Large Clinical Trials of Statin-Associated Muscle Symptoms

HomeCirculationVol. 135, No. 17Letter by Koh Regarding Article, “Pleiotropic Effects of PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) Inhibitors?” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter by Koh Regarding Article, “Pleiotropic Effects of PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) Inhibitors?” Kwang Kon Koh, MD, PhD Kwang Kon KohKwang Kon Koh From Department of Cardiovascular Medicine, Heart Center, Gachon University Gil Medical Center; and Gachon Cardiovascular Research Institute, Incheon, Korea. Search for more papers by this author Originally published25 Apr 2017https://doi.org/10.1161/CIRCULATIONAHA.116.026821Circulation. 2017;135:e1006–e1007To the Editor:In her recent article, Bittner discussed pleiotropic effects of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors.1 PCSK9 is a serine protease that is secreted by the liver, binds to the low-density lipoprotein (LDL) receptor, and directs the LDL receptor toward lysosomal degradation. PCSK9 inhibitors achieve LDL-cholesterol (LDL-C) reductions of 45% to 60% and similarly LDL particle number, small and large LDL particles, and apolipoprotein B levels. The impact of PCSK9 inhibition is not limited to reduction in LDL-C but also affects other aspects of lipoprotein metabolism, inflammation, thrombosis, and immune function. PCSK9 inhibitors lower lipoprotein (a) by as much as 30% and variably reduce triglyceride-rich lipoproteins possibly through enhanced clearance by LDL receptors and very LDL (VLDL) receptors or by lowering production of triglyceride-rich lipoproteins. Thus, PCSK9 antibodies lower LDL-C and other atherogenic lipoproteins and seem to favorably affect the complex inflammatory and thrombotic mechanisms related to atherosclerosis progression and acute events. Therefore, broad effects of PCSK9 inhibitors on multiple physiological systems come with concerns about the potential for unintended effects.1On the other hand, subjects with genetic variants in PCSK9 or HMGCR with reduced LDL levels had similar decreases in cardiovascular disease (CVD) risk per unit decrease in LDL-C.2,3 In subjects with preexisting glucose intolerance, variants in both genes were associated with independent and additive effects to increase risk of diabetes mellitus (also associated with LDL lowering albeit with smaller effect size than CVD risk).2 PCSK9 inhibitors and statins use distinct mechanisms to lower LDL-C, the common downstream effect that is likely related to both protection against CVD and promotion of diabetes mellitus. Together, these data strongly support large clinical outcome studies to determine whether a further increase in diabetes mellitus occurs with statin therapy.These data provide insights into the potential adverse effects of LDL-C-lowering therapy. What should we target, CVD risk or diabetes mellitus? Because new-onset diabetes mellitus adds substantially to CVD risk, a dilemma exists with combination therapy of high-potency statins combined with PCSK9 inhibitors. Also, we should think about cost-effectiveness. PCSK9 inhibitors are expensive and would be unnecessary except in patients with a CVD event or familial hypercholesterolemia+inadequate lowering of LDL-C with statins with or without stain intolerance. Statins are important, but we should also endeavor to control residual risk because reduction of LDL-C prevents <50% of CVD events.We have proposed statins-based combined therapy to balance cardiometabolic benefits and risks of statins. Statins-based combined therapy would simultaneously prevent new-onset diabetes mellitus and improve cardiovascular outcome because of the beneficial effects of renin-angiotensin system or ezetimibe on insulin resistance and endothelial dysfunction.4,5 In this regard, combined therapy demonstrates additive/synergistic effects on endothelial dysfunction and insulin resistance in addition to lowering LDL-C levels and blood pressure when compared with either monotherapy in patients. This finding is mediated by both distinct and interrelated mechanisms.4,5Kwang Kon Koh, MD, PhDAcknowledgmentsI deeply appreciate Dr Robert H. Eckel, Division of Endocrinology, Metabolism and Diabetes, University of Colorado, Denver, for his comment.DisclosuresNone.FootnotesCirculation is available at http://circ.ahajournals.org.

