Treating hypercholesterolaemia with HMG CoA reductase inhibitors: a direct comparison of simvastatin and pravastatin

Proapoptotic and antitumor activities of the HMG-CoA reductase inhibitor, lovastatin, against Dalton's Lymphoma Ascites tumor in mice

BACKGROUND

Diet rich in fat have a clear effect on the tumor incidence in humans. Increased level of lipid peroxidation were found in colon, liver, breast and kidney carcinogenesis. Although the beneficial effects of statins for cardiovascular diseases are well established, their importance in the area of cancer therapeutics has recently gained recognition. Many studies of lovastatin in in vitro systems and experimental animals have been reported as an effective antitumor agent. However, phase I/II clinical trials in cancer patients demonstrated a minor to non-significant responses. Hence more studies in different tumor models using doses corresponding to that used to reduce lipid in human are required to support the antitumor activity.

METHODS

The antitumor activity was evaluated using Daltons' Lymphoma Ascites (DLA) cell line-induced ascites tumor model in mice. Proapoptotic activity was evaluated in DLA cell line induced ascites animals after the treatment of lovastatin. Apoptosis was analyzed morphologically by staining with Giemsa and biochemically by observing the laddering of DNA in agarose gel electrophoresis. In vitro cytotoxic activity of lovastatin was studied by trypan blue dye exclusion method. Lipid peroxidation inhibiting activity was demonstrated in Fe2+-ascorbate induced rat whole liver homogenate.

RESULTS

Lovastatin dose dependently inhibited the ascites tumor growth at 4 and 16 mg/kg body wt (p.o). The percentage increase in life span (%ILS) in the 16 mg/kg treated group was 61.8% (P<0.01). Single dose of lovastatin (16 mg/kg body wt, p.o) was also effective to accelerate the apoptosis in the ascites tumor bearing mice that was evident from the multiple fragmentation of DNA in gel electrophoresis. Further the morphological analysis of DLA cells aspirated from the lovastatin treated animals showed a significant (P<0.01) increase of apoptotic cells (15.5+/-3%) than the control animals (6.5+/-1%). Concentration of lovastatin required for the 50% of the cytotoxicity was 37+/-5 microg/ml. Lovastatin at its low concentrations were effective to inhibit lipid peroxidation.

CONCLUSIONS

The antitumor activity of lovastatin against the ascites tumor is due to its proapoptotic and cytotoxic activities. Lovastatin at low concentrations inhibited Fe2+ induced lipid peroxidation in in vitro system. The proapoptotic and lipid peroxidation inhibiting activities of the lipid lowering drug lovastatin may further suggest its possible therapeutic use as a cancer chemopreventive agent.

Double-masked comparison of the quality of life of hypercholesterolemic men treated with simvastatin or pravastatin. International Quality of Life Multicenter Group

The efficacy, safety, and impact on quality of life of once-daily treatment with simvastatin 20 mg and pravastatin 40 mg were compared in a multinational, randomized, double-masked trial involving 387 men 21 to 72 years of age with primary mild-to-moderate hypercholesterolemia. The trial consisted of a 12-week baseline period, which included 6 weeks of single-masked placebo administration, and a 12-week double-masked active treatment period. Throughout the trial, patients were maintained on a standard lipid-lowering diet. Efficacy variables were plasma lipid levels and a measurement of health-related quality of life evaluated by means of a self-administered questionnaire (the Nottingham Health Profile [NHP]) and other questionnaires related to general health, sexual function, and stress/life events. Clinic visits were scheduled at study entry (week -12), at initiation and week 5 of placebo (weeks -6 and -1, respectively); at randomization (week 1, day 1); and after 4, 8, and 12 weeks of active treatment. At each visit, blood samples were collected for determination of lipid levels and the NHP, the principal measure of health-related quality of life, was administered. Primary safety measures were adverse events and laboratory test results. All statistical comparisons were two-sided, and significance was defined as P< or =0.05 except for the NHP questionnaire, which was P< or =0.01. Treatment with simvastatin 20 mg/d for 12 weeks (n = 194) resulted in significantly greater reductions in plasma total cholesterol and low-density lipoprotein cholesterol levels (25.7% and 33.6%, respectively) compared with pravastatin 40 mg/d for 12 weeks (n = 193) (19.0% and 26.3%, respectively) (P<0.001). No detrimental effects on health-related quality-of-life measurements were reported with either drug. A small but statistically significant improvement in emotional reaction from baseline (P<0.001) was observed after 12 weeks of treatment with simvastatin. At least 75% of simvastatin-treated patients indicated no change in response from baseline on NHP domain scores; these findings were similar to those for pravastatin-treated patients. The differences in the changes in lipid profiles between the 2 treatment groups were not associated with any observed differences in tolerability or health-related quality-of-life measures.

