This is a phase I, randomised, single-blind placebo-controlled, 2-part study to assess the safety, tolerability, pharmacokinetics, pharmacodynamics and food effect of single and multiple oral doses of HRS-6257 in healthy volunteers.

Inclusion Criteria:

1. Aged between 18 and 55 years old (based on the time of signing the informed consent form), both males and females are eligible.
2. The body weight of males ≥ 50 kg, and that of females ≥ 45 kg, and body mass index (BMI): 19 - 28 kg/m².
3. Female subjects must be non-pregnant or non-childbearing potential;
4. Subjects must understand the study procedures and methods, voluntarily participate in this study and sign the ICF in person.

Exclusion Criteria:

1. History of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological disease;
2. Known or suspected hypersensitivity to trial product(s) or related products;
3. 12-lead ECG demonstrating QTcF >450 msec or history or risk factors for QT prolongation;
4. Blood donation of more than 200 mL within the last 6 months
5. Use of prescription or nonprescription drugs and dietary and herbal supplements within 14 days or 7 half-lives;
6. Positive screening tests for hepatitis B or C, HIV, alcohol, drugs of abuse.
7. Previous administration with an investigational product (drug or vaccine) within 3 months;