Effects of ezetimibe on plasma lipoproteins in severely hypercholesterolemic patients treated with regular LDL-apheresis and statins

Effect of Ezetimibe Monotherapy on Plasma Lipoprotein(a) Concentrations in Patients with Primary Hypercholesterolemia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIMS

Ezetimibe reduces plasma low-density lipoprotein cholesterol (LDL-C) levels by up to 20%. However, its effect on plasma lipoprotein(a) [Lp(a)] concentrations in patients with primary hypercholesterolemia has not been defined.

OBJECTIVE

Therefore, we performed a systematic review and meta-analysis to assess this effect based on the available randomized controlled trials (RCTs).

METHODS

We searched the PubMed and SCOPUS databases from inception until 28 February 2017 to identify RCTs that investigated the effect of ezetimibe monotherapy on plasma Lp(a) concentrations in patients with primary hypercholesterolemia. We pooled mean percentage changes in plasma Lp(a) concentrations as a mean difference (MD) with a 95% confidence interval (CI).

RESULTS

Seven RCTs with 2337 patients met the selection criteria and were included in the analysis. Overall pooled analysis suggested that ezetimibe 10 mg significantly reduced plasma Lp(a) concentrations in patients with primary hypercholesterolemia by - 7.06% (95% CI - 11.95 to - 2.18; p = 0.005) compared with placebo. No significant heterogeneity was observed (χ² = 5.34; p = 0.5). Excluding one study from the analysis resulted in insignificant differences between the two groups (p = 0.2). Meta-regression did not find a significant association between the mean percentage changes in Lp(a) and other potential moderator variables, which included the mean percentage changes of LDL-C concentrations (p = 0.06) and baseline Lp(a) mean values (p = 0.46).

CONCLUSIONS

Ezetimibe monotherapy (10 mg/day) showed a small (7.06%) but statistically significant reduction in the plasma levels of Lp(a) in patients with primary hypercholesterolemia. According to current literature, this magnitude of reduction seems to have no clinical relevance. However, further studies are warranted to clarify the mechanism mediating this effect of ezetimibe and to investigate its efficacy in combination with other drugs that have shown promise in lowering Lp(a) levels.

Impact of ezetimibe on plasma lipoprotein(a) concentrations as monotherapy or in combination with statins: a systematic review and meta-analysis of randomized controlled trials

The aim of this meta-analysis of randomized placebo-controlled clinical trials was to assess the effect of ezetimibe on plasma lipoprotein(a) concentrations. Only randomized placebo-controlled trials investigating the impact of ezetimibe treatment on cholesterol lowering that include lipoprotein(a) measurement were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to February 26th, 2018). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipoprotein concentrations. This meta-analysis of data from 10 randomized placebo-controlled clinical trials (15 treatment arms) involving a total of 5188 (3020 ezetimibe and 2168 control) subjects showed that ezetimibe therapy had no effect on altering plasma Lp(a) concentrations (WMD: -2.59%, 95% CI: -8.26, 3.08, p = 0.370; I2 = 88.71%, p(Q) < 0.001). In the subgroup analysis, no significant alteration in plasma Lp(a) levels was observed either in trials assessing the impact of monotherapy with ezetimibe versus placebo (WMD: -4.64%, 95% CI: -11.53, 2.25, p = 0.187; I2 = 65.38%, p(Q) = 0.005) or in trials evaluating the impact of adding ezetimibe to a statin versus statin therapy alone (WMD: -1.04%, 95% CI: -6.34, 4.26, p = 0.700; I2 = 58.51%, p(Q) = 0.025). The results of this meta-analysis suggest that ezetimibe treatment either alone or in combination with a statin does not affect plasma lipoprotein(a) levels.

Successful Direct Adsorption of Lipoproteins (DALI) Apheresis During Pregnancy in an Omani Woman with Homozygous Familial Hypercholesterolemia

We report our experience with Direct Adsorption of Lipoproteins (DALI) apheresis in an Omani pregnant woman affected by homozygous familial hypercholesterolemia. To the best of our knowledge this is the first successful pregnancy treated with DALI apheresis. The patient had a history of coronary artery disease, supra-aortic valvular stenosis and severe carotid artery disease with right carotid artery stenting. She was on a regular biweekly DALI apheresis since 2008. In May 2013, she became pregnant and rosuvastatin and ezetimibe were stopped while she continued on DALI apheresis biweekly. This treatment during pregnancy was successful with no major complications. The average low-density lipoprotein cholesterol reduction during therapy was 50%. She spontaneously delivered a healthy male infant (2,400 g) at 37 weeks. We showed that DALI apheresis therapy was safe during pregnancy with a good outcome for both mother and neonate.

