Raul D Santos, et al.

Background: Evolocumab, a fully human monoclonal antibody directed against proprotein convertase subtilisin-kexin type 9, is widely used in adult patients to lower low-density lipoprotein (LDL) cholesterol levels.Its effects in pediatric patients with heterozygous familial hypercholesterolemia are not known.

Methods: We conducted a 24-week, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of evolocumab in pediatric patients with heterozygous familial hypercholesterolemia.Patients 10 to 17 years of age who had received stable lipid-lowering treatment for at least 4 weeks before screening and who had an LDL cholesterol level of 130 mg per deciliter (3.4 mmol per liter) or more and a triglyceride level of 400 mg per deciliter (4.5 mmol per liter) or less were randomly assigned in a 2:1 ratio to receive monthly subcutaneous injections of evolocumab (420 mg) or placebo.The primary end point was the percent change in LDL cholesterol level from baseline to week 24; key secondary end points were the mean percent change in LDL cholesterol level from baseline to weeks 22 and 24 and the absolute change in LDL cholesterol level from baseline to week 24.

Results: A total of 157 patients underwent randomization and received evolocumab (104 patients) or placebo (53 patients).At week 24, the mean percent change from baseline in LDL cholesterol level was -44.5% in the evolocumab group and -6.2% in the placebo group, for a difference of -38.3 percentage points (P<0.001).The absolute change in the LDL cholesterol level was-77.5 mg per deciliter (-2.0 mmol per liter) in the evolocumab group and -9.0 mg per deciliter (-0.2 mmol per liter) in the placebo group, for a difference of -68.6 mg per deciliter (-1.8 mmol per liter) (P<0.001).Results for all secondary lipid variables were significantly better with evolocumab than with placebo.The incidence of adverse events that occurred during the treatment period was similar in the evolocumab and placebo groups.

Conclusions: In this trial involving pediatric patients with familial hypercholesterolemia, evolocumab reduced the LDL cholesterol level and other lipid variables.