Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases plasma low-density lipoprotein-cholesterol (LDL-C) by decreasing the expression of the LDL-receptor on hepatic cells. Ongericimab (JS002) is a novel PCSK9 monoclonal antibody that exhibits a long-acting LDL-C lowering effect by exclusively inhibiting PCSK9 in pre-clinical studies. Two randomized, double-blind, placebo-controlled trials were conducted to evaluate the safety, tolerability, efficacy, immunogenicity, pharmacokinetic, and pharmacodynamic profiles of ongericimab in healthy subjects and patients with hypercholesterolemia. Eighty-four healthy subjects in the phase Ia study received a single dose of placebo or ongericimab (15-450 mg). Ninety patients with hypercholesterolemia in the phase Ib/II study received placebo or ongericimab 150 mg Q2W, 300 mg Q4W, or 450 mg Q4W for 12 weeks. Ongericimab exhibited non-linear kinetics. The apparent clearance decreased as the dosage increased, with terminal elimination half-life (t1/2) values of 4.5-6.5 days. Overall, ongericimab was well tolerated in both studies. A single dose of ongericimab reduced LDL-C levels by 30%-73% in healthy subjects, and repeated doses of ongericimab reduced LDL-C levels by 67%-80% in patients with hypercholesterolemia. At the end of the dosing interval in the phase Ib/II study, over 70% of patients' LDL-C levels decreased by more than 50% from baseline. The results showed that ongericimab had a significant long-acting LDL-C lowering effect with good safety and potential for clinical application.