Italian multicenter study on low-density lipoprotein apheresis Working Group 2009 survey

We present results of the second survey of the Italian Multicenter Study on Low-Density Lipoprotein Apheresis (IMSLDLa-WG/2). The study involved 18 centers in 2009, treating 66 males and 35 females, mean age 47 ± 18 years. Mean age for initiation of drug treatment before low-density lipoprotein apheresis (LDLa) was 31 ± 18 years, mean age to the first LDLa was 37 ± 20 years and average duration of treatment was 9 ± 6 years. The techniques used included direct adsorption of lipids, dextran sulfate cellulose adsorption, heparin-mediated low-density lipoprotein (LDL) precipitation, cascade filtration, and plasma exchange. The mean treated plasma/blood volumes/session were 3127 ± 518 mL and 8666 ± 1384 mL, respectively. The average plasma volume substituted was 3500 ± 300 mL. Lipid therapy before LDLa included ezetimibe, statins, ω-3 fatty acids and fenofibrate. Baseline mean LDL cholesterol (LDLC) levels were 386 ± 223 mg/dL. The mean before/after apheresis LDLC level decreased by 67% from 250 ± 108 mg/dL (P = 0.05 vs. baseline) to 83 ± 37 mg/dL (P = 0.001 vs. before). Baseline mean Lipoprotein(a) [Lp(a)] level was 179 ± 136 mg/dL. Mean before/after apheresis Lp(a) level decreased by 71% from 133 ± 120 mg/dL (P = 0.05 vs. baseline) to 39 ± 44 mg/dL (P = 0.001 vs. before). Major and minor side effects occurred in 27 and 62 patients, respectively. Among patients with coronary artery disease (CAD), 62.3% had coronary angiography and 50.4% coronary revascularization before LDLa. Single vessel, double vessel and triple vessel CAD occurred in 19 (30.1%), 15 (23.8%) and 29 (46%) patients, respectively. Both CAD and extra-CAD occurred in 41.5%, 39% had hypertension, 9.9% were smokers, 9.9% consumed alcohol and 42% were physically active. Ischemic cardiovascular events were not observed in any patient over 9 ± 6 years of treatment. Two centers have also treated 34 patients (females: 17/males 17; no. sessions: 36; average plasma volume treated: 3000 mL) for sudden hearing loss (SHL). Relief of symptoms was obtained, independently of the system used (HELP; cascade-filtration).

First Case Report of Familial Hypercholesterolemia in an Omani Family Due to Novel Mutation in the Low-Density Lipoprotein Receptor Gene

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder. Mutations have been found in at least 3 genes: the low-density lipoprotein receptor ( LDLR), apolipoprotein B ( APOB), and proprotein convertase subtilisin/kexin type 9 ( PCSK9). We report the first case of FH in an Omani family due to a novel mutation in the LDLR gene. A 9-year-old female was referred to our lipid clinic with eye xanthelasmata and thickening of both Achilles tendons. Evaluation of the lipid profile showed the off treatment total cholesterol of 896 mg/dL (23.2 mmol/L), low-density lipoprotein cholesterol (LDL-C) of 853 mg/dL (22.1 mmol/L), APOB of 4.5 g/L, triglyceride of 71 mg/dL (0.8 mmol/L), and high-density lipoprotein cholesterol of 0.74 mmol/L. Genetic analysis of the LDLR gene showed a homozygous frameshift deletion mutation (272delG) at exon 3. The female patient was treated with a combination of rosuvastatin/ezetimibe and LDL apheresis.

Combination therapy of statin and ezetimibe for the treatment of familial hypercholesterolemia

High-dose potent statin therapy in combination with ezetimibe is now standard practice for the treatment of adult patients with heterozygous familial hypercholesterolemia (heFH), as the result of numerous studies in patients with primary hypercholesterolemia or heFH. These studies have shown the combination to be both effective and safe in the short to medium term. Recently, short-term ezetimibe therapy has also been shown to be effective and safe in combination with statin therapy for children and adolescents with heFH. Effective statin–ezetimibe combination therapy is capable of achieving near-normal lipid profiles in heFH patients, with expected improvement in risk for cardiovascular disease (CVD) and improved life expectancy resulting predominantly from reduction in levels of low-density lipoprotein cholesterol. There are few data to support a pleiotropic action of ezetimibe with regard to CVD benefit, unlike therapy with statins. No serious and unexpected clinical adverse effects of combination statin–ezetimibe therapy have emerged till date, although data are limited in children and adolescents, for whom longer-term studies are required. Recent data suggesting possible proatherogenic effects of ezetimibe require confirmation. One large long-term randomized controlled clinical outcomes trial is in progress in non-FH patients to determine the efficacy and safety of ezetimibe therapy; it is unlikely that such a trial will ever be performed in patients with FH.

