A Study of Olezarsen (ISIS 678354) in Participants With Hypertriglyceridemia and Atherosclerotic Cardiovascular Disease, or With Severe Hypertriglyceridemia

This is a Phase 3, multi-center, placebo-controlled study in approximately 1475 participants with hypertriglyceridemia and atherosclerotic cardiovascular disease. The study consists of 3 periods: 1) Screening Period: Week -12 to Week -1 (up to 12 weeks); 2) Treatment Period up to Week 53; and 3) Post-Treatment Follow-up Period: Week 54 to Week 66 (13 weeks). Participants enrolled will receive olezarsen or placebo once every 4 weeks during the 53-week Treatment Period.

The Screening Period was extended with no impact to overall study timelines.

A coronary computed tomographic angiography (CTA) sub study will be performed to assess whether triglyceride lowering through inhibition of apoC-III protein synthesis may reduce coronary plaque progression.

Inclusion criteria

• Participants must fall into 1 of the following groups (a or b):

a. Hypertriglyceridemia with fasting TG ≥200 mg/dL (2.26 millimoles per liter [mmol/L]) and <500 mg/dL (5.65 mmol/L) with either

• Clinical diagnosis of atherosclerotic cardiovascular disease (ASCVD) or
• At increased risk for ASCVD

b. Severe hypertriglyceridemia with fasting TG ≥500 mg/dL (5.65 mmol/L)

• Participants should be on standard of care (SOC) lipid-lowering medications per local guidelines. Lipid-lowering medications should be optimized and stabilized for at least 4 weeks prior to Screening to minimize changes in these medications during the study.

Exclusion criteria

• Hemoglobin A1c (HbA1c) ≥ 9.5% at Screening
• Alanine aminotransferase or aspartate aminotransferase > 3.0 × upper limit of normal
• Total bilirubin > 1.5 upper limit of normal unless due to Gilbert's syndrome
• Estimated GFR < 30 mL/min/1.73 m^2

NOTE: Other Inclusion/Exclusion criteria may apply.