Real-World Effectiveness of PCSK9 Inhibitors in Reducing LDL-C in Patients With Familial Hypercholesterolemia in Italy: A Retrospective Cohort Study Based on the AIFA Monitoring Registries

Real-world effectiveness of monoclonal antibody inhibitors of PCSK9 in patients with heterozygous familial hypercholesterolemia: A retrospective cohort study

BACKGROUND

Heterozygous familial hypercholesterolemia (HeFH) is a genetic condition that is associated with a high risk of atherosclerotic cardiovascular disease (ASCVD) due to elevated lipid levels. Proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibody inhibitors have been shown to reduce low-density lipoprotein cholesterol (LDL-C) substantially. This study aimed to assess the real-world effectiveness of PCSK9 inhibitor therapy among patients with HeFH.

METHODS

Retrospective cohort study of patients with probable or definite HeFH on a PCSK9 inhibitor at a specialized lipid clinic between 2015 and 2022. The primary objective was the proportion of patients who attained a ≥50% reduction in LDL-C after 12 months of treatment.

RESULTS

In total, 141 patients were screened and 95 were included. Mean age was 63 years, 51% were female, and mean baseline LDL-C level was 4.0 mmol/L (155 mg/dL). A majority of patients (60%) had statin intolerance, and 73% were on ezetimibe. The most common PCSK9 inhibitor was evolocumab (94%). Overall, 74% of patients achieved a ≥50% reduction in LDL-C after 12 months of therapy. Mean LDL-C concentration decreased to 1.7 mmol/L (66 mg/dL) (approximately 59% reduction from baseline) after 12 months of follow-up but increased to 1.9 mmol/L (73 mg/dL) after ≥24 months of follow-up. Similar trends were observed in non-high-density lipoprotein cholesterol and apolipoprotein B. Lipoprotein(a) was significantly reduced by 45% over 12 months. Twelve percent of patients permanently discontinued therapy. Barriers to PCSK9i use were mostly related to cost.

CONCLUSIONS

In a real-world cohort of HeFH patients, most of which were intolerant to statins, a high majority were able to achieve a ≥50% reduction in LDL-C after 12 months of PCSK9 inhibitor therapy (mean reduction of approximately 59%), which is similar to clinical trial data of patients with ASCVD. A significant reduction in non-high-density lipoprotein cholesterol, apolipoprotein B, and lipoprotein(a) were also observed.

Effectiveness of PCSK9 inhibitors: A Target Trial Emulation framework based on Real-World Electronic Health Records

Low-Density Lipoprotein (LDL) cholesterol is one of the main target for cardiovascular (CV) prevention and therapy. In the last years, Proprotein Convertase Subtilisin-Kexin type 9 inhibitors (PCSK9-i) has emerged as a key therapeutic target to lower LDL and were introduced for prevention of CV events. Recently (June 2022) the Italian Medicines Agency (AIFA) modified the eligibility criteria for the use of PCSK9-i. We designed an observational study to estimate the prevalence of eligible subjects and evaluate the effectiveness of PCSK9-i applying a Target Trial Emulation (TTE) approach based on Electronic Health Records (EHR). Subjects meeting the eligibility criteria were identified from July 2017 (when PCSK9-i became available) to December 2020. Outcomes were all-cause death and the first hospitalization. Among eligible subjects, we identified those treated at date of the first prescription. Inverse Probability of Treatment Weights (IPTW) were estimated including demographic and clinical covariates, history of treatment with statins and the month/year eligibility date. Competing risk models on weighted cohorts were used to derive the Average Treatment Effect (ATE) and the Conditional Average Treatment Effect (CATE) in subgroups of interest. Out of 1976 eligible subjects, 161 (8%) received treatment with PCSK9-i. Treated individuals were slightly younger, predominantly male, had more severe CV conditions, and were more often treated with statin compared to the untreated subjects. The latter exhibited a higher prevalence of non-CV comorbidities. A significant absolute and relative risk reduction of death and a lower relative risk for the first hospitalization was observed. The risk reduction for death was confirmed in CATE analysis. PCSk9-i were prescribed to a minority of eligible subjects. Within the TTE framework, the analysis confirmed the association between PCSK9-i and lower risk of events, aligning with findings from randomized clinical trials (RCTs). In our study, PCSK9-i provided protection specifically against all-cause death, expanding upon the evidence from RCTs that had primarily focused on composite CV outcomes.