Despite the availability of effective drug therapies that reduce low-density lipoprotein (LDL)-cholesterol (LDL-C), cardiovascular disease (CVD) remains an important cause of mortality and morbidity. Therefore, additional LDL-C reduction may be warranted, especially for patients who are unresponsive to, or unable to take, existing LDL-C-reducing therapies. By inhibiting the proprotein convertase subtilisin/kexin type 9 (PCSK9) enzyme, monoclonal antibodies (PCSK9 inhibitors) may further reduce LDL-C, potentially reducing CVD risk as well. Primary To quantify short-term (24 weeks), medium-term (one year), and long-term (five years) effects of PCSK9 inhibitors on lipid parameters and on the incidence of CVD. Secondary To quantify the safety of PCSK9 inhibitors, with specific focus on the incidence of type 2 diabetes, cognitive function, and cancer. Additionally, to determine if specific patient subgroups were more or less likely to benefit from the use of PCSK9 inhibitors. We identified studies by systematically searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Web of Science. We also searched Clinicaltrials.gov and the International Clinical Trials Registry Platform and screened the reference lists of included studies. We identified the studies included in this review through electronic literature searches conducted up to May 2016, and added three large trials published in March 2017. All parallel-group and factorial randomised controlled trials (RCTs) with a follow-up time of at least 24 weeks were eligible. Two review authors independently reviewed and extracted data. When data were available, we calculated pooled effect estimates. We included 20 studies with data on 67,237 participants (median age 61 years; range 52 to 64 years). Twelve trials randomised participants to alirocumab, three trials to bococizumab, one to RG7652, and four to evolocumab. Owing to the small number of trials using agents other than alirocumab, we did not differentiate between types of PCSK9 inhibitors used. We compared PCSK9 inhibitors with placebo (thirteen RCTs), ezetimibe (two RCTs) or ezetimibe and statins (five RCTs).Compared with placebo, PCSK9 inhibitors decreased LDL-C by 53.86% (95% confidence interval (CI) 58.64 to 49.08; eight studies; 4782 participants; GRADE: moderate) at 24 weeks; compared with ezetimibe, PCSK9 inhibitors decreased LDL-C by 30.20% (95% CI 34.18 to 26.23; two studies; 823 participants; GRADE: moderate), and compared with ezetimibe and statins, PCSK9 inhibitors decreased LDL-C by 39.20% (95% CI 56.15 to 22.26; five studies; 5376 participants; GRADE: moderate).Compared with placebo, PCSK9 inhibitors decreased the risk of CVD events, with a risk difference (RD) of 0.91% (odds ratio (OR) of 0.86, 95% CI 0.80 to 0.92; eight studies; 59,294 participants; GRADE: moderate). Compared with ezetimibe and statins, PCSK9 inhibitors appeared to have a stronger protective effect on CVD risk, although with considerable uncertainty (RD 1.06%, OR 0.45, 95% CI 0.27 to 0.75; three studies; 4770 participants; GRADE: very low). No data were available for the ezetimibe only comparison. Compared with placebo, PCSK9 probably had little or no effect on mortality (RD 0.03%, OR 1.02, 95% CI 0.91 to 1.14; 12 studies; 60,684 participants; GRADE: moderate). Compared with placebo, PCSK9 inhibitors increased the risk of any adverse events (RD 1.54%, OR 1.08, 95% CI 1.04 to 1.12; 13 studies; 54,204 participants; GRADE: low). Similar effects were observed for the comparison of ezetimibe and statins: RD 3.70%, OR 1.18, 95% CI 1.05 to 1.34; four studies; 5376 participants; GRADE: low. Clinical event data were unavailable for the ezetimibe only comparison. Over short-term to medium-term follow-up, PCSK9 inhibitors reduced LDL-C. Studies with medium-term follow-up time (longest median follow-up recorded was 26 months) reported that PCSK9 inhibitors (compared with placebo) decreased CVD risk but may have increased the risk of any adverse events (driven by SPIRE-1 and -2 trials). Available evidence suggests that PCSK9 inhibitor use probably leads to little or no difference in mortality. Evidence on relative efficacy and safety when PCSK9 inhibitors were compared with active treatments was of low to very low quality (GRADE); follow-up times were short and events were few. Large trials with longer follow-up are needed to evaluate PCSK9 inhibitors versus active treatments as well as placebo. Owing to the predominant inclusion of high-risk patients in these studies, applicability of results to primary prevention is limited. Finally, estimated risk differences indicate that PCSK9 inhibitors only modestly change absolute risks (often to less than 1%).

