Limitations of cholesterol lowering with PCSK9 inhibitors

A Critical Review of the Efficacy and Safety of Inclisiran

The association between low-density cholesterol (LDL-C) and cardiovascular disease (CVD) is well-established, with an emphasis on lowering LDL-C levels to reduce cardiovascular events. Statin therapy has been the traditional treatment for LDL-C reduction, in addition to lifestyle modifications, but studies have shown that a substantial proportion of patients does not reach target LDL-C goals despite receiving maximally tolerated statin medications. Additionally, statin therapy is associated with a few shortcomings as many patients initiated on these medications discontinue treatment within 1 year because of lack of tolerability. Furthermore, guidelines from both the American College of Cardiology and the American Heart Association highlight the importance of obtaining LDL-C goals because of the residual atherosclerotic CVD risk that remains in high-risk populations. That the residual cardiovascular risk remains despite statin therapy highlights the importance of evaluating therapeutic approaches that possess effective lipid lowering that can be used adjunctively with statins. Much focus has been directed towards the proprotein convertase subtilisin/kexin type 9 (PCSK9) pathway, leading to the development of evolocumab and alirocumab, two human monoclonal antibodies directed against PCSK9. These agents have been shown to markedly decrease LDL-C levels and significantly reduce cardiovascular risk, but the need for biweekly or monthly subcutaneous injections has generated concerns for patient compliance. A new pathway is being studied in which a synthetic small interfering ribonucleic acid (siRNA) targets the PCSK9 gene expressed in hepatocytes to prevent PCSK9 production. The siRNA, inclisiran sodium, significantly reduces hepatic production of PCSK9, causing a marked reduction in LDL-C levels, and exhibits sustained pharmacodynamic effects when dosed subcutaneously every 6 months. This review presents and discusses the current clinical and scientific evidence pertaining to inclisiran sodium.

Lomitapide-a Microsomal Triglyceride Transfer Protein Inhibitor for Homozygous Familial Hypercholesterolemia

PURPOSE OF REVIEW

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition characterized by high levels of Low density lipoprotein cholesterol (LDL-C); overt, early-onset atherosclerotic cardiovascular disease (ASCVD); and premature cardiovascular events and mortality. Lomitapide is a first-in-class microsomal triglyceride transfer protein inhibitor for the treatment of HoFH. This review provides an update on data emerging from real-world studies of lomitapide following on from its pivotal phase 3 clinical trial in HoFH.

RECENT FINDINGS

Recent registry data have confirmed that HoFH is characterized by delayed diagnosis, with many patients not receiving effective therapy until they are approaching the age when major adverse cardiovascular events may occur. Data from case series of varying sizes, and from a 163-patient registry of HoFH patients receiving lomitapide, have demonstrated that lomitapide doses are lower and adverse events less severe than in the phase 3 study. Lomitapide enables many patients to reach European Atherosclerosis Society LDL-C targets. Some patients are able to reduce frequency of lipoprotein apheresis or, in some cases, stop the procedure altogether-unless there is significant elevation of lipoprotein (a). Modelling analyses based on historical and clinical trial data indicate that lomitapide has the potential to improve cardiovascular outcomes and survival in HoFH. Real-world clinical experience with lomitapide has shown the drug to be effective with manageable, less marked adverse events than in formal clinical studies. Event modelling data suggest a survival benefit with lomitapide in HoFH.