Nelfinavir, sold under the brand name Viracept, is an
antiretroviral medication
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do n ...
used in the treatment of
HIV/AIDS
Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...
. Nelfinavir belongs to the class of drugs known as
protease inhibitors
Protease inhibitors (PIs) are medications that act by interfering with enzymes that cleave proteins. Some of the most well known are antiviral drugs widely used to treat HIV/AIDS and hepatitis C. These protease inhibitors prevent viral replicat ...
(PIs) and like other PIs is almost always used in combination with other antiretroviral drugs.
Nelfinavir is an orally bioavailable human immunodeficiency virus
HIV-1 protease
HIV-1 protease (PR) is a retroviral aspartyl protease (retropepsin), an enzyme involved with peptide bond hydrolysis in retroviruses, that is essential for the life-cycle of HIV, the retrovirus that causes AIDS. HIV protease cleaves newly synthes ...
inhibitor (K
i = 2 nM) and is widely prescribed in combination with
HIV
The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...
reverse transcriptase inhibitors for the treatment of HIV infection.
It was patented in 1992 and approved for medical use in 1997.
Toxicity
Common (>1%) side effects include
insulin resistance
Insulin resistance (IR) is a pathological condition in which cell (biology), cells fail to respond normally to the hormone insulin.
Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood gluco ...
,
hyperglycemia
Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...
and
lipodystrophy
Lipodystrophy syndromes are a group of genetic or acquired disorders in which the body is unable to produce and maintain healthy fat tissue. The medical condition is characterized by abnormal or degenerative conditions of the body's adipose tissue. ...
.
[
Nelfinavir can produce a range of adverse side effects. Flatulence, ]diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
, or abdominal pain are common (i.e. experienced by more than one in one hundred patients). Fatigue, urination, rash
A rash is a change of the human skin which affects its color, appearance, or texture.
A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cr ...
, mouth ulcer
A mouth ulcer (aphtha) is an ulcer that occurs on the mucous membrane of the oral cavity. Mouth ulcers are very common, occurring in association with many diseases and by many different mechanisms, but usually there is no serious underlying cause ...
s, or hepatitis
Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pa ...
are less frequent effects (experienced by one in one thousand to one in one hundred patients). Nephrolithiasis
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
, arthralgia
Arthralgia (from Greek ''arthro-'', joint + ''-algos'', pain) literally means ''joint pain''. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication.
According to MeSH, ...
, leukopenia
Leukopenia () is a decrease in the number of leukocytes (WBC). Found in the blood, they are the white blood cells, and are the body's primary defense against an infection. Thus the condition of leukopenia places individuals at increased risk of inf ...
, pancreatitis
Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic pancr ...
, or allergic
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
reactions may occur, but are rare (less than one in one thousand patients) .
Other bioactivity
Antiviral
Nelfinavir inhibits maturation and export of the herpes simplex 1 virus and the Kaposi's sarcoma virus
Kaposi's sarcoma-associated herpesvirus (KSHV) is the ninth known human herpesvirus; its formal name according to the International Committee on Taxonomy of Viruses (ICTV) is ''Human gammaherpesvirus 8'', or HHV-8 in short. Like other herpesvirus ...
.
Anti-virulence activity
Nelfinavir and simple derivatives have been found to inhibit the production of the virulence factor
Virulence factors (preferably known as pathogenicity factors or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following ...
streptolysin S
Streptolysins are two hemolytic exotoxins from ''Streptococcus''. Types include streptolysin O (SLO; ''slo''), which is oxygen-labile, and streptolysin S (SLS; ''sagA''), which is oxygen-stable.
SLO is part of the thiol-activated cytolysin fami ...
, a cytolysin
Cytolysin refers to the substance secreted by microorganisms, plants or animals that is specifically toxic to individual cells, in many cases causing their dissolution through lysis. Cytolysins that have a specific action for certain cells are n ...
produced by the human pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
''Streptococcus pyogenes
''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus ''Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They are ...
''. Nelfinavir and these related molecules did not exhibit detectable antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
activity, but did also inhibit the production of other biologically active molecules, including plantazolicin
Plantazolicin (PZN) is a natural antibiotic produced by the gram-positive soil bacterium ''Bacillus velezensis'' FZB42 (previously ''Bacillus amyloliquefaciens'' FZB42). PZN has specifically been identified as a selective bactericidal agent ac ...
(antibiotic), listeriolysin S (cytolysin), and clostridiolysin S (cytolysin), by other bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
.
Interactions
Nelfinavir's interaction profile is similar to that of other protease inhibitors
Protease inhibitors (PIs) are medications that act by interfering with enzymes that cleave proteins. Some of the most well known are antiviral drugs widely used to treat HIV/AIDS and hepatitis C. These protease inhibitors prevent viral replicat ...
