This trial is testing a medication called olezarsen to see if it is safe and can be tolerated by people with very high levels of blood fat (triglycerides). The study involves up to 700 participants who will take the medication for several months. The goal is to help reduce the fat in their blood and prevent serious health issues. Olezarsen significantly reduced apoC-III, triglycerides, and atherogenic lipoproteins in patients with moderate hypertriglyceridaemia and at high risk for or with established cardiovascular disease.