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

A bibliometric analysis of PCSK9 inhibitors from 2007 to 2022

Background

Since the approval of the proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies for marketing in 2015, PCSK9 inhibitors have attracted significant interest in the field of cardiovascular endocrinology. A large number of clinical trials have confirmed the efficacy and safety of PCSK9 inhibitors in reducing cholesterol and the risk of cardiovascular events. No bibliometric analysis of PCSK9 inhibitors has been performed as of yet. This study aims to analyze the research trends and hotspots of PCSK9 inhibitors through bibliometric analysis.

Methods

We searched the Web of Science Core Collection (WoSCC) database for PCSK9 inhibitor-related publications from 2007 to 2022. Data visualization analysis was performed using CiteSpace software. Microsoft Excel and Graphpad software were used for the drawing of some tables and figures.

Results

A total of 1072 pieces of literature were retrieved between 2007 and 2022. The number of publications concerning PCSK9 inhibitors is growing annually. The top five countries with the most articles published were the United States, England, Canada, Italy, and France. Harvard University, Amgen, Brigham & Women's Hospital, Harvard Medical School, and Imperial College London are the five institutions with the highest output. The Journal of Clinical Lipidology is the most popular journal in this field. The most frequently cited journal is the New England Journal of Medicine. As for authors, Sabatine MS and Giugliano RP from Brigham & Women's Hospital have the highest number of published articles. Amgen is the funding agency for most of the research. According to keyword analysis, "low density lipoprotein", "familial hypercholesterolemia", "PCSK9 inhibitor", "PCSK9", and "efficacy" are the five keywords with the highest frequency of co-occurrence.

Conclusion

The past 15 years have witnessed a rapid and fruitful development of PCSK9 inhibitors. The research trend and focus for PCSK9 inhibitors are from the mechanism of reducing low-density lipoprotein cholesterol to related clinical trials. Developed countries such as the United States have contributed prominently in this area. Coronary artery and inflammation are currently at the forefront of research in the field and are in an explosion period.

Mechanisms of unusual response to lipid-lowering therapy: PCSK9 inhibition

The efficacy of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition has broadened lipid-lowering therapy thus providing decreased risk in atherosclerotic cardiovascular disease. Unfortunately, the widespread use of PCSK9 inhibitors (PCSK9i), ie, monoclonal antibodies, has led to the findings of unusual responsiveness, ie, a phenomenon defined as an LDL-C reduction of <30% vs the average LDL-C reduction efficacy of 50-60%. This unusual responsiveness to PCSK9i is attributable to several factors, ie, lack of adherence, impaired absorption, poor distribution or early elimination as well as abnormal effects of PCSK9i in the presence of anti-antibodies or mutations in PCSK9 and LDLR. Unexpectedly increased lipoprotein (Lp)(a) also appear to contribute to the unusual responsiveness scenario. Identification of these responses and mechanisms underlying them are essential for effective management of LDL-C and cardiovascular risk. In this review, we describe plausible reasons underlying this phenomenon supported by findings of clinical trials. We also elaborate on the need for education and regular follow-up to improve adherence. Collectively, the review provides a summary of the past, present, and future of mechanisms and countermeasures revolving around unusual responses to PCSK9i therapy.

Inter-Individual Variability in Lipid Response: A Narrative Review

Lipid-lowering guidelines emphasize shared decision-making between clinicians and patients, resulting in patients anticipating the degree of response from diet or drug therapy. Challenging for physicians is understanding the sources of variability complicating their management decisions, which include non-adherence, genetic considerations, additional lipid parameters including lipoprotein (a) levels, and rare systemic responses limiting benefits that result in non-responsiveness to monoclonal antibody injection. In this narrative review, we focus on the variability of low-density lipoprotein cholesterol (LDL-C) response to guideline-directed interventions such as statins, ezetimibe, bile acid sequestrants, fibrates, proprotein/convertase subtilisin-kexin type 9 inhibitors, and LDL-C-lowering diets. We hypothesize that the variability in individual lipid responses is multifactorial. We provide an illustrative model with a check list that can be used to identify factors that may be present in the individual patient.

PCSK9 inhibitors revisited: Effectiveness and safety of PCSK9 inhibitors in a real-life Spanish cohort

INTRODUCTION

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) have emerged as a therapeutic option for patients with hypercholesterolemia who do not attain low-density lipoprotein cholesterol (LDL-C) goals and/or are intolerant to other lipid-lowering drugs. Our aim was to analyze the effectiveness and safety of PCSK9i in routine clinical practice and factors related to poor outcomes.

MATERIALS AND METHODS

We conducted an ambispective study in 115 patients who recieved alirocumab or evolocumab, in a tertiary level hospital. From February 2017 to April 2020, patients were recruited and followed up for a median of 20.4 months. The main outcomes were relative reduction in LDL-C, percentage of patients achieving the therapeutic goals established by 2016 ESC/EAS guidelines, incidence of major cardiovascular events (MACEs) and drug-related adverse events (ADRs).

RESULTS

The median LDL-C achieved was 57.0 mg/dL (relative reduction of 59.9% from baseline, p< 0.001). After adjusting for confounders, smaller LDL-C reductions were related to female sex, absence of concomitant lipid-lowering therapy and treatment with alirocumab. Overall, 84.6% of the patients achieved the therapeutic goals. During follow-up, 7 MACEs were detected. ADRs, generally considered mild, affected 38.1% of the participants (mainly mialgias and arthralgias) and triggered discontinuations in 8.7% of cases.

