COX-2 inhibitors are a type of
nonsteroidal anti-inflammatory drug
Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...
(NSAID) that directly targets cyclooxygenase-2,
COX-2
Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (The HUGO official symbol is PTGS2; HGNC ID, HGNC:9605), also known as cyclooxygenase-2 or COX-2, is an enzyme that in humans is encoded by the ''PTGS2'' gene. ...
, an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
responsible for
inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
and
pain
Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
. Targeting selectivity for COX-2 reduces the risk of
peptic ulcer
Peptic ulcer disease (PUD) is a break in the inner lining of the stomach, the first part of the small intestine, or sometimes the lower esophagus. An ulcer in the stomach is called a gastric ulcer, while one in the first part of the intestines i ...
ation and is the main feature of
celecoxib
Celecoxib, sold under the brand name Celebrex among others, is a COX-2 inhibitor and nonsteroidal anti-inflammatory drug (NSAID). It is used to treat the pain and inflammation in osteoarthritis, acute pain in adults, rheumatoid arthritis, ankyl ...
,
rofecoxib
Rofecoxib is a COX-2 inhibitor, COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenor ...
, and other members of this drug class.
After several COX-2-inhibiting drugs were approved for marketing, data from clinical trials revealed that COX-2 inhibitors caused a significant increase in heart attacks and strokes, with some drugs in the class having worse risks than others. Rofecoxib (sold under the brand name
Vioxx
Rofecoxib is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenorrhea. Rofecoxib ...
) was taken off the market in 2004 because of these concerns, while celecoxib (sold under the brand name
Celebrex
Celecoxib, sold under the brand name Celebrex among others, is a COX-2 inhibitor and nonsteroidal anti-inflammatory drug (NSAID). It is used to treat the pain and inflammation in osteoarthritis, acute pain in adults, rheumatoid arthritis, ankyl ...
) and traditional NSAIDs received
boxed warning
In the United States, a boxed warning (sometimes "black box warning", colloquially) is a type of warning that appears on the package insert for certain prescription drugs, so called because
the U.S. Food and Drug Administration specifies that it ...
s on their labels. Many COX-2-specific inhibitors have been removed from the US market. As of December 2011, only Celebrex (generic name of celecoxib) is still available for purchase in the United States. In the European Union, celecoxib,
parecoxib
Parecoxib, sold under the brand name Dynastat among others, is a water-soluble and injectable prodrug of valdecoxib. Parecoxib is a COX2 selective inhibitor. It is injectable. It is approved through much of Europe for short term perioperative p ...
and
etoricoxib
Etoricoxib, sold under the trade name Arcoxia, is a selective COX-2 inhibitor from McOLSON Research Laboratories. Currently it is approved in more than 80 countries worldwide but not in the US, where the Food and Drug Administration (FDA) has r ...
has been approved for use by the
European Medicines Agency
The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Euro ...
.
Paracetamol
Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol.
At a standard dose, paracetamol only slightly decreases body temperature; it is inferior ...
(acetaminophen) is also a COX-2 inhibitor almost exclusively within the brain, and only minimally in the rest of the body although its not considered an NSAID since it has only minor anti-inflammatory activity.
Medical uses
Some COX-2 inhibitors are used in a single dose to treat pain after surgery.
In this role
Etoricoxib
Etoricoxib, sold under the trade name Arcoxia, is a selective COX-2 inhibitor from McOLSON Research Laboratories. Currently it is approved in more than 80 countries worldwide but not in the US, where the Food and Drug Administration (FDA) has r ...
appears as good as, if not better than, other pain medications and,
Celecoxib
Celecoxib, sold under the brand name Celebrex among others, is a COX-2 inhibitor and nonsteroidal anti-inflammatory drug (NSAID). It is used to treat the pain and inflammation in osteoarthritis, acute pain in adults, rheumatoid arthritis, ankyl ...
appears to be about as useful as
ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arte ...
.
NSAIDs are often used in treatment of acute
gout
Gout ( ) is a form of inflammatory arthritis characterized by recurrent attacks of a red, tender, hot and swollen joint, caused by deposition of monosodium urate monohydrate crystals. Pain typically comes on rapidly, reaching maximal intensit ...
attacks. COX-2 inhibitors appear to work as well as nonselective NSAIDS, such as Aspirin.
They have not been compared to other treatment options such as colchicine or glucocorticoids.
Cancer
COX-2 appears to be related to cancers and abnormal growths in the intestinal tract. Overexpression of COX-2 produces excess prostaglandins which have been shown to increase the possibility of colorectal cancer. COX inhibitors have been shown to reduce the occurrence of cancers and pre-cancerous growths. The National Cancer Institute has done some studies on COX-2 and cancer.
