Cidofovir, brand name Vistide, is a

topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...

injectable An injection (often and usually referred to as a "shot" in US English, a "jab" in UK English, or a "jag" in Scottish English and Scots) is the act of administering a liquid, especially a drug, into a person's body using a needle (usually a hyp ...

antiviral 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. Antiviral drugs are a class of antimicrobials ...

medication primarily used as a treatment for

cytomegalovirus ''Cytomegalovirus'' (CMV) (from ''cyto-'' 'cell' via Greek - 'container' + 'big, megalo-' + -''virus'' via Latin 'poison') is a genus of viruses in the order '' Herpesvirales'', in the family '' Herpesviridae'', in the subfamily '' Betaherp ...

(CMV)

retinitis Retinitis is inflammation of the retina in the eye, which can permanently damage the retina and lead to blindness. The retina is the eye's "sensing" tissue. Retinitis may be caused by a number of different infectious agents. Its most common form, ...

(an infection of the retina of the eye) in people with

AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

. Cidofovir was approved for medical use in 1996.

Medical use

DNA virus

Its only indication that has received regulatory approval worldwide is

retinitis. Cidofovir has also shown efficacy in the treatment of

aciclovir Aciclovir, also known as acyclovir, is an antiviral medication. It is primarily used for the treatment of herpes simplex virus infections, chickenpox, and shingles. Other uses include the prevention of cytomegalovirus infections following tran ...

-resistant HSV infections. Cidofovir has also been investigated as a treatment for

progressive multifocal leukoencephalopathy Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal viral disease characterized by progressive damage (''-pathy'') or inflammation of the white matter (''leuko-'') of the brain (''-encephalo-'') at multiple locations (''mu ...

with successful case reports of its use. Despite this, the drug failed to demonstrate any efficacy in controlled studies. Cidofovir might have anti-

smallpox Smallpox was an infectious disease caused by Variola virus (often called Smallpox virus), which belongs to the genus '' Orthopoxvirus''. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (W ...

efficacy and might be used on a limited basis in the event of a

bioterror Bioterrorism is terrorism involving the intentional release or dissemination of biological agents. These agents include bacteria, viruses, insects, fungi, and/or their toxins, and may be in a naturally occurring or a human-modified form, in muc ...

incident involving smallpox cases.

Brincidofovir Brincidofovir, sold under the brand name Tembexa, is an antiviral drug used to treat smallpox. Brincidofovir is a prodrug of cidofovir. Conjugated to a lipid, the compound is designed to release cidofovir intracellularly, allowing for higher int ...

, a cidofovir derivative with much higher activity against smallpox that can be taken orally has been developed. It has inhibitory effects on varicella-zoster virus replication ''in vitro'' although no clinical trials have been done to date, likely due to the abundance of safer alternatives such as

. Cidofovir shows anti-

BK virus The BK virus, also known as Human polyomavirus 1, is a member of the polyomavirus family. Past infection with the BK virus is widespread, but significant consequences of infection are uncommon, with the exception of the immunocompromised and the ...

activity in a subgroup of transplant recipients. Cidofovir is being investigated as a complementary intralesional therapy against

papillomatosis Papillomatosis is skin surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae.Kumar, Vinay; Fausto, Nelso; Abbas, Abul (2004) ''Robbins & Cotran Pathologic Basis of Disease'' (7th ed.). Saunders. Page 1230. . These p ...

caused by

HPV Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and ...

. It first received

FDA 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 ...

approval on 26 June 1996, TGA approval on 30 April 1998 and

EMA Ema or EMA may refer to: Biology and medicine * Anti-Endomysial Antibodies test * Epithelial membrane antigen * European Medicines Agency, a European Union agency for the evaluation of medicinal products * European Medical Association, associa ...

approval on 23 April 1997. It has been used topically to treat

warts Warts are non-cancerous viral growths usually occurring on the hands and feet but which can also affect other locations, such as the genitals or face. One or many warts may appear. They are distinguished from cancerous tumors as they are caus ...

Other

It has been suggested as an antitumour agent, due to its suppression of

FGF2 Fibroblast growth factor 2 (FGF-2), also known as basic fibroblast growth factor (bFGF) and FGF-β, is a growth factor and signaling protein encoded by the ''FGF2'' gene. It binds to and exerts effects via specific fibroblast growth factor recep ...

Administration

Cidofovir is only available as an intravenous formulation. Cidofovir is to be administered with

probenecid Probenecid, also sold under the brand name Probalan, is a medication that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia. Probenecid was developed as an alternative to caronamide to competitive ...

which decreases side effects to the kidney. Probenecid mitigates nephrotoxicity by inhibiting organic anion transport of the proximal tubule epithelial cells of the kidney. In addition, hydration must be administered to patients receiving cidofovir. 1 liter of normal saline is recommended in conjunction with each dose of cidofovir.