A population-based treat-to-target pharmacoeconomic analysis of HMG-CoA reductase inhibitors in hypercholesterolemia

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors have become the drugs of choice for the treatment of patients with hypercholesterolemia. However, one of the major concerns with these drugs is cost. In an attempt to develop a cost-effective treatment strategy for patients referred to our lipid clinic, we conducted a meta-analysis to estimate the lipid-lowering efficacy of the various HMG-CoA reductase inhibitors alone or in combination with niacin or cholestyramine. Based on cholesterol-lowering efficacy estimates derived from a literature-based meta-analysis, we performed a population-based treat-to-target analysis. Fifty-six trials with 101 monotherapy cohorts and 20 trials with 31 combination-therapy cohorts (573 patients) were included in the meta-analysis. Based on reduction in low-density lipoprotein cholesterol (LDL-C), the most effective monotherapy was atorvastatin and the least effective monotherapy was fluvastatin. Combination therapy was more effective in reducing LDL-C than monotherapy with the respective HMG-CoA reductase inhibitor. However, on the basis of dollars spent per percentage of LDL-C reduction, combination therapy was frequently less cost-effective than monotherapy. In addition, combination therapy was associated with a higher rate of noncompliance and a greater risk of drug-drug interactions. As a result, we based our treat-to-target analysis on the use of monotherapy as first-line treatment, with combination therapy reserved for patients failing to achieve the target LDL-C levels of the US National Cholesterol Education Program Adult Treatment Panel II (NCEP ATP-II) with monotherapy. In the population-based treat-to-target analysis, atorvastatin was the most cost-effective drug for high-risk patients (those with coronary heart disease [CHD]), whereas fluvastatin was the most cost-effective agent for low-risk patients (<2 risk factors for CHD) and moderate-risk patients (> or =2 risk factors for CHD). If 1 drug is chosen to treat all patients (i.e., in cases of formulary restriction), atorvastatin would be the most cost-effective agent. In adapting the findings on cholesterol-lowering efficacy from this analysis to our lipid clinic, we concluded that the most cost-effective treatment approach is to individualize the selection of an HMG-CoA reductase inhibitor based on both coronary risk and the LDL-C reduction required to achieve NCEP ATP-II goals. Based on our results, 2 agents--atorvastatin and fluvastatin--should be available on the formulary.

Clinical efficacy and safety of cerivastatin: summary of pivotal phase IIb/III studies

