PCSK9 Inhibitor Wars: How Does Inclisiran Fit in with Current Monoclonal Antibody Inhibitor Therapy? Considerations for Patient Selection

Chemical constituents from the roots of Cynanchum wilfordii with PCSK9 secretion inhibitory activities

From the Cynanchum wilfordii roots, 32 compounds, including 5 previously undescribed (1, 4-6, 12) and 27 known (2, 3, 7-11, 13-32) compounds, were isolated, and their structures were elucidated using NMR spectroscopic data and MS data aided by ECD calculations or the modified Mosher's reaction. All isolates were tested for their inhibitory effects on proprotein convertase subtilisin/kexin type 9 (PCSK9) secretion. Among the isolates, compound 4, a methyl cholesterol analog, exhibited the most potent effect in reducing PCSK9 secretion, along with PCSK9 downregulation at the mRNA and protein levels via FOXO1/3 upregulation. Moreover, compound 4 attenuated statin-induced PCSK9 expression and enhanced the uptake of DiI-LDL low-density lipoprotein. Thus, compound 4 is suggested to be a potential candidate for controlling cholesterol levels.

Postmarketing Reports of Incomplete Dosing-Related Complications with Self-Injected PCSK9 Inhibitors: A Descriptive Study and Disproportionality Analysis

BACKGROUND

Evolocumab and alirocumab are self-injected proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors indicated for low-density lipoprotein cholesterol reduction. Complications in the use or functionality of self-injection devices may precipitate incomplete dosing.

OBJECTIVE

This study sought to characterize postmarketing dosing failure reports involving self-injected PCSK9 inhibitors.

METHODS

US Food and Drug Administration Adverse Event Reporting System (FAERS) [2016-second quarter of 2023] data were utilized for a disproportionality analysis. Eight self-injected comparator medications served as referents. Medical Dictionary for Regulatory Activities preferred terms indicating explicit or probable failure to administer a complete dose classified cases. Proportional reporting ratios (PRRs) > 2.0 and lower 95% confidence intervals (CIs) > 1.0 indicated disproportionality signals. US FDA Manufacturer and User Facility Device Experience (MAUDE) [2013-2023] data underwent a narrative review.

RESULTS

During the study period, 194,781 (evolocumab, n = 152,831; alirocumab, n = 41,950) drug-event pairs and 43,725 (evolocumab, n = 38,489; alirocumab, n = 5236) cases reported to FAERS identified PCSK9 inhibitors. MAUDE contained six evolocumab reports, half describing dose omission, and no alirocumab reports. A potential dosing failure signal was detected for evolocumab (PRR 2.01; 95% CI 1.98-2.03), but not alirocumab (PRR 0.99; 95% CI 0.97-1.02), relative to pooled comparator reports. Across three case term subcategories, incomplete dosing disproportionality signals were further identified for evolocumab patient usage complication terms (PRR 3.44; 95% CI 3.38-3.50) and alirocumab device malfunction terms (PRR 2.09; 95% CI 1.98-2.22).

CONCLUSIONS

Proprotein convertase subtilisin kexin type 9 inhibitor incomplete dosing-related complications are frequently reported in the postmarketing setting. Systematic efforts to understand the incidence and mechanisms of dosing failure and associated patient burdens are needed.

PCSK9 inhibition with orally administered NNC0385-0434 in hypercholesterolaemia: a randomised, double-blind, placebo-controlled and active-controlled phase 2 trial

BACKGROUND

Currently available injectable drugs that target proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce serum LDL cholesterol and improve cardiovascular outcomes. This phase 2 study assessed NNC0385-0434, an oral PCSK9 inhibitor, in individuals receiving oral lipid-lowering therapy.

METHODS

In this randomised, double-blind, placebo-controlled and active-controlled trial, 42 research sites across seven countries (Belgium, Germany, Greece, Japan, the Netherlands, Poland, and the USA) recruited individuals with established atherosclerotic cardiovascular disease (aged ≥40 years) or at high risk of atherosclerotic cardiovascular disease (aged >50 years), who had LDL cholesterol concentration of at least 1·8 mmol/L and were receiving maximum tolerated statins and stable lipid-lowering therapy. The study randomly allocated participants (3:1) with an interactive web response system to receive either NNC0385-0434 (15 mg, 40 mg, or 100 mg) once a day co-formulated with the oral absorption enhancer sodium N-[8-(2-hydroxybenzoyl)amino] caprylate (500 mg); placebo; or open-label evolocumab (140 mg) every 2 weeks administered subcutaneously. Blinding was performed within each dose level. The primary endpoint was percentage change from baseline in LDL cholesterol measured by β quantification at week 12. All randomly assigned participants received at least one dose of treatment and were included in both safety and efficacy analyses. The trial was registered on ClinicalTrials.gov, NCT04992065, and is completed.

