Inclisiran, the billion-dollar drug, to lower LDL cholesterol - is it worth it?

INTRODUCTION: If statins are unsuccessful at achieving the LDL cholesterol level goal in subjects with hypercholesterolemia, non-statin therapy should be added to reduce cardiovascular morbidity and mortality. The first inhibitors of proprotein convertase substilisin-kexin type 9 (PCSK9) were human monoclonal antibodies and these reduced LDL cholesterol and cardiovascular events. Inclisiran is a small interfering RNA molecule (siRNAs) directed against PCSK9. AREAS COVERED: This key paper evaluation focuses on Phase 3 trials that assess inclisiran in the treatment of hypercholesterolemia and heterozygous familial hypercholesterolemia. EXPERT OPINION: To date, the findings with inclisiran have been very promising as it causes large decreases in LDL cholesterol with few adverse effects. However, there are some limitations to its widespread use. Firstly, cardiovascular outcomes trials have not been completed, so we do not know how inclisiran compares to the PCSK9 monoclonal antibodies, which, seem to me, to only have a modest effect on cardiovascular outcomes. Secondly, a major problem with the PCSK9 monoclonal antibodies is that they are expensive, and their use is often discontinued or not pursued, which can leave the subjects intended for treatment at high cardiovascular risk. At present, it is not clear whether similar problems around cost will apply to inclisiran.

Homozygous familial hypercholesterolemia in a young woman with dual gene mutations of low-density lipoprotein receptor and proprotein convertase subtilisin/kexin type 9.

A 28-year-old woman with a rare combination of homozygous LDLR and heterozygous PCSK9 mutations had a phenotype consistent with homozygous familial hypercholesterolemia. She reported a clinical history of coronary and extracoronary atherosclerosis treated with 3 coronary stenting procedures, one coronary bypass, and aortic and mitral valve replacements. Because the patient refused lipoprotein apheresis, lipid-lowering therapy with statins, ezetimibe, and evolocumab was started. The desired low-density lipoprotein cholesterol target was not achieved. Dose-escalated lomitapide therapy (up to 30 mg/d) was added, enabling achievement of low-density lipoprotein cholesterol levels of 45 mg/dL during 24 months' follow-up. During this period, no cardiovascular events or clinical evidence of side effects occurred. In this case, lomitapide has been used in combination with maximum-tolerated statin therapy to successfully treat a patient with a rare combination of mutations in both LDLR and PCSK9 genes.

Differential impact of severe familial hypercholesterolemia on regional skeletal muscle and organ blood flows during exercise: Effects of PDE5 inhibition.

OBJECTIVE: Swine with familial hypercholesterolemia (FH) exhibit attenuated exercise-induced systemic vasodilation that is restored by phosphodiesterase 5 (PDE5) inhibition. Whether the impacts of FH and PDE5 inhibition to impair and restore exercise-induced vasodilation, respectively, results from tissue-specific or generalized effects remains unclear. Thus, we hypothesized that FH induces generalized impairment of skeletal muscle vasodilation that would be alleviated by PDE5 inhibition. METHODS: Systemic vascular responses to exercise were assessed in chronically instrumented normal and FH swine before and after PDE5 inhibition with EMD360527. Skeletal muscle and organ blood flows and conductances were determined via the microsphere technique. RESULTS: As previously reported, vs normal swine, FH swine have pronounced elevation of total cholesterol and impaired exercise-induced vasodilation that is restored by PDE5 inhibition. Blood flows to several, not all, skeletal muscle vascular beds were severely impaired by FH associated with reduced blood flow to many visceral organs. PDE5 inhibition differentially impacted skeletal muscle and organ blood flows in normal and FH swine. CONCLUSIONS: These data indicate that FH induces regional, not generalized, vasomotor dysfunction and that FH and normal swine exhibit unique tissue blood flow responses to PDE5 inhibition thereby adding to accumulating evidence of vascular bed-specific dysfunction in co-morbid conditions.

Treatment patterns and patient characteristics among early initiators of PCSK9 inhibitors.