PCSK9 inhibition is an effective therapy to reduce LDL cholesterol (LDL-C) and cardiovascular events. A recent study shows that one or two doses of inclisiran, a long-acting synthetic small-interfering RNA (siRNA) that selectively targets hepatic PCSK9, causes a sustained reduction of plasma LDL-C for up to 6 months. Pending further studies of safety and efficacy, this may represent an important addition to the armamentarium for inhibiting PCSK9.

Joint statement from the European Atherosclerosis Society and European Society of Vascular Medicine focuses on patients with peripheral arterial disease

HomeStrokeVol. 51, No. 11Correction to: PCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) Inhibition and Stroke Prevention: Another Step Forward Free AccessCorrectionPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCorrectionPDF/EPUBCorrection to: PCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) Inhibition and Stroke Prevention: Another Step Forward Originally published26 Oct 2020https://doi.org/10.1161/STR.0000000000000352Stroke. 2020;51:e348This article corrects the followingPCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) Inhibition and Stroke PreventionIn the article by Alberts and Thompson, “PCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) Inhibition and Stroke Prevention: Another Step Forward,” which published online on April 21, 2020 (Stroke. doi: 10.1161/STROKEAHA.120.028567) a correction is needed.On page 1361, paragraph one, reads “…FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk; Improved Reduction of Outcomes: Vytorin Efficacy International Trial)….” It should read “FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk)….”Paragraph two reads “The current report focuses on reduction in stroke events seen in high-risk patients treated with PCSKi evolocumab….” It should read, “The current report focuses on reduction in stroke events seen in high-risk patients treated with the PCSKi evolocumab….”In addition, typos of FOURIER and evolocumab were corrected throughout the article.This correction has been made to the current online version of the article, which is available at https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.028567. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesPCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) Inhibition and Stroke PreventionMark J. Alberts, et al. Stroke. 2020;51:1361-1362 November 2020Vol 51, Issue 11 Advertisement Article InformationMetrics © 2020 American Heart Association, Inc.https://doi.org/10.1161/STR.0000000000000352PMID: 33104492 Originally publishedOctober 26, 2020 PDF download Advertisement

PCSK9 Inhibitors: What Lies Beyond Monoclonal Antibodies?

BackgroundWe sought to examine the efficacy and safety of 2 PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors: alirocumab and evolocumab.Methods and ResultsWe performed a systematic review and meta‐analysis of randomized controlled trials comparing treatment with and without PCSK9 inhibitors; 35 randomized controlled trials comprising 45 539 patients (mean follow‐up: 85.5 weeks) were included. Mean age was 61.0±2.8 years, and mean baseline low‐density lipoprotein cholesterol was 106±22 mg/dL. Compared with no PCSK9 inhibitor therapy, treatment with a PCSK9 inhibitor was associated with a lower rate of myocardial infarction (2.3% versus 3.6%; odds ratio [OR]: 0.72 [95% confidence interval (CI), 0.64–0.81]; P<0.001), stroke (1.0% versus 1.4%; OR: 0.80 [95% CI, 0.67–0.96]; P=0.02), and coronary revascularization (4.2% versus 5.8%; OR: 0.78 [95% CI, 0.71–0.86]; P<0.001). Overall, no significant change was observed in all‐cause mortality (OR: 0.71 [95% CI, 0.47–1.09]; P=0.12) or cardiovascular mortality (OR: 1.01 [95% CI, 0.85–1.19]; P=0.95). A significant association was observed between higher baseline low‐density lipoprotein cholesterol and benefit in all‐cause mortality (P=0.038). No significant change was observed in neurocognitive adverse events (OR: 1.12 [95% CI, 0.88–1.42]; P=0.37), myalgia (OR: 0.95 [95% CI, 0.75–1.20]; P=0.65), new onset or worsening of preexisting diabetes mellitus (OR: 1.05 [95% CI, 0.95–1.17]; P=0.32), and increase in levels of creatine kinase (OR: 0.84 [95% CI, 0.70–1.01]; P=0.06) or alanine or aspartate aminotransferase (OR: 0.96 [95% CI, 0.82–1.12]; P=0.61).ConclusionsTreatment with a PCSK9 inhibitor is well tolerated and improves cardiovascular outcomes. Although no overall benefit was noted in all‐cause or cardiovascular mortality, such benefit may be achievable in patients with higher baseline low‐density lipoprotein cholesterol.

