ION775A Study to Assess the Safety, Tolerability and Efficacy of ION775

Key Inclusion Criteria:

1. Adult males and females with HTG (fasting TG more than or equal to (≥) 350 milligrams per deciliter (mg/dL) \[3.95 millimoles per liter (mmol/L)\] or with sHTG (fasting TG ≥ 500 mg/dL \[5.65 mmol/L\]).
2. Participants should be on standard of care lipid-lowering medications per local guidelines.

Key Exclusion Criteria:

1. Hemoglobin A1c (HbA1c) ≥ 8.5% at Screening.
2. Alanine aminotransferase or aspartate aminotransferase > 2.0 × upper limit of normal.
3. Total bilirubin > 1.5 upper limit of normal unless due to Gilbert's syndrome.
4. Estimated GFR < 30 mL/min/1.73 m\^2.

Note: Other protocol pre-specified inclusion/exclusion criteria may apply.