Claude Gagné

Efficacy and safety of ezetimibe added to ongoing statin therapy for treatment of patients with primary hypercholesterolemia.

Ezetimibe is a lipid-lowering drug that inhibits the intestinal absorption of dietary and biliary cholesterol by blocking passage across the intestinal wall. The efficacy and safety of adding ezetimibe to ongoing statin therapy in patients with primary hypercholesterolemia was evaluated in a randomized, double-blind, placebo-controlled study. The study group included 769 adults (aged > or =18 years) with primary hypercholesterolemia who had not achieved National Cholesterol Education Program (NCEP) Adult Treatment Panel II goals with dietary alteration and statin monotherapy. Patients receiving a stable dose of a statin for > or =6 weeks were randomized to receive concurrent treatment with placebo (n = 390) or ezetimibe (n = 379), 10 mg/day, in addition to continuing their open-label statin for 8 weeks. The primary efficacy variable was the percent change in low-density lipoprotein (LDL) cholesterol from baseline with statin monotherapy to end point after intervention (secondary variables: high-density lipoprotein [HDL] cholesterol and triglycerides). Ongoing statin therapy plus ezetimibe led to changes of -25.1% for LDL cholesterol (HDL cholesterol +2.7%; triglycerides -14.0%) compared with LDL cholesterol -3.7% (p <0.001), HDL cholesterol +1.0% (p <0.05), and triglycerides -2.9% (p <0.001) for placebo added to ongoing statin therapy. Among patients not at LDL cholesterol goal at on-statin baseline, 71.5% receiving statin plus ezetimibe versus 18.9% receiving statin plus placebo reached goal at end point (odds ratio 23.7; p <0.001). The co-administration of statin and ezetimibe was generally well tolerated. Adding ezetimibe to ongoing statin therapy led to substantial additional reduction in LDL cholesterol levels, facilitating attainment of NCEP goals. Ezetimibe offers a new therapeutic option for patients receiving statins who require further reduction in LDL cholesterol.

Efficacy and Safety of Ezetimibe Coadministered With Atorvastatin or Simvastatin in Patients With Homozygous Familial Hypercholesterolemia

Background—Patients with homozygous familial hypercholesterolemia (HoFH) have a high incidence of cardiovascular morbidity and mortality from premature atherosclerosis, and the efficacy of pharmacological therapy has been limited. We evaluated the efficacy, safety, and tolerability of ezetimibe, a novel cholesterol absorption inhibitor, in a multicenter, double-blind, randomized trial of HoFH patients receiving atorvastatin or simvastatin. Methods and Results—Fifty patients with a diagnosis of HoFH on the National Cholesterol Education Program Step 1 or stricter diet and taking open-label atorvastatin 40 mg/d or simvastatin 40 mg/d (statin-40) with (n=25) or without (n=25) concomitant LDL apheresis were randomized to 1 of 3 double-blind treatments: atorvastatin or simvastatin 80 mg/d (statin-80, n=17); ezetimibe 10 mg/d plus atorvastatin or simvastatin 40 mg/d (n=16); or ezetimibe 10 mg/d plus atorvastatin or simvastatin 80 mg/d (n=17) for 12 weeks. The primary end point was mean percentage change in LDL cholesterol (LDL-C) from statin-40 baseline to the end point for patients receiving statins alone (statin-80) versus patients receiving ezetimibe plus atorvastatin or simvastatin at either dose (ezetimibe plus statin-40/80). Ezetimibe plus statin-40/80 significantly reduced LDL-C levels compared with statin-80 (−20.7% versus −6.7%, P =0.007). In the high-dose statin cohorts, ezetimibe plus statin-80 reduced LDL-C by an additional 20.5% (P =0.0001) versus statin-80. Similar significant reductions in LDL-C concentrations were observed for patients with genotype-confirmed HoFH (n=35). Ezetimibe was safe and well tolerated. Conclusions—Ezetimibe coadministered with atorvastatin or simvastatin in patients with HoFH produced clinically important LDL-C reductions compared with best current therapy. Ezetimibe provides a new, complementary pharmacological approach for this high-risk population.

