Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and Month 10.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and Months 10 and 12.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and Month 10.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and Month 12.

All adverse events (AEs) and serious adverse events (SAEs) reported by the Investigator during the study that are consistent with an event of acute pancreatitis will be adjudicated by a blinded, independent committee according to the 2013 Atlanta definition meeting 2 of the following 3 criteria:

1. Abdominal pain consistent with acute pancreatitis (acute onset of a persistent, severe, epigastric pain often radiating to the back)
2. Serum lipase activity (or amylase activity) ≥3 times the upper limit of normal (×ULN)
3. Characteristic findings of acute pancreatitis on contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), or transabdominal ultrasonography.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. The Statistical Analysis Plan pre-specified that the ARO-APOC3 25 mg and 50 mg groups were to be pooled together to be compared with placebo for the Randomized Period.

All adverse events (AEs) and serious adverse events (SAEs) reported by the Investigator during the study that are consistent with an event of acute pancreatitis will be adjudicated by a blinded, independent committee according to the 2013 Atlanta definition meeting 2 of the following 3 criteria:

1. Abdominal pain consistent with acute pancreatitis (acute onset of a persistent, severe, epigastric pain often radiating to the back)
2. Serum lipase activity (or amylase activity) ≥3 times the upper limit of normal (×ULN)
3. Characteristic findings of acute pancreatitis on contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), or transabdominal ultrasonography.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. A pattern-mixture model is used as the imputation method for the missing values of Month 10 in fasting non-HDL-Cs.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. A pattern-mixture model is used as the imputation method for the missing values of Month 12 in fasting non-HDL-Cs.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. A pattern-mixture model is used as the imputation method for the missing values of Month 10 in fasting HDL-Cs.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. A pattern-mixture model is used as the imputation method for the missing values of Month 12 in fasting HDL-Cs.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. A pattern-mixture model is used as the imputation method for the missing values of Month 12 in fasting non-HDL-Cs.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Observed cases.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Observed cases.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and Month 10.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and given timepoint.

Full Analysis Set: all randomized participants regardless of adherence to the treatment, analyzed according to the treatment assigned at randomization. Participants with an assessment at baseline and given timepoint.

AE: any untoward medical occurrence which does not necessarily have to have a causal relationship with treatment. Treatment-emergent AEs (TEAEs): AEs with onset after administration of the study drug, or when a preexisting medical condition increases in severity or frequency after study drug administration. SAE: AE that fulfills one or more of the following: results in death; is immediately life-threatening; requires in-patient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability or incapacity; results in a congenital abnormality or birth defect; is an important medical event that may jeopardize the patient or may require medical intervention to prevent one of the outcomes listed above. Severity was reported as: mild, moderate, severe, life threatening, death.

Safety Analysis Set: all randomized participants who received at least 1 dose of study drug, analyzed according to the treatment they actually received.

AE: any untoward medical occurrence which does not necessarily have to have a causal relationship with treatment. Treatment-emergent AEs (TEAEs): AEs with onset after administration of the study drug, or when a preexisting medical condition increases in severity or frequency after study drug administration. SAE: AE that fulfills one or more of the following: results in death; is immediately life-threatening; requires in-patient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability or incapacity; results in a congenital abnormality or birth defect; is an important medical event that may jeopardize the patient or may require medical intervention to prevent one of the outcomes listed above. Severity was reported as: mild, moderate, severe, life threatening, death.