Beneficial effects of PCSK9 inhibition with alirocumab in familial hypercholesterolemia involve modulation of new immune players.

Familial hypercholesterolemia (FH) is associated with low-grade systemic inflammation, a key driver of premature atherosclerosis. We investigated the effects of inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9) function on inflammatory state, endothelial dysfunction and cardiovascular outcomes in patients with FH. Fourteen patients with FH were evaluated before and 8 weeks after administration of a PCSK9 blocking monoclonal antibody (alirocumab, 150 mg/subcutaneous/14 days). In vivo and ex vivo analysis revealed that alirocumab blunted the attachment of leukocytes to TNFα-stimulated human umbilical arterial endothelial cells (HUAEC) and suppressed the activation of platelets and most leukocyte subsets, which was accompanied by the diminished expression of CX3CR1, CXCR6 and CCR2 on several leukocyte subpopulations. By contrast, T-regulatory cell activation was enhanced by alirocumab treatment, which also elevated anti-inflammatory IL-10 plasma levels and lowered circulating pro-inflammatory cytokines. Plasma levels of IFNγ positively correlated with levels of total and LDL-cholesterol, whereas circulating IL-10 levels negatively correlated with these key lipid parameters. In vitro analysis revealed that TNFα stimulation of HUAEC increased the expression of PCSK9, whereas endothelial PCSK9 silencing reduced TNFα-induced mononuclear cell adhesion mediated by Nox5 up-regulation and p38-MAPK/NFκB activation, concomitant with reduced SREBP2 expression. PCSK9 silencing also decreased endothelial CX3CL1 and CXCL16 expression and chemokine generation. In conclusion, PCSK9 inhibition impairs systemic inflammation and endothelial dysfunction by constraining leukocyte-endothelium interactions. PCSK9 blockade may constitute a new therapeutic approach to control the inflammatory state associated with FH, preventing further cardiovascular events in this cardiometabolic disorder.

Awareness, diagnosis and treatment of heterozygous familial hypercholesterolemia (HeFH) - Results of a US national survey.

BACKGROUND: HeFH is a common inherited disorder that leads to markedly elevated LDL-cholesterol from birth and premature cardiovascular disease. HeFH is frequently underdiagnosed and undertreated. OBJECTIVE: To compare how well primary care physicians and cardiologists recognize and treat HeFH. METHODS: The National Lipid Association surveyed 500 primary care physicians and 500 cardiologists in the US who have patients with baseline LDL-cholesterol ≥ 190 mg/dL. The survey was conducted between August 29 and September 30, 2019. RESULTS: For a hypothetical case of HeFH, 57% of cardiologists versus 43% of primary care physicians made the correct diagnosis (P<0.001). Among respondents, 21% of cardiologists versus 29% of primary care physicians have never made a diagnosis of HeFH in a patient with an LDL-cholesterol ≥ 190 mg/dL (P<0.004). Only 7% of cardiologists versus 5% of primary care physicians would refer to a lipid specialist (P=0.05). For additional LDL-cholesterol lowering after statins, 58% of cardiologists versus 48% of primary care physicians would prescribe a PCSK9 inhibitor (P=0.004); however, 30% of cardiologists versus 53% of primary care physicians have never prescribed a PSCK9 inhibitor in an HeFH patient (P<0.001). CONCLUSION: Although cardiologists compared to primary care physicians are somewhat more likely to recognize and treat HeFH patients according to guidelines, both physician specialties do not adequately recognize or treat HeFH. There is a need for more education and training in recognizing and treating HeFH, greater access to lipid specialists, and fewer barriers for PCSK9 inhibitor use.

Efficacy of PCSK9 inhibitors in the treatment of heterozygous familial hypercholesterolemia: A clinical practice experience.