PURPOSE: To describe patient characteristics and treatment patterns among early initiators of proprotein convertase subtilisin/kexin type nine inhibitors (PCSK9is) who initiated treatment within the first 6 months of market availability. PATIENTS AND METHODS: This retrospective cohort study used IQVIA's longitudinal open-source point-of-sale pharmacy claims database (LRx) and PharMetrics Plus (P+) health plan claims database to identify patients initiating a PCSK9i between January 1, 2016 and June 30, 2016. The index date was defined as the date of the first PCSK9i prescription (index claim) during the enrollment window; patients were followed for ≥6 months postindex. Patient characteristics including use of baseline lipid-lowering therapy (LLT) and measures such as persistence and adherence to PCSK9i therapy were evaluated with respect to health plan type (commercial vs Medicare). RESULTS: Overall, patients initiating PCSK9i (n=13,151) had a mean age of 66 years, and 51% were male. Approximately 67.4% of patients used some form of LLT (statin and/or ezetimibe) in the 24 months prior to initiating PCSK9i therapy. The proportion of patients covered by a commercial health plan (51.2%) was similar to that covered by Medicare (48.8%). Persistence on PCSK9i was marginally longer for patients with commercial insurance than Medicare (mean days on therapy 202.2 vs 198.5). Overall, 42.6% of patients discontinued their PCSK9i during the 180 days of follow-up. CONCLUSION: This study demonstrates that a large proportion of patients discontinue PCSK9i therapy at 30 and 90 days, which are the time frames for which many health plans require recertification to continue access to PCSK9i. Future studies looking at treatment patterns among patients who initiate PCSK9i therapy after the first 180 days once health plan formularies and utilization management criteria were finalized are needed to understand more comprehensively real-world PCSK9i usage patterns.

Case reports of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition nonresponse.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, a novel class of monoclonal antibodies, reduces low-density lipoprotein cholesterol levels and improves cardiovascular outcomes. Given the short time frame, these agents have been available for use; reports of nonresponse to the PCSK9 inhibitor therapy are scarce in literature. We describe 2 cases with substantially lesser than expected low-density lipoprotein cholesterol lowering on PCSK9 therapy. Nonresponse to PCSK9 inhibition was attributed to autosomal recessive hypercholesterolemia (secondary to low-density lipoprotein receptor adaptor protein 1 mutation) and plasmapheresis after PCSK9 inhibitor drug injections. Additional PCSK9 inhibitor nonresponders are likely to emerge as the use of these agents increases overtime.

Ossabaw Pigs With a PCSK9 Gain-of-Function Mutation Develop Accelerated Coronary Atherosclerotic Lesions: A Novel Model for Preclinical Studies.

BACKGROUND: Ossabaw pigs are unique miniature swine with genetic predisposition to develop metabolic syndrome and coronary atherosclerosis after extended periods receiving atherogenic diets. We have hypothesized that transgenic Ossabaw swine expressing chimp PCSK9 (proprotein convertase subtilisin-like/kexin type 9) containing the D374Y gain of function would develop familial hypercholesterolemia and coronary artery plaques more rapidly than Landrace swine with the same transgene. METHODS AND RESULTS: Ossabaw and Landrace PCSK9 gain-of-function founders were generated by Sleeping Beauty transposition and cloning. Histopathologic findings in the Ossabaw founder animal showed more advanced plaques and higher stenosis than in the Landrace founder, underscoring the Ossabaw genetic predisposition to atherosclerosis. We chose to further characterize the Ossabaw PCSK9 gain-of-function animals receiving standard or atherogenic diets in a 6-month longitudinal study using computed tomography, magnetic resonance (MR) imaging, intravascular ultrasound, and optical coherence tomography, followed by pathological analysis of atherosclerosis focused on the coronary arteries. The Ossabaw model was consistently hypercholesterolemic, with or without dietary challenge, and by 6 months had consistent and diffuse fibrofatty or fibroatheromatous plaques with necrosis, overlying fibrous caps, and calcification in up to 10% of coronary plaques. CONCLUSIONS: The Ossabaw PCSK9 gain-of-function model provides consistent and robust disease development in a time frame that is practical for use in preclinical therapeutic evaluation to drive innovation. Although no animal model perfectly mimics the human condition, this genetic large-animal model is a novel tool for testing therapeutic interventions in the context of developing and advanced coronary artery disease.

Lipoprotein-associated phospholipase A2 activity is increased in patients with definite familial hypercholesterolemia compared with other forms of hypercholesterolemia.