Cerivastatin is a new, third-generation 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor ("statin"), which is administered to hypercholesterolemic patients at doses equivalent to 1-3% of the doses of other statins. This report reviews the pivotal Phase IIb/III clinical trials in which the efficacy and safety of cerivastatin was compared with placebo and active comparator statins (lovastatin, simvastatin, and pravastatin) after both short- and long-term administration. Overall, the studies showed that at doses of 0.025-0.4 mg/day, cerivastatin produced dose-dependent reductions in low-density lipoprotein (LDL) cholesterol and total cholesterol, which were significantly greater than placebo. The greatest reductions were achieved with 0.4 mg/day cerivastatin. On this dose, >40% of patients achieved reductions in LDL cholesterol >40% and in a further 9% of patients, LDL cholesterol was decreased by >50%. At higher doses, cerivastatin also demonstrated potent triglyceride-lowering effects in a subgroup of patients with raised plasma triglycerides. Reductions in atherogenic lipids and lipoproteins were accompanied by significant increases in high-density lipoprotein (HDL) cholesterol, apolipoprotein A-I, and antiatherogenic lipoprotein A-I. Long-term administration of cerivastatin for periods of up to 2 years was associated with persistent reductions in LDL cholesterol, total cholesterol, triglycerides, and apolipoprotein B as well as increases in HDL cholesterol similar to those observed after initial administration. Long-term cerivastatin treatment was also well tolerated. There was no significant difference between the incidence of adverse effects with cerivastatin and comparator statins or between cerivastatin and other statins with respect to clinically significant increases in either hepatic enzymes or creatine phosphokinase. In conclusion, these studies indicate that cerivastatin is a safe and effective long-term treatment for patients with primary hypercholesterolemia and also suggest that higher doses should be investigated.

Comparative dose efficacy study of atorvastatin versus simvastatin, pravastatin, lovastatin, and fluvastatin in patients with hypercholesterolemia (the CURVES study)

The objective of this multicenter, randomized, open-label, parallel-group, 8-week study was to evaluate the comparative dose efficacy of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor atorvastatin 10, 20, 40, and 80 mg compared with simvastatin 10, 20, and 40 mg, pravastatin 10, 20, and 40 mg, lovastatin 20, 40, and 80 mg, and fluvastatin 20 and 40 mg. Investigators enrolled 534 hypercholesterolemic patients (low-density lipoprotein [LDL] cholesterol > or = 160 mg/dl [4.2 mmol/L] and triglycerides < or = 400 mg/dl [4.5 mmol/L]). The efficacy end points were mean percent change in plasma LDL cholesterol (primary), total cholesterol, triglycerides, and high-density lipoprotein cholesterol concentrations from baseline to the end of treatment (week 8). Atorvastatin 10, 20, and 40 mg produced greater (p < or = 0.01) reductions in LDL cholesterol, -38%, -46%, and -51%, respectively, than the milligram equivalent doses of simvastatin, pravastatin, lovastatin, and fluvastatin. Atorvastatin 10 mg produced LDL cholesterol reductions comparable to or greater than (p < or = 0.02) simvastatin 10, 20, and 40 mg, pravastatin 10, 20, and 40 mg, lovastatin 20 and 40 mg, and fluvastatin 20 and 40 mg. Atorvastatin 10, 20, and 40 mg produced greater (p < or = 0.01) reductions in total cholesterol than the milligram equivalent doses of simvastatin, pravastatin, lovastatin, and fluvastatin. All reductase inhibitors studied had similar tolerability. There were no incidences of persistent elevations in serum transaminases or myositis.

Simvastatin. A reappraisal of its pharmacology and therapeutic efficacy in hypercholesterolaemia

