| Pharmacotherapeutic group: HMG-CoA reductase inhibitors in combination with other lipid modifying agents, ATC code: C10BA02INEGY (ezetimibe/simvastatin) is a lipid-lowering product that selectively inhibits the intestinal absorption of cholesterol and related plant sterols and inhibits the endogenous synthesis of cholesterol.Mechanism of action: INEGY Plasma cholesterol is derived from intestinal absorption and endogenous synthesis. INEGY contains ezetimibe and simvastatin, two lipid-lowering compounds with complementary mechanisms of action. INEGY reduces elevated total cholesterol (total-C), LDL-C, apolipoprotein B (Apo B), triglycerides (TG), and non-high-density lipoprotein cholesterol (non-HDL-C), and increases high-density lipoprotein cholesterol (HDL-C) through dual inhibition of cholesterol absorption and synthesis.Ezetimibe Ezetimibe inhibits the intestinal absorption of cholesterol. Ezetimibe is orally active and has a mechanism of action that differs from other classes of cholesterol-reducing compounds (e.g., statins, bile acid sequestrants [resins], fibric acid derivatives, and plant stanols). The molecular target of ezetimibe is the sterol transporter, Niemann-Pick C1-Like 1 (NPC1L1), which is responsible for the intestinal uptake of cholesterol and phytosterols.Ezetimibe localises at the brush border of the small intestine and inhibits the absorption of cholesterol, leading to a decrease in the delivery of intestinal cholesterol to the liver; statins reduce cholesterol synthesis in the liver and together these distinct mechanisms provide complementary cholesterol reduction. In a 2-week clinical study in 18 hypercholesterolaemic patients, ezetimibe inhibited intestinal cholesterol absorption by 54%, compared with placebo.A series of preclinical studies was performed to determine the selectivity of ezetimibe for inhibiting cholesterol absorption. Ezetimibe inhibited the absorption of [14C]-cholesterol with no effect on the absorption of triglycerides, fatty acids, bile acids, progesterone, ethinyl estradiol, or fat soluble vitamins A and D.Simvastatin After oral ingestion, simvastatin, which is an inactive lactone, is hydrolysed in the liver to the corresponding active β-hydroxyacid form which has a potent activity in inhibiting HMG-CoA reductase (3 hydroxy - 3 methylglutaryl CoA reductase). This enzyme catalyses the conversion of HMG-CoA to mevalonate, an early and rate-limiting step in the biosynthesis of cholesterol.Simvastatin has been shown to reduce both normal and elevated LDL-C concentrations. LDL is formed from very-low-density protein (VLDL) and is catabolised predominantly by the high affinity LDL receptor. The mechanism of the LDL-lowering effect of simvastatin may involve both reduction of VLDL-cholesterol (VLDL-C) concentration and induction of the LDL receptor, leading to reduced production and increased catabolism of LDL-C. Apolipoprotein B also falls substantially during treatment with simvastatin. In addition, simvastatin moderately increases HDL-C and reduces plasma TG. As a result of these changes, the ratios of total- to HDL-C and LDL- to HDL-C are reduced.CLINICAL TRIALS In controlled clinical studies, INEGY significantly reduced total-C, LDL-C, Apo B, TG, and non-HDL-C, and increased HDL-C in patients with hypercholesterolaemia. Primary Hypercholesterolaemia In a double-blind, placebo-controlled, 8-week study, 240 patients with hypercholesterolaemia already receiving simvastatin monotherapy and not at National Cholesterol Education Program (NCEP) LDL-C goal (2.6 to 4.1 mmol/l [100 to 160 mg/dl], depending on baseline characteristics) were randomised to receive either ezetimibe 10 mg or placebo in addition to their on-going simvastatin therapy. Among simvastatin-treated patients not at LDL-C goal at baseline (~80%), significantly