Efficacy and Safety of Statin Therapy in Children With Familial Hypercholesterolemia A Randomized, Double-Blind, Placebo-Controlled Trial With Simvastatin

Background—A multicenter, randomized, double-blind, placebo-controlled study was conducted to evaluate LDL cholesterol–lowering efficacy, overall safety, and tolerability and the influence on growth and pubertal development of simvastatin in a large cohort of boys and girls with heterozygous familial hypercholesterolemia (heFH). Methods and Results—A total of 173 heFH children (98 boys and 75 girls) were included in this study. After a 4-week diet/placebo run-in period, children with heFH were randomized to either simvastatin or placebo in a ratio of 3:2. Simvastatin was started at 10 mg/d and titrated at 8-week intervals to 20 and then 40 mg/d. During a 24-week extension period, the patients continued to receive simvastatin (40 mg) or placebo according to their assignment. After 48 weeks of simvastatin therapy, there were significant reductions of LDL cholesterol (−41%), total cholesterol (−31%), apolipoprotein B (−34%), VLDL cholesterol (−21%), and triglyceride (−9%) levels. HDL cholesterol and apolipoprotein A-I levels were increased by 3.3% and 10.4%, respectively (not significant). No safety issues became evident. Except for small decreases in dehydroepiandrosterone sulfate compared with placebo, there were no significant changes from baseline in adrenal, gonadal, and pituitary hormones in either treatment group. Conclusions—Simvastatin significantly reduced LDL cholesterol, total cholesterol, triglyceride, VLDL cholesterol, and apolipoprotein B levels and was well tolerated in children with heFH. There was no evidence of any adverse effect of simvastatin on growth and pubertal development. Therefore, simvastatin at doses up to 40 mg is a well-tolerated and effective therapy for heFH children.

Increase in plasma high-density lipoprotein concentration following complete androgen blockage in men with prostatic carcinoma

There is evidence that endogenous estrogens have a positive effect on plasma high density lipoprotein (HDL) concentration, whereas the relation between HDL and male sex hormones is unclear, since both positive and negative effects have been reported. This study examined the effects of LHRH agonist in combination with an antiandrogen on plasma lipids and lipoproteins in 17 elderly men with prostatic carcinoma. Subjects were examined prior to and after therapy at 4-week intervals up to 16 weeks. Prior to therapy, their lipid and lipoprotein profiles were not significantly different from a control group composed of individuals of similar age and living in the same community area. Following therapy plasma levels of testosterone and dihydrotestosterone were markedly decreased (above 90%) and their residual activity neutralized through effective use of an antiandrogen. Plasma estradiol decreased between 65% and 85% and the concentration of cortisol was unaffected. The very low density lipoprotein (VLDL) apo-B decreased and low density lipoprotein (LDL) apo-B increased; thus, no change was observed in the total plasma apo-B levels. Total plasma cholesterol increased by 6% (baseline v peak values, mg/dL, mean +/- SEM; 219 +/- 9 v 233 +/- 9, P less than 0.05) due to a significant rise in HDL cholesterol concentration (45.5 +/- 2.8 v 56.5 +/- 3.6, P less than 0.01). Both VLDL and LDL cholesterol levels remained unchanged. The mean elevation of 21% in HDL cholesterol was accompanied by a significant rise in HDL apo-A concentration (161 +/- 6 v 193 +/- 10, P less than 0.01), thus suggesting an increase in HDL mass and/or particle number.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein B Synthesis Inhibition with Mipomersen in Heterozygous Familial Hypercholesterolemia: Results of a Randomized, Double-Blind, Placebo Controlled Trial to Assess Efficacy and Safety as Add-on Therapy in Patients with Coronary Artery Disease

