Nelfinavir

Nelfinavir (Viracept®) is an antiretroviral drug used in the treatment of the human immunodeficiency virus (HIV). Nelfinavir belongs to the class of drugs known as protease inhibitors (PIs) and like other PIs is generally used in combination with other antiretroviral drugs. Nelfinavir is presented as the mesilate (mesylate) ester prodrug.

Nelfinavir mesylate (Viracept, formally AG1343) is a potent and orally bioavailable human immunodeficiency virus HIV-1 protease inhibitor (Ki=2nM) and is being widely prescribed in combination with HIV reverse transcriptase inhibitors for the treatment of HIV infection. Nelfinavir mesylate contains the Castor oil derivative Cremophor EL.^[1]

Additional recommended knowledge

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History

Nelfinavir was developed by Agouron Pharmaceuticals as part of a joint venture with Japan Tobacco. 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. The Food and Drug Administration approved it for therapeutic use on March 14, 1997, making it the twelfth approved antiretroviral. It never secured a large market share and newer PIs are generally preferred for first-line therapy.

Agouron's patent on the drug will expire in 2014.

On the 6th June 2007 both the Medicines and Healthcare products Regulatory Agency and the European Medicines Agency^[2] put out an alert requesting the recall of any of the drug in circulation because of fears that batches of the therapy may have been contaminated with potentially cancer-causing chemicals

Nelfinavir is currently under investigation for potential repositioning as an anti-cancer agent. When applied to cancer cells in culture, both apoptotic and non-apoptotic cell death is observed. However, there is no evidence that Nelfinavir actually targets cancer cells within a native tumor in a person. ^[3]

Pharmacology

Nelfinavir should be taken with food. The bioavailability of Nelfinavir is increased 2.5 to 5 times when taken with food.^{[citation needed]} Taking the drug with food also decreases the risk of diarrhea as a side effect.

Mode of action

Nelfinavir is a protease inhibitor: it inhibits HIV-1 and HIV-2 proteases. This protease is an enzyme which cleaves viral protein molecules into smaller fragments, and it is vital for both the replication of the virus within the cell and also the release of mature viral particles from an infected cell. Though this mode of action is common to all protease inhibitors, the precise mode of binding of nelfinavir to 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.

Toxicity

Nelfinavir can produce a range of adverse effects. Common (experienced by more than one in one hundred patients; greater than 1%) are flatulence, diarrhea or abdominal pain. Infrequent (experienced by one in one thousand to one in one hundred patients; 0.01 - 0.1%) adverse effects are fatigue, urination, rash, mouth ulcers or hepatitis. Rarely (less than one in one thousand patients; under 0.01%) nephrolithiasis, arthralgia, Leukopenia, pancreatitis or allergic reactions may occur.

Interactions

Nelfinavir's interaction profile is similar to that of other protease inhibitors. Most interactions occur at the level of the Cytochrome P450 isozymes 3A4 and CYP2C19, by which nelfinavir is metabolised.

See also

• HIV-1 protease
• Cremophor EL
• Castor oil

References

1. ^ Circulating metabolites of the Human Immunodeficiency Virus Protese Inhibitor Nelfinavir in Humans:. PubMed. Retrieved on 2007-01-07.
2. ^ Press release from the European Medicines Agency regarding possible genotoxic ethyl mesylate contamination
3. ^ J.J. Gills et al. (2007). "Nelfinavir, A Lead HIV Protease Inhibitor, Is a Broad-Spectrum, Anticancer Agent that Induces Endoplasmic Reticulum Stress, Autophagy, and Apoptosis In vitro and In vivo". Clinical Cancer Research 13: 5183-5194.

Pai VB, Nahata MC. Nelfinavir mesylate: a protease inhibitor. Ann Pharmacother 1999; 33: 325–39.

Bardsley-Elliot A, Plosker GL. Nelfinavir: an update on its use in HIV infection. Drugs 2000; 59: 581–620.