. Most interactions occur at the level of the Cytochrome P450
Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...
isozymes 3A4 and CYP2C19
Cytochrome P450 2C19 (abbreviated CYP2C19) is an enzyme protein. It is a member of the CYP2C subfamily of the cytochrome P450 mixed-function oxidase system. This subfamily includes enzymes that catalyze metabolism of xenobiotics, including some pr ...
, by which nelfinavir is metabolised.
Pharmacology
Nelfinavir should be taken with food. Taking the drug with food decreases the risk of diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
as a side effect.
Mechanism of action
Nelfinavir is a protease inhibitor: it inhibits HIV-1
The subtypes of HIV include two major types, HIV type 1 (HIV-1) and HIV type 2 (HIV-2). HIV-1 is related to viruses found in chimpanzees and gorillas living in western Africa, while HIV-2 viruses are related to viruses found in the sooty mangabey, ...
and HIV-2 proteases. HIV protease is an aspartate protease
Aspartic proteases are a catalytic type of protease enzymes that use an activated water molecule bound to one or more aspartate residues for catalysis of their peptide substrates. In general, they have two highly conserved aspartates in the acti ...
which splits viral protein molecules into smaller fragments, and it is vital to both the replication of the virus within the cell, and also to the release of mature viral particles from an infected cell. Nelfinavir is a competitive inhibitor (2 nM) which is designed to bind tightly and is not cleaved due to the presence of a hydroxyl group as opposed to a keto group in the middle amino acid residue mimic, which would be otherwise S-phenylcysteine. All protease inhibitors bind to the protease, the precise mode of binding determines how the molecule inhibits the protease. The way Nelfinavir binds the enzyme may be sufficiently unique to reduce cross-resistance between it and other PIs. Also, not all PIs inhibit both HIV-1 and HIV-2 proteases.
History
Nelfinavir was developed by Agouron Pharmaceuticals as part of a joint venture with Eli Lilly and Company. Agouron Pharmaceuticals was acquired by Warner Lambert in 1999 and is now a subsidiary of Pfizer. It is marketed in Europe by Hoffman-La Roche
F. Hoffmann-La Roche AG, commonly known as Roche, is a Swiss multinational healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, Roche Holding AG, has shares listed on the SIX S ...
and elsewhere by ViiV Healthcare
ViiV Healthcare ( ) is a pharmaceutical company specializing in the development of therapies for HIV infection that was created as a joint venture by Pfizer and GlaxoSmithKline in November 2009 with both companies transferring their HIV assets ...
.
The U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) approved it for therapeutic use on March 14, 1997, making it the twelfth approved antiretroviral. The initial product launched proved to be the largest "biotech launch" in the history of the pharmaceutical industry, achieving first full year sales exceeding $US335M. Agouron's patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...
on the drug expired in 2014.
On the 6 June 2007, both the Medicines and Healthcare products Regulatory Agency
The Medicines and Healthcare products Regulatory Agency (MHRA) is an executive agency of the Department of Health and Social Care in the United Kingdom which is responsible for ensuring that medicines and medical devices work and are acceptably ...
and 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 ...
put out an alert requesting the recall of any of the drug in circulation, because some batches may have been contaminated with potentially cancer-causing chemicals.
Research
Since 2009, nelfinavir has been under investigation for potential use as an anti-cancer agent. When applied to cancer cells in culture (in vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...
), it can inhibit the growth of a variety of cancer types and can trigger cell death (apoptosis
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...
). When Nelfinavir was given to laboratory mice with tumors of the prostate or of the brain, it could suppress tumor growth in these animals. At the cellular level, nelfinavir exerts multiple effects to inhibit cancer growth; the two main ones appear to be inhibition of the Akt/PKB signaling pathway The Akt signaling pathway or PI3K-Akt signaling pathway is a signal transduction pathway that promotes survival and growth in response to extracellular signals. Key proteins involved are PI3K (phosphatidylinositol 3-kinase) and Akt (protein kinase B ...
and activation of endoplasmic reticulum
The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...
stress with subsequent unfolded protein response
The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum (ER) stress. It has been found to be conserved between all mammalian species, as well as yeast and worm organisms.
The UPR is activated in resp ...
.
In the United States, about three dozen clinical trials are being conducted (or have been completed) in order to determine whether nelfinavir is effective as a cancer therapeutic agent in humans. In some of these trials, nelfinavir is used alone in monotherapy fashion, whereas in others it is combined with other modes of cancer therapy, such as well-established chemotherapeutic agents
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothera ...
or radiation therapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...
.
, nelfinavir is being studied as a radiosensitizing agent
A radiosensitizer is an agent that makes tumor cells more sensitive to radiation therapy. It is sometimes also known as a radiation sensitizer or radio-enhancer.
Mechanism of action
Conventional chemotherapeutics are currently being used in con ...
as part of treatment of advanced cervical cancer.
References
Further reading
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External links
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