Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibition and the Future of Lipid Lowering Therapy

Low-density lipoprotein cholesterol (LDL-C) reduction with statins is the cornerstone of atherosclerotic cardiovascular disease (CVD) prevention. The LDL-C lowering non-statin therapy ezetimibe also modestly reduces CVD risk when added to statin therapy. There remains a clinical need for additional LDL-C lowering agents to reduce CVD risk in patients with genetic hypercholesterolemia, statin intolerance, or who are at high risk due to clinical CVD or diabetes. In clinical trials, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition using monoclonal antibodies has demonstrated robust LDL-C lowering efficacy of 50–65% and a favorable safety profile. These agents are a promising therapeutic strategy for addressing the unmet needs for additional CVD risk reduction. Regulatory approval for PCSK9 monoclonal antibodies may occur in the near future, and additional agents for PCSK9 inhibition are under development. This review focuses on the mechanism of LDL-C reduction using PCSK9 inhibition, as well as the phase I to III clinical trials of PCSK9 inhibitors. Results of the ongoing phase III CVD outcome trials are eagerly awaited.