JS002 is a recombinant human anti-PCSK9 monoclonal antibody.The study is a multicenter, randomized, double-blind, placebo-controlled Phase III clinical study in Chinese patients with heterozygous familial hypercholesterolemia (HeFH). Objective To evaluate the efficacy and safety of JS002 150 mg (Q2W) and 450 mg (Q4W) subcutaneous injection (SC).

A randomized, double-blind, placebo-controlled Phase III clinical study evaluating the efficacy and safety of JS002 in patients with heterozygous familial hypercholesterolemia. 120 subjects are planned to be enrolled. Each subject is required a maximum of 6 weeks of screening, 24 weeks of treatment, and 8 weeks of follow-up. To evaluate the lipid-lowering efficacy of subcutaneous injection of JS002 at 24 weeks compared with placebo in heterozygous familial hypercholesterolemia patients under optimized lipid lowing therapy . Subjects meeting the study inclusion criteria will be randomly assigned in a 2:1:2:1 ratio to JS002 150 mg Q2W or JS002 450 mg Q4W or matched placebo to receive the study drug (JS002) or placebo subcutaneously for 24 weeks.

treatment cohorts: JS002 150mg Cohort:JS002 150mg or placebo treatment(JS002 :Placebo=2:1) Q2W JS002 450mg Cohort:JS002 450mg or placebo treatment(JS002 :Placebo=2:1)Q4W

Inclusion Criteria:

1. Signed informed consent.
2. Males and females ≥ 18 to ≤ 80 years of age
3. DLCN>8 in HeFH
4. Stable lipid-lowering therapies for at least 4 weeks
5. Patients with ASCVD LDL cholesterol≥1.4mmol/L at screening Patients without ASCVD LDL cholesterol≥2.6mmol/L at screening
6. Triglyceride≤4.5 mmol/L（400 mg/dL）;

Exclusion Criteria:

1. HoFH or meet the diagnostic criteria of HoFH
2. New York Heart Association (NYHA) class III or IV or last known left ventricular ejection fraction < 30%
3. History of uncontrolled arrhythmia within 90 days
4. Myocardial infarction, unstable angina, percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG) or stroke within 90 days of randomization
5. Planned cardiac surgery or revascularization.
6. Uncontrolled diabetes mellitius (HbA1c>8.0%）.
7. Uncontrolled hypertension.
8. Other conditions that the researchers considered inappropriate to participate in the study.