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 the FDA for sale in the United States. Some drugs go through the FDA’s accelerated approval process and are approved before a Phase III clinical trial is complete. After a drug is approved by the 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 is currently being studied in a Phase III clinical trial.2
A new drug application (NDA) for elvitegravir for the treatment of HIV-1 infection in adults who have already taken HIV medicines (treatment-experienced) was submitted to the FDA in June 2012.3
In a Phase III study, ritonavir-boosted elvitegravir taken once daily was compared to the FDA-approved integrase inhibitor raltegravir (brand name: Isentress) taken twice daily in treatment-experienced, HIV-infected participants. Study participants also received additional HIV medicines as part of their optimized background regimens. (An optimized background regimen is a combination of drugs, chosen on the basis of a person’s resistance test results and treatment history, 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.) The background regimen therapy included a boosted protease inhibitor plus another HIV medicine.7,8
In this study, ritonavir-boosted elvitegravir proved as effective as raltegravir. In terms of safety, elvitegravir was comparable to raltegravir. However, diarrhea was reported more frequently in patients taking elvitegravir than raltegravir, while elevated liver enzymes occurred more frequently in patients receiving raltegravir than elvitegravir.7,8
In the Phase III study discussed under the previous question, diarrhea was reported as a side effect.8
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.
1. United States National Library of Medicine. ChemIDplus Advanced.
2. National Institute of Allergy and Infectious Diseases (NIAID). NIAID ChemDB, HIV Drugs in Development.
3. Gilead Sciences: Press Releases. Gilead Submits New Drug Application to U.S. FDA for HIV Integrase Inhibitor Elvitegravir for Treatment-Experienced Patients. Accessed May 29, 2013.
4. Lee JS, Calmy A, Andrieux-Meyer I, Ford N. Review of the safety, efficacy, and pharmacokinetics of elvitegravir with an emphasis on resource-limited settings. HIV AIDS (Auckl). 2012;4:5-15.
5. U.S. Food and Drug Administration (FDA). Stribild Full Prescribing Information. Accessed May 29, 2013.
6. National Institutes of Health (NIH). NIH Clinical Research Trials and You.
7. Elion R, Molina JM, Arribas-Lopez JR, et al. Efficacy and safety results from a randomized, double blind, active controlled trial of elvitegravir (once-daily) versus raltegravir (twice-daily) in treatment-experienced HIV-positive patients: long term 96-week data. Abstract presented at: 19th International AIDS Conference; July 22-27, 2012; Washington, DC. Abstract TUAB0105.
8. Molina JM, Lamarca A, Andrade-Villanueva J, et al. Efficacy and safety of once daily elvitegravir versus twice daily raltegravir in treatment-experienced patients with HIV-1 receiving a ritonavir-boosted protease inhibitor: randomised, double-blind, phase 3, non-inferiority study. Lancet Infect Dis. 2012 Jan;12(1):27-35.
Last Reviewed: May 29, 2013
Last Updated: May 29, 2013