Targeting PCSK9 as a promising new mechanism for lowering low-density lipoprotein cholesterol.

Statins and other lipid-lowering drugs have dominated the market for many years for achievement of recommended levels of low-density lipoprotein cholesterol (LDL-C). However, a substantial number of high-risk patients are unable to achieve the LDL-C goal. Proprotein convertase subtilisin/kexin 9 (PCSK9) has recently emerged as a new, promising key therapeutic target for hypercholesterolemia. PCSK9 is a protease involved in chaperoning the low-density lipoprotein receptor to the process of degradation. PCSK9 inhibitors and statins effectively lower LDL-C. The PCSK9 inhibitors decrease the degradation of the LDL receptors, whereas statins mainly interfere with the synthetic machinery of cholesterol by inhibiting the key rate limiting enzyme, the HMG CoA reductase. PCSK9 inhibitors are currently being developed as monoclonal antibodies for their primary use in lowering LDL-C. They may be especially useful for patients with homozygous familial hypercholesterolemia, who at present receive minimal benefit from traditional statin therapy. The monoclonal antibody PCSK9 inhibitors, recently granted FDA approval, show the most promising safety and efficacy profile compared to other, newer LDL-C lowering therapies. This review will primarily focus on the safety and efficacy of monoclonal antibody PCSK9 inhibitors in comparison to statins. The review will also address new, alternative PCSK9 targeting drug classes such as small molecules, gene silencing agents, apolipoprotein B antisense oligonucleotides, and microsomal triglyceride transfer protein inhibitors.

Della Badia LA ，Elshourbagy NA ，Mousa SA 《-》

New LDL-cholesterol lowering therapies: pharmacology, clinical trials, and relevance to acute coronary syndromes.

Reduction in plasma low-density lipoprotein cholesterol (LDL-C) is a fundamental treatment for the prevention of acute coronary syndromes (ACS). Although statin therapy confers significant protection against ACS in both primary and secondary prevention, a considerable residual risk remains after intensive therapy. In addition, a significant proportion of high-risk patients do not achieve the optimal LDL-C goal recommended in the current guidelines (<1.8 mmol/L). Hence, novel LDL-C-lowering agents that act via mechanisms distinct from HMG-CoA reductase inhibition are under investigation. We reviewed the recent literature on the development of novel LDL-C-lowering agents that could potentially be used as an alternative or adjunct to statin therapy in high-risk coronary patients. PubMed and Scopus databases were searched to retrieve studies on the efficacy and/or tolerability of novel LDL-C-lowering agents in animals and humans. Agents that inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein (apo) B, and microsomal triglyceride transfer protein (MTTP) are the most promising therapies. Inhibition of PCSK9, apoB, and MTTP has been achieved mostly via fully humanized monoclonal antibodies (mAbs), antisense oligonucleotides, and synthetic compounds, respectively. PCSK9 inhibitors increase the hepatic uptake of LDL-C, while apoB and MTTP inhibitors decrease the synthesis and secretion of apoB-containing lipoproteins. These 3 mechanisms lead to marked reductions in plasma LDL-C in patients with hypercholesterolemia at risk for ACS, particularly those with familial hypercholesterolemia. Moreover, these agents can exert additional benefits by decreasing plasma levels of apoB, triglycerides, and lipoprotein(a). Mipomersen and lomitapide have been approved by the United States Food and Drug Administration (US FDA) for use in patients with homozygous familial hypercholesterolemia. PCSK9 inhibitors are currently under final evaluation in clinical outcomes studies and are anticipated to find wide application either as monotherapy or as an adjunct to statins. A main safety concern is the risk for hepatic steatosis with apoB and MTTP inhibitors, which needs to be explored in prospective, long-term trials. PCSK9, apoB, and MTTP inhibitors can exert potent reductions in plasma LDL-C and apoB concentrations, either as monotherapy or in combination with statins. These effects are particularly relevant to high-risk individuals with marked hypercholesterolemia, such as those with familial hypercholesterolemia. Although the use of mipomersen and lomitapide is limited to severe familial hypercholesterolemia as a replacement for LDL-apheresis, PCSK9 inhibitors are likely to be more widely prescribed in patients at high risk for CVD, especially those who are resistant to or intolerant of high-intensity statin therapy. PCSK9 mAbs are efficacious and have an excellent safety profile, but their long-term impact on cardiovascular events is currently under investigation. Whether PCSK9 mAbs decrease the rates of recurrent cardiovascular events within 3 months following ACS is questionable; however, these agents, unlike statins, may not have pleiotropic benefits on the unstable plaque.

Sahebkar A ，Watts GF 《-》

Management of Hypercholesterolemia, Appropriateness of Therapeutic Approaches and New Drugs in Patients with High Cardiovascular Risk.

Agabiti Rosei E ，Salvetti M 《-》

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors: Present perspectives and future horizons.

Our comprehensive review highlights the drug development and pharmacogenomics leading to the recent approval of PCSK9 inhibitors. We also review the anticipated future advances into the uses of PCSK9 inhibition. Despite the present advances in pharmacotherapy, atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality worldwide. Low density lipoprotein-cholesterol (LDL-C) lowering is the primary target for ASCVD risk reduction, showing demonstrable benefits in mortality. However, 70% of events occur even in the presence of statins. This residual risk may be approached with additional LDL-C reduction. Statin intolerance is a common clinical concern affecting adherence and the benefit with statins. There is also significant variation of individual lipid-lowering. Following rapid development, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have progressed from genetic observations, to mechanistic studies, to closer realization of the goal of CVD risk reduction. This review discusses the science behind PCSK9 inhibition, evidence of trials involving efficacy and safety, and reflections of its present and future role in clinical care, especially in high-risk patients with ASCVD, persons with suboptimal responses to statins and familial hyperlipidemia. Monoclonal antibodies have demonstrated LDL-C lowering of up to 57% as monotherapy and up to 73% when added to statins. Statins have limited efficacy in reduction of LDL-C due to an increased number of LDL-receptors. Elevated lipoprotein (a) levels may also be significantly lowered by PCSK9i. The journey from discovery to PSCK9 target validation took less than five years, and development and approval of therapeutic modalities for PCSK9 inhibitors happened over the next seven. This review highlights the drug development and pharmacogenomics leading to the recent approval of two agents, alirocumab and evolocumab, with a third bococizumab, and other novel approaches to the pathway pending. We searched MEDLINE database via Pubmed for reviews, research publications and relevant trials available on PCSK9 inhibition. Despite decades of medical advances, ASCVD remains one of the major causes of morbidity and mortality worldwide. Statin use has multiplied since the validation of LDL hypothesis, however, it is undeniable a more effective and well-tolerated agent is needed in significant number or patients. With the arrival of the era of unprecedented CV protection with PCSK9 inhibition, this exciting new therapy holds a pivotal promise as the future of lipid management. The data available already indicate safety, tolerability and superb efficacy of these agents, which are already changing contemporary cholesterol management. The rapid translation of innovative basic science research into drug development may lead to CV outcomes reduction and confirm that this pathway will become prominently utilized.

Yadav K ，Sharma M ，Ferdinand KC 《-》

PCSK9 inhibitors: a non-statin cholesterol-lowering treatment option.

Pokrywka GS 《-》