more patients randomised to ezetimibe coadministered with simvastatin achieved their LDL-C goal at study endpoint compared to patients randomised to placebo coadministered with simvastatin, 76% and 21.5%, respectively. The corresponding LDL-C reductions for ezetimibe or placebo coadministered with simvastatin were also significantly different (27% or 3%, respectively). In addition, ezetimibe coadministered with simvastatin significantly decreased total-C, Apo B, and TG compared with placebo coadministered with simvastatin. In a multicentre, double-blind, 24-week trial, 214 patients with type 2 diabetes mellitus treated with thiazolidinediones (rosiglitazone or pioglitazone) for a minimum of 3 months and simvastatin 20 mg for a minimum of 6 weeks with a mean LDL-C of 2.4 mmol/L (93 mg/dl), were randomised to receive either simvastatin 40 mg or the coadministered active ingredients equivalent to INEGY 10 mg/20 mg. INEGY 10 mg/20 mg was significantly more effective than doubling the dose of simvastatin to 40 mg in further reducing LDL-C (-21% and 0%, respectively), total-C (-14% and -1%, respectively), Apo B (-14% and -2%, respectively), and non-HDL-C (-20% and -2%, respectively) beyond the reductions observed with simvastatin 20 mg. Results for HDL-C and TG between the two treatment groups were not significantly different. Results were not affected by type of thiazolidinedione treatment.The efficacy of the different dose-strengths of INEGY (10/10 to 10/80 mg/day) was demonstrated in a multicentre, double-blind, placebo-controlled 12-week trial that included all available doses of INEGY and all relevant doses of simvastatin. When patients receiving all doses of INEGY were compared to those receiving all doses of simvastatin, INEGY significantly lowered total-C, LDL-C, and TG (see Table 1) as well as Apo B (-42% and -29%, respectively), non-HDL-C (-49% and -34%, respectively) and C-reactive protein (-33% and -9%, respectively). The effects of INEGY on HDL-C were similar to the effects seen with simvastatin. Further analysis showed INEGY significantly increased HDL-C compared with placebo.Table 1Response to INEGY in Patients with Primary Hypercholesterolaemia(Meana % Change from Untreated Baselineb)| Treatment
| | | | | | | (Daily Dose)
| N
| Total-C
| LDL-C
| HDL-C
| TGa | | Pooled data (All INEGY doses)c | 353
| -38
| -53
| +8
| -28
| | Pooled data (All simvastatin doses)c | 349
| -26
| -38
| +8
| -15
| | Ezetimibe10 mg
| 92
| -14
| -20
| +7
| -13
| | Placebo
| 93
| +2
| +3
| +2
| -2
| | INEGY by dose
| | | | | | | 10/10
| 87
| -32
| -46
| +9
| -21
| | 10/20
| 86
| -37
| -51
| +8
| -31
| | 10/40
| 89
| -39
| -55
| +9
| -32
| | 10/80
| 91
| -43
| -61
| +6
| -28
| | Simvastatin by dose
| | | | | | | 10 mg
| 81
| -21
| -31
| +5
| -4
| | 20 mg
| 90
| -24
| -35
| +6
| -14
| | 40 mg
| 91
| -29
| -42
| +8
| -19
| | 80 mg
| 87
| -32
| -46
| +11
| -26
| a For triglycerides, median % change from baselineb Baseline - on no lipid-lowering drugc INEGY doses pooled (10/10-10/80) significantly reduced total-C, LDL-C, and TG, compared to simvastatin, and significantly increased HDL-C compared to placebo.In a similarly designed study, results for all lipid parameters were generally consistent. In a pooled analysis of these two studies, the lipid response to INEGY was similar in patients with TG levels greater than or less than 200 mg/dl.In a multicenter, double-blind, controlled clinical study (ENHANCE), 720 patients with heterozygous familial hypercholesterolemia were randomized to receive ezetimibe 10 mg in combination with simvastatin 80 mg (n = 357) or simvastatin 80 mg (n = 363) for 2 years. The primary objective of the study was to investigate the effect of the ezetimibe/simvastatin combination therapy on carotid artery intima-media thickness (IMT) compared