An investigational drug is one that is under study and is not approved by the U.S. Food and Drug Administration (FDA) for sale in the United States. Medical research studies are conducted to evaluate the safety and effectiveness of an investigational drug. These research studies are also called clinical trials. Once an investigational drug has been proven safe and effective in clinical trials, FDA may approve the drug for sale in the United States.
Elvitegravir, used as a stand alone agent, is an investigational drug that is being studied for the treatment of HIV infection.
Elvitegravir belongs to a class (group) of HIV drugs called integrase inhibitors.2 Integrase inhibitors block an HIV enzyme called integrase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking integrase, integrase inhibitors prevent HIV from multiplying and can reduce the amount of HIV in the body.
Elvitegravir requires boosting with an additional drug, such as the FDA-approved HIV medicine ritonavir (brand name: Norvir) or the investigational drug cobicistat. (Boosting involves the use of a second drug to increase the effectiveness of the main [first] drug.)4
Elvitegravir is a component of the FDA-approved, fixed-dose combination (FDC) HIV medicine elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (brand name: Stribild). (FDC drugs include two or more drugs in a single dosage form, such as a capsule or tablet.)5
Clinical trials are conducted in phases. Each phase has a different purpose and helps researchers answer different questions.6
In most cases, an investigational drug must be proven safe and effective in a Phase III clinical trial to be considered for approval by FDA for sale in the United States. Some drugs go through FDA’s accelerated approval process and are approved before a Phase III clinical trial is complete. After a drug is approved by FDA and made available to the public, researchers track its safety in Phase IV trials to seek more information about the drug’s risks, benefits, and optimal use.6
Elvitegravir has gone through Phase III testing in adults. A new drug application (NDA) for elvitegravir for the treatment of HIV infection in treatment-experienced adults was accepted by the FDA in April 2014.3
In a Phase III study, the safety and effectiveness of ritonavir-boosted elvitegravir taken once daily was compared to the safety and effectiveness of the FDA-approved integrase inhibitor medicine raltegravir (brand name: Isentress) taken twice daily in HIV-infected adults. Participants had previously taken HIV medicines before entering the study (called treatment-experienced). All study participants also received a ritonavir-boosted protease inhibitor plus another HIV medicine as part of their background regimens. (A background regimen is a combination of drugs that are not being studied as the investigational drug[s] in the clinical trial, but are given to help control a participant’s HIV infection.)7,8
In this study, ritonavir-boosted elvitegravir proved as effective as raltegravir. In terms of safety, elvitegravir was comparable to raltegravir. The number of serious side effects and number of participants who stopped taking their study medicines because of a side effect were similar across both groups.7-9
Ritonavir-boosted elvitegravir is also being studied in HIV-infected, treatment-experienced pediatric participants.10 In addition, elvitegravir is being studied as part of an investigational FDC tablet containing elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide.11
In the Phase III study discussed under the previous question, diarrhea was reported more often in patients taking elvitegravir than in patients taking raltegravir, while elevated liver enzymes occurred more frequently in patients taking raltegravir than in those taking elvitegravir.9
Because elvitegravir is still being studied, information on possible side effects of the drug is not complete. As testing of elvitegravir continues, additional information on possible side effects will be gathered.
More information about elvitegravir-related research studies is available from the AIDSinfo database of ClinicalTrials.gov study summaries. Click on the title of any trial in the list to see the ClinicalTrials.gov trial summary and more information about the study.
Participating in a clinical trial can provide benefits. For example, a volunteer participant can benefit from new research treatments before they are widely available. Participants also receive regular and careful medical attention from a research team that includes doctors and other health professionals. However, clinical trials may also involve risks of varying degrees, such as unpleasant, serious, or even life-threatening side effects from the treatment being studied.6
Your health care provider can help you decide whether participating in a clinical trial is right for you. For more information, visit NIH Clinical Research Trials and You.
Last Reviewed: August 20, 2014
Last Updated: August 20, 2014