This is a first in Chinese population study to evaluate the safety, tolerability, PK and PD of multiple dose of modified-release IBI353 administered orally in healthy subjects. The study enrolls 20 healthy subjects and consists of 1 week of screening, 3 weeks of treatment period and 1 week of safety follow up after completion of last dose.

Inclusion Criteria:

1. Healthy male or female 18 to 45 years of age at the time of consent
2. BMI of 19-27Kg/m2 and weight of 50-100kg (male) or 45-100kg (female)
3. Participants are in good health condition at screening stage based on past history, lab tests, EEG, physical examinations, and vital signs.
4. Must provide written informed consent, and in the investigator's opinion, subject is able to understand the nature of the study and any risks involved in participation, and willing to cooperate and comply with the protocol restrictions and requirements

Exclusion Criteria:

1. Subjects who have a medical history of liver, kidney, cardiovascular, nervous / mental, gastrointestinal, respiratory, urinary, endocrine system;
2. Subjects who have a history of relapse or chronic infection, or a history of acute infection treated by antibiotics within 3 months;
3. Subjects who have previously used PDE4 inhibitor dugs;
4. Subjects who have clinically significant abnormalities determined by vital signs, physical examination, and laboratory measurements;
5. Subjects who are not suitable for this trial due to other reasons In the investigator' opinion