Clinical Research Directory

Inclusion Criteria: * Male or female participants, 2 to \<12 years of age at screening * HoFH diagnosed by genetic confirmation \- Note: Participants with known null (negative) mutations in both LDLR alleles are not eligible (see also exclusion criteria) * Fasting LDL-C \>130 mg/dL (3.4 mmol/L) at screening * On an optimal dose of statin (investigator's discretion), unless statin intolerant, with or without other lipid-lowering therapy (e.g. ezetimibe) * Participants on lipid-lowering therapies (such as e.g. statins, ezetimibe) must be on a stable dose for ≥30 days before screening with no planned medication or dose changes during study participation * Participants on a documented regimen of LDL-apheresis for ≥ 3 months before screening will be allowed to continue the apheresis during the study, if needed. The apheresis schedule/settings/duration must be stable prior to screening, are not allowed to change during the double-blind period of the trial and must permit that an apheresis coincides with each study visit. Exclusion Criteria: * Documented evidence of a null (negative) mutation in both LDLR alleles * Previous treatment (within 90 days of screening) with monoclonal antibodies directed towards PCSK9 * History of poor response to therapy with any monoclonal antibody directed towards PCSK9 (e.g. \<15% reduction in LDL-C) * Treatment with mipomersen or lomitapide (within 5 months of screening) * Secondary hypercholesterolemia, e.g. hypothyroidism or nephrotic syndrome * Heterozygous familial hypercholesterolemia (HeFH) * Body weight (at the screening and/or randomization (Day 1) visit) \<16 kg for participants 6 to \<12 years (at screening) or \<11 kg for participants 2 to \<6 years (at screening) * Active liver disease defined as any known current infectious, neoplastic, or metabolic pathology of the liver or unexplained alanine aminotransferase (ALT), aspartate aminotransferase (AST) elevation \>3x ULN, or total bilirubin elevation \>2x ULN (except patients with Gilbert's syndrome) * Pregnant or nursing females * Recent and/or planned use of other investigational medicinal products or devices