Simvastatin is an HMG-CoA reductase inhibitor used in the treatment of patients with hypercholesterolaemia. Since the time simvastatin was previously reviewed in Drugs, a number of large clinical trials have confirmed its clinical efficacy. Thus, reductions from baseline were approximately 20 to 40% for serum levels of total cholesterol, 35 to 45% for low density lipoprotein (LDL)-cholesterol and 10 to 20% for triglycerides in patients with primary hypercholesterolaemia receiving simvastatin 10 to 40 mg/day. High density lipoprotein (HDL)-cholesterol levels were increased modestly by about 5 to 15%. Recent data from long term studies indicate that little or no attenuation of these changes in serum lipid and lipoprotein levels occurred with administration of simvastatin for 3 to 5.4 years. Comparative studies with other HMG-CoA reductase inhibitors (lovastatin, pravastatin and fluvastatin), which were lacking at the time of the previous review of simvastatin, demonstrated greater reductions in serum levels of total cholesterol and LDL-cholesterol with simvastatin than equal dosages of lovastatin or pravastatin. Reductions in serum levels of total cholesterol and LDL-cholesterol were similar between agents only when lovastatin or pravastatin were administered at a total daily dosage twice that of simvastatin and when fluvastatin was administered at a total daily dosage approximately 8 times that of simvastatin. In general, simvastatin 10 to 40 mg/day was also more effective than standard dosages of bile acid sequestrants, fibrates or probucol in lowering serum levels of total cholesterol and LDL-cholesterol; however, fibrates usually produced greater reductions in serum triglycerides and greater elevations in HDL-cholesterol levels. The Scandinavian Simvastatin Survival Study (4S), a large secondary prevention study in patients with coronary heart disease and concomitant hypercholesterolaemia, demonstrated that simvastatin 20 to 40 mg/day for a median of 5.4 years significantly reduced overall mortality (the primary end-point of the study) by 30% compared with placebo, which was attributed to a 42% relative reduction in coronary mortality. Coronary morbidity was also significantly reduced by simvastatin in the 4S trial. The tolerability profile of simvastatin appears to be comparable to that of other HMG-CoA reductase inhibitors. The most frequently reported adverse events are gastrointestinal disturbances, which are generally mild and tend to occur less frequently than with cholestyramine. In conclusion, simvastatin is among the most effective agents available for treating patients with hypercholesterolaemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative evaluation of the safety and efficacy of HMG-CoA reductase inhibitor monotherapy in the treatment of primary hypercholesterolemia

OBJECTIVE

To evaluate the comparative efficacy and safety of the 4 currently available hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, fluvastatin, lovastatin, pravastatin, and simvastatin, in the treatment of primary hypercholesterolemia.

DATA SOURCES

English-language clinical studies, abstracts, and review articles identified from MEDLINE searches and bibliographies of identified articles. Unpublished data were obtained from the Food and Drug Administration in accordance with the Freedom of Information Act.

STUDY SELECTION

Placebo-controlled and comparative studies of HMG-CoA reductase inhibitor monotherapy in the treatment of primary hypercholesterolemia.

DATA EXTRACTION

Pertinent studies were selected and the data were synthesized into a review format.

DATA SYNTHESIS

The chemistry, pharmacology, and pharmacokinetics of the 4 HMG-CoA reductase inhibitors are reviewed. Clinical trials evaluating the hypocholesterolemic efficacy of the HMG-CoA reductase inhibitors are examined, and results on the comparative efficacy and safety of these agents are summarized. On a milligram-per-milligram basis, simvastatin is twice as potent as lovastatin and pravastatin. The hypocholesterolemic effects of fluvastatin appear to be approximately 30% less than that of lovastatin. In posttransplant patients receiving cyclosporine, safety has been documented for low doses of lovastatin and simvastatin, but when a higher dosage of an HMG-CoA reductase inhibitor is warranted, pravastatin should be considered the drug of choice because of a lower incidence of myopathy. Relevant data on the incidence of adverse effects are presented. Pertinent outcomes data from clinical trials evaluating the effect of HMG-CoA reductase inhibitors on atherosclerosis regression and coronary mortality, as well as published economic analyses of cholesterol-lowering agents, are summarized. Recommendations on the selection of an HMG-CoA reductase inhibitor in various clinical situations are provided.

CONCLUSIONS

The literature supports the comparable safety and tolerability of all 4 currently available HMG-CoA reductase inhibitors. Therefore, the choice of an HMG-CoA reductase inhibitor should depend on the extent of cholesterol lowering needed to meet the recommended treatment goal established by the National Cholesterol Education Program. Direct comparative studies are needed to confirm the relative, long-term cost-effectiveness of the various HMG-CoA reductase inhibitors in the treatment of primary hypercholesterolemia.