Presentation on theme: "To Cholesterol and Beyond: New Uses for Statin Therapy"— Presentation transcript:
1To Cholesterol and Beyond: New Uses for Statin Therapy
2Statins First identified in the 1970s Mevacor® (lovastatin) Mevastatin, a molecule produced by the fungus Penicillium citrinumNever marketedMevacor® (lovastatin)The first statin on the marketProduced by Merck in 19871994 “4S” studyAfter 5 yrs, patients on simvastatin had a 42% less chance of dying of a heart attack.Now the most commonly prescribed cholesterol-lowering medication.Endo
3Statins Site of action: liver Mechanism of action: reversibly inhibit HMG-CoA reductasePreventing the liver from manufacturing cholesterol.Leads to upregulation of LDL receptorsIncreased uptake of VLDL, IDL, and Lp(a)Pleiotropic effectsReverse endothelial dysfunctionAnti-thrombotic activityAnti-inflammatory/AntioxidantPlaque stabilityStatins
5New Statin ResearchGrowing evidence that statins have many more effects unrelated to cholesterol lowering.Emerging evidence that statins may be useful in other disease states that may greatly impact geriatric patients.OsteoporosisDementiaCancer
6OsteoporosisThe most common disease of bone, affects about 10 million people in the U.S. >50 yrs old.As the elderly population grows, the prevalence increases.Characterized by reduced bone mass, microarchitectural deterioration, and increased skeletal fragility.Often a silent disease until there is a fracture14-35% will die within 1 year of hip fractureCaused by an imbalance between bone formation and bone resorption.
7OsteoporosisDrugs such as bisphosphanates, estrogen, and selective estrogen receptor modulators(SERMs) are used to slow bone loss.Nitrogenous Bisphosphanates are the most commonly prescribed anti-osteoporotic agent.They don’t however increase bone formationNitrogenous bisphophonates (Boniva®, Fosamax®, Actonel®) act on bone metabolism by binding and blocking the enzyme farnesyl diphosphate synthase…
9Mechanism of ActionFPPS happens to be downstream in the HMG-CoA reductase pathwayFPPS prevents the formation of two metabolites that are essential for connecting proteins to the cell membrane aka prenylation.Bisphosphonates are specific for bone and inhibiting prenylation affects many proteins found in osteoclastsStatin drugs may do this, but unlike bisphosphonates, they aren’t specific to bone tissue.This alone is not promising..Protein trafficking
10Pathway Second mechanism! In mice, lovastatin was shown to activate the promoter region for bone morphogenetic protein-2This protein is a growth factor that causes osteoblasts to proliferateBone volume increased nearly 50% compared with placeboSimilar effects found with fluvastatin, simvastatin, and mevastatinMundy et al
11Clinical StudiesActual human data is mixed on whether statins reduce the incidence of fractures in humans.None of the studies were RCTs designed to examine the issue.
12Clinical Studies Investigators Design No. of Statin users Fracture siteFindingsMeier et al(15)2001 JAMACase-control1,030AllOR 0.55 ( )Bauer et al(18)(SOF and FIT trial)Cohort598HipOR 0.30 ( )LaCroix et al(19)WHI-OS7,847HR 0.98 (Reid et al(21)(LIPID study)Randomized4,512HR 1.05 ( )Meier(1980s)LIPID study used pravastatin; LaCroix only used statins for <3yrs. Mostly looked at women. LaCroix, AC: Does Statin Use Reduce Risk of Fracture in Postmenopausal Women? Results from the Women's Health Initiative Observational Study (WHI-OS)Meier CR, Schlienger RG, Kraenzlin ME, Schlegel B, Jick H. HMG-CoA reductase inhibitors and the risk of fractures. JAMA 2000;283:3205–10.Bauer DC, Mundy GR, Jamal SA et al. Use of statins and fracture: results of 4 prospective studies and cumulative meta-analysis of observational studies and controlled trials. Arch Intern Med 2004;164:146–52.Reid IR, Hague W, Emberson J et al. Effect of pravastatin on frequency of fracture in the LIPID study: secondary analysis of a randomised controlled trial. Long-term Intervention with Pravastatin in Ischaemic Disease. Lancet
13Why Inconsistent Findings? Doses may need to be higher to affect bone than to lower cholesterol.Non-controlled trialsObesity: more likely to be on cholesterol, but less likely to have a fracture.Test a specific statinDuration of therapy not long enough
14DiscussionConsensus seems to be that statins increase bone density, but not all studies demonstrate this association.The mechanism for statin bone formation and fracture protection have been identified.Statins may be subotimal for treating osteoporosisHowever, this may lead to a drug with similar MOA that can more effectively lead to both bone formation and inhibition of resorption.