to simvastatin monotherapy. The impact of this surrogate marker on cardiovascular morbidity and mortality is still not demonstrated.The primary endpoint, the change in the mean IMT of all six carotid segments, did not differ significantly (p= 0.29) between the two treatment groups as measured by B-mode ultrasound. With ezetimibe 10 mg in combination with simvastatin 80 mg or simvastatin 80 mg alone, intima-medial thickening increased by 0.0111 mm and 0.0058 mm, respectively, over the study's 2 year duration (baseline mean carotid IMT 0.68 mm and 0.69 mm respectively.Ezetimibe 10 mg in combination with simvastatin 80 mg lowered LDL-C, total-C, Apo B, and TG significantly more than simvastatin 80 mg. The percent increase in HDL-C was similar for the two treatment groups. The adverse reactions reported for ezetimibe 10 mg in combination with simvastatin 80 mg were consistent with its known safety profile.INEGY contains simvastatin. In two large placebo-controlled clinical trials, the Scandinavian Simvastatin Survival Study (20-40 mg; N=4,444 patients) and the Heart Protection Study (40 mg; N=20,536 patients), the effects of treatment with simvastatin were assessed in patients at high risk of coronary events because of existing coronary heart disease, diabetes, peripheral vessel disease, history of stroke or other cerebrovascular disease. Simvastatin was proven to reduce: the risk of total mortality by reducing CHD deaths; the risk of non-fatal myocardial infarction and stroke; and the need for coronary and non-coronary revascularisation procedures.The Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) evaluated the effect of treatment with simvastatin 80 mg versus 20 mg (median follow-up 6.7 yrs) on major vascular events (MVEs; defined as fatal CHD, non-fatal MI, coronary revascularization procedure, non-fatal or fatal stroke, or peripheral revascularization procedure) in 12,064 patients with a history of myocardial infarction. There was no significant difference in the incidence of MVEs between the 2 groups; simvastatin 20 mg (n = 1553; 25.7 %) vs. simvastatin 80 mg (n = 1477; 24.5 %); RR 0.94, 95 % CI: 0.88 to 1.01. The absolute difference in LDL-C between the two groups over the course of the study was 0.35 ± 0.01 mmol/L. The safety profiles were similar between the two treatment groups except that the incidence of myopathy was approximately 1.0 % for patients on simvastatin 80 mg compared with 0.02 % for patients on 20 mg. Approximately half of these myopathy cases occurred during the first year of treatment. The incidence of myopathy during each subsequent year of treatment was approximately 0.1 %.A beneficial effect of INEGY or ezetimibe on cardiovascular morbidity and mortality has not yet been demonstrated.Clinical Studies in Paediatric Patients (10 to 17 years of age) In a multicentre, double-blind, controlled study, 142 boys (Tanner stage II and above) and 106 postmenarchal girls, 10 to 17 years of age (mean age 14.2 years) with heterozygous familial hypercholesterolaemia (HeFH) with baseline LDL-C levels between 4.1 and 10.4 mmol/l were randomised to either ezetimibe10 mg co-administered with simvastatin (10, 20 or 40 mg) or simvastatin (10, 20 or 40 mg) alone for 6 weeks, co-administered ezetimibe and 40 mg simvastatin or 40 mg simvastatin alone for the next 27 weeks, and open-label co-administered ezetimibe and simvastatin (10 mg, 20 mg, or 40 mg) for 20 weeks thereafter.At Week 6, ezetimibe co-administered with simvastatin (all doses) significantly reduced total-C (38 % vs 26 %), LDL-C (49 % vs 34 %), Apo B (39 % vs 27 %), and non-HDL-C (47 % vs 33 %) compared to simvastatin (all doses) alone. Results for the two treatment groups were similar for TG and HDL-C (-17 % vs -12 % and +7 % vs +6 %, respectively). At Week 33, results were consistent