Eprotirome is a liver selective thyroid hormone that can reduce several independent risk factors for cardiovascular disease, while an euthyroid state is preserved in the extrahepatic tissue.

The purpose of this Phase III study is to assess the long-term efficacy and safety of Eprotirome in Patients with heterozygous Familial Hypercholesterolaemia who are on optimal standard of care.

Inclusion Criteria:

• Patients with confirmed HeFH and 18 years of age at screening
• Presence of clinical atherosclerotic disease that confers high risk for CAD events together with an LDL-C more than 2 mmol/L (more than 80 mg/dL)
• Presence of risk factors for CVD (other than the HeFH diagnosis) together with an LDL-C more than 2.5 mmol/L (more than 100 mg/dL)
• On an optimal standard of care, defined as being on a stable dose of statin (rosuvastatin, atorvastatin, or simvastatin) with or without ezetimibe for 8 weeks prior to randomisation

Exclusion Criteria:

• Significant health problems in recent past including heart failure,cardiac electrophysiologic instability, rheumatoid arthritis, thyroid dysfunction, liver disease, cancer, secondary dyslipidaemia