Elevated low-density lipoprotein cholesterol (LDLC) levels in the plasma is the most important causative factor of atherosclerosis and associated ischemic cardiovascular diseases. The LDL receptor (LDLR) is the preferential pathway through which LDLs are cleared from the circulation. LDLs bound to the LDLR are internalized into clathrin-coated pits and subsequently undergo lysosomal degradation, whereas the LDLR is recycled back to the plasma membrane. See accompanying article on page 1333 Familial hypercholesterolemia (FH) is an autosomal dominant disorder associated with elevated LDL levels and premature coronary heart disease. FH is caused primarily by mutations of the LDLR or of apolipoprotein B100 (apoB100), the protein component of LDL that interacts with the LDLR. In 2003, “gain of function” mutations on a newly identified gene, proprotein convertase subtilisin/kexin type 9 ( PCSK9), were associated with FH. In 2005, a causative association was established between “loss of function” mutations in PCSK9 and low LDLC levels in 2% of the African-American population. The coronary heart disease risk in these individuals was reduced by 88%. As a result of these landmark studies (reviewed in Reference 1), PCSK9 became the subject of intensive research to discover the underlying mechanisms. PCSK9 is a serine protease mainly expressed in the liver and the intestine. It acts by reducing the amount of LDLR in hepatocytes. This was demonstrated in vitro and in mouse models …

Background and Aims: RNA interference therapy targeting the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene lower low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB) levels and is approved worldwide. As opposed to monoclonal antibodies neutralizing PCSK9 in the circulation, their effect on atherosclerotic cardiovascular disease (ASCVD) outcomes is unknown. We used drug-target Mendelian randomization (MR) to assess the potential impact of RNA interference therapies targeting PCSK9 on cardiometabolic traits and outcomes. Methods: We performed RNA-sequencing of 246 liver samples and genome-wide genotyping was performed to identify single-nucleotide polymorphisms (SNPs) associated with liver expression of PCSK9. Genome-wide association study (GWAS) summary statistics of plasma protein levels of PCSK9 from the deCODE study (n=35,559) were used to instrument inhibition of circulating PCSK9 levels. A three-sample MR approach was undertaken using SNPs that influence liver PCSK9 gene expression levels (mimicking PCSK9 RNA interference) or plasma PCSK9 protein levels (mimicking PCSK9 neutralizing antibodies) as study exposures. Genetic instruments were standardized for their effect on apoB levels. Main outcomes measures included GWAS summary statistics on coronary artery disease (CAD), ischemic stroke (IS) and type 2 diabetes (T2D). Results: Each SD decrease in apoB was linked with a 55% and 56% reduction in CAD risk, respectively for genetically predicted reductions in plasma PCSK9 levels (OR [odds ratio]=0.45 [95% CI], 0.36-0.56, p=1.7e-13) and liver PCSK9 gene expression levels (OR=0.44 [95% CI], 0.22-0.88, p=0.02). Genetically predicted reductions in plasma PCSK9 levels and liver PCSK9 gene expression levels were associated with slightly lower IS risk (OR=0.82 [95% CI], 0.68-0.98, p=0.03 and OR=0.73 [95% CI], 0.51-1.04, p=0.08, respectively). Genetically predicted reductions in plasma PCSK9 levels and liver PCSK9 gene expression levels were not associated with T2D risk (OR=1.08 [95% CI], 0.92-1.28, p=0.34 and OR=1.26 [95% CI], 0.93-1.71, p=0.14, respectively). The effect of PCSK9 inhibition on CAD was entirely mediated by reductions in apoB levels. Conclusions: Genetically predicted reductions in plasma PCSK9 levels and liver PCSK9 gene expression levels were associated with lower ASCVD risk, suggesting that LDL-C/apoB reductions may provide cardiovascular benefits, regardless of how PCSK9 function is inhibited.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a circulating protein that plays a key role in the regulation of plasma low-density lipoprotein (LDL) cholesterol levels. PCSK9 binding to the LDL receptor (LDLR) leads to receptor-mediated endocytosis and lysosomal degradation of LDLR. Prior studies have shown that PCSK9 increases production of triglyceride-rich apoB-lipoproteins via up-regulation of lipogenic genes, and that PCSK9 inhibition reduces plasma triglyceride levels. However, the effect of PCSK9 inhibition on hepatic lipogenic genes expression remain unclear. Using a human hepatocellular carcinoma cell line (HepG2) we show that overexpression of PCSK9 upregulated the expression of several lipogenic genes, including a 1.5-fold increase in ATP citrate lyase (ACLY), a 1.2-fold increase in Fatty Acid Synthase (FAS), a 1.2-fold increase in HMG-CoA-reductase, and a 1.8-fold increase in microsomal triglyceride transfer protein (MTTP), when compared with untransfected HepG2 cells. Overexpression of a gain-of-function mutant of PCSK9 (PCSK9-D374Y) had stronger effects in the same direction: a 2.3-fold increase in ACLY, a 1.8-fold increase in FAS, a 1.6-fold increase in HMG-CoA-reductase, and a 2.1-fold increase in MTTP. In HepG2 cells overexpressing either normal PCSK9 or PCSK9-D374Y, inhibition of PCSK9 function using a monoclonal antibody blocked PCSK9-mediated degradation of LDLR, and reduced expression of SREBP-dependent genes (ACLY, FAS and HMG-CoA-reductase) to levels of untransfected HepG2 cells. Interestingly, while inhibition of PCSK9 function via monoclonal antibody did not affect MTTP gene expression in these cells, inhibition of PCSK9 production via RNA interference reduced MTTP gene expression by 66%. We conclude that inhibition of PCSK9 production decreases MTTP gene expression, whereas blockade of PCSK9 function (and cellular re-entry) only decreases SREBP-dependent genes expression, but does not affect MTTP gene expression. This study shows that while PCSK9 exerts an influence on genes related to both lipogenesis and lipoprotein assembly, any inhibition of PCSK9 controls SREPB-dependent genes but only inhibiting PCSK9 production controls MTTP gene expression.