with those at Week 6 and significantly more patients receiving ezetimibe and 40 mg simvastatin (62 %) attained the NCEP AAP ideal goal (< 2.8 mmol/L [110 mg/dL]) for LDL-C compared to those receiving 40 mg simvastatin (25 %). At Week 53, the end of the open label extension, the effects on lipid parameters were maintained.The safety and efficacy of ezetimibe co-administered with doses of simvastatin above 40 mg daily have not been studied in paediatric patients 10 to 17 years of age. The long-term efficacy of therapy with ezetimibe in patients below 17 years of age to reduce morbidity and mortality in adulthood has not been studied.Homozygous Familial Hypercholesterolaemia (HoFH) A double-blind, randomised, 12-week study was performed in patients with a clinical and/or genotypic diagnosis of HoFH. Data were analysed from a subgroup of patients (n=14) receiving simvastatin 40 mg at baseline. Increasing the dose of simvastatin from 40 to 80 mg (n=5) produced a reduction of LDL-C of 13% from baseline on simvastatin 40 mg. Coadministered ezetimibe and simvastatin equivalent to INEGY (10 mg/40 mg and 10 mg/80 mg pooled, n=9), produced a reduction of LDL-C of 23% from baseline on simvastatin 40 mg. In those patients coadministered ezetimibe and simvastatin equivalent to INEGY (10 mg/80 mg, n=5), a reduction of LDL-C of 29% from baseline on simvastatin 40 mg was produced.Aortic Stenosis The Simvastatin and Ezetimibe for the Treatment of Aortic Stenosis (SEAS) study was a multi-center, double-blind, placebo-controlled study with a median duration of 4.4 years conducted in 1873 patients with asymptomatic aortic stenosis (AS), documented by Doppler-measured aortic peak flow velocity within the range of 2.5 to 4.0 m/s. Only patients who were considered not to require statin treatment for purposes of reducing atherosclerotic cardiovascular disease risk were enrolled. Patients were randomized 1:1 to receive placebo or co-administered ezetimibe 10 mg and simvastatin 40 mg daily.The primary endpoint was the composite of major cardiovascular events (MCE) consisting of cardiovascular death, aortic valve replacement (AVR) surgery, congestive heart failure (CHF) as a result of progression of AS, nonfatal myocardial infarction, coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), hospitalization for unstable angina, and nonhemorrhagic stroke. The key secondary endpoints were composites of subsets of the primary endpoint event categories.Compared to placebo, ezetimibe/simvastatin 10/40 mg did not significantly reduce the risk of MCE. The primary outcome occurred in 333 patients (35.3%) in the ezetimibe/ simvastatin group and in 355 patients (38.2%) in the placebo group (hazard ratio in the ezetimibe / simvastatin group, 0.96; 95% confidence interval, 0.83 to 1.12; p = 0.59).Aortic valve replacement was performed in 267 patients (28.3%) in the ezetimibe / simvastatin group and in 278 patients (29.9%) in the placebo group (hazard ratio, 1.00; 95% CI, 0.84 to 1.18; p = 0.97). Fewer patients had ischemic cardiovascular events in the ezetimibe / simvastatin group (n=148) than in the placebo group (n=187) (hazard ratio, 0.78; 95% CI, 0.63 to 0.97; p = 0.02), mainly because of the smaller number of patients who underwent coronary artery bypass grafting.Cancer occurred more frequently in the ezetimibe / simvastatin group (105 versus 70, p = 0.01). The clinical relevance of this observation is uncertain. In a meta-analysis including interim results from two large, long-term, ongoing studies with ezetimibe / simvastatin (n=10,319 actively treated, 10,298 control treated; patient-years = 18,246 actively treated, 18,255 control treated) there was not an increased rate of cancer (313 active treatment, 326 control; risk ratio, 0.96; 95% confidence interval, 0.82 to 1.12; p = 0.61). | |