A Double-blind, Randomized, Multicenter Study to Evaluate the Safety and Efficacy of Evolocumab, Compared With Ezetimibe, in Hypercholesterolemic Subjects Unable to Tolerate an Effective Dose of a HMG-CoA Reductase Inhibitor Due to Muscle Related Side Effects

The study is divided into 3 parts (A, B, C). After an initial 4-week washout period in which any statins, ezetimibe, or other lipid-lowering agents were discontinued, participants were enrolled in phase A, a double-blind, placebo-controlled crossover procedure to rechallenge patients with atorvastatin. Patients were randomly assigned in a 1:1 ratio to receive either atorvastatin (20 mg daily) or matching placebo for the first 10 weeks (period 1), then underwent a 2-week washout period, followed by crossover to the alternate therapy for a second 10-week period (period 2). Patients who experienced intolerable muscle symptoms during the first period did not complete the full 10 weeks of exposure but entered a 2-week washout period before proceeding to period 2.

Participants who did not develop muscle-related side effects were removed from the study, as were patients who reported muscle-related side effects during a placebo period.

After completion of phase A, patients who experienced muscle-related adverse effects while taking atorvastatin but not placebo were eligible for phase B, a 24-week, double-blind randomization to ezetimibe or evolocumab using a double-dummy design in which patients received either injectable placebo and oral ezetimibe or injectable evolocumab and oral placebo. A patient could proceed directly to phase B if they had a documented history of creatine kinase (CK) elevation more than 10 times the upper limit of normal accompanied by muscle symptoms while taking statin therapy, with documented resolution of both CK elevation and symptoms upon discontinuation of statin therapy.

These study procedures were designed to ensure that only patients with reproducible statin-associated muscle symptoms entered phase B of the study. For phase B, participants were randomized 2:1 to receive subcutaneously administered evolocumab (420 mg monthly) or oral ezetimibe (10 mg daily). Randomization in part B was stratified by screening LDL-C level (< 180 mg/dL [4.66 mmol/L] vs. ≥ 180 mg/dL) at study baseline.

Participants who completed phase B and did not discontinue SC investigational product for any reason, including an adverse event, were eligible to proceed to the 2-year open-label extension phase C to evaluate the long-term safety and efficacy of evolocumab in statin-intolerant patients. Participants in phase C were allowed to choose quarterly between evolocumab 420 mg SC QM or evolocumab 140 mg SC every 2 weeks (Q2W).