Low density lipoprotein (LDL) and the other atherogenic lipoproteins (VLDL; IDL and Lipoprotein”a”) the Apo B containing lipoproteins are the cornerstone of the pathophysiology of atherosclerotic vascular disease (ASCVD). The continued debate as well-established modifiable risk factors for cardiovascular disease, is how low to drive these lipoproteins in the prevention and management of ASCVD.
Monoclonal antibodies that inhibit proprotein convertase subtilisin–kexin type 9 (PCSK9) have emerged as a new class of drugs that effectively lower Apo B containing lipoproteins. See my post PCSK9 story continues to intrigue and tantalise….posted on March 19, 2015
Published in NEJM and announced at the 2017 American Heart Association meeting 17 March was the FOURIER trial (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk). This was a dedicated cardiovascular outcomes trial that tested the clinical efficacy and safety of evolocumab when added to high-intensity or moderate-intensity statin therapy in patients with clinically evident atherosclerotic cardiovascular disease.
The FOURIER trial was a randomized, double-blind, placebo-controlled, multinational clinical trial in which 27 564 patients at 1242 sites in 49 countries underwent randomization. Patients were eligible for participation in the trial if they were between 40 and 85 years of age and had clinically evident atherosclerotic cardiovascular disease (ASCVD), defined as a history of myocardial infarction, non-hemorrhagic stroke, or symptomatic peripheral artery disease, as well as additional characteristics that placed them at higher cardiovascular risk. Patients had to have a fasting LDL cholesterol level of 70 mg per deciliter (1.8 mmol per liter) or higher or a non–high-density lipoprotein (HDL) cholesterol level of 100 mg per deciliter (2.6 mmol per liter) or higher while they were taking an optimized regimen of lipid-lowering therapy, which was defined as preferably a high-intensity statin but must have been at least Atorvastatin at a dose of 20 mg daily or its equivalent, with or without ezetimibe.
Eligible patients were randomly assigned in a 1:1 ratio to receive subcutaneous injections of evolocumab (either 140 mg every 2 weeks or 420 mg every month, according to patient preference) or matching placebo.
The primary efficacy end point was major cardiovascular events, defined as the composite of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, or coronary revascularization. The key secondary efficacy end point was the composite of cardiovascular death, myocardial infarction, or stroke.
When added to statin therapy, the PCSK9 inhibitor evolocumab lowered LDL cholesterol levels by 59% from baseline levels as compared with placebo, from a median of 92 mg per deciliter (2.4 mmol per liter) to 30 mg per deciliter (0.78 mmol per liter). This effect was sustained without evidence of attenuation.
In this dedicated cardiovascular outcomes trial, the addition of evolocumab to statin therapy significantly reduced the risk of cardiovascular events, with a 15% reduction in the risk of the primary composite end point of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, or coronary revascularization and a 20% reduction in the risk of the more clinically serious key secondary end point of cardiovascular death, myocardial infarction, or stroke.
The data from this trial provide insight into the benefit of decreasing Apo B containing lipoproteins to median levels lower than those in previous trials. These observations align well with the effects of evolocumab and aggressive LDL reduction on coronary atherosclerotic plaque volume in the Global Assessment of Plaque Regression with a PCSK9 Antibody as Measured by Intravascular Ultrasound (GLAGOV) trial. See my post Atherosclerotic plaque regression with intense Apo B lipoprotein lowering posted on November 17, 2016