Adjustment of the clinical development plan for this product globally

This is a randomized, double-blind, placebo-controlled, single dose escalation phase 1 study. The objective of this study is to evaluate the safety, tolerability, pharmacokinetics pharmacodynamics and immunogenicity of subcutaneous administered SHR-1703 in healthy subjects.

The study will consist of one dose esclation part with a total of 3 dose levels. The Subjects will be randomized to receive SHR-1703 as reflected by the guiding principle for the dose esclation/expansion phase. Each dose group includes a screening period, a baseline period, an observational period, and a safety follow-up period.

Inclusion Criteria:

1. Healthy Caucasian subjects, male and female, 18 to 55 years of age, inclusive;
2. Body weight ≥45 kg (Both male and female), body mass index (BMI) between ≥19.0 and ≤29.9 kg/m2, inclusive;
3. No clinically significant abnormalities in medical history, general physical examination, vital signs, laboratory tests (hematology, urinalysis, blood chemistry and coagulation function) and ECG at the investigator's discretion during screening and baseline.
4. Men and women of childbearing potential (WOCBP) must agree to take effective contraceptive methods and have no plan to have a child from signing the consent form to 30-days after last scheduled follow-up visit.

Exclusion Criteria:

1. Known history or suspected of being allergic to the study drug.
2. Positive hepatitis B virus (HBsAg), hepatitis C virus (HCV-Ab), human immunodeficiency virus (HIV-Ab) at screening.
3. Participation in clinical trials of other investigational drugs or medical devices within 3 months prior to screening or within 5 half-lives of any drugs during screening visit, or in the follow-up period of a clinical study whichever is longer
4. Use of any medicine within 4-weeks prior to the IP administration
5. Blood donation or loss of more than 400 mL of blood within 1 month of screening; or received blood transfusion within 2 months before screening.
6. Live (attenuated) vaccination within 1 month before screening or plan to be vaccinated
7. Severe injuries or major surgeries within 6 months before screening or plan to do surgeries during the trial
8. Patients with known or suspected parasitic infection within 6 months before screening
9. Either ALT, AST, ALP, GGT or total bilirubin level exceeds upper limit of normal range (ULN) at screening or baseline visits (confirmed by a single repeat, as per investigator's judgment)
10. More than 5 cigarettes daily (or products with equivalent amount of nicotine) for 3 months prior to screening.
11. History of alcohol abuse within 3 months prior to the IP administration