FINDINGS

Between Aug 16, 2021, and Jan 28, 2022, we randomly assigned 267 patients to one of the three NNC0385-0434 dose cohorts (n=53 per cohort), matching placebo (n=54), or open-label evolocumab (n=54). The study population comprised 82 (31%) women and 185 (69%) men; mean age was 64·3 years (SD 9·0). Baseline mean LDL cholesterol concentration was 2·7 mmol/L (SD 0·8). Treatment with NNC0385-0434 resulted in reductions in LDL cholesterol from baseline to week 12, of 32·0 percentage points (95% CI 20·9 to 43·0) in the 15 mg cohort, 44·9 percentage points (33·8 to 56·0) in the 40 mg cohort, and 61·8 percentage points (50·7 to 72·9) in the 100 mg cohort, compared with the placebo group (p<0·0001 for each). Patients treated with evolocumab had similar LDL cholesterol reductions (59·6% [SE 4·1] decrease from baseline) to patients receiving NNC0385-0434 100 mg (56·2% [4·0]). The estimated treatment difference between NNC0385-0434 100 mg and evolocumab 140 mg was 3·4 percentage points [95% CI -7·8 to 14·7]. The most frequently reported adverse event was COVID-19, which affected 31 (12%) of 267 patients, with similar numbers across treatment groups. Investigative sites reported gastrointestinal disorders as the most frequent treatment-related adverse event (26 patients and 35 events total in the three NNC0385 cohorts and one patient and one event each in the placebo and evolocumab cohorts). No deaths or treatment-related serious adverse events occurred.

INTERPRETATION

This study showed excellent 12-week LDL cholesterol lowering efficacy and good patient tolerance of an oral PCSK9 inhibitor, NNC0835-0434, similar to an injectable drug. However, the sponsor chose to discontinue further development of NNC0835-0434 due to portfolio considerations.

FUNDING

Novo Nordisk.

New Oral PCSK9 Inhibitor: "MK-0616"

MK-0616, a novel oral macrocyclic peptide inhibitor of proprotein convertase subtilisin/kexin type 9 (PCSK9), represents a significant advancement in the treatment of hypercholesterolemia. Unlike current PCSK9 inhibitors, which are injectable monoclonal antibodies and siRNA molecules, MK-0616 offers a patient-friendly alternative. The development of MK-0616 involved innovative synthetic chemistry and in vitro mRNA display technology. This cutting-edge approach led to the creation of an orally administered peptide with the ability to cover a larger portion of PCSK9 compared to smaller, linear peptides. Phase 1 and 2b clinical trials have demonstrated MK-0616's safety, efficacy, and pharmacokinetics. These trials indicate the drug's dose-dependent systemic absorption and long half-life. Notably, MK-0616 has exhibited comparable low-density lipoprotein cholesterol-lowering effects to currently available PCSK9 inhibitors, all while maintaining good tolerability in diverse patient populations, including those concurrently on statin therapy. As MK-0616 advances to Phase 3 trials, its lipid-lowering potential for heterozygous familial hypercholesterolemia and its impact on reducing the time to adverse cardiac events will be evaluated in a broad and diverse population, including underrepresented groups. The results achieved so far are promising for individuals with hypercholesterolemia, as they offer a potential solution for effectively lowering low-density lipoprotein cholesterol in patients on statin therapy and mitigating the risk of cardiovascular events. Ongoing research and monitoring will be critical to establish its long-term safety and efficacy, but MK-0616 may emerge as a valuable addition to the array of lipid-lowering therapies available to patients.

Optimization of the MACE endpoint composition to increase power in studies of lipid-lowering therapies-a model-based meta-analysis

Aims

To develop a model-informed methodology for the optimization of the Major Adverse Cardiac Events (MACE) composite endpoint, based on a model-based meta-analysis across anti-hypercholesterolemia trials of statin and anti-PCSK9 drugs.

Methods and results

Mixed-effects meta-regression modeling of stand-alone MACE outcomes was performed, with therapy type, population demographics, baseline and change over time in lipid biomarkers as predictors. Randomized clinical trials up to June 28, 2022, of either statins or anti-PCSK9 therapies were identified through a systematic review process in PubMed and ClinicalTrials.gov databases. In total, 54 studies (270,471 patients) were collected, reporting 15 different single cardiovascular events. Treatment-mediated decrease in low density lipoprotein cholesterol, baseline levels of remnant and high-density lipoprotein cholesterol as well as non-lipid population characteristics and type of therapy were identified as significant covariates for 10 of the 15 outcomes. The required sample size per composite 3- and 4-point MACE endpoint was calculated based on the estimated treatment effects in a population and frequencies of the incorporated events in the control group, trial duration, and uncertainty in model parameters.

