September 4, 2012
Elvitegravir (also known as GS-9137) is a drug used for antiviral therapy against HIV. It is manufactured by Gilead.
Elvitegravir is the second "integrase inhibitor" drug. When HIV infects a cell, it combines its genetic code into the cell's own code. This is shown in Fact Sheet 106, step 5. Elvitegravir blocks this process. When elvitegravir blocks integration, HIV infects a cell but cannot make more copies of itself.
Stribild is approved for treatment-naïve patients -- those who have not yet started treatment. Gilead has asked the FDA to approve elvitegravir for use by patients who have already taken HIV medications.
There are no absolute rules about when to start antiviral drugs. You and your health care provider should consider your CD4 cell count (see Fact Sheet 124,) your viral load (see Fact Sheet 125,) any symptoms you are having, and your attitude about taking HIV medications. Fact Sheet 404 has more information about guidelines for the use of antiviral medications.
The HIV virus is sloppy when it makes copies of its genetic code (RNA). Many new copies of HIV are mutations: they are slightly different from the original virus. Some mutations can continue to multiply even when you are taking an antiviral drug. When this happens, the drug will stop working. This is called "developing resistance" to the drug. See Fact Sheet 126 for more information on resistance.
Elvitegravir has shown activity against HIV that already has resistance to several other HIV medications.
Resistance to elvitegravir is not yet well understood. Sometimes, if you develop resistance to one drug, you will also have resistance to other antiviral drugs. This is called "cross-resistance". Because elvitegravir is in a new class of antiviral drugs, it seems to have almost no cross resistance with antiviral drugs in older classes. However, cross-resistance is expected is expected between raltegravir (Isentress, see Fact Sheet 465) and elvitegravir.
With combination therapy (taking more than one antiviral drug at the same time), HIV mutates much more slowly. Resistance takes longer to develop. It is very important to take antiviral medications according to instructions, on schedule, and not to skip or reduce doses.
In clinical trials, the most common side effects in people taking elvitegravir were diarrhea, nausea, and headache along with diarrhea, upper respiratory tract infection, and bronchitis.
Elvitegravir has been studied to see if it interacts with other drugs. Rifampin, used to treat tuberculosis (see Fact Sheet 518) decreases blood levels of elvitegravir. A higher dose of elvitegravir must be used.
Elvitegravir has not been studied with all medicines, over-the-counter drugs or vitamin or herbal supplements. Studies are underway. Be sure your doctor knows about all medications and supplements that you are taking.
Elvitegravir is the second drug in a new class, integrase inhibitors. It has not yet been approved by itself. However, it is part of the approved combination medication Stribild. It stops HIV from inserting its genetic code into an infected cell. This prevents the virus from making new copies of HIV. Elvitegravir helps control HIV, even when it is resistant to other medications.