Side effects

The major dose-limiting side effect of cidofovir is nephrotoxicity (i.e., kidney damage). Other common side effects (occurring in >1% of people treated with the drug) include: * Nausea * Vomiting *

Neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...

* Hair loss * Weakness * Headache * Chills * Decreased intraocular pressure *

Uveitis Uveitis () is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and ...

Iritis Uveitis () is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and i ...

Whereas uncommon side effects include:

anaemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availab ...

and elevated liver enzymes and rare side effects include:

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...

and

Fanconi syndrome Fanconi syndrome or Fanconi's syndrome (, ) is a syndrome of inadequate reabsorption in the proximal renal tubules of the kidney. The syndrome can be caused by various underlying congenital or acquired diseases, by toxicity (for example, from t ...

Probenecid Probenecid, also sold under the brand name Probalan, is a medication that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia. Probenecid was developed as an alternative to caronamide to competitive ...

(a uricosuric drug) and intravenous saline should always be administered with each cidofovir infusion to prevent this nephrotoxicity.

Contraindications

Hypersensitivity to cidofovir or probenecid (as probenecid needs to be given concurrently to avoid nephrotoxicity).

Interactions

It is known to interact with nephrotoxic agents (e.g.

amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococ ...

foscarnet Foscarnet (phosphonomethanoic acid), known by its brand name Foscavir, is an antiviral medication which is primarily used to treat viral infections involving the Herpesviridae family. It is classified as a pyrophosphate Structural analog, analog ...

, IV

aminoglycosides Aminoglycoside is a medicinal chemistry, medicinal and bacteriology, bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside ...

, IV pentamide,

vancomycin Vancomycin is a glycopeptide antibiotic medication used to treat certain bacterial infections. It is administered intravenously ( injection into a vein) to treat complicated skin infections, bloodstream infections, endocarditis, bone an ...

tacrolimus Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After Allotransplantation, allogenic organ transplant, the risk of organ Transplant rejection, rejection is moderate. To lower the risk of organ rejectio ...

, non-steroid anti-inflammatory drugs, etc.) to increase their nephrotoxic potential. As it must be given concurrently with probenecid it is advised that drugs that are known to interact with probenecid (e.g. drugs that probenecid interferes with the renal tubular secretion of, such as paracetamol, aciclovir, aminosalicylic acid, etc.) are also withheld.

Mechanism of action

Its active metabolite, cidofovir diphosphate, inhibits viral replication by selectively inhibiting viral

DNA polymerases A DNA polymerase is a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphates, the molecular precursors of DNA. These enzymes are essential for DNA replication and usually work in groups to create t ...

. It also inhibits human polymerases, but this action is 8–600 times weaker than its actions on viral DNA polymerases. It also incorporates itself into viral DNA, hence inhibiting viral DNA synthesis during reproduction. It possesses ''in vitro'' activity against the following viruses: *

Human herpesviruses ''Orthoherpesviridae'', previously named and more widely known as ''Herpesviridae'', is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are commonly known as herpe ...

Adenoviruses Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from the ...

* Human

poxviruses ''Poxviridae'' is a family of double-stranded DNA viruses. Vertebrates and arthropods serve as natural hosts. The family contains 22 genera that are assigned to two subfamilies: ''Chordopoxvirinae'' and ''Entomopoxvirinae''. ''Entomopoxvirinae'' ...

(including the

virus) *

Human papillomavirus Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and r ...

History

Cidofovir was discovered at the Institute of Organic Chemistry and Biochemistry, Prague, by

Antonín Holý Antonín Holý (1 September 1936 – 16 July 2012) was a pioneering Czech scientist. He specialised in the field of chemistry and cooperated on the development of important antiretroviral drugs used in the treatment of HIV and hepatitis B. He ...

, and developed by

Gilead Sciences Gilead Sciences, Inc. () is an American biopharmaceutical company headquartered in Foster City, California, that focuses on researching and developing antiviral drugs used in the treatment of HIV/AIDS, hepatitis B, hepatitis C, influenza, and CO ...

and is marketed with the brand name Vistide by Gilead in the US, and by

Pfizer Pfizer Inc. ( ) is an American Multinational corporation, multinational Pharmaceutical industry, pharmaceutical and biotechnology corporation headquartered at The Spiral (New York City), The Spiral in Manhattan, New York City. Founded in 184 ...

elsewhere.

Synthesis

Cidofovir can be synthesized from a pyrimidone

derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

and a

protected Protection is any measure taken to guard something against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although ...

derivative of

glycidol Glycidol is an organic compound with the formula . The molecule contains both epoxide and alcohol functional groups. Being simple to make and bifunctional, it has a variety of industrial uses. The compound is a colorless, slightly viscous liqui ...

. :

References

{{Antivirals Gilead Sciences Anti-herpes virus drugs Pyrimidones Amines Ethers Phosphonic acids Primary alcohols