. COX-2 can act as an anti-tumor enzyme, but only in specific cases. The FDA has approved Celebrex for treatment of
familial adenomatous polyposis
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited condition in which numerous Adenomatous polyps, adenomatous Colorectal polyp, polyps form mainly in the epithelium of the colon (anatomy), large intestine. While these polyps s ...
(FAP). COX-2 inhibitors are currently being studied in
breast cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
and appear to be beneficial.
Neuropsychiatric disorders
COX-2 inhibitors have been found to be effective in suppressing inflammatory neurodegenerative pathways, with beneficial results in animal studies for
major depressive disorder
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...
, as well as
schizophrenia
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
,
bipolar disorder
Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
, and
obsessive-compulsive disorder.
These need to be confirmed in human clinical trials.
Current studies support an association of disorders such as these with chronic inflammation, which appears to decrease with the use of COX-2 inhibitors.
Other targets
The inhibition of COX-2 is paramount for the
anti-inflammatory
Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as o ...
and
analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
function of the selective COX-2 inhibitor celecoxib. However, with regard to this drug's promise for the therapy of advanced cancers, it is unclear whether the inhibition of COX-2 plays a dominant role, and this has become a controversial and intensely researched issue. In recent years, several additional intracellular components (besides COX-2) were discovered that appear to be important for mediating the anticancer effects of celecoxib in the absence of COX-2. Moreover, a recent study with various malignant tumor cells showed that celecoxib could inhibit the growth of these cells, even though some of these cancer cells didn't even contain COX-2.
Additional support for the idea that other targets besides COX-2 are important for celecoxib's anticancer effects has come from studies with chemically modified versions of celecoxib. Several dozen
analogs of celecoxib were generated with small alterations in their
chemical structure
A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of at ...
s.
Some of these analogs retained COX-2 inhibitory activity, whereas many others didn't. However, when the ability of all these compounds to kill tumor cells in
cell culture
Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This te ...
was investigated, it turned out that the antitumor potency did not at all depend on whether or not the respective compound could inhibit COX-2, showing that inhibition of COX-2 was not required for the anticancer effects.
One of these compounds, 2,5-dimethyl-celecoxib, which entirely lacks the ability to inhibit COX-2, actually turned out to display stronger anticancer activity than celecoxib itself and this anticancer effect could also be verified in highly drug-resistant tumor cells
and in various animal tumor models.
Adverse effects
Analysis of clinical trial data revealed that there was a significant increase in the rate of vascular events with COX-2 inhibitors compared with placebo; "vascular events" are non-fatal
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
(MI) or heart attack, non-fatal
stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
, and death from a vascular event such as MI or stroke.
These results led Merck to voluntarily withdraw (rofecoxib) from the market in September 2004 and to regulatory authorities imposing a boxed warning on the label of celecoxib.
Traditional NSAIDs were also found to have cardiovascular risks, leading to similar boxed warnings.
The cause of the cardiovascular problems became, and remains, a subject of intensive research.
As of 2012 results have been converging on the hypothesis that the adverse cardiovascular effects are most likely due to inhibition of COX-2 in
blood vessels
The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...
, which leads to a decrease in the production of
prostacyclin
Prostacyclin (also called prostaglandin I2 or PGI2) is a prostaglandin member of the eicosanoid family of lipid molecules. It inhibits platelet activation and is also an effective vasodilator.
When used as a drug, it is also known as epoprosteno ...
in them. Prostacyclin usually prevents
platelet aggregation
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...
and
vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessel ...
, so its inhibition can lead to excess clot formation and higher blood pressure.
Research
Research history
The COX-2 enzyme was discovered in 1988 by Daniel Simmons, a
Brigham Young University
Brigham Young University (BYU, sometimes referred to colloquially as The Y) is a private research university in Provo, Utah. It was founded in 1875 by religious leader Brigham Young and is sponsored by the Church of Jesus Christ of Latter-day ...
researcher.
The mouse COX-2 gene was cloned by UCLA scientist Harvey Herschman, a finding published in 1991.
The basic research leading to the discovery of COX-2 inhibitors has been the subject of at least two lawsuits. Brigham Young University has sued
Pfizer
Pfizer Inc. ( ) is an American multinational pharmaceutical and biotechnology corporation headquartered on 42nd Street in Manhattan, New York City. The company was established in 1849 in New York by two German entrepreneurs, Charles Pfizer ...
, alleging breach of contract from relations BYU had with the company at the time of Simmons's work.