BACKGROUND AND AIM: Lipoprotein-associated phospholipase A2 (Lp-PLA2) plays a key role in atherosclerosis development. It is considered a marker of increased risk of cardiovascular disease (CVD) and plaque vulnerability. Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated plasma levels of low-density lipoprotein cholesterol and a higher prevalence of early CVD. Our aim was to evaluate the differences in Lp-PLA2 activity in a population of hypercholesterolemic patients with and without definite FH. METHODS AND RESULTS: Hypercholesterolemic patients were consecutively recruited. Definite FH was defined according to Dutch Lipid Clinic Network criteria ≥8. All patients underwent routine clinical examination and biological assessments and Lp-PLA2 activity was measured in blood samples. Among 469 patients, 118 had a definite diagnosis of FH. Lp-PLA2 activity was significantly higher in definite FH patients compared to non-definite FH patients (206.5 ± 54.5 vs. 180.8 ± 48.4 nmol/min/mL, p < 0.0001). Lp-PLA2 positively correlated with total cholesterol, LDL-C and apolipoprotein B and negatively with HDL-C and apolipoprotein A-1. In multivariate analysis, definite FH diagnosis, LDL-C, HDL-C and statin treatment remained correlates of Lp-PLA2 independently of systolic blood pressure. CONCLUSIONS: Lp-PLA2 activity was higher in definite FH than in non-definite FH patients independently of LDL-C levels and statin treatment. These results highlight the particular phenotype of FH subjects among hypercholesterolemic patients. As increased Lp-PLA2 activity suggests, FH patients exhibit higher arterial inflammation that may contribute to their high cardiovascular risk. Our results reinforce the potential beneficial role of statins pleiotropic effects and the need for proper identification and treatment of FH patients.

PCSK9 inhibitors in clinical practice: Delivering on the promise?

BACKGROUND AND AIMS: In clinical trials, protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors robustly lowered LDL-cholesterol (LDL-c) and had a favorable tolerability and safety profile. Based on these findings, PCSK9 inhibitors are incorporated in updates of clinical treatment guidelines. However, trial results do not necessarily predict the effectiveness under real-world conditions. The aim of the current study is to determine the efficacy and tolerability of PCSK9 inhibitors in routine outpatient care. METHODS: The cohort comprised all patients who were prescribed evolocumab or alirocumab at the outpatient clinic of a large university hospital in the Netherlands. Eligible patients required additional lipid-lowering despite maximally tolerated statin therapy and ezetimibe, or were statin intolerant. Data were systematically collected during routine outpatient visits. RESULTS: The study included 238 patients of whom 67.2% had familial hypercholesterolemia (FH) and 42.9% were statin intolerant. The mean LDL-c reduction was 55.0% from a baseline of 4.4 mmol/L. LDL-c goals were attained by 62.3% of patients. Side effects were reported by 15.5% of patients and 2.5% discontinued treatment. No meaningful differences in efficacy or tolerability were observed between patients with FH or statin intolerance, or across treatment regimens. CONCLUSIONS: The observed lipid reductions and side effects profile of PCSK9 inhibitors in a routine care setting were comparable to observations in clinical trials.

Current insights into the German lipoprotein apheresis standard: PCSK9-inhibitors, lipoprotein apheresis or both?

According to current European guidelines, lipid lowering therapy for progressive cardiovascular disease including cardiovascular events has to be focused on a target level for LDL-C. In contrast for Lp(a) a threshold has to be defined with respect to the method of measurement. However, due to new lipid lowering drug developments like PCSK9-inhibitors (PCSK-9-I) a therapeutic algorithm for patients with severe hypercholesterolemia or isolated Lipoprotein(a)-hyperlipoproteinemia with progressive cardiovascular disease may be necessary to manage the use of PCSK9-I, lipoprotein apheresis (LA) or both. The therapeutic approach for patients with homozygous familial hypercholesterolemia is unambiguous: In addition to LA, in order to improve LDL-C reduction, PCSK9-I could be applied. In patients with heterozygous familial hypercholesterolemia, PCSK9-I is to be applied first. If in addition to a pronounced LDL-C elevation, cardiovascular complications exist or if imaging techniques documented atherosclerotic changes pre-disposing for a cardiovascular event while LDL-C reduction is insufficiently reduced (LDL-C > 100 mg/dl (2.6 mmol/l)), LA treatment should then be applied as last resort. In patients with elevated Lp(a) concentrations (Lp(a) > 60 mg/dl (>120 nmol/l)) and established cardiovascular disease, therapy should rely primarily on LA methods. If in addition to high Lp(a) levels insufficiently treated LDL-C concentrations (LDL-C > 100 mg/dl (2.6 mmol/l)) exist, in rare cases PCSK9-I can supplement the lipid lowering concept.

Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitor Therapy: Payer Approvals and Rejections, and Patient Characteristics for Successful Prescribing.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are a novel class of medications for patients with familial hypercholesterolemia or clinical atherosclerotic cardiovascular disease requiring additional lipid lowering beyond dietary measures and statin use. Because of the drugs' high cost, rates of prescription approval by payers may be low. We aimed to identify payer approval and rejection rates for PCSK9i prescriptions and the potential factors influencing these rates. METHODS: This is a retrospective, descriptive cohort study using nationwide pharmacy claims linked to electronic medical records from a nationwide data warehouse. The data set includes >220 million patients from all 50 states and all payer types with 5140 distinct health plans. PCSK9i prescriptions were submitted for 51 466 patients in the pharmacy data set. The main outcome was approval or rejection of PCSK9i prescription claims. Factors associated with approval and rejection of these medications in the United States were assessed. RESULTS: Among patients who were prescribed a PCSK9i, 47.0% were approved for coverage by the payer. Variables that were associated with PCSK9i approval included age >65 years (P<0.01), history of atherosclerotic cardiovascular disease (P<0.01), prescription by a cardiologist or nonprimary care provider (P<0.01), statin intolerance (P=0.03), longer statin duration (P=0.01), and noncommercial payers (P<0.01). Higher low-density lipoprotein cholesterol levels were not associated with higher approval rates. Commercial third-party payers had the lowest approval rates (24.4%) and Medicare had the highest (60.9%). CONCLUSIONS: Rates of approval for PCSK9i therapy are low, even for patients who appear to meet labeled indications. Although a combination of clinical characteristics increases the likelihood of approval, payer type is the most significant factor.

Anti-PCSK9 antibodies for the treatment of heterozygous familial hypercholesterolemia: patient selection and perspectives.

Heterozygous familial hypercholesterolemia (FH) is a genetic disorder characterized by high low-density lipoprotein cholesterol levels from birth, which exposes the arteries to high levels of atherogenic lipoproteins lifelong and results in a significantly increased risk of premature cardiovascular events. The diagnosis of FH, followed by an appropriate and early treatment is critical to reduce the cardiovascular burden in this population. Phase I-III clinical trials showed the benefit of proprotein convertase subtilisin kexin 9 inhibitors, both alirocumab and evolocumab, in these patients with an average low-density lipoprotein cholesterol reduction ranging from -40% to -60%. The aim of this review is to address the unmet needs in cholesterol management, elucidate the biology and the clinical benefit of proprotein convertase subtilisin kexin 9 inhibition and finally discuss the open gaps and future directions in the treatment of patients with heterozygous FH.

Mature proprotein convertase subtilisin/kexin type 9, coronary atheroma burden, and vessel remodeling in heterozygous familial hypercholesterolemia.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9), an important contributor to low-density lipoprotein metabolism in heterozygous familial hypercholesterolemia (HeFH), exhibits direct proatherogenic effects. PCSK9 circulates as mature and furin-cleaved forms, which differ in its biological activity. However, it remains to be elucidated whether each PCSK9 subtype has different atherogenic properties. OBJECTIVE: To investigate the association of each PCSK9 subtype with coronary atherosclerosis in HeFH. METHODS: About 204 nonculprit segments in 138 HeFH subjects with coronary artery disease were evaluated by using intravascular ultrasound. Mature, furin-cleaved PCSK9 and total concentration of PCSK9 subtypes were measured by using enzyme-linked immunosorbent assay (BML Inc., Tokyo, Japan). The relationship of these PCSK9 values with intravascular ultrasound measures was investigated. RESULTS: Mature PCSK9 level was positively associated with percent atheroma volume (PAV: r = 0.78, P = .003). Despite extensive atheroma under a higher mature PCSK9 level, vessel volume did not change across any mature PCSK9 levels (r = 0.05, P = .78). These responses resulted in smaller lumen volume, which was negatively correlated to mature PCSK9 level (r = 0.65, P = .009). By contrast, there were no significant relationships of PAV with furin-cleaved (r = 0.12, P = .45) and total PCSK9 (r = 0.37, P = .25) levels. On multivariate analysis, mature PCSK9 level independently contributed to PAV (odds ratio: 1.45, 95% confidence interval: 1.11-1.67, P = .01). Even in subjects with low-density lipoprotein cholesterol level <2.6 mmol/L, greater PAV was still observed in association with an elevated mature PCSK9 level (P = .003). CONCLUSIONS: Mature PCSK9 associated with atheroma volume and impaired vessel remodeling in HeFH patients with coronary artery disease. These findings suggest the potential role of mature PCSK9 in propagation of coronary atherosclerosis in HeFH.

Proprotein convertase subtilisin/kexin 9 inhibition in patients with familial hypercholesterolemia: Initial clinical experience.

