Longer-Term Efficacy and Safety of Evinacumab in Patients With Refractory Hypercholesterolemia

Importance

Patients with refractory hypercholesterolemia who do not achieve their guideline-defined low-density lipoprotein cholesterol (LDL-C) thresholds despite treatment with maximally tolerated combinations of lipid-lowering therapies (LLTs) have an increased risk of atherosclerotic cardiovascular disease (ASCVD).

Objective

To evaluate longer-term efficacy and safety of evinacumab in patients with refractory hypercholesterolemia.

Design, Setting, and Participants

This randomized clinical trial included a 2-week screening period followed by a 16-week double-blind treatment period (DBTP) for subcutaneous regimens (evinacumab, 450 mg, once weekly [QW]; evinacumab, 300 mg, QW; evinacumab, 300 mg, every 2 weeks; or placebo QW) or a 24-week DBTP for intravenous regimens (evinacumab, 15 mg/kg, every 4 weeks [Q4W]; evinacumab, 5 mg/kg, Q4W; or placebo Q4W); a 48-week open-label treatment period (OLTP) for intravenous treatment only; and a 24-week follow-up period. Patients from 85 sites across 20 countries were recruited for the study; patients with primary hypercholesterolemia (defined as heterozygous familial hypercholesterolemia or established clinical ASCVD without familial hypercholesterolemia) who entered the 48-week OLTP were included. In addition, the patients' hypercholesterolemia was refractory to maximally tolerated LLTs.

Interventions

All patients entering the OLTP received evinacumab, 15 mg/kg, intravenously Q4W.

Main Outcomes and Measures

Efficacy outcomes included change in LDL-C level and other lipid/lipoprotein parameters from baseline to week 72 (end of the OLTP). Safety outcomes included assessment of treatment-emergent adverse events (TEAEs).

Results

A total of 96 patients (mean [SD] age, 54.4 [11.3] years; 52 female [54.2%]) entered the OLTP, of whom 88 (91.7%) completed the OLTP. Mean (SD) baseline LDL-C level was 145.9 (55.2) mg/dL. At week 72, evinacumab, 15 mg/kg, reduced mean (SD) LDL-C level from baseline by 45.5% (28.7%) in the overall cohort. Evinacumab, 15 mg/kg, reduced mean (SD) apolipoprotein B (38.0% [22.1%]), non-high density lipoprotein cholesterol (48.4% [23.2%]), total cholesterol (42.6% [17.5%]), and median (IQR) fasting triglyceride (57.2% [65.4%-44.4%]) levels at week 72 from baseline in the overall cohort. TEAEs occurred in 78 of 96 patients (81.3%). Serious TEAEs occurred in 9 of 96 patients (9.4%); all were considered unrelated to study treatment.

Conclusions and Relevance

In patients with refractory hypercholesterolemia, evinacumab provided sustained reductions in LDL-C level and was generally well tolerated.

Trial Registration

ClinicalTrials.gov Identifier: NCT03175367.

Evinacumab in Patients with Refractory Hypercholesterolemia

BACKGROUND

Patients with refractory hypercholesterolemia, who have high low-density lipoprotein (LDL) cholesterol levels despite treatment with lipid-lowering therapies at maximum tolerated doses, have an increased risk of atherosclerosis. In such patients, the efficacy and safety of subcutaneous and intravenous evinacumab, a fully human monoclonal antibody against angiopoietin-like 3, are not known.

METHODS

In this double-blind, placebo-controlled, phase 2 trial, we enrolled patients with or without heterozygous familial hypercholesterolemia who had refractory hypercholesterolemia, with a screening LDL cholesterol level of 70 mg per deciliter or higher with atherosclerosis or of 100 mg per deciliter or higher without atherosclerosis. Patients were randomly assigned to receive subcutaneous or intravenous evinacumab or placebo. The primary end point was the percent change from baseline in the LDL cholesterol level at week 16 with evinacumab as compared with placebo.

RESULTS

In total, 272 patients were randomly assigned to the following groups: subcutaneous evinacumab at a dose of 450 mg weekly (40 patients), 300 mg weekly (43 patients), or 300 mg every 2 weeks (39 patients) or placebo (41 patients); or intravenous evinacumab at a dose of 15 mg per kilogram of body weight every 4 weeks (39 patients) or 5 mg per kilogram every 4 weeks (36 patients) or placebo (34 patients). At week 16, the differences in the least-squares mean change from baseline in the LDL cholesterol level between the groups assigned to receive subcutaneous evinacumab at a dose of 450 mg weekly, 300 mg weekly, and 300 mg every 2 weeks and the placebo group were -56.0, -52.9, and -38.5 percentage points, respectively (P<0.001 for all comparisons). The differences between the groups assigned to receive intravenous evinacumab at a dose of 15 mg per kilogram and 5 mg per kilogram and the placebo group were -50.5 percentage points (P<0.001) and -24.2 percentage points, respectively. The incidence of serious adverse events during the treatment period ranged from 3 to 16% across trial groups.

CONCLUSIONS

In patients with refractory hypercholesterolemia, the use of evinacumab significantly reduced the LDL cholesterol level, by more than 50% at the maximum dose. (Funded by Regeneron Pharmaceuticals; ClinicalTrials.gov number, NCT03175367.).

Evinacumab for Homozygous Familial Hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia is characterized by premature cardiovascular disease caused by markedly elevated levels of low-density lipoprotein (LDL) cholesterol. This disorder is associated with genetic variants that result in virtually absent (null-null) or impaired (non-null) LDL-receptor activity. Loss-of-function variants in the gene encoding angiopoietin-like 3 (ANGPTL3) are associated with hypolipidemia and protection against atherosclerotic cardiovascular disease. Evinacumab, a monoclonal antibody against ANGPTL3, has shown potential benefit in patients with homozygous familial hypercholesterolemia.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned in a 2:1 ratio 65 patients with homozygous familial hypercholesterolemia who were receiving stable lipid-lowering therapy to receive an intravenous infusion of evinacumab (at a dose of 15 mg per kilogram of body weight) every 4 weeks or placebo. The primary outcome was the percent change from baseline in the LDL cholesterol level at week 24.

RESULTS

The mean baseline LDL cholesterol level in the two groups was 255.1 mg per deciliter, despite the receipt of maximum doses of background lipid-lowering therapy. At week 24, patients in the evinacumab group had a relative reduction from baseline in the LDL cholesterol level of 47.1%, as compared with an increase of 1.9% in the placebo group, for a between-group least-squares mean difference of -49.0 percentage points (95% confidence interval [CI], -65.0 to -33.1; P<0.001); the between-group least-squares mean absolute difference in the LDL cholesterol level was -132.1 mg per deciliter (95% CI, -175.3 to -88.9; P<0.001). The LDL cholesterol level was lower in the evinacumab group than in the placebo group in patients with null-null variants (-43.4% vs. +16.2%) and in those with non-null variants (-49.1% vs. -3.8%). Adverse events were similar in the two groups.

CONCLUSIONS

In patients with homozygous familial hypercholesterolemia receiving maximum doses of lipid-lowering therapy, the reduction from baseline in the LDL cholesterol level in the evinacumab group, as compared with the small increase in the placebo group, resulted in a between-group difference of 49.0 percentage points at 24 weeks. (Funded by Regeneron Pharmaceuticals; ELIPSE HoFH ClinicalTrials.gov number, NCT03399786.).