A settlement was reached in April 2012 in which Pfizer agreed to pay $450 million.
The other litigation is based on United States Pat. No. 6,048,850 owned by
University of Rochester
The University of Rochester (U of R, UR, or U of Rochester) is a private research university in Rochester, New York. The university grants undergraduate and graduate degrees, including doctoral and professional degrees.
The University of Roc ...
, which claimed a method to treat pain without causing gastro-intestinal distress by selectively inhibiting COX-2. When the patent issued, the university sued Searle (later Pfizer) in a case called, ''University of Rochester v. G.D. Searle & Co.'', 358 F.3d 916 (Fed. Cir. 2004). The court ruled in favor of Searle in 2004, holding in essence that the university had claimed a method requiring, yet provided no written description of, a compound that could inhibit COX-2 and therefore the patent was invalid.
In the course of the search for a specific
inhibitor
Inhibitor or inhibition may refer to:
In biology
* Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity
* Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...
of the negative effects of
prostaglandin
The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...
s that spared the positive effects, it was discovered that prostaglandins could indeed be separated into two general classes that could loosely be regarded as "good prostaglandins" and "bad prostaglandins", according to the structure of a particular
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
involved in their
biosynthesis
Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. ...
,
cyclooxygenase
Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as prosta ...
.
Prostaglandins whose synthesis involves the
cyclooxygenase-I enzyme, or COX-1, are responsible for maintenance and protection of the
gastrointestinal tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...
, while prostaglandins whose synthesis involves the cyclooxygenase-II enzyme, or COX-2, are responsible for inflammation and pain.
The existing nonsteroidal anti-inflammatory drugs (
NSAID
Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...
s) differ in their relative specificities for COX-2 and COX-1; while aspirin and ibuprofen inhibit COX-2 and COX-1 enzymes, other NSAIDs appear to have partial COX-2 specificity, particularly
meloxicam
Meloxicam, sold under the brand name Mobic among others, is a nonsteroidal anti-inflammatory medication (NSAID) used to treat pain and inflammation in rheumatic diseases and osteoarthritis. It is used by mouth or by intravenous, injection into a ...
(
Mobic). Aspirin is ≈170-fold more potent in inhibiting COX-1 than COX-2. Studies of meloxicam 7.5 mg per day for 23 days find a level of gastric injury similar to that of a
placebo
A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures.
In general ...
, and for meloxicam 15 mg per day a level of injury lower than that of other NSAIDs; however, in clinical practice meloxicam can still cause some
ulcer
An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...
complications.
Valdecoxib and rofecoxib were about 300 times more potent at inhibiting COX-2 than COX-1, but too toxic for the heart, suggesting the possibility of relief from pain and inflammation without gastrointestinal irritation, and promising to be a boon for those who had previously experienced adverse effects or had
comorbidities
In medicine, comorbidity - from Latin morbus ("sickness"), co ("together"), -ity (as if - several sicknesses together) - is the presence of one or more additional conditions often co-occurring (that is, concomitant or concurrent) with a primary c ...
that could lead to such complications. Celecoxib is approximately 30 times more potent at inhibiting COX-2 than COX-1, with etoricoxib being 106 times more potent.
Research fraud
Between 1996 and 2009,
Scott Reuben
Scott S. Reuben (born 1958) is an American anesthesiologist who falsified data heralding the benefits of the Pfizer pain medication Celebrex while downplaying its negative side effects.
He was Professor of Anesthesiology and Pain Medicine at T ...
purportedly conducted clinical research on the use of COX-2 inhibitors, often in combination with
gabapentin
Gabapentin, sold under the brand name Neurontin among others, is an anticonvulsant medication primarily used to treat partial seizures and neuropathic pain. It is a first-line medication for the treatment of neuropathic pain caused by diabet ...
or
pregabalin
Pregabalin, sold under the brand name Lyrica among others, is an anticonvulsant, analgesic and anxiolytic medication used to treat epilepsy, neuropathic pain, fibromyalgia, restless leg syndrome, opioid withdrawal and generalized anxiety disord ...
, for the prevention and treatment of
post-surgical pain
Perioperative medicine is the medical care of patients from the time of contemplation of surgery through the operative period to full recovery. Perioperative care may be provided by an anesthesiologist, Intensivist, an internal medicine generali ...
, research which was found in 2009 to have been faked. Reuben pleaded guilty, paid fines and served six months in jail, and lost his medical license.
A 2009 review of
meta-articles used in
evidence-based medicine
Evidence-based medicine (EBM) is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients". The aim of EBM is to integrate the experience of the clinician, the values of t ...
found that while some reviews were no longer valid when the Reuben studies were removed, the conclusions in the majority of them remained unchanged.
