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Fact Sheet
Nucleoside Analog Reverse Transcriptase Inhibitors in Development

April 4, 2011

NOTE: Several fact sheets describe drugs that are being tested against HIV:

These drugs have not been approved by the Food and Drug Administration (FDA) for use against HIV.

Nucleoside Analog Reverse Transcriptase Inhibitors

These drugs stop HIV from multiplying by blocking the reverse transcriptase enzyme. This enzyme changes HIV's genetic material (RNA) into the form of DNA. This step has to occur before HIV's genetic code gets combined with an infected cell's own genetic codes. The nucleoside analogs (often called "nukes") mimic the building blocks used by reverse transcriptase to make copies of the HIV genetic material. These fake building blocks disrupt the copying.

Nucleoside Analogs (Nukes) in Development

Apricitabine (ATC, AVX754) by Avexa. A meeting with the FDA in early 2011 discussed results from Phase II/III studies. Avexa is proceeding with its development.

CMX157 by Chimerix is a version of tenofovir with better properties in the body. It has completed a Phase I trial.

Dexelvucitabine (DFC, Reverset), formerly known as Reverset, is being developed by Pharmasset. DFC is a once-daily pill. DFC has shown activity against HIV that is already resistant to several antiretroviral drugs.

DOT (Dioxolane thymidine) is being studied by the University of Georgia in Phase I trials.

Elvucitabine (ACH-126,443, Fd4C) by Achillion Pharmaceuticals is a once-daily drug with activity against HIV that is resistant to several other nukes. It is also effective against hepatitis B. It has successfully completed one year of a Phase II study.

Festinavir (E-d4T, OBP-601) by Bristol-Myers Squibb showed good results in a Phase I trial. It may be a once-daily drug.

GS7340 is a new version of tenofovir. It is a "prodrug" of tenofovir: when it is broken down in the body, it produces tenofovir. Phase Ib study results showed it is much more potent than tenofovir and may have fewer side effects.

MIV-210 (FLG) by GlaxoSmithKline and Medivir shows good activity against HIV with resistance to other nukes. It is in Phase I trials.

Racivir by Pharmasset Inc is active against HIV and hepatitis B in laboratory studies. In a Phase I/II study, Racivir showed anti HIV activity that lasted more than 2 weeks after the drug was stopped. The makers hope that Racivir can be used as a once-daily drug.

Nukes No Longer in Development

The following drugs are no longer being developed for use against HIV:

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