Introduction Percutaneous coronary intervention (PCI) is the gold standard for the management of acute coronary syndrome, and has been benefited from advances in pharmacotherapy and device innovation. Nevertheless, in-stent restenosis and stent thrombosis remain serious complications following PCI procedure with stent implantation. Proprotein convertase subtilisin kexin type 9 (PCSK9) is an enzyme known for its role in plasma cholesterol homeostasis. Efficiently reducing plasma cholesterol, PCSK9 inhibition recently became a pivotal treatment strategy for hypercholesterolemia. However, the effect of PCSK9 inhibition on stent implantation outcomes remains uninvestigated. Methods Carotid artery bare-metal stent (BMS) implantation was performed on C57Bl/6 mice, which then a parallel assessment of various inflammatory mediators was performed. To inhibit PCSK9, alirocumab was administered weekly to antiplatelet-treated mice started before stent implantation. Six weeks after the stent implantation procedure, animals were harvested and histomorphometric analysis was performed on stented arteries. In vitro cell migration and cellular senescence were also assessed on alirocumab-treated primary human aortic endothelial (EC) and vascular smooth muscle cells (VSMC). Results Compared to sham intervention, stent implantation was associated with increased expression of several inflammatory mediators, including PCSK9. Interestingly, the increase in PCSK9 level was confirmed in the stented vascular tissue, but not in plasma (Fig 1A). Following alirocumab treatment, PCSK9 inhibition results in an increased intimal hyperplasia in the stented vascular segment of alirocumab-treated animals compared to controls (Fig 1B). In vitro, alirocumab promoted migration and inhibited the onset of senescence in primary human VSMC, while blunted the migration and increased the senescence of EC. Conclusion The results of this study demonstrated that antibody-based PCSK9 inhibition worsen bare-metal stent implantation outcome in mice. This observed effect is mediated, in part, by the differential effect on VSMC and EC senescence, thus promoting in-stent intimal hyperplasia while blunting vascular healing. The herein-reported data warrant additional investigations concerning the use of PCSK9 inhibitors in patients undergoing PCI with stent implantation.

