|What is cobicistat?
- Cobicistat, formerly known as GS-9350, is a pharmacokinetic enhancer (a drug used to boost other medications in the blood to make them more effective) by Gilead Sciences. It is a component of the approved fixed-dose combination tablet Stribild.
- Cobicistat is not active against HIV. It works by inhibiting an enzyme called CYP3A4 that is responsible for breaking down (or metabolism) of certain medications, including several HIV drugs. This helps boost the effectiveness of these drugs, while allowing fewer pills or doses on a daily basis.
- cobicistat was developed to be used in combination with other drugs.
What is already known about cobicistat?
- The cobicist dose is 150 mg, once a day, in combination with HIV medications that require boosting. Stribid contains 150 mg cobicistat.
- Compared with Norvir (ritonavir), an HIV protease inhibitor frequently used to boost other antiretrovirals, cobicistat blocks fewer ezymes in the body responsible for breaking down (metabolizing) drugs, meaning that it will likely result in fewer drug-drug interactions. However, cobicistat still interacts with a number of medications, including those used to treat HIV. It is important that your health care provider be aware of all drugs you are taking, including those you buy without a prescription.
- Stribild contains cobicistat, the integrase inhibitor elvitegravir, tenofovir (found in Viread, Truvada, Complera and Atripla) and emtricitabine (found in Emtriva, Truvada, Complera and Atripla). Cobicistat is also being studied as a stand-alone drug in combination with non-Gilead antiretrovirals, such as the protease inhibitors Reyataz (atazanavir) and Prezista (darunavir).
What about drug interactions?
- Like the protease inhibitor Norvir (ritonavir), which is primarily used to boost blood levels of other HIV medications in the body, cobicistat is expected to have a number of interactions with other (HIV and non-HIV) drugs. However, cobicistat only affects the CYP3A4 enzyme, whereas Norvir interacts with CYP3A4 and others. Studies on potential interactions between cobicistat and other drugs are ongoing.
What is known about side effects?
- According to clinical trials completed thus far, cobicistat may cause gastrointestinal side effects, including nausea, vomiting and diarrhea. The drug may also exacerbate kidney impairment in some people.
Who should not take cobicistat?
- It is not known whether cobicistat will harm an unborn baby. It is very important to treat HIV/AIDS during pregnancy to reduce the risk of infecting your baby. Talk to your doctor about your treatment options.
- It is not known whether cobicistat passes into breast milk and what effect it may have on a nursing baby. To prevent transmission of the virus to uninfected babies, it is recommended that HIV-positive mothers not breast-feed.
Where can I learn more about clinical trials of cobicistat?
- If you would like to find out if you are eligible for any clinical trials that include cobicistat, visit ClinicalTrials.gov, a site run by the U.S. National Institutes of Health. The site has information about all HIV-related clinical studies in the United States. For more info, you can call their toll-free number at 1-800-HIV-0440 (1-800-448-0440) or email firstname.lastname@example.org.