BACKGROUND: PCSK9 inhibitors are a treatment option for patients with familial hypercholesterolemia not on low-density lipoprotein cholesterol goals despite the use of maximally tolerated high intensity-statins dose. OBJECTIVE: To evaluate the efficacy of alirocumab and evolocumab in LDL-C reduction and targets attainment in patients with heterozygous familial hypercholesterolemia in clinical practice setting. METHODS: SAFEHEART is an open, long-term prospective study of a cohort of subjects with molecular diagnosis of familial hypercholesterolemia. This study analyze subjects ≥ 20 years of age on stable lipid-lowering therapy, who received PCSK9 inhibitors during the period 2016 to January 2020. RESULTS: 433 patients (mean age 55 years, 53% male, 39% with cardiovascular disease) were included and followed-up for a median of 2.5 years (IQR 1.6-3.0). Median LDL-C level prior to PCSK9 inhibitors was 145 mg/dL (IQR 125-173). The addition of PCSK9 inhibitors (211 alirocumab, 222 evolocumab) reduced LDL-C by 58% (IQR 41-70) p<0.001, in men and women, achieving a median LDL-C level of 62 mg/dL (IQR 44-87) without differences between both PCSK9 inhibitors. Out of them 67% with and 80% without cardiovascular disease reached 2016 ESC/EAS LDL-C targets, and 46% very high risk and 50% high risk patients achieved 2019 ESC/EAS LDL-C goals. Independent predictor factors for attainment of 2019 ESC/EAS LDL-C goals were to be male, smoking and the use of statins with ezetimibe. Both inhibitors were well tolerated. CONCLUSIONS: PCSK9 inhibitors on top of maximum lipid-lowering treatment significantly reduced LDL-C levels in patients with familial hypercholesterolemia and improved the achievement of LDL-C targets.

Inclisiran for the Treatment of Heterozygous Familial Hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia is characterized by an elevated level of low-density lipoprotein (LDL) cholesterol and an increased risk of premature atherosclerotic cardiovascular disease. Monoclonal antibodies directed against proprotein convertase subtilisin-kexin type 9 (PCSK9) have been shown to reduce LDL cholesterol levels by more than 50% but require administration every 2 to 4 weeks. In a phase 2 trial, a twice-yearly injection of inclisiran, a small interfering RNA, was shown to inhibit hepatic synthesis of PCSK9 in adults with heterozygous familial hypercholesterolemia. METHODS: In this phase 3, double-blind trial, we randomly assigned, in a 1:1 ratio, 482 adults who had heterozygous familial hypercholesterolemia to receive subcutaneous injections of inclisiran sodium (at a dose of 300 mg) or matching placebo on days 1, 90, 270, and 450. The two primary end points were the percent change from baseline in the LDL cholesterol level on day 510 and the time-adjusted percent change from baseline in the LDL cholesterol level between day 90 and day 540. RESULTS: The median age of the patients was 56 years, and 47% were men; the mean baseline level of LDL cholesterol was 153 mg per deciliter. At day 510, the percent change in the LDL cholesterol level was a reduction of 39.7% (95% confidence interval [CI], -43.7 to -35.7) in the inclisiran group and an increase of 8.2% (95% CI, 4.3 to 12.2) in the placebo group, for a between-group difference of -47.9 percentage points (95% CI, -53.5 to -42.3; P<0.001). The time-averaged percent change in the LDL cholesterol level between day 90 and day 540 was a reduction of 38.1% (95% CI, -41.1 to -35.1) in the inclisiran group and an increase of 6.2% (95% CI, 3.3 to 9.2) in the placebo group, for a between-group difference of -44.3 percentage points (95% CI, -48.5 to -40.1; P<0.001). There were robust reductions in LDL cholesterol levels in all genotypes of familial hypercholesterolemia. Adverse events and serious adverse events were similar in the two groups. CONCLUSIONS: Among adults with heterozygous familial hypercholesterolemia, those who received inclisiran had significantly lower levels of LDL cholesterol than those who received placebo, with an infrequent dosing regimen and an acceptable safety profile. (Funded by the Medicines Company; ORION-9 ClinicalTrials.gov number, NCT03397121.).