Management of a patient with a null low-density lipoprotein receptor mutation: a case report

A 13-year-old Greek boy with severe dyslipidemia, large tuberous xanthomas over the knees and elbows, Achilles' tendon xanthomas, and a bilateral corneal arcus was referred to the Lipid Clinic. He had a supravalvular aortic stenosis, 50% to 60% stenosis of both carotid arteries, and normal coronary arteries. Familial hypercholesterolemia was clinically diagnosed. A V408M null low-density lipoprotein receptor (LDLR) mutation was identified in homozygosity. He responded to lipid-lowering drugs by decreasing total cholesterol by 32%, low-density lipoprotein cholesterol by 33%, and triglyceride levels by 30%. Additional treatment with low-density lipoprotein-apheresis further decreased total cholesterol by 52%, low-density lipoprotein cholesterol by 55%, and triglycerides by 43%. Low-density lipoprotein cholesterol levels between apheresis sessions showed a declining pattern. A significant regression of tuberous xanthomas was noted. A suitable combination of lipid-lowering drugs is effective even in this case of homozygosity for a null LDLR mutation. Furthermore, the coadministration of statins, cholestyramine, and ezetimibe during low-density lipoprotein-apheresis tends to counterbalance the postapheresis relapse in low-density lipoprotein cholesterol levels.

Non-low-density lipoprotein cholesterol-associated actions of ezetimibe: an overview

Ezetimibe, an intestinal cholesterol absorption inhibitor, lowers circulating low-density lipoprotein cholesterol (LDL-C) levels both when administered as monotherapy and in combination with other hypolipidaemic drugs, mostly statins. This review focuses on the effects of ezetimibe on non-LDL-C-associated variables. In most studies, ezetimibe effectively reduced triglyceride and increased high density lipoprotein cholesterol levels. The authors also consider the effect of ezetimibe on other variables such as C-reactive protein levels, insulin sensitivity and endothelial function. Ezetimibe is useful in patients with sitosterolaemia (a rare inherited disorder) as it significantly reduces plasma phytosterol concentrations. Ezetimibe fulfils two of the three essential characteristics of any drug (efficacy and safety). However, clinical studies are required to provide evidence of its ability to reduce vascular events.

Effect of ezetimibe on low-density lipoprotein subtype distribution: results of a placebo-controlled, double-blind trial in patients treated by regular low-density lipoprotein apheresis and statins

Ezetimibe, a cholesterol absorption inhibitor, can be combined with statins to lower low-density lipoprotein (LDL) cholesterol. We have previously shown that ezetimibe can decrease LDL cholesterol by 16% even in patients treated by regular LDL apheresis and statins (Atherosclerosis. 2005;180:107-112). However, it is unclear whether ezetimibe decreases all LDL subfractions equally in patients with hypercholesterolemia. We therefore evaluated the effect of ezetimibe (5 weeks, 10 mg/d) on LDL subtype distribution in a placebo-controlled, double-blind randomized crossover study in 20 patients (age, 56+/-9 years; body mass index, 27.5+/-4 kg/m2) with severe hyperlipoproteinemia and coronary heart disease who are treated by statins and regular LDL apheresis. Both treatment periods (placebo and ezetimibe) were separated by a 5-week washout period. Low-density lipoprotein subtype distribution was determined at the end of each treatment period before apheresis by density gradient ultracentrifugation (LDL1, 1.020-1.024; LDL2, 1.025-1.029; LDL3, 1.030-1.034; LDL4, 1.035-1.040; LDL5, 1.041-1.047; LDL6, 1.048-1.057; LDL7, 1.058-1.066 g/mL). Overall, the LDL subtype distribution did not change significantly (large-buoyant LDL [LDL1+LDL2], 17.2%+/-6.4% vs 16.3%+/-7.1%; intermediate LDL [LDL3+LDL4], 49.3%+/-4.5% vs 48.2%+/-5.2%; small-dense LDL [LDL5+LDL6+LDL7], 33.5%+/-8.0% vs 35.5%+/-10% during placebo and ezetimibe treatments, respectively). With respect to the individual LDL subfractions, cholesterol was significantly (P<.05, Wilcoxon test) reduced by ezetimibe in LDL1 to LDL5 with a somewhat more pronounced reduction in larger LDL (mean+/-SD, -20%+/-28%, -17%+/-32%, -14%+/-25%, -13%+/-27%, -11%+/-21%, -7%+/-21%, -4%+/-19%; median, -28%, -12%, -18%, -16%, -4%, -4%, -2% for LDL subfractions 1-7, respectively). We therefore conclude that ezetimibe decreases cholesterol in nearly all LDL subfractions. Although this was established in patients concomitantly treated with statins and apheresis, this may also hold true in other clinically relevant situations.