Monoclonal Anti-PCSK9 Antibodies: Real-World Data

Background: Real-world data on the use of lipid-lowering therapy (LLT) in clinical practice show that about 80% of (very) high-cardiovascular (CV)-risk patients disregard the 2019 European Society of Cardiology (ESC) Guidelines' recommendations on dyslipidemias. The availability of proprotein convertase subtilisin/kexin type 9 monoclonal antibodies (PCSK9mAb) should reduce this gap. Our aim was to provide data on PCSK9mAb use in clinical practice, investigating the achievement of the ESC Guidelines' recommendations in the real world. Methods: Between April 2018 and December 2022, patients who started on PCSK9mAb therapy (140 mg of evolocumab or 75 mg or 150 mg of alirocumab, subcutaneous injection every 2 weeks) were included in a prospective registry. Our cohort consisted of 256 patients: 95 (37.1%) were women (mean age: 65.43 ± 11.12 yrs), 53 (20.7%) were at high CV risk, and 203 (79.3%) were at very high CV risk. Results: After one year of PCSK9mAb treatment, nearly 60% of patients demonstrated full adherence to the ESC Guidelines' recommendations, defined as achieving at least a 50% reduction in low-density lipoprotein cholesterol (LDL-C) levels along with reaching LDL-C target levels (≤55 and ≤70 mg/dL for very high and high risk, respectively). Concomitant high-dose statin therapy emerged as the primary predictor of LDL-C target attainment. Heterozygous familial hypercholesterolemia (HeFH), statin intolerance, and female gender were associated with a significant lower probability of achieving LDL-C target levels. Conclusions: Our analysis confirms that PCSK9mAb treatment is safe and effective, enabling 60% of our cohort to fully achieve the LDL-C guideline recommendations. The use of high-intensity statins emerged as a significant predictor of efficacy. Conversely, familial hypercholesterolemia and female gender were identified as predictors of therapeutic failure. Hence, it is crucial to address disparities in cardiovascular disease prevention between genders and to enhance strategies for managing elevated LDL-C in HeFH patients.

Recurrent Acute Coronary Syndrome in Young Man with Familial Hypercholesterolemia: Efficacy of Evolocumab Add-On Treatment Demonstrated via Serial Coronary Angiography

In patients with acute coronary syndrome (ACS), lipid-lowering therapy plays an important role in the prevention of the recurrence of cardiovascular disease. Recent guidelines recommend the use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in patients with ACS if their low-density lipoprotein cholesterol (LDL-C) levels are not adequately controlled with statins and ezetimibe. Based on this, we report a case in which administering a PCSK9 inhibitor successfully lowered the patient's LDL-C level to the target level and managed the coronary artery disease (CAD) recurrence. A 39-year-old man who was taking statins presented to the hospital with chest pain and was diagnosed with unstable angina. He started taking maximum doses of statins and ezetimibe to lower his LDL-C. However, the patient's unstable angina recurred 1 year later, and a de novo lesion with plaque rupture was demonstrated via coronary angiography. The LDL-C failed to reach the target level despite maintaining the maximum dose of statin and ezetimibe. Accordingly, evolocumab was initiated in addition to rosuvastatin/ezetimibe 20/10 mg daily. Subsequently, coronary angiography was performed twice, and on follow-up, the patient remained free of CAD recurrence. This case highlights the efficacy of lipid-lowering therapy with evolocumab in high-risk patients with repeated ACS.

Surgical Treatment of Multiple Large Tuberous and Tendinous Xanthoma Secondary to Familial Hypercholesterolaemia: A Case Report

Xanthomas are well-circumscribed skin lesions that are commonly seen in patients with familial hypercholesterolemia (FH). The aim of this report is to present a rare case of multiple large tuberous and tendinous xanthomas. A 17-year-old female patient in this report presented with multiple asymptomatic and papulo-nodular masses in both sides of palms, elbows, buttocks, knees, and Achilles tendons. Surgical removal of the masses was carried out in combination with lipid-lowering therapy. A following up of 3 months showed all wounds were healing well, and no recurrence of masses was observed. Therefore, for patients with xanthomas related with familial hypercholesterolaemia, lipid-lowering therapy has reportedly reduced the size of masses, but surgical treatment may be essential for large xanthomas caused pain or limitation of daily activities.

Targeting Allosteric Site of PCSK9 Enzyme for the Identification of Small Molecule Inhibitors: An In Silico Drug Repurposing Study

The primary cause of atherosclerotic cardiovascular disease (ASCVD) is elevated levels of low-density lipoprotein cholesterol (LDL-C). Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in this process by binding to the LDL receptor (LDL-R) domain, leading to reduced influx of LDL-C and decreased LDL-R cell surface presentation on hepatocytes, resulting higher circulating levels of LDL-C. As a consequence, PCSK9 has been identified as a crucial target for drug development against dyslipidemia and hypercholesterolemia, aiming to lower plasma LDL-C levels. This research endeavors to identify promising inhibitory candidates that target the allosteric site of PCSK9 through an in silico approach. To start with, the FDA-approved Drug Library from Selleckchem was selected and virtually screened by docking studies using Glide extra-precision (XP) docking mode and Smina software (Version 1.1.2). Subsequently, rescoring of 100 drug compounds showing good average docking scores were performed using Gnina software (Version 1.0) to generate CNN Score and CNN binding affinity. Among the drug compounds, amikacin, bestatin, and natamycin were found to exhibit higher docking scores and CNN affinities against the PCSK9 enzyme. Molecular dynamics simulations further confirmed that these drug molecules established the stable protein-ligand complexes when compared to the apo structure of PCSK9 and the complex with the co-crystallized ligand structure. Moreover, the MM-GBSA calculations revealed binding free energy values ranging from -84.22 to -76.39 kcal/mol, which were found comparable to those obtained for the co-crystallized ligand structure. In conclusion, these identified drug molecules have the potential to serve as inhibitors PCSK9 enzyme and these finding could pave the way for the development of new PCSK9 inhibitory drugs in future in vitro research.