Other Antiretroviral Drugs in Development
March 4, 2011
These drugs have not been approved by the Food and Drug Administration (FDA) for use against HIV.
After HIV's genetic code is changed from a single strand to a double strand by the reverse transcriptase enzyme, it gets inserted (integrated) into the genetic code of the infected cell. Then the HIV genetic code gets "read," producing new viruses. Scientists hope that integration will be another point in the HIV life cycle that can be targeted by drugs.
Elvitegravir (also known as Gilead 9137 and JTK-303) is now in a phase III study. The drug is used boosted with ritonavir or with Gilead's new booster GS 9350. It is eliminated almost entirely via the feces, not the kidneys, so no dose adjustments are needed for patients with kidney problems.
Dolutegravir (S/GSK1349572) by ViiV Healthcare is an integrase inhibitor. Results from Phase II trials showed better results with twice-daily dosing compared to once-daily. It is going into Phase III trials. It does not require boosting.
S/GSK 1265744 by ViiV Healthcare is an integrase inhibitor. It is in a Phase IIa trial.
A new type of drug inhibits the development of HIV's internal structures in a new virus. The first "maturation inhibitor" was bevirimat by Myriad Pharmaceuticals. A backup compound was also in development. Early results showed good antiretroviral activity and tolerability. However, in 2010, Myriad announced that it was stopping development of maturation inhibitors.
The inner core of HIV is called the nucleocapsid. It is held together by structures called "zinc fingers." Zinc finger inhibitors (or zinc ejectors) are drugs that can break apart these structures and prevent the virus from functioning.
Scientists believe that the nucleocapsid core cannot mutate very easily, so a drug that works against zinc fingers might be effective for a long time. Unfortunately, zinc fingers are not only used by the HIV virus. Drugs that attack them could have serious side effects.
One zinc finger inhibitor -- azodicarbonamide (ADA) -- has been tested in a Phase I/II trial, but there are no recent reports on its development.
SB-728-T by Sangamo BioSciences is a zinc finger gene therapy. It started Phase I clinical trials in 2009.
A new type of drug under development encourages mutations in HIV to the point that the virus is no longer functional.
KP1461 by Koronis Pharmaceuticals development was discontinued in 2008 but was reinstated following positive results from a Phase 2a clinical trial.
Bevirimat (PA457) by Myriad Genetics
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