Background— Heterozygous familial hypercholesterolemia (HeFH) is a common genetic disorder leading to premature coronary artery disease. Despite statins and additional lipid-lowering therapies, many HeFH patients fail to achieve low-density lipoprotein cholesterol (LDL-C) goals. We evaluated mipomersen, an apolipoprotein B synthesis inhibitor, to further lower LDL-C in HeFH patients with coronary artery disease. Methods and Results— This double-blind, placebo-controlled, phase 3 trial randomized patients with HeFH and coronary artery disease on maximally tolerated statin and LDL-C ≥2.6 mmol/L (≥100 mg/dL) to weekly subcutaneous mipomersen 200 mg or placebo (2:1) for 26 weeks. The primary end point was percent change in LDL-C from baseline at week 28. Safety assessments included adverse events, laboratory tests, and magnetic resonance imaging assessment of hepatic fat. Of 124 randomized patients (41 placebo, 83 mipomersen), 114 (41 placebo, 73 mipomersen) completed treatment. Mean (95% confidence interval) LDL-C decreased significantly with mipomersen (−28.0% [−34.0% to −22.1%] compared with 5.2% [−0.5% to 10.9%] increase with placebo; P <0.001). Mipomersen significantly reduced apolipoprotein B (−26.3%), total cholesterol (−19.4%), and lipoprotein(a) (−21.1%) compared with placebo (all P <0.001). No significant change occurred in high-density lipoprotein cholesterol. Adverse events included injection site reactions and influenza-like symptoms. Five mipomersen patients (6%) had 2 consecutive alanine aminotransferase values ≥3 times the upper limit of normal at least 7 days apart; none were associated with significant bilirubin increases. Hepatic fat content increased a median of 4.9% with mipomersen versus 0.4% with placebo ( P <0.001). Conclusions— Mipomersen is an effective therapy to further reduce apolipoprotein B–containing lipoproteins, including LDL and lipoprotein(a), in HeFH patients with coronary artery disease on statins and other lipid-lowering therapy. The significance of hepatic fat and transaminase increases remains uncertain at this time. Clinical Trial Registration— URL: . Unique identifier: [NCT00706849][1]. # Clinical Perspective {#article-title-34} [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00706849&atom=%2Fcirculationaha%2F126%2F19%2F2283.atomBackground— Heterozygous familial hypercholesterolemia (HeFH) is a common genetic disorder leading to premature coronary artery disease. Despite statins and additional lipid-lowering therapies, many HeFH patients fail to achieve low-density lipoprotein cholesterol (LDL-C) goals. We evaluated mipomersen, an apolipoprotein B synthesis inhibitor, to further lower LDL-C in HeFH patients with coronary artery disease. Methods and Results— This double-blind, placebo-controlled, phase 3 trial randomized patients with HeFH and coronary artery disease on maximally tolerated statin and LDL-C ≥2.6 mmol/L (≥100 mg/dL) to weekly subcutaneous mipomersen 200 mg or placebo (2:1) for 26 weeks. The primary end point was percent change in LDL-C from baseline at week 28. Safety assessments included adverse events, laboratory tests, and magnetic resonance imaging assessment of hepatic fat. Of 124 randomized patients (41 placebo, 83 mipomersen), 114 (41 placebo, 73 mipomersen) completed treatment. Mean (95% confidence interval) LDL-C decreased significantly with mipomersen (−28.0% [−34.0% to −22.1%] compared with 5.2% [−0.5% to 10.9%] increase with placebo; P<0.001). Mipomersen significantly reduced apolipoprotein B (−26.3%), total cholesterol (−19.4%), and lipoprotein(a) (−21.1%) compared with placebo (all P<0.001). No significant change occurred in high-density lipoprotein cholesterol. Adverse events included injection site reactions and influenza-like symptoms. Five mipomersen patients (6%) had 2 consecutive alanine aminotransferase values ≥3 times the upper limit of normal at least 7 days apart; none were associated with significant bilirubin increases. Hepatic fat content increased a median of 4.9% with mipomersen versus 0.4% with placebo (P<0.001). Conclusions— Mipomersen is an effective therapy to further reduce apolipoprotein B–containing lipoproteins, including LDL and lipoprotein(a), in HeFH patients with coronary artery disease on statins and other lipid-lowering therapy. The significance of hepatic fat and transaminase increases remains uncertain at this time. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00706849.

