A Study to Evaluate Effectiveness and Safety of a TYK2 Inhibitor in Subjects With Moderate to Severe Plaque Psoriasis

Who May Qualify: - Male and female, ages 18 to 70 years - Body weight \>40 kg, body mass index (BMI) of 18 to 40 kg/m2 - Clinical diagnosis of plaque psoriasis for ≥6 months before the Baseline visit - Women of childbearing potential (WOCBP) and males who are sexucally active must agree to follow instructions for method(s) of contraception. Who Should NOT Join This Trial: - Diagnosed with non-plaque psoriasis - Previously received tyrosine kinase 2 (TYK2) inhibitors - Previously received other psoriasis treatments such as biological agents, immunoregulators, or hormonal drugs within a specific period before administration, and the investigator deems it may affect the immunity of the subjects - Has participated in any clinical trials within 30 days or 5 half-lives of the drug before the first administration, or currently undergoing visits for other clinical trials; - Has history of chronic disease that may affect the study, or acute or chronic severe infectious diseases, such as a history of active or inadequately treated latent tuberculosis infection, severe bone or joint infections within 6 months before screening, and other acute infectious diseases. - Has known or suspected skin or systemic autoimmune conditions (where your immune system attacks your own body)s other than psoriasis and psoriatic arthritis; - Other conditions that the investigator deems unsuitable for participation in this study. Other protocol defined inclusion/exclusion criteria could apply Always talk to your doctor about whether this trial is right for you.