Inclisiran: A Novel Agent for Lowering Apolipoprotein B–containing Lipoproteins

Abstract: Hypercholesterolemia is a leading cause of cardiovascular morbidity and mortality. Accordingly, efforts to lower apolipoprotein B–containing lipoproteins in plasma are the centerpiece of strategies for cardiovascular prevention and treatment in primary and secondary management. Despite the importance of this endeavor, many patients do not achieve appropriate low-density lipoprotein cholesterol (LDL-C) and non–high-density lipoprotein cholesterol (non-HDL-C) goals, even among those who have experienced atherosclerotic cardiovascular disease. The development of new LDL-C-lowering medications with alternative mechanisms of action will facilitate improved goal achievement in high-risk patients. Inclisiran is a novel small interfering RNA–based drug that is experimental in the United States and approved for clinical use in the European Union. It lowers LDL-C and other apolipoprotein B–containing lipoproteins by reducing production of proprotein convertase subtilisin/kexin Type 9 (PCSK9), a protein that normally contributes to LDL-receptor degradation, thereby increasing LDL-receptor density and recycling in hepatocytes. Although the lipid-lowering efficacy of inclisiran is comparable with results achieved with PCSK9-blocking monoclonal antibodies (alirocumab and evolocumab), there are several important differences between the 2 drug classes. First, inclisiran reduces levels of PCSK9 both intracellularly and extracellularly by blocking translation of and degrading PCSK9 messenger RNA. Second, the long biological half-life of inclisiran produces sustained LDL-C lowering with twice yearly dosing. Third, although PCSK9-blocking monoclonal antibodies drugs are proven to reduce atherosclerotic cardiovascular disease events, clinical outcomes trials with inclisiran are still in progress. In this article, we review the clinical development of inclisiran, its mechanism of action, lipid-lowering efficacy, safety and tolerability, and potential clinical role of this promising new agent.