ASCOT-LLA: questions about the benefits of atorvastatin

ArticleinThe Lancet 361(9373):1986; author reply 1986-7 · July 2003with 90 Reads
Ad

Do you want to read the rest of this article?

Request full-text
Request Full-text Paper PDF
This research hasn't been cited in any other publications.
  • Article
    The purpose of this study was to determine if long-term use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (atorvastatin, fluvastatin, lovastatin, pravastatin, or simvastatin) resulted in tachyphylaxis (a decreasing response to a physiologically active agent). To determine this, the charts of 254 patients treated with statins from the years 1996 to 1998 were retrospectively reviewed. During treatment, the low-density lipoprotein (LDL) cholesterol levels of patients were followed for a minimum of 300 days. To characterize LDL cholesterol changes during statin therapy, linear and nonlinear kinetic models were generated. Tachyphylaxis, defined as a positive slope of LDL cholesterol over time, after maximum LDL cholesterol reduction, was identified in patients treated with atorvastatin at exposure doses of 10 or 20 mg/day. All other statins, at all doses reviewed, showed no [corrected] evidence of tachyphylaxis. LDL cholesterol tachyphylaxis appeared to be a unique response to prolonged use of long half-life atorvastatin therapy at exposure dosages.
  • Article
    Full-text available
    Hypercholesterolemia is considered an important risk factor in coronary artery disease. Thus the possibility of controlling de novo synthesis of endogenous cholesterol, which is nearly two-thirds of total body cholesterol, represents an effective way of lowering plasma cholesterol levels. Statins, fungal secondary metabolites, selectively inhibit hydroxymethyl glutaryl-coenzyme A (HMG-CoA) reductase, the first enzyme in cholesterol biosynthesis. The mechanism involved in controlling plasma cholesterol levels is the reversible inhibition of HMG-CoA reductase by statins, related to the structural similarity of the acid form of the statins to HMG-CoA, the natural substrate of the enzymatic reaction. Currently there are five statins in clinical use. Lovastatin and pravastatin (mevastatin derived) are natural statins of fungal origin, while symvastatin is a semi-synthetic lovastatin derivative. Atorvastatin and fluvastatin are fully synthetic statins, derived from mevalonate and pyridine, respectively. In addition to the principal natural statins, several related compounds, monacolins and dihydromonacolins, isolated fungal intermediate metabolites, have also been characterized. All natural statins possess a common polyketide portion, a hydroxy-hexahydro naphthalene ring system, to which different side chains are linked. The biosynthetic pathway involved in statin production, starting from acetate units linked to each other in head-to-tail fashion to form polyketide chains, has been elucidated by both early biogenetic investigations and recent advances in gene studies. Natural statins can be obtained from different genera and species of filamentous fungi. Lovastatin is mainly produced by Aspergillus terreus strains, and mevastatin by Penicillium citrinum. Pravastatin can be obtained by the biotransformation of mevastatin by Streptomyces carbophilus and simvastatin by a semi-synthetic process, involving the chemical modification of the lovastatin side chain. The hypocholesterolemic effect of statins lies in the reduction of the very low-density lipoproteins (VLDL) and LDL involved in the translocation of cholesterol, and in the increase in the high-density lipoproteins (HDL), with a subsequent reduction of the LDL- to HDL-cholesterol ratio, the best predictor of atherogenic risk. The use of statins can lead to a reduction in coronary events related to hypercholesterolemia, but the relationship between benefit and risk, and any possible interaction with other drugs, must be taken into account.
  • Article
    Full-text available
    The lowering of cholesterol concentrations in individuals at high risk of cardiovascular disease improves outcome. No study, however, has assessed benefits of cholesterol lowering in the primary prevention of coronary heart disease (CHD) in hypertensive patients who are not conventionally deemed dyslipidaemic. Of 19 342 hypertensive patients (aged 40-79 years with at least three other cardiovascular risk factors) randomised to one of two antihypertensive regimens in the Anglo-Scandinavian Cardiac Outcomes Trial, 10,305 with nonfasting total cholesterol concentrations 6.5 mmol/L or less were randomly assigned additional atorvastatin 10 mg or placebo. These patients formed the lipid-lowering arm of the study. We planned follow-up for an average of 5 years, the primary endpoint being non-fatal myocardial infarction and fatal CHD. Data were analysed by intention to treat. Treatment was stopped after a median follow-up of 3.3 years. By that time, 100 primary events had occurred in the atorvastatin group compared with 154 events in the placebo group (hazard ratio 0.64 [95% CI 0.50-0.83], p = 0.0005). This benefit emerged in the first year of follow-up. There was no significant heterogeneity among prespecified subgroups. Fatal and non-fatal stroke (89 atorvastatin vs 121 placebo, 0.73 [0.56-0.96], p = 0.024), total cardiovascular events (389 vs 486, 0.79 [0.69-0.90], p = 0.0005), and total coronary events (178 vs 247, 0.71 [0.59-0.86], p = 0.0005) were also significantly lowered. There were 185 deaths in the atorvastatin group and 212 in the placebo group (0.87 [0.71-1.06], p = 0.16). Atorvastatin lowered total serum cholesterol by about 1.3 mmol/L compared with placebo at 12 months, and by 1.1 mmol/L after 3 years of follow-up. The reductions in major cardiovascular events with atorvastatin are large, given the short follow-up time. These findings may have implications for future lipid-lowering guidelines.