Conclusion

A quantitative tool was developed and used to benchmark different compositions of 3- and 4-point MACE for statins and anti-PCSK9 therapies, based on the minimum population size required to achieve statistical significance in relative risk reduction, following meta-regression modeling of the single MACE components. The approach we developed may be applied towards the optimization of the design of future trials in dyslipidemia disorders as well as in other therapeutic areas.

Lipid Lowering Drugs in Acute Coronary Syndromes (ACS)

PURPOSE OF REVIEW

The purpose of this review is to critically discuss whether more aggressive lipid-lowering strategies are needed in patients with acute coronary syndromes (ACS).

RECENT FINDINGS

Currently, available data on early (in-hospital/discharge) administration of potent lipid-lowering drugs, such as proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors in patients during the vulnerable post-ACS phase, have clearly demonstrated clinical efficacy of the "strike early and strike strong" approach not only for rapid reduction of low-density lipoprotein cholesterol (LDL-C) to unprecedentedly low levels, but also for associated favorable composition of coronary plaque. Intensive lipid-lowering therapy with rapid achievement of the LDL-C treatment goal in ACS patients seems reasonable. However, whether such profound LDL-C reduction would result in additional benefit on the reduction of future CV events still has to be established. Thus, data addressing CV outcomes in such vulnerable patients at extreme CV risk are urgently needed.

Beyond statins: New pharmacological targets to decrease LDL-cholesterol and cardiovascular events

The pharmacological treatment of dyslipidemia, a major modifiable risk factor for developing atherosclerotic cardiovascular disease (ASCVD), remains a debated and controversial issue, not only in terms of the most appropriate therapeutic range for lipid levels, but also with regard to the optimal strategy and sequence approach (stepwise vs upstream therapy). Current treatment guidelines for the management of dyslipidemia focus on the intensity of low-density lipoprotein cholesterol (LDL-C) reduction, stratified according to risk for developing ASCVD. Beyond statins and ezetimibe, different medications targeting LDL-C have been recently approved by regulatory agencies with potential innovative mechanisms of action, including proprotein convertase subtilisin/kexin type 9 modulators (monoclonal antibodies such as evolocumab and alirocumab; small interfering RNA molecules such as inclisiran), ATP-citrate lyase inhibitors (bempedoic acid), angiopoietin-like 3 inhibitors (evinacumab), and microsomal triglyceride transfer protein inhibitors (lomitapide). An understanding of their pharmacological aspects, benefit-risk profile, including impact on hard cardiovascular endpoints beyond LDL-C reduction, and potential advantages from the patient perspective (e.g., adherence) - the focus of this evidence-based review - is crucial for practitioners across medical specialties to minimize therapeutic inertia and support clinical practice.

Acyclic Triterpenoids from Alpinia katsumadai Seeds with Proprotein Convertase Subtilisin/Kexin Type 9 Expression and Secretion Inhibitory Activity

Cholesterol is one of the primary causes of cardiovascular disease. Investigating and developing potential drugs to effectively treat hypercholesterolemia are therefore of critical importance. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been developed to lower the levels of low-density lipoprotein cholesterol in patients with hypercholesterolemia. In this study, we aimed to identify compounds that inhibit the PCSK9 mRNA expression and secretion. The bioassay-guided investigation of Alpinia katsumadai seeds utilizing a PCSK9 mRNA expression monitoring assay yielded the isolation and identification of seven new compounds. Among these were three acyclic triterpenoids (1-3), an acyclic sesquiterpenoid (5), one arylpentanoid (6), and two diarylheptanoids (7 and 8), alongside 10 known compounds. The structures of these compounds were determined using nuclear magnetic resonance (NMR) spectroscopy, vibrational circular dichroism (VCD), and electronic circular dichroism (ECD). The absolute configurations of compounds 1 and 2 were identified by comparing the calculated and experimental VCD data as the ECD method was unable to distinguish the diastereomers. All the isolated compounds were evaluated for their regulatory effects on the low-density lipoprotein receptor (LDLR) and PCSK9 mRNA expression, as well as PCSK9 secretion. Of the tested compounds, two of the acyclic triterpenoids (1 and 2) demonstrated potent effects in downregulating PCSK9 at both the mRNA and protein levels, compared with the positive control (berberine chloride). Additionally, compound 1 inhibited PCSK9 secretion to a level comparable to that of berberine chloride. This study identifies compounds that inhibit PCSK9 mRNA expression and secretion, offering significant contributions to the development of novel drugs for the effective treatment of hypercholesterolemia..

