A Phase I Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics Profile of YKYY033 Injection

This is a randomized, double-blind, ascending-dose Phase 1 clinical study to investigate the safety and tolerability of YKYY033 when administered in healthy adult male and female participants

Inclusion criteria

• Participant must voluntarily consent to participate in this study and provide their written informed consent prior to start of any study-specific procedures.
• Participant must be between 18 and 55 years of age (inclusive), male or female.
• Participant's body mass index (BMI) must be between 19 and 28 kg/m^2 (inclusive). The body weight should be ≥50 kg for men and ≥45 kg for women.

4．Participants (including their spouses or partners) are willing to sign the informed consent form and have no plans to have children or donate sperm (eggs) within 6-12 months after administration, and voluntarily take effective contraceptive measures (including abstinence, condoms, intrauterine devices, etc.) 5. Participants are able to communicate effectively with the investigators and understand and comply with the requirements of this study.

Exclusion criteria

• History or present history of clinically significant hematological, circulatory, respiratory, digestive, urinary, neurological, immune, endocrine, or psychiatric disorders, or other diseases that investigators believe may affect the safety of participants in the study.
• History or evidence of any abnormal bleeding or coagulation disorders, or there may be coagulation dysfunction (such as Von Willebrand disease, hemophilia), long-term or unexplained clinically significant bleeding, or evidence of frequent unexplained bruising or thrombosis, or have a history of spontaneous bleeding, or diseases with increased risk of bleeding (such as active and meaningful peptic ulcers judged by investigators.
• Individuals with a history of cardiovascular diseases, including but not limited to myocardial infarction, congenital heart disease, heart valve disease, coronary revascularization, angina, heart failure, and other heart diseases and arrhythmias that may cause QT prolongation; Or there may be other risk factors that lead to tip twisting ventricular tachycardia; Or there may be a history of atrial flutter, atrial fibrillation, or other conditions that may interfere with electrocardiogram measurements.
• History of intolerance to SC injection or significant abdominal scars that may significantly affect the administration of the investigational drug or the assessment of local safety.
• Major surgery within 6 months prior to screening (such as heart, brain, liver, kidney, knee replacement, or other surgeries that researchers believe may affect the conduct of the trial), or have undergone surgeries that may affect drug absorption, distribution, metabolism or excretion, or plan to undergo surgery during the study.
• Evidence of acute febrile illness or active infection within 7 days prior to administration.
• An abnormal result judged by the physician during the screening period to be clinically significant in physical examination, vital signs examination, laboratory examinations (blood routine, urine routine, blood biochemistry) or other auxiliary examination results.
• The coagulation time (APTT), prothrombin time (PT), or international normalized ratio (INR) are outside the normal range specified by the laboratory (except for those who are mildly below the lower limit of normal (LLN) and have no other coagulation function indicators combined with abnormalities) during the screening period.
• An abnormal result judged by the physician to be clinically significant in the 12-lead electrocardiogram, or the adjusted QTc interval ≥450 ms for males and ≥470 ms for females, or PR interval ≥210 ms, or QRS interval ≥210 ms.
• During the screening process, any of the urine drug abuse screening results were positive, or screen for individuals with a history of drug abuse or drug use within the past 3 years.
• Any one of hepatitis B surface antigen, hepatitis C antibody, treponema pallidum antibody and HIV antibody was positive during screening.
• Pregnant women (with positive serum pregnancy results) and lactating women during screening.
• Those who have special dietary requirements and cannot accept unified dietary arrangements during the study.
• Drink strong tea, coffee, and/or caffeinated beverages daily (≥ 8 cups/day, 1 cup=250mL) within 3 months before administration; Or ingested any food or drink containing caffeine (such as coffee, strong tea, cola, chocolate, etc.) or xanthine (such as animal viscera, sardine, soy products, etc.) within 48 hours before randomization.
• Smoking more than 5 cigarettes per day within the first 3 months of screening; During hospitalization, the use of any tobacco products (such as cigarettes, electronic cigarettes) cannot be stopped.
• The average weekly alcohol consumption within the first 3 months of screening is greater than 14 units (1 unit of alcohol ≈ 355 mL of beer or 45 mL of spirits with an alcohol content of 40% or 150 mL of wine); Or the alcohol breath test result is positive; Or randomly select individuals who cannot abstain from alcohol within the first 48 hours and during hospitalization.
• There is any previous history of small interfering RNA (siRNA) or antisense oligonucleotides (ASO) drug therapy (including clinical trials).
• Those who use anticoagulant or thrombotic drugs (such as warfarin, vitamin K1, etc.) within 4 weeks before administration or during the trial study.
• Participants who have used any drugs that investigators believe may affect the pharmacokinetic characteristics of the investigational drug within 2 weeks prior to administration, including prescription drugs, over-the-counter drugs, herbal medicines, health supplements, vitamins, etc
• Received any vaccine within 8 weeks prior to administration, or planned to receive the vaccine during the study period.
• Have participated in any other clinical trials within the past 3 months prior to screening.
• Blood donation or significant blood loss (>400 mL) within the first 3 months of screening; Or receiving blood transfusions or using blood products (such as albumin); Or plan to donate blood during the study.
• History of drug allergy or any severe allergic disease.
• Difficulty in venous blood collection or intolerance to venipuncture, or history of needle and blood dizziness.
• Due to other reasons, the study may not be completed, or it may be deemed unsuitable for inclusion by the investigator.