A Phase I, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Single Ascending Doses of SIM0811 Injection in Healthy Chinese Adult Subjects

This study plans to set up 5 dose groups across 7 cohorts, including intravenous bolus plus infusion administration as well as intravenous bolus alone. The study plans to enroll 8 subjects per cohort (investigational drug: placebo = 6:2), including both males and females, totaling 56 healthy subjects. The study begins with dose-escalation enrollment starting from Cohort 1. Each cohort receives a single dose, sequentially completing Cohorts 2, 3, 4, 5, 6, and 7. After each cohort's dosing is completed, a 7-day observation period is conducted for safety evaluation. If the termination criteria are not met, the study may proceed to the next dose level following assessment by the Safety Review Committee. By collecting adverse events, as well as abnormal indicators from vital signs, electrocardiograms, and laboratory tests, and collecting blood samples at planned time points to measure SIM0811 plasma concentration and thrombotic molecular markers, the study aims to evaluate the tolerability and safety of SIM0811 injection in Chinese healthy adult subjects, characterize its pharmacokinetic profile after single-dose administration, and explore the change curves of thrombotic molecular markers (plasmin-α2 antiplasmin complex PIC, fibrin degradation products FDP)