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

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.