Inclusion Criteria:  Based on medical history, evidence of TG ≥ 150 mg/dL but ≤ 499 mg/dL on more than one occasion Fasting levels at Screening of LDL-C ≥ 70 mg/dL OR non-HDL-C ≥ 100 mg/dL after at least 4 weeks of stable optimal statin therapy Mean fasting TG ≥ 150 mg/dL and ≤ 499 mg/dL during Screening collected at two separate and consecutive visits and at least 7 days apart and not more than 14 days apart Willing to follow diet counseling and maintain a stable diet per Investigator judgment based on local standard of care Women of childbearing potential on must have a negative pregnancy test, cannot be breastfeeding, and must be willing to use contraception Women of childbearing potential on hormonal contraceptives must be stable on the medication for ≥ 2 menstrual cycles prior to Day 1 Willing to provide written informed consent and to comply with study requirements  Exclusion Criteria:  Current use or use within 365 days from Day 1 of any hepatocyte targeted siRNA or antisense oligonucleotide molecule Active pancreatitis within 12 weeks prior to Day 1 Any planned bariatric surgery or similar procedures to induce weight loss from consent to end of study Acute coronary syndrome event within 24 weeks of Day 1 Major surgery within 12 weeks of Day 1 Planned coronary intervention (e.g., stent placement or heart bypass) during the study Uncontrolled hypertension Human immunodeficiency virus (HIV) infection, seropositive for Hepatitis B (HBV), seropositive for Hepatitis C (HCV) Uncontrolled hypothyroidism or hyperthyroidism Hemorrhagic stroke within 24 weeks of Day 1 History of bleeding diathesis or coagulopathy Current diagnosis of nephrotic syndrome Systemic use of corticosteroids or anabolic steroids within 4 weeks prior to Day 1 or planned use during the study Malignancy within the last 2 years prior to date of consent requiring systemic treatment (some exceptions apply)  Note: additional inclusion/exclusion criteria may apply per protocol