A Phase I Study of SSGJ-716 in Healthy Adults and Participants With Moderate-to-Severe Atopic Dermatitis

The purpose of this Phase 1 study is to evaluate the safety and tolerability of a new investigational drug called SSGJ-716 in healthy adults and in participants with moderate-to-severe atopic dermatitis (AD). The study has two parts. The first part (Single Ascending Dose, SAD) will enroll healthy adults.The second part (Multiple Ascending Dose, MAD) will enroll participants with moderate-to-severe AD.

Inclusion Criteria: Able to understand protocol requirements and sign a written ICF. Male or female subjects aged 18-45 years when signing the ICF. Male subjects with body weight ≥ 50 kg, and female subjects with body weight ≥ 45 kg. Subjects with BMI between 18 and 28 kg/m2. Subjects whose test results are normal, or abnormal without clinical significance as determined by the investigator. Female subjects with childbearing potential and male subjects (and their female partners) must agree to take highly effective contraceptive measures. Exclusion Criteria: History of severe allergy, or with a history of allergy to the study treatment or related excipients. With any clinically significant diseases prior to the screening visit. Subjects with positive test results for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (HCV) antibody, anti-human immunodeficiency virus (HIV) antibody. History of of significant alcohol abuse. History of significant drug abuse. Subjects who have positive result for urine nicotine test at screening. Pregnant, or nursing females.