15Future Study Prospective randomized controlled trials Exclude confounding variablesStudies looking at specific statinsOften grouped togetherPravastatin has consistently failed to demonstrate fracture protectionSynergism between bisphosphonates and statins
16DementiaDementia is the decline of reasoning, memory, and cognitive functions caused by underlying medical conditions/diseases. This decline eventually impairs the ability to carry out everyday activitiesIt is estimated that more than 5 million people live with some form of dementia in the US.Alzheimer’s is the most common age-related memory loss disease; 30-50% ppl >85 yrs of age.#1 reason for placing elderly in the nursing home6th leading cause of death
17DementiaEvidence that patients using statins may have better cognitive performance compared with those not using statins.Some studies, high cholesterol levels appear to accelerate the formation of beta-amyloid plaques.
18Anti-Amyloidogenic Pathway ApoE: lipoprotein found on the surface of chylomicrons and IDL. Also plays a role in Alzheimer’s disease and cognition.Elevated cholesterol levels in brain neurons may alter membrane functioning and result in the cascade leading to plaque formation and ADThe E4 allele increases the risk of developing AD by 10-30% by age 75.ApoE can signal the production of amyloid-beta.ApoE4 carriers tend to have high cholesterol.apoE is glycoprotein synthesized in liver, CNS, and CSF. E2 protective
19Anti-Amyloidogenic Pathway Statins maay reduce production of beta-amyloid protein.Statins that cross blood-brain barrier may reduce the ability of beta-amyloid to act as a seed for neurofibrillary tangle formation.Hydrophilic vs. lipophilicMemory loss however, is listed as a possible side effect for statins.
20Vascular Dementia The second most common cause of dementia. Caused by atherosclerosis or hardening of the arteries in the brain.Partially blocking blood flow can cause an infarctionAssociated with hypertension and high cholesterolTreating these conditions can slow the progress of vascular dementia.
21Increase or Decrease? Myelin hypothesis Cholesterol is essential in the formation of myelin. The more lipophilic statins are able to cross the blood-brain barrier and decrease the amount of CNS cholesterol below the critical value necessary for the formation of myelinInadequate myelin production results in demyelination of nerve fibers in the CNS, resulting in memory loss
22Studies HERS study (Heart and Estrogen/progestin Replacement Study) 4 yr study, took the Modified Mini-Mental State Examination (3MS) at the end of HERS1037 postmenopausal women with coronary heart diseaseMean age 71 yrs of age
23ResultsOver the 4-year HERS study period, reducing LDL cholesterol levels was associated with improved cognition and an approximately 50% risk reduction of having cognitive impairment.Mean 3MS scores were 93.7 and 92.7 for statin users and non-statin users, respectively (p=0.02). Overall, 6% of women taking statins and 9% of women not taking statins had cognitive impairment (OR 0.67). The association between use of statins and better cognitive function appeared to be independent of lipid levels
24Discussion Cholesterol plays a vital role in brain function. 25% of the total cholesterol in the body is found in the brain, and it is present in abundance both in the synapses and in the myelin sheath. The cholesterol in both of these places has been shown to play an absolutely essential role in signal transport and in growth and repair.Cholesterol also seems to affect β-amyloid plaques.Better designed controlled trials are needed to validate the finding that statin therapy may be protective against cognitive decline in older patients
25Statins for CancerAccording to the National Cancer Institute, taking a statin may help protect you against some forms of cancer.Breast, Colorectal, Liver, Lung, Ovarian and Prostate cancer studied so far.Studies show statins may be useful in both prevention and treatment of cancer.
