Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ICP-538 in Healthy Subjects

Inclusion criteria

• Voluntarily sign the ICF..
• BMI between 18-26 kg/m² (inclusive). Male weight ≥50 kg; female weight ≥45 kg.
• Vital signs, physical examination, ECG, Chest X-ray, Abdominal ultrasound results at screening are within normal range or showing minor deviations deemed not clinically significant by the investigator.
• Laboratory test results at screening and baseline are within the normal reference range.
• Reproductive Status：Females of non-childbearing potential . Male participants and their partners must agree to use effective contraception throughout the study and for 3 months after the last dose. Male participants must not donate sperm during this period.

Exclusion criteria

• Evidence or history of clinically significant diseases, or Evidence or history of allergic diseases .
• Clinically significant gastrointestinal dysfunction that may affect drug intake, transport, or absorption.
• Acute illness within 14 days before dosing.
• Severe infection within 6 months before dosing, or chronic/recurrent infections.
• Participant and/or first-degree relative with hereditary immunodeficiency.
• Major trauma or surgery within 3 months before dosing.
• History of active/latent TB or contact with an open TB case within 6 months before dosing.
• Positive urine drug screen.
• Alcohol abuse.
• Use of tobacco/nicotine products within 3 months before the first dose.
• Use of any prescription/non-prescription drugs, herbal medicines, supplements within 14 days before first dose; or systemic corticosteroids, immunosuppressants/modulators, hormone replacement therapy within 30 days before first dose; or any other factor affecting drug absorption, distribution, metabolism, and excretion.
• Consumption of caffeine-containing foods/beverages within 48 hours before the first dose.
• Use of known CYP3A4 inducers/inhibitors within 14 days or 5 half-lives (whichever is longer) before the first dose.
• Dieting, dietary therapy within 30 days before the first dose.
• Positive for syphilis antibody, HCV-Ab, HBsAg, HBcAb, or HIV-Ab at screening.
• Administration of live vaccines within 6 weeks before the first dose or planned during study or within 8 weeks after study.