A First in Human Study of STT-5058, an Antibody That Binds ApoC3

Inclusion Criteria: * in good health * Able to comprehend and willing to sign an ICF and to abide by the study restrictions. * Females will not be pregnant or lactating, and females of childbearing potential and males will agree to use contraception Parts A, B and D * BMI between 18 and 35 kg/m2 inclusive * Fasting Triglycerides between 150 and 400mg/dL inclusive Part C * Fasting Triglycerides between 200 and 400 mg/dL inclusive * Fasting LDL-C between 70 and 160 mg/dL inclusive * BMI between 18 and 40 kg/m2 Exclusion Criteria: * significant history or clinical manifestation of metabolic, allergic, dermatological, hepatic, renal, haematological, pulmonary, cardiovascular, gastrointestinal, neurological, respiratory, endocrine, or psychiatric disorder, as determined by the Investigator * Confirmed (eg, 2 consecutive measurements) systolic blood pressure \>150 or \<90 mmHg, diastolic blood pressure \>90 or \<50 mmHg, and heart rate \>90 or \<40 beats per minute at Screening, Check-in, or prior to dosing on Day 1. * History of alcoholism or drug/chemical abuse within 2 years prior to Check-in. * Participation in a clinical study involving administration of an investigational drug (new chemical entity) in the past 90 days or 5 half-lives (if known), whichever is longer, prior to dosing.