BACKGROUND: Despite optimal lipid-lowering therapy, a minority of patients with familial hypercholesterolemia (FH) reach low-density lipoprotein cholesterol (LDL-c) target goals. In randomized trials, proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors led to impressive LDL-c reductions and a favorable safety profile. However, data about the efficacy and safety outside clinical trials are not available yet. OBJECTIVE: The purpose of the study is to describe efficacy and side effects of PCSK9 inhibitors in FH patients in clinical practice. METHODS: Registry of all consecutive FH patients who started with a PCSK9 inhibitor at a lipid clinic of a university hospital. RESULTS: We analyzed 83 FH patients (79 heterozygous FH [heFH]-65 with a genetically confirmed heFH and 14 with clinical heFH-and 4 homozygous FH [hoFH]), with a mean age of 55.1 ± 11.6 years. Treatment with a PCSK9 inhibitor resulted in an additional reduction of 55% ± 21% in mean LDL-c levels. Patients with heFH had more LDL-c decrease than those with hoFH (56% vs 38%). Patients using ezetimibe monotherapy because of statin intolerance (n = 24, 29%) had less LDL-c decrease compared with patients who concurrently used statin therapy (47% and 58%, P = .03). Side effects of PCSK9 inhibitors were reported by 32 patients (39%). Flu-like symptoms (n = 12) and injection site reactions (n = 11) were most frequent. Seven patients (8%) discontinued treatment, 5 because of side effects and 2 because of nonresponse. CONCLUSION: Our initial experience of PCSK9 inhibition in FH patients in a clinical setting showed comparable reduction in LDL-c levels but more side effects compared with clinical trials.

How many familial hypercholesterolemia patients are eligible for PCSK9 inhibition?

BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) is a high cardiovascular risk condition. Less than 20% of patients achieve the LDL targets. Although PCSK9 inhibitors improve control and reduce cardiovascular events, official recommendations for their use are restrictive. We aim to assess the number of FH patients suitable for PCSK9 inhibition according to the European guidelines. METHODS: A total of 2685 FH patients, with a minimum follow-up of 6 months, included in the Dyslipidemia Registry of the Spanish Arteriosclerosis Society, were sorted according to the intensity of their lipid-lowering therapy (LLT) and LDL cholesterol levels achieved. The number of patients who met the recommendations for PCSK9 inhibition treatment according to the European Atherosclerosis Society (ESC/EAS), Spanish Arteriosclerosis Society and the European Medicines Agency was calculated. RESULTS: In total, 1573 patients were on high-intensity LLT; 607 were on moderate-intensity statins; 82 were on low-intensity LLT, and 423 were neither on statins nor on ezetimibe in the last visit registered. The mean LDL reduction among those on high-intensity LLT was 54%. Ninety-one percent of patients on high-intensity LLT had an LDL below 5.2 mmol/L, 53% below 3.4 mmol/L, and 23% below 2.6 mmol/L. Only 12% of FH patients with cardiovascular disease achieved 1.8 mmol/L. Despite this, only 17% of patients qualified for PCSK9 inhibition according to ESC/EAS guidelines. CONCLUSIONS: For patients with a condition that exposes them to high cardiovascular risk and who have extreme difficulties in achieving LDL targets, wider access to PCSK9 inhibitor therapy is warranted.

Old challenges and new opportunities in the clinical management of heterozygous familial hypercholesterolemia (HeFH): The promises of PCSK9 inhibitors.

Heterozygous familial hypercholesterolemia (HeFH) is a common (early estimates suggested a prevalence of 1 in 500 individuals, but recent studies have indicated that it may be higher) genetic disorder characterized by markedly elevated plasma concentrations of low-density lipoprotein cholesterol (LDL-C). HeFH is associated with an elevated risk of premature coronary heart disease, stroke, and peripheral vascular disease. Despite the availability of reliable diagnostic criteria (high LDL-C levels, family history or premature CHD and hypercholesterolemia, cerebral/peripheral vascular disease, and the presence of tendon xanthomata or presence of arcus cornealis before age of 45), HeFH is underdiagnosed and undertreated worldwide. Moreover, while there are effective treatments available to decrease LDL-C and prevent early-onset heart disease in individuals with HeFH, because of the high baseline levels of LDL-C, the achievement of target LDL-C levels remains a challenge. In recent years, a number of novel therapies to lower LDL-C levels in HeFH have been developed, including the monoclonal antibodies against serine protease proprotein convertase subtilisin/kexin type 9 (PCSK9), alirocumab and evolocumab, which have the potential to reduce LDL-C by an additional 50%-60% when prescribed in combination with standard lipid-lowering drugs. This review summarizes the challenges in clinical management of subjects with HeFH, with a focus on emerging treatments, and highlights the status of HeFH diagnosis and treatment in Italy.