A Study of SAL003 in Participants With Hypercholesterolemia and Mixed Dyslipidemia

This is a multicenter, randomized, double-blind, placebo-controlled, Phase 3 clinical trial. The study consists of four periods: a Screening Period (up to 1 week), a Run-in Period (2 weeks), a Double-blind Treatment Period (12 weeks), and an Extended Treatment Period (40 weeks), with a total study duration of approximately 55 weeks per participant. Approximately 600 participants will be randomized. Eligible participants must be aged 18-75 years with a fasting LDL-C level between 2.6 mmol/L and 4.9 mmol/L, who are either statin-naïve or have washed out from lipid-lowering drugs for at least 3 months. Key exclusion criteria include familial hypercholesterolemia, established atherosclerotic cardiovascular disease (ASCVD), uncontrolled hypertension, poorly controlled diabetes, and significant hepatic or renal impairment. In the Double-blind Period, participants will be stratified by baseline LDL-C (\<3.4 mmol/L or ≥3.4 mmol/L) and randomized to receive either SAL003 140 mg or placebo via subcutaneous injection every 4 weeks for 3 doses (Days 1, 29, and 57). After completing the 12-week double-blind period, all participants will enter the Extended Treatment Period and receive open-label SAL003 140 mg Q4W for 10 additional doses (from Week 12 to Week 52). The primary efficacy endpoint is the percent change from baseline in LDL-C at Week 12. Key secondary endpoints include the change from baseline in LDL-C at Week 12, the proportion of participants achieving LDL-C target goals at Week 12 and Week 52, and the percent change from baseline in other lipid parameters (e.g., TC, TG, Non-HDL-C, ApoB) at Week 12 and Week 52. Safety, immunogenicity, and pharmacokinetics will be assessed throughout the study. The primary analysis will be performed on the Full Analysis Set (FAS) using a repeated measures mixed-effects model (MMRM) to compare the least-squares mean difference between the SAL003 and placebo groups at Week 12.