26In Vitro StudiesBreast Cancer – Many studies demonstrated in vitro inhibition of breast cancer cells by statins and synergistic effects with other agents as well, an example would be Campbell et al’s Breast cancer growth prevention by statins in Cancer Res., 2006 Sep 1;66(17):Colon Cancer – There are many reports of statins inducing apoptosis in human colon cancer cells and preventing its carcinogenesis. Furthermore, synergism with cox-2 inhibitors, gamma tocotrienol, chemotherapy, TRAIL, butyrate has been demonstrated in vitro and studies showing statins ability to reduce inflammation in colon tissue raises the hope that it may be useful in inflammatory bowel diseases as a chemopreventative against colon cancer.Ovarian Cancer – There is research to establish that statins induces cell death in ovarian cancer. What is interesting is the existence of possible differential effect between lipophilic (eg simvastatin) v. hydrophilic (e.g. pravastatin) statins (Kato et al, J Cell Mol Med May 11)TNF-related apoptosis-inducing ligand
28Clinical EvidenceUnlike the in vitro, there is not as much clinical evidence in humans.There was actually concern in 2000s that statin use may increase cancerDispelled after the analysis of large studiesStill the possibility of carcinogenic propertiesIn humans, studies use statins as either adjuvants to treat cancer or to prevent cancer.Journal of the American College of Cardiology
29Evidence for Risk Reduction Breast Cancer - In a review by Kochhar and team of 40,421 females, statin use was associated with a 51% risk reduction of breast cancer after controlling for age, smoking, alcohol use, and diabetes (J Clin Oncology 23: 7S, 2005).In the same vein, Kwan et al. observed that breast cancer patients who took statins after diagnosis were less likely to have had recurrences than were patients who did not take stains (Breast Ca Res Treat Jun;109(3):573-9). In 2008, Kumar et al. made the interesting observation that women on statins who develop breast cancers develop less aggressive cancers which are of lower grade and less invasive (Cancer Epidemiol Biomarkers Prev May;17(5): ).Journal of cli
30Evidence for Risk Reduction Lung Cancer – Use of statins for more than 6 months reduced the risk for lung cancer by 55%, according to the results of a large scale case-control study involving almost a half million patients, published in the May 2007 issue of Chest. (Chest, 2007;131: ).Even more intriguing was that longer duration of statin use was associated with enhanced risk reduction, rising from 55% to 77% for those who have been on statins for 4 years or more.
31Evidence for adjuvant treatment Potentiates sorafenib (Nexavar®) cytotoxicity (Cancer Lett Feb 1;288(1):57-67)Synergizes with, the cox-2 (Celebrex) inhibitor, against colon cancer (Int J Oncol Nov;35(5): ; also Int J Cancer Feb 15;126(4):852-63)Enhances the cytotoxic and apoptotic effects of doxorubicin chemotherapy against human colon cancer cells and in murine tumor models (Oncol Rep May;19(5): )Synergizes with zoledronic acid (Zometa, a bisphosphonate) against myeloma (Anticancer Drugs Jul;17(6):621-9)Kidney cancer
32DiscussionA serious look should be taken at statins for primary/secondary cancer prevention.As long as patient has no other contraindications, it is reasonable to consider statin therapy in specific clinical trials.Not all statins are equal and some may work better than others.Although most of the available evidence suggests a possible beneficial effect of statins on cancer, further study is needed with better designed trials
33Other areas of potential Auto-immune conditionsOrgan transplantationPolycystic ovarian syndrome (PCOS)ArrhythmiasChronic obstructive pulmonary disease (COPD)SepsisContrast-induced nephropathyCataractAge-related macular degenerationSub-arachnoid hemorrhageAsthmaThromboembolism
34ConclusionStatins have great untapped potential in many disease states.This potential should be looked at closely but also skeptically.Beneficial for drug companies to add as many indications as possibleClosely look at the data presented and evaluate with an open mindUnfortunately with many statins coming off patent, there isn’t much incentive for companies to fund other studies.
35ReferencesLaCroix, AC: Does Statin Use Reduce Risk of Fracture in Postmenopausal Women? Results from the Women's Health Initiative Observational Study (WHI-OS)Meier CR, Schlienger RG, Kraenzlin ME, Schlegel B, Jick H. HMG-CoA reductase inhibitors and the risk of fractures. JAMA 2000;283:3205–10.Bauer DC, Mundy GR, Jamal SA et al. Use of statins and fracture: results of 4 prospective studies and cumulative meta-analysis of observational studies and controlled trials. Arch Intern Med 2004;164:146–52.Reid IR, Hague W, Emberson J et al. Effect of pravastatin on frequency of fracture in the LIPID study: secondary analysis of a randomised controlled trial. Long-term Intervention with Pravastatin in Ischaemic Disease. LancetHulley S, Grady D, Bush T et al. Randomized Trial of Estrogen Plus Progestin for Secondary Prevention of Coronary Heart Disease in Postmenopausal Women. JAMA. 1998;280(7):Campbell et al’s Breast cancer growth prevention by statins in Cancer Res., 2006 Sep 1;66(17):Kumar et al Breast Cancer Res Treat Jun;109(3):573-9Proc Natl Acad Sci U S A 1999;96:7797–802Kato et al, J Cell Mol Med May 11NOF Clinician’s Guide to Prevention and Treatment of Osteoporosis.The Scandinavian Simvastatin Survival Study Group. Randomized trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet 1994;344: