria:

• Have a diagnosis of AD that has been present for >=1 year prior to the Screeningvisit

• Moderate-to-severe AD at Screening and Baseline visits

• History of inadequate response to treatment with topical medications, or medicaldetermination that topical therapies are inadvisable

• Applied a stable dose of non-medicated over-the-counter emollient/moisturizer oftheir choice on their skin for >=14 days prior to Baseline visit and agrees tocontinue using the same moisturizer throughout the study except the day of the studyvisits.

• Have completed itch questionnaires in the electronic diary for >=4 of 7 days priorto Baseline visit

Exclusion Criteria:

• Participation in a prior study with APG777.

• Prior treatment with protocol-specified monoclonal antibodies (mAbs)

• Has used any AD-related topical medications within 7 days prior to Baseline visit.

• Has used systemic treatments (other than biologics) and/or phototherapies and/orlaser therapy that could affect AD within 4 weeks prior to Baseline visit

Note: Other protocol defined inclusion/exclusion criteria may apply.