Pharmacological Strategies beyond Statins: Ezetimibe and PCSK9 Inhibitors

Dyslipidemia, highly elevated, low-density lipoprotein (LDL) cholesterol, is a major cardiovascular risk factor. Statins have been proven to effectively reduce the risk of atherosclerotic cardiovascular disease (ASCVD) and are recommended as a first-line therapy for the primary and secondary prevention of ASCVD. However, statins may not be sufficient in decreasing LDL cholesterol levels and pose a significant on-treatment residual risk of major cardiovascular events (i.e., residual cholesterol risk) according to meta-analyses of statin trials. Current guidelines for cholesterol management to achieve additional LDL cholesterol reduction and reduce ASCVD risk recommend two hyperlipidemic agents besides statins. Use of ezetimibe, a cholesterol absorption inhibitor, leads to additional LCL cholesterol reduction and decreased ASCVD risk, when added to statin therapy, without raising significant safety concerns. Furthermore, in combination with a mild-to-moderate statin intensity, ezetimibe is used in situations of statin-associated adverse effects such as myalgia and the combination therapy is relatively safer. Monoclonal antibody of proprotein convertase subtilisin/kexin type 9 (PCSK9), alirocumab, and evolocumab, have been approved to lower LDL cholesterol level. While there are drawbacks to the use of PCSK9 inhibitors, including high cost and adverse events such as injection site reaction, they significantly decreased serum LDL cholesterol levels and thereby ASCVD risks when added to maximally tolerated statin therapy.