Statins and PCSK9 inhibitors: A new lipid-lowering therapy

The clinical benefit of lipid-lowering therapies is to reduce circulating levels of atherogenic particles and to ameliorate the risk of atherosclerotic cardiovascular disease (ASCVD). The completion of two major clinical trials on PCSK9 inhibitors (PCSK9i), the FOURIER and the ODYSSEY outcome trials, has marked the beginning of a new era of lipid-lowering drugs. PCSK9i, evolocumab and alirocumab, are monoclonal antibodies that inactivate the liver proprotein convertase subtilisin kexin 9 (PCSK9). Inhibition of PCSK9 increases the number of low-density lipoprotein (LDL) receptors available leading to a profound reduction in circulating LDL particles. By preventing LDL receptor destruction, PCSK9i as adjunct to statin therapy can reduce LDL-C by 50-60% above that achieved by statin therapy alone. In addition, PCSK9i in combination with high-dose statins may reduce cardiovascular events and all-cause mortality in patients with clinical ASCVD. Based on evidence from clinical trials, the 2019 European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guidelines for the management of dyslipidemias now include the use of PCSK9i to very high-risk ASCVD patients who are not achieving treatment goals on a maximum tolerated dose of a statin and ezetimibe. However, the cost-effectiveness of PCSK9i therapy is limited to secondary prevention in high-risk patients. This review outlines the main clinical trials leading to a change in the guidelines, clinical practice as well as the future challenges of PCSK9i therapy.