Study Overview: This study is looking at the long-term safety and effectiveness of a medicine called plozasiran in adults with hypertriglyceridemia (HTG), which means they have high levels of triglycerides, a type of fat, in their blood. Some people may have even higher levels, known as severe hypertriglyceridemia (SHTG). Participants must have completed previous studies and meet all the necessary health criteria. Key Points:

• Participants in the study will receive plozasiran through an injection under the skin every 3 months for 2 years.
• Participants will need to follow a low-fat diet throughout the study to help manage their triglyceride levels.
• The study requires participants to continue using any current medications for reducing fats and triglycerides, unless they are intolerant.

Eligibility: To join, participants must be adults who agree to use effective birth control if needed, and have completed all required visits in a previous related study. They should not have certain health conditions or be using other specific medications that could interfere with the study. Participants also need to have controlled blood sugar levels if they have diabetes. Note: Consult your doctor to know if you meet the eligibility criteria and understand all requirements before considering participation.