PCSK9 in context: A contemporary review of an important biological target for the prevention and treatment of atherosclerotic cardiovascular disease.

The identification of the critical role of proprotein convertase subtilisin/kexin type 9 (PCSK9) has rapidly led to the development of PCSK9 inhibition with monoclonal antibodies (mAbs). PCSK9 mAbs are already in limited clinical use and are the subject of major cardiovascular outcomes trials, which, if universally positive, could see much wider clinical application of these agents. Patients with familial hypercholesterolaemia are the most obvious candidates for these drugs, but other patients with elevated cardiovascular risk, statin intolerance or hyperlipoproteinaemia(a) may also benefit. PCSK9 mAbs, administered once or twice monthly, reduce LDL cholesterol levels by 50% to 70%, and appear to be safe and acceptable to patients over at least 2 years of treatment; however, treatment-emergent adverse effects are not always identified in clinical trials, as well-evidenced by statin myopathy. Inclisiran is a promising RNA-based therapy that promotes the degradation of PCSK9 mRNA transcripts and has similar efficacy to mAbs, but with a much longer duration of action. The cost-effectiveness and long-term safety of therapies targeted at inhibiting PCSK9 remain to be demonstrated if they are to be used widely in coronary prevention.