Safety and Efficacy of IBI306 in HeFH Patients

The study plans to enroll 148 patients with heterozygous familial hypercholesterolemia. Subjects will maintain a low-fat diet and stable current lipid-lowering therapy for at least 4 weeks and will be randomized into different dose groups at a 1:1 ratio, followed by a 2:1 randomization double-blind treatment with subcutaneous IBI306 150 mg (n=49) or placebo (n=25) every two weeks; or subcutaneous injection of IBI306 450mg (n=49) or placebo (n=25) every four weeks. Treatment lasts for 12 weeks. After 12 weeks, each group enters a 12-week open-label treatment, in which IBI306 subjects continue to receive IBI306, and placebo subjects shift to receive IBI306. The primary endpoint is the percent change in LDL-C levels relative to baseline at 12 weeks. Secondary endpoints include changes in baseline lipid levels, drug safety, and immunogenicity at 12 weeks and 24 weeks. The exploratory endpoint is the population pharmacokinetic profile of IBI306 in Chinese subjects with heterozygous familial hypercholesterolemia. If necessary, the dose of IBI306 will be adjusted accordingly based on the results of the ongoing multi-dose escalation study. After the open period, the subjects will be given a safety visit for 8 weeks.