This is a single-center, randomized, double-blind, placebo-controlled study . The objective is to evaluate the safety , tolerability and PK profile of KHN707 tablets in Chinese healthy participants.

This study will enroll approximately 38 participants across 5 dose cohorts. Participants will be administered with a single dose or two doses of KHN707 or its matching placebo under a fasting or fed state.

The safety and tolerability will be evaluated by monitoring and assessment of AEs, clinical laboratory tests (hematology, urinalysis, biochemistry, coagulation, etc.), physical examination findings, etc.

Inclusion Criteria:

• 1.Age: 18 to 45 years old (inclusive), Male or female.
• 2.Body weight: ≥ 50 kg for male and ≥ 45 kg for female, body mass index: 19~26 kg/m2 (inclusive).
• 3. Effective contraception measures and no sperm/egg donation plan from signing the informed consent to 3 months after last dose.
• 4.Fully understand the procedures and sigh the informed consent.

Exclusion Criteria:

• 1. Participants with clinically significant abnormalities in physical examination, vital signs, 12-lead electrocardiogram, laboratory tests, abdominal ultrasound , or chest X-ray as judged by the investigator during screening .
• 2.Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) and/or bilirubin above the upper limit of normal, or creatinine (Cr) above the upper limit of normal at screening or baseline.
• 3.Positive test for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, human immunodeficiency virus (HIV) antibody and treponema pallidum antibody at ScreeningDysphagia or history of gastrointestinal diseases, liver and kidney diseases that can affect the pharmacokinetic behavior of drugs as judged by the investigator.
• 4.Participants with medical history of clinically significant conditions that may affect the study per investigator assessment-including but not limited to disorders of the central nervous, cardiovascular, respiratory, digestive, urinary, endocrine, hematologic or immune systems; malignancies; metabolic disorders; any physiological conditions interfering with trial results; or psychiatric/cerebral dysfunction disorders based on investigator determination of unsuitability..
• 5.Participants with dysphagia or a history of gastrointestinal diseases or liver/kidney diseases that, in the investigator's judgment, could affect the pharmacokinetic behavior of the drug.
• 6. Participants who have undergone surgery within 3 months prior to screening, or plan to undergo surgery during the study period, or have undergone surgery that may affect drug absorption, distribution, metabolism, or excretion.
• 7. Participants who are allergic to the investigational drug or any of its excipients, or have a history of two or more allergies to other drugs, foods, or environmental factors, or have a constitution prone to allergic symptoms such as rash or urticaria.
• 8. Participants with cardiac diseases, including but not limited to congenital long QT syndrome, torsade de pointes, or risk factors for torsade de pointes (e.g., hypokalemia, family history of long QT syndrome), current use of Class IA (e.g., quinidine or procainamide) or Class III (e.g., amiodarone or sotalol) antiarrhythmic drugs or other drugs known to affect the QT interval, or a QTc interval corrected by Fridericia's formula (QTcF) >450 ms for males or >470 ms for females at screening, or other clinically significant abnormalities on 12-lead ECG.
• 9. Participants who have taken insomnia-related medications or received insomnia-related treatment within 3 months prior to screening.
• 10. Participants who have received vaccination within 30 days prior to screening.
• 11. Participants who have used any drugs/products that affect drug absorption, metabolism, or elimination (e.g., barbiturates, carbamazepine, phenytoin, rifampin, itraconazole, ketoconazole, cimetidine, cyclosporine, macrolides, verapamil, quinolones, azole antifungals, HIV protease inhibitors, gemfibrozil, etc.) within 30 days prior to dosing.
• 12. Participants who have used any medications or health products (including herbal medicines, vitamins) for any reason within 14 days prior to the first dose of the study drug.
• 13. Participants with special dietary requirements who cannot comply with the provided diet and corresponding regulations.
• 14. Participants who have consumed any beverages or foods containing alcohol or caffeine, or engaged in vigorous exercise, or had other factors affecting drug absorption, distribution, metabolism, or excretion within 48 hours prior to the first dose; or participants who do not agree to abstain from tea, coffee, and/or caffeinated beverages and foods during the study period.
• 15. Participants who have donated blood or lost a significant amount of blood (>400 mL) within 3 months prior to screening.
• 16. Participants who have participated in another clinical trial within 3 months prior to screening.
• 17. Participants who have smoked an average of more than 5 cigarettes per day within 3 months prior to screening, or who cannot refrain from smoking during the study period.
• 18. Participants with a history of alcohol abuse, or a positive alcohol test at study admission; or participants who cannot abstain from alcohol during the study period.
• 19. Participants with a history of drug abuse, or a positive urine drug screen.
• 20. Female participants with a positive pregnancy test, or breastfeeding women.
• 21. Participants who, based on the Columbia-Suicide Severity Rating Scale at screening, or in the investigator's clinical judgment, are at risk of suicide, or have a history of suicidal or self-injurious behavior.
• 22. Participants with other factors deemed ineligible to participate in the trial by the Investigator.