Molecular pathobiology of the human lipoprotein lipase gene

Lipoprotein lipase (LPL; E.C. 3.1.1.34) is a key enzyme in the metabolism of lipids. Many diseases, including obesity, coronary heart disease, chylomicronemia (pancreatitis), and atherosclerosis, appear to be directly or indirectly related to abnormalities in LPL function. Human LPL is a member of a superfamily of lipases that includes hepatic lipase and pancreatic lipase. These lipases are characterized by extensive homology, both at the level of the gene and the mature protein, suggesting that they have a common evolutionary origin. A large number of natural mutations have been discovered in the human LPL gene, which are located at different sites in the gene and affect different functions of the mature protein. There is a high prevalence of two of these mutations (207 and 188) in the Province of Québec, and one of them (207) is almost exclusive to the French-Canadian population. A study of these and other naturally occurring mutant LPL molecules, as well as those created in vitro by site-directed mutagenesis, indicate that the sequence of LPL is organized into multiple structural and functional units that act in concert in the normal enzyme. In this review, we discuss the interrelationships of LPL structure and its function, the molecular etiology of abnormal LPL in humans, and the clinical and therapeutic aspects of LPL deficiency.

Homozygous familial hypercholesterolemia among French Canadians in Québec Province.

Nineteen patients with homozygous familial hypercholesterolemla (FH) living at the time of the 1981 Canada census are the subject of this report Their mean age at that time was 15, with a range of 1 to 26 years. All patients had extensive xanthomatosls but showed variable clinical manifestations of coronary heart disease (CHD); five (mean age, 21; range, 11 to 27 years) died from sudden death due to CHD. Plasma cholesterol levels varied more than twofold (557 to 1532 mg/dl). Variation In the concentrations of both plasma and low density llpoproteln cholesterol, as well as apolipoproteln B, were related neither to age at death from CHD nor to the clinical course of CHD. The mean high density llpoproteln cholesterol concentration (37 mg/dl) was lower than the mean value (49 mg/dl) in the control population (p<0.001). Both the clinical and biochemical features of this cohort are typical of homozygous FH. The prevalence of homozygotes among French Canadians in Quebec was ∼1:275 000, and the minimum estimated frequency of heterozygotes was 1 270. In northeastern Quebec, the frequency of homozygotes was ∼1:100 000, and the minimum estimated frequency of heterozygotes was 1 154. Only Afrikaaners In South Africa have correspondingly higher frequencies.

Heterozygous familial hypercholesterolemia. Relationship between plasma lipids, lipoproteins, clinical manifestations and ischaemic heart disease in men and women.