The review found that the key Reuben claims that needed to be re-examined were "the absence of detrimental effects of coxibs on bone healing after spine surgery, the beneficial long-term outcome after preemptive administration of coxibs including an allegedly decreased incidence of chronic pain after surgery, and the analgesic efficacy of
ketorolac
Ketorolac, sold under the brand names Toradol, and Biorolac among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain. Specifically it is recommended for moderate to severe pain. Recommended duration of treatment is less ...
or
clonidine
Clonidine, sold under the brand name Catapres among others, is an α2-adrenergic agonist medication used to treat high blood pressure, ADHD, drug withdrawal ( alcohol, opioids, or nicotine), menopausal flushing, diarrhea, spasticity, and c ...
when added to
local anesthetics
A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...
for
intravenous regional anesthesia
Intravenous regional anesthesia (IVRA) or Bier's block anesthesia is an anesthetic technique on the body's extremities where a local anesthetic is injected intravenously and isolated from circulation in a target area. The technique usually involv ...
."
Early COX-2-inhibiting drugs
Celebrex (and other brand names for celecoxib) was introduced in 1999 and rapidly became the most frequently prescribed new drug in the United States. By October 2000, its US sales exceeded 100 million prescriptions per year for $3 billion, and was still rising. Sales of Celebrex alone reached $3.1 billion in 2001. A
Spanish
Spanish might refer to:
* Items from or related to Spain:
**Spaniards are a nation and ethnic group indigenous to Spain
**Spanish language, spoken in Spain and many Latin American countries
**Spanish cuisine
Other places
* Spanish, Ontario, Cana ...
study found that between January 2000 and June 2001, 7% of NSAID prescriptions and 29% of NSAID expenditures were for COX-2 inhibitors. Over the period of the study, COX-2 inhibitors rose from 10.03% of total NSAIDs prescribed by specialty physicians to 29.79%, and from 1.52% to 10.78% of NSAIDs prescribed by
primary care physician
A primary care physician (PCP) is a physician who provides both the first contact for a person with an undiagnosed health concern as well as continuing care of varied medical conditions, not limited by cause, organ system, or diagnosis. The term ...
s (98.23% of NSAIDs and 94.61% of COX-2 inhibitors were prescribed by primary care physicians). For specialty physicians, rofecoxib and celecoxib were third and fifth most frequently prescribed NSAIDs but first and second in cost, respectively; for primary-care physicians they were ninth and twelfth most frequently prescribed NSAIDs and first and fourth in cost.
Sales and marketing efforts were supported by two large trials, the Celecoxib Long-term Arthritis Safety Study (CLASS) in ''
JAMA
''The Journal of the American Medical Association'' (''JAMA'') is a peer-reviewed medical journal published 48 times a year by the American Medical Association. It publishes original research, reviews, and editorials covering all aspects of biom ...
'', and the Vioxx Gastrointestinal Outcomes Research (VIGOR). The VIGOR trial was later proven to have been based on faulty data, and Vioxx was eventually withdrawn from the market.
VIGOR study and publishing controversy
The VIGOR (Vioxx Gastrointestinal Outcomes Research) trial, "which was the making of Merck's drug rofecoxib (Vioxx),"
was at the center of a dispute about the ethics of medical journals. In the VIGOR trial, over 8,000 patients were randomized to receive either naproxen or rofecoxib (Vioxx). Both studies concluded that COX-2 specific NSAIDs were associated with significantly fewer adverse gastrointestinal effects. In the CLASS trial which compared Celebrex 800 mg/day to
ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arte ...
2400 mg/day and
diclofenac
Diclofenac, sold under the brand name Voltaren, among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth or rectally in a suppository, used by injection, or ...
150 mg/day for
osteoarthritis
Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...
or
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
for six months, Celebrex was associated with significantly fewer upper gastrointestinal complications (0.44% vs. 1.27%, ''p'' = 0.04), with no significant difference in incidence of
cardiovascular
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
events in patients not taking aspirin for cardiovascular
prophylaxis
Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...
.
The VIGOR trial results were published in 2000 in the ''New England Journal of Medicine''
Bombardier and his research team claimed that there was "an increase in myocardial infarction in the patients given rofecoxib (0.4%) compared with those given naproxen (0.1%)" and "patients given naproxen experienced 121 side effects compared with 56 in the patients taking rofecoxib," a "marvellous result for Merck" which "contributed to huge sales of rofecoxib."
