This study was a single-center, randomized, double-blind, placebo-controlled study divided into a Single Ascending Dose (SAD) stage and a Multiple Ascending Dose (MAD) stage. The primary objective was to evaluate the safety and tolerability of KH607 tablets in Chinese healthy volunteers.

This study consists of two parts: Part 1-SAD phase and Part 2- MAD phase. There will be eight cohorts in Part 1 and three cohorts in Part 2 of this study.

The SAD study will enroll approximately 58 HVs across 8 dose cohorts. The dose cohorts will include the following dose levels: 2 mg, 5 mg, 10 mg, 20 mg, 30 mg, 40 mg, 50mg and 60 mg. All participants in Part 1 will be administered with a single oral dose of KH607 or its matching placebo under fasted condition.

Approximately 30 HVs will be enrolled in the multiple ascending dose study. The dose cohorts will include the following dose levels: 10 mg, 20 mg, 30 mg.At each cohort, 10 subjects will be randomized in a ratio of 8:2 to be receive KH607 or placebo once daily for continuous 7 days (QDx7d) in a double-blind manner.

Additionally, this study will explore the effect of food on the PK of a single oral administration of KH607 in one selected SAD cohort.

Inclusion Criteria:

1. Adult, male and female volunteers, 18 to 55 years of age, inclusive.
2. Male weight ≥ 50kg, female weight ≥ 45kg, and body mass index ≥ 19 to ≤ 28 kg/m2 at the screening period.

Exclusion Criteria:

1. Vulnerable groups include the Investigator and his or her immediate family members (spouse, parents, children, siblings), non-immediate family members involved in the study, or individuals who may be participating under coercion or undue influence.
2. Subjects whose C-SSRS suggests that they are at risk for suicide at the screening period, or with the risk for suicide based on the Investigator's clinical judgment, or with a history of suicidal or self-harming behavior.
3. Subjects with SSS ≥3 or MOAA/S ≤4 during the screening period.
4. Subjects with a history of surgery for gastrointestinal disorders or current GI disorders that may interfere with drug absorption, or who have undergone major surgery within the 3 months prior to the screening period.