CONCLUSIONS

PCSK9i are effective and safe, although certain factors may influence their effectiveness. Interestingly, our results suggest that alirocumab and evolocumab may not be therapeutic equivalents, as initially suggested.

Real-World Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors (PCSK9i) in Heterozygous Familial Hypercholesterolemia Patients Referred for Lipoprotein Apheresis

BACKGROUND A small proportion of familial hypercholesterolemia (FH) patients can adequately control this condition, although achieving the recommended targets for low-density lipoprotein cholesterol (LDL-c) levels remains a challenge. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are new and potent lipid-lowering drugs. However, there is scarce literature on real-world data about their use in patients with FH. MATERIAL AND METHODS We examined the reduction in LDL-c levels from the baseline, after PCSK9i initiation in heterozygous familial hypercholesterolemia patients referred for lipoprotein apheresis in our regional lipid clinic. The study was conducted from March 2018 to September 2019, the period immediately after PCSK9i reimbursement was available in France. PCSK9i was added on top of the patients' maximal tolerated lipid-lowering regimens. RESULTS The study had 123 patients with heterozygous FH. The mean age of the patients was 59±11 years. The mean baseline LDL-c for all the participants was 277±78 mg/dl. It was 283±81 mg/dl in the PCSK9i monotherapy group (n=83), 247±68 mg/dl in the PCSK9i plus ezetimibe group (n=12), and 264±78 mg/dl in the PCSK9i plus statin and ezetimibe group (n=28). The mean decrease observed in the LDL-c level from baseline was 136±70 mg/dl (n=123), 125±60 mg/dl (n=83), 103±77 mg/dl (n=12), and 175±70 mg/dl (n=28), respectively. CONCLUSIONS An overall reduction of 49.1% from the baseline LDL-c was observed in the heterozygous FH population after PCSK9i initiation in a real-world experience. The group treated with PCSK9i ezetimibe plus statin showed further reduction of their LDL-c levels with a better responder rate, achieving the target 50% reduction in LDL-c from the baseline.

Ineffective Subtilisin/Kexin Type 9 (PCSK9) Inhibitors Monotherapy in Dyslipidemia with Low-Density Lipoprotein Cholesterol (LDL-C) Receptor Abnormalities: A Report of 2 Cases

Case series

Patients: Male, 44-year-old • Female, 71-year-old

Final Diagnosis: Resistance to PCSK9I overcomed by adding statin

Symptoms: Dyslipidemia

Medication: —

Clinical Procedure: —

Specialty: Cardiology

Autosomal recessive hypercholesterolemia: update for 2020

PURPOSE OF REVIEW

This review summarizes the current knowledge regarding autosomal recessive hypercholesterolemia (ARH) and provides new insight into the natural history and therapeutic management of this lipid disorder.

RECENT FINDINGS

Novel homozygous and compound heterozygous ARH-causing mutations have been reported in the literature, to date. The long-term follow-up of a cohort of ARH patients demonstrated that, despite intensive treatment with conventional lipid-lowering therapies, their low-density lipoprotein (LDL) cholesterol levels remain far from target and this translates into a poor cardiovascular prognosis. ARH is also associated with increased risk of developing aortic valve stenosis. However, lomitapide, a microsomal triglyceride transfers protein inhibitor, may represent a new opportunity for the effective treatment of ARH.

SUMMARY

ARH is an ultrarare disorder of LDL metabolism caused by mutations in the LDLRAP1 gene. It is inherited as a recessive trait and causative mutations, though heterogeneous, are all predicted to be loss-of-function. Recent investigations have demonstrated that ARH can be considered a phenocopy of homozygous familial hypercholesterolemia, where the risk of atherosclerotic cardiovascular diseases and aortic valve stenosis remains elevated despite conventional therapies. The combination of lomitapide with the conventional LDL-C-lowering medications appears to be a promising approach to treat this condition.

PCSK9 inhibitors in clinical practice: Novel directions and new experiences

BACKGROUND

In randomized clinical trials, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) effectively reduce low-density lipoprotein-cholesterol (LDL-C) with a favorable tolerability and safety profile. Our purpose is to provide real-world data regarding the indications, efficacy and safety of PCSK9i.

METHODS

The cohort comprised 141 patients who attended the lipid clinic of 3 hospitals in Greece and started using PCSK9i. Patients were requested to attend the lipid clinic at 3 months and at 1 year.

RESULTS

Ninety percent of patients had heterozygous familial hypercholesterolaemia (heFH) and 75% had cardiovascular disease (CVD). A PCSK9i [evolocumab 140 mg/2 weeks (n = 82), alirocumab 75 mg/2 weeks (n = 46) and alirocumab 150 mg/2 weeks (n = 13)] was prescribed due to failure to achieve LDL-C targets despite maximum lipid-lowering therapy (LLT) in 75% of patients, while in the remaining cases, the indication was statin intolerance. The mean reduction of LDL-C at 3 months was 56.2% and remained constant at 12 months (55.8% reduction from baseline). LDL-C target was achieved by 68.1% of patients at 3 months. "Totally" intolerant to statins patients (unable to tolerate any statin dose, n = 23) showed the lowest LDL-C reduction (47.7%). Side effects attributed to treatment were reported by 14 patients (10%). The total number of patients who stopped PCSK9i at 1 year was 14 (10%) but only 2 (1.4%) discontinued treatment because of side effects (myalgias).

CONCLUSIONS

Our real-world results of PCSK9i showed comparable efficacy and tolerability to those reported in clinical trials and highlighted the value of treatment with PCSK9i heFH patients not achieving LDL-C targets despite maximum LLT and high or very high risk statin intolerant patients.