Merck's scientists incorrectly interpreted the finding as a protective effect of naproxen, telling the FDA that the difference in heart attacks "is primarily due to" this protective effect.
In September 2001, the United States
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) sent a warning letter to the CEO of Merck, stating, "Your promotional campaign discounts the fact that in the VIGOR study, patients on Vioxx were observed to have a four to five fold increase in myocardial infarctions (MIs) compared to patients on the comparator nonsteroidal anti-inflammatory drug (NSAID), Naprosyn (naproxen)."
This led to the introduction, in April 2002, of warnings on Vioxx labeling concerning the increased risk of cardiovascular events (heart attack and stroke). By 2005 ''The New England Journal of Medicine'' published an editorial accusing the Bombardier et al. of deliberately withholding data.
Claire Bombardier, a University of Toronto rheumatologist, had claimed that the VIGOR trial showed that
Vioxx
Rofecoxib is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenorrhea. Rofecoxib ...
50 mg/day had benefits over
naproxen
Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulati ...
for rheumatoid arthritis, specifically that Vioxx reduced the risk of symptomatic ulcers and clinical upper gastrointestinal events (
perforations
A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes collectively are called a ''perforation''. The process of creating perforations is called perfor ...
,
obstructions and
bleeding
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
) by 54%, to 1.4% from 3%, the risk of complicated
upper gastrointestinal events (complicated perforations, obstructions and bleeding in the
upper gastrointestinal tract) by 57%, and the risk of bleeding from anywhere in the gastrointestinal tract by 62%. An enormous
marketing
Marketing is the process of exploring, creating, and delivering value to meet the needs of a target market in terms of goods and services; potentially including selection of a target audience; selection of certain attributes or themes to emph ...
effort capitalized on these publications; Vioxx was the most heavily advertised prescription drug in 2000, and Celebrex the seventh, according to
IMS Health
IMS Health was an American company that provided information, services and technology for the healthcare industry. IMS stood for Intercontinental Medical Statistics. It was the largest vendor of U.S. physician prescribing data. IMS Health was fou ...
.
Neuroblastomas
Small tumors of the
sympathetic nervous system
The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of th ...
(
neuroblastoma
Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands but can also develop in the neck, chest, abdomen, or spine. Symptoms may include bone pain, a lump in the ...
) appear to have abnormal levels of COX-2 expressed.
These studies report that overexpression of the COX-2 enzyme has an adverse effect on the tumor suppressor,
p53
p53, also known as Tumor protein P53, cellular tumor antigen p53 (UniProt name), or transformation-related protein 53 (TRP53) is a regulatory protein that is often mutated in human cancers. The p53 proteins (originally thought to be, and often s ...
. p53 is an apoptosis
transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
normally found in the
cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells (intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...
. When
cellular DNA is damaged beyond repair, p53 is transported to the
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
where it promotes p53 mediated apoptosis.
Two of the metabolites of COX-2,
prostaglandin A2 (PGA2) and A1 (PGA1), when present in high quantities, bind to p53 in the cytosol and inhibit its ability to cross into the nucleus. This essentially sequesters p53 in the cytosol and prevents apoptosis.
Coxibs such as Celebrex (celecoxib), by selectively inhibiting the overexpressed COX-2, allow p53 to work properly. Functional p53 allows DNA damaged neuroblastoma cells to commit
suicide
Suicide is the act of intentionally causing one's own death. Mental disorders (including depression, bipolar disorder, schizophrenia, personality disorders, anxiety disorders), physical disorders (such as chronic fatigue syndrome), and s ...
through apoptosis, halting tumor growth.
COX-2 up-regulation has also been linked to the
phosphorylation
In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, wh ...
and activation of the E3
ubiquitin ligase
A ubiquitin ligase (also called an E3 ubiquitin ligase) is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin ...
HDM2, a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that mediates p53 ligation and tagged destruction, through
ubiquitination
Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 1980s. Fo ...
.
The mechanism for this neuroblastoma HDM2 hyperactivity is unknown. Studies have shown that COX-2 inhibitors block the phosphorylation of HDM2 preventing its activation. In vitro, the use of COX-2 inhibitors lowers the level of active HDM2 found in neuroblastoma cells. The exact process of how COX-2 inhibitors block HDM2 phosphorylation is unknown, but this mediated reduction in active HDM2 concentration level restores the cellular p53 levels. After treatment with a COX-2 inhibitor, the restored p53 function allows DNA damaged neuroblastoma cells to commit suicide through apoptosis reducing the size of growth of the tumor.
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{{Prostanoids
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Experimental medical treatments
Nonsteroidal anti-inflammatory drugs