Statins are the cornerstone of the management of dyslipidaemias and prevention of cardiovascular disease. Although statins are, overall, safe and well tolerated, adverse events can occur and constitute an important barrier to maintaining long-term adherence to statin treatment. In patients who cannot tolerate statins, alternative treatments include switch to another statin, intermittent-dosage regimens and non-statin lipid-lowering medications. Nonetheless, a high proportion of statin-intolerant patients are unable to achieve recommended low-density lipoprotein (LDL) cholesterol goals, thereby resulting in substantial residual cardiovascular risk. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protease implicated in LDL receptor degradation and plays a central role in cholesterol metabolism. In recent studies, PCSK9 inhibition by means of monoclonal antibodies achieved LDL cholesterol reductions of 50% to 70% across various patient populations and background lipid-lowering therapies, while maintaining a favourable safety profile. The efficacy and safety of the monoclonal antibodies alirocumab and evolocumab were confirmed in statin-intolerant patients, indicating that PCSK9 inhibitors represent an attractive treatment option in this challenging clinical setting. PCSK9 inhibitors recently received regulatory approval for clinical use and may be considered in properly selected patients according to current consensus documents, including patients with statin intolerance. In this review we summarise current evidence regarding diagnostic evaluation of statin-related adverse events, particularly statin-associated muscle symptoms, and we discuss current recommendations on the management of statin-intolerant patients. In view of emerging evidence of the efficacy and safety of PCSK9 inhibitors, we further discuss the role of monoclonal PCSK9 antibodies in the management of statin-intolerant hypercholesterolaemic patients.

S-palmitoylation of PCSK9 induces sorafenib resistance in liver cancer by activating the PI3K/AKT pathway.

Scientific relevance. The main cause of cardiovascular pathologies is atherosclerosis, which is secondary to lipid metabolism disorders, in particular, the accumulation of low-density lipoprotein (LDL) cholesterol. Dyslipidaemia treatment with the largest evidence base predominantly includes statins in combination therapy, but their use is limited by into lerance in some patients. Alternatively, the treatment may include proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors.Aim. The study aimed to analyse the applicability of PCSK9 inhibitors in patients with statin intolerance.Discussion. According to the literature analysis, the most common presentation of statin intolerance is statin-associated muscle symptoms. The pathogenesis of statin-associated adverse events is mainly mediated by HMGCoA reductase inhibition, treatment effects on cellular and subcellular processes and skeletal muscles, and patients’ genetic makeup. The mechanism of action of PCSK9 inhibitors is entirely different and involves binding and inactivation of the PCSK9 protein, which lowers blood LDL cholesterol levels. PCSK9 inhibitors have been associated with some adverse drug reactions, most notably immunogenicity; however, PCSK9 inhibitors effectively reduce LDL levels even if patients develop antibodies.Conclusions. Therefore, PCSK9 inhibitors are a safe, well-tolerated, and effec tive therapeutic strategy for hyperlipidaemia in patients with statin intolerance.

Proprotein convertase subtilisin/kexin type-9 (PCSK9) is a key regulator of low-density lipoprotein (LDL) metabolism involved in the degradation of the low-density lipoprotein receptor (LDLR) through complex mechanisms. The PCSK9 plasma levels change according to lipid lowering therapy (LLT). Few data exist regarding the role of PCSK9 in vascular damage. We aimed to evaluate the impact of PCSK9 plasma levels on pulse wave velocity (PWV) and the effect of PCSK9 inhibitors (PCSK9-i) on circulating PCSK9 and PWV in a cohort of heterozygous familial hypercholesterolemia (HeFH) subjects. In a previous step, HeFH patients were enrolled and LLT was prescribed according to guidelines. Biochemical analyses and PWV assessment were performed at baseline (T0), after 6 months of high-efficacy statin plus ezetimibe (T1) and after 6 months of PCSK9-i (T2). The PCSK9 levels were evaluated in 26 selected HeFH subjects at the three time points and 26 healthy subjects served as controls for the reference value for PCSK9 plasma levels. The PWV values decreased at each time point in HeFH subjects after LLT starting (8.61 ± 2.4 m/s, −8.7%; p < 0.001 vs. baseline at T1, and 7.9 ± 2.1 m/s, −9.3%; p < 0.001 vs. both T1 and baseline) and it was correlated to PCSK9 (r = 0.411, p = 0.03). The PCSK9 levels increased on statin/EZE therapy (+42.8% at T1) while it decreased after PCSK9-i was started (−34.4% at T2). We noted a significant relationship between PCSK9 levels and PWV changes at T1 and T2. In conclusion, PCSK9 levels were associated with baseline PWV values in HeFH subjects; moreover, we found that PCSK9 level variations seemed to be correlated with PWV changes on LLT. A longer observation time and wider sample size are needed to assess the potential role of PCSK9 plasma levels on the vascular function and remodelling, and to clarify the effects of PCSK9-i in these pathways.