This is a two-part study, intended to investigate the safety, tolerability, characteristics of PK and PD of single SC dose of SRSD216 and to identify a dose range for further studies in subjects with elevated Lp(a) level with or without ASCVD history.

Inclusion Criteria:

• Able to comprehend and willing to sign an informed consent form (ICF) and to abide by the study restrictions;
• Males or females, of any race;
• Body mass index (BMI) between 18.0 and 40.0 kg/m2, inclusive;
• Male subjects are not allowed to donate sperm, and female subjects are not allowed to donate eggs from the time the ICF is signed until at least 3 months after the last follow-up.

Exclusion Criteria:

• Any history or evidence of abnormal bleeding or coagulopathy; or evidence of prolonged or unexplained, clinically significant bleeding, or frequent unexplained bruising or thrombosis; or history of spontaneous bleeding;
• Evidence of active or suspected cancer within 3 years prior to screening (non-melanoma skin cancer, localized prostate cancer treated with curative intent, or other in situ carcinoma that does not require systemic therapy and is considered cured for at least 1 years is allowed);
• Acute febrile illness within 7 days prior to dose administration or evidence of active infection;
• Any major surgery within 3 months prior to screening or plan to have any major surgery during the study;
• History of clinically significant hypersensitivity, intolerance, or allergy to any oligonucleotide or GalNAc as determined by the investigator;
• Fasting TG≥ 500 mg/dL (5.6 mmol/L) during screening;
• Receipt of an investigational drug within 30 days or 5 half-lives of that drug, whichever is longer, prior to dose administration in this study;
• Have previously completed or withdrawn from this study or any other study investigating SRSD216 and have previously received SRSD216.