Abstract A large cohort of 264 men and 311 women with heterozygous familial hypercholesterolemia (FH) is analysed for the presence of xanthomas, ischaemic heart disease (IHD) and plasma lipids and lipoproteins. The plasma and low density lipoprotein (LDL) cholesterol are elevated to the same extent in both sexes, but on the contrary high density lipoprotein (HDL) cholesterol is decreased in both sexes as compared to normal controls. Thus an increase in LDL and a decrease in HDL may account for the early development of IHD in both men and women with FH. Although tendon xanthomas are equally observed in both sexes, IHD is not only precocious in men but its prevalence is also higher in men as compared to women. IHD is also more severe in men as seen from the higher incidence of myocardial infarction and fatal events. Plasma triglyceride levels are significantly higher in men, but they do not account for the higher prevalence of IHD in men, since the incidence of IHD is lower in men with type IIb hyperlipoproteinemia as compared to Ila. HDL-cholesterol is significantly lower in men as compared to women with FH and therefore it may explain the differences in IHD between men and women. Irrespective of sex, the presence of tendinous xanthomas is related to elevated levels of both plasma and LDL cholesterol and higher LDL/HDL cholesterol ratio. The women with tendinous xanthomas, whether with or without IHD have similar levels of plasma lipids and lipoprotein cholesterol as compared to men with similar clinical manifestations. Although no significant differences are noted in the plasma lipid and lipoprotein levels between men either with or without IHD; in women, the occurrence of IHD is related to lower concentration of HDL-cholesterol which is not only similar to that in men with IHD, but is also significantly lower than the level observed in women with tendinous xanthomas but no IHD. These findings lead us to suggest that lower prevalence of IHD in women with FH in due to their higher concentration of HDL-cholesterol.

Evidence of increased secretion of apolipoprotein B-48-containing lipoproteins in subjects with type 2 diabetes

Patients with type 2 diabetes have high levels of triglyceride-rich lipoproteins (TRLs), including apolipoprotein B-48 (apoB-48)-containing TRLs of intestinal origin, but the mechanism leading to overaccumulation of these lipoproteins remains to be fully elucidated. Therefore, the objective of this study was to examine the in vivo kinetics of TRL apoB-48 and VLDL, intermediate density lipoprotein (IDL), and LDL apoB-100 in type 2 diabetic subjects (n = 11) and nondiabetic controls (n = 13) using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h in the fed state. Diabetic subjects had significantly higher fasting glycemia, higher fasting insulinemia, higher plasma triglyceride, and lower HDL-cholesterol levels than controls. Compared with controls, diabetic subjects had increased TRL apoB-48, VLDL apoB-100, and IDL apoB-100 pool sizes as a result of increased production rates (PRs) and reduced fractional catabolic rates of these lipoprotein subfractions. Furthermore, multiple linear regression analyses revealed that the diabetic/control status was an independent predictor of TRL apoB-48 PR and represented nearly 35% of its variance. These results suggest that the overaccumulation of TRLs seen in patients with type 2 diabetes is attributable to increased PRs of both intestinally derived apoB-48-containing lipoproteins and TRL apoB-100 of hepatic origin and to decreased catabolism of these subfractions.

A Mutation in the Human Lipoprotein Lipase Gene as the Most Common Cause of Familial Chylomicronemia in French Canadians

BACKGROUND Lipoprotein lipase hydrolyzes the triglyceride core of chylomicrons and very-low-density lipoproteins and has a crucial role in regulating plasma lipoprotein levels. Deficiencies of lipoprotein lipase activity lead to aberrations in lipoprotein levels. Worldwide, the frequency of lipoprotein lipase deficiency is highest among French Canadians. We sought to determine the molecular basis of the disorder in this population. METHODS The entire coding sequence of the lipoprotein lipase gene from one French Canadian patient was amplified by the polymerase chain reaction and sequenced. Exon 5 from 36 other French Canadian patients was amplified and analyzed by dot blot hybridization with allele-specific oligonucleotides. RESULTS Sequence analysis revealed a missense substitution of leucine (CTG) for proline (CCG) at residue 207 in exon 5. This mutation was found on 54 of the 74 mutant alleles (73 percent) in the patients. Studies of site-directed in vitro mutagenesis have confirmed that this mutation generates inactive lipoprotein lipase and is the cause of lipoprotein lipase deficiency. CONCLUSIONS We have identified a missense mutation at residue 207 of the lipoprotein lipase gene that is the most common cause of lipoprotein lipase deficiency in French Canadians. This mutation can be easily detected by dot blot analysis, providing opportunity for definitive DNA diagnosis of the disorder and identification of heterozygous carriers.