Inclisiran, Low-Density Lipoprotein Cholesterol and Lipoprotein (a)

Dyslipidemia treatment is of major importance in reducing the risk of atherosclerotic cardiovascular disease (ASCVD), which is still the most common cause of death worldwide. During the last decade, a novel lipid-lowering drug category has emerged, i.e., proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. Apart from the two available anti-PCSK9 monoclonal antibodies (alirocumab and evolocumab), other nucleic acid-based therapies that inhibit or "silence" the expression of PCSK9 are being developed. Among them, inclisiran is the first-in-class small interfering RNA (siRNA) against PCSK9 that has been approved by both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of hypercholesterolemia. Importantly, inclisiran therapy may improve low-density lipoprotein cholesterol (LDL-C) target achievement by offering a prolonged and significant LDL-C-lowering effect with the administration of only two doses per year. The present narrative review discusses the ORION/VICTORION clinical trial program that has been designed to investigate the impact of inclisiran on atherogenic lipoproteins and major adverse cardiac events in different patient populations. The results of the completed clinical trials are presented, focusing on the effects of inclisiran on LDL-C and lipoprotein (a) (Lp(a)) levels as well as on other lipid parameters such as apolipoprotein B and non-high-density lipoprotein cholesterol (non-HDL-C). Ongoing clinical trials with inclisiran are also discussed.

Inclisiran—A Revolutionary Addition to a Cholesterol-Lowering Therapy

Hypercholesterolemia plays a crucial role in the development of atherosclerosis, but it remains an undertreated and underdiagnosed disease. Taking into consideration the high prevalence of lipid disorders, long duration of the asymptomatic course of the disease, life-threatening complications resulting from inaccurate therapy, and stringent treatment goals concerning LDL cholesterol level in the prevention of cardiovascular events, novel lipid-lowering therapies have been introduced in the last few years. In this article, a drug belonging to the group of small interfering RNA (siRNA) called inclisiran is described. It is a novel molecule that increases the number of LDL receptors (LDLRs) on the surface of hepatic cells by preventing the formation of proprotein convertase subtilisin/kexin type 9 (PCSK9) responsible for the degradation of LDLRs. With great potential for lowering plasma LDL cholesterol level, high liver specificity, comfortable dosing regimen, and good tolerance without significant adverse effects, it could play an important part in future hypolipemic therapies.

Chemical constituents from Morus alba with proprotein convertase subtilisin/kexin type 9 expression and secretion inhibitory activity

Six new flavanones, including sanggenol W (1), morusalnol D-F (2-4) and neovanone A and B (5 and6), and fourteen known compounds were isolated from the methanol extract of the dried root bark of Morus alba using various column chromatographic methods. Their structures were elucidated using spectroscopic methods. The isolated compounds were tested in vitro for LDLR, PCSK9 and IDOL mRNA regulatory activity, and it was found that betulinic acid (13) showed the most potent effect on downregulation of PCSK9 and upregulation of LDLR at both mRNA and protein levels, showing comparable results to berberine, the positive control. In addition, betulinic acid (13) inhibited PCSK9 secretion, indicating its role as a future PCSK9 synthesis inhibitor.

The formation and consequences of cholesterol-rich deposits in atherosclerotic lesions

Cardiovascular diseases remain the leading cause of death throughout the world. Accumulation of lipoprotein-associated lipids and their interaction with macrophages are early steps in the development of atherosclerotic lesions. For decades, it has been known that aggregates of lipoproteins in the subendothelial space are found in early plaques, and these aggregates are tightly associated with extracellular matrix fibers. Additionally, most of the cholesterol in these subendothelial aggregates is unesterified, in contrast to the core of low-density lipoproteins (LDL), in which cholesteryl esters predominate. This suggests that the hydrolysis of cholesteryl esters occurs extracellularly. At the cellular level, macrophages in early plaques engage with the LDL and ingest large amounts of cholesterol, which is esterified and stored in lipid droplets. When excessive lipid droplets have accumulated, endoplasmic reticulum stress responses are activated, leading to cell death. The cholesterol-laden dead cells must be cleared by other macrophages. For many years, it was unclear how unesterified (free) cholesterol could be formed extracellularly in early lesions. Papers in the past decade have shown that macrophages form tightly sealed extracellular attachments to aggregates of LDL. These sealed regions become acidified, and lysosomal contents are secreted into these compartments. Lysosomal acid lipase hydrolyzes the cholesteryl esters, and the free cholesterol is transported into the macrophages. High concentrations of cholesterol can also lead to formation of crystals of cholesterol hydrate, and these crystals have been observed in atherosclerotic blood vessels. Characterization of this process may lead to novel therapies for the prevention and treatment of atherosclerosis.