This study focuses on patients with atopic dermatitis, a chronic inflammatory skin condition that causes itchy, red, and inflamed skin. The research evaluates a medication called APG777, which is given as a subcutaneous injection (an injection under the skin). The purpose is to assess the long-term safety and effectiveness of APG777 in people with moderate-to-severe atopic dermatitis who have previously received this treatment.

The study will involve participants who have already completed an earlier trial of APG777. During this extended treatment period, participants will continue receiving APG777 injections for up to three years. Some participants may receive a placebo during the study. Throughout the study, participants will be allowed to use non-medicated moisturizers to help manage their skin condition.

The research will monitor how well the medication controls atopic dermatitis symptoms over time, including improvements in skin appearance, reduction in affected areas, and relief from itching. The study will also track any side effects that may occur during the extended treatment period. Regular assessments will measure the amount of APG777 in participants’ blood to understand how the medication works in the body over a longer period.