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.
S/GSK1265744 is an investigational drug that is being studied for the treatment of HIV infection.
S/GSK1265744 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.
S/GSK1265744 does not require boosting with an additional drug. (Boosting involves the use of a second drug to increase the effectiveness of the main [first] drug.)4
Clinical trials are conducted in phases. Each phase has a different purpose and helps researchers answer different questions.5
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.5
S/GSK1265744 is currently being studied in Phase IIb clinical trials.2
In a Phase I/II study, different strengths of unboosted S/GSK1265744 taken orally were compared to placebo in both healthy participants and HIV-infected participants. HIV-infected study participants did not receive any additional HIV medicines; they received only the investigational study drug, S/GSK1265744.6,7
This study showed that S/GSK1265744 may be given once daily without boosting. In HIV-infected adults, S/GSK1265744 was effective in reducing viral load (the amount of HIV in the blood). In terms of safety, S/GSK1265744 was well tolerated and most side effects were considered mild. The most common side effect that occurred was headache. More studies are needed to determine the safety and efficacy of S/GSK1265744.7
A Phase I study of healthy adults taking a long-acting formulation of S/GSK1265744 given by injection has been completed. (A long-acting drug formulation works over a long period of time. Using this type of drug might mean that the drug could be taken less often, making a treatment regimen simpler to take.) This study indicated that long-acting injectable formulations of S/GSK1265744 may be an effective delivery method, with the potential for achieving substantial antiviral activity by using monthly or quarterly (every 12 weeks) dosing.8 Further studies of S/GSK1265744 long-acting injectable formulations are under way.9
An additional Phase II study of once-daily S/GSK1265744 taken orally is ongoing.10
In the Phase I/II study discussed under the previous question, most side effects were mild, with the most common side effect being headache.7
In the Phase I study of an injectable form of S/GSK1265744 discussed under the previous question, the most common side effect was temporary, mild-to-moderate injection site reactions, such as skin redness, irritation, or bumps (nodules).8
Because S/GSK1265744 is still being studied, information on possible side effects of the drug is not complete. As testing of S/GSK1265744 continues, additional information on possible side effects will be gathered.
More information about S/GSK1265744-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.5
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. ViiV Healthcare website. Our Pipeline. Accessed April 24, 2013.
4. Ford SL, Gould E, Chen S, et al. Effects of etravirine on the pharmacokinetics of the integrase inhibitor S/GSK1265744. Antimicrob Agents Chemother. 2013 Jan;57(1):277-80.
5. National Institutes of Health (NIH). NIH Clinical Research Trials and You.
6. Min S, DeJesus E, McCurdy L, et al. Pharmacokinetics (PK) and Safety in Healthy and HIV-Infected Subjects and Short-Term Antiviral Efficacy of S/GSK1265744, a Next Generation Once Daily HIV Integrase Inhibitor. 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC); September 12–15, 2009; San Francisco, CA. Levin: Conference reports for National AIDS Treatment Advocacy Project (NATAP); 2009. Accessed April 23, 2013.
7. Min S, DeJesus E, McCurdy L, et al. Pharmacokinetics (PK) and Safety in Healthy and HIV-Infected Subjects and Short-Term Antiviral Efficacy of S/GSK1265744, a Next Generation Once Daily HIV Integrase Inhibitor. Abstract presented at: 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC); September 12–15, 2009; San Francisco, CA. Abstract H-1228.
8. Spreen W, Ford SL, Chen S, et al. Pharmacokinetics, safety and tolerability of the HIV integrase inhibitor S/GSK1265744 long acting parenteral nanosuspension following single dose administration to healthy adults. Abstract presented at: 19th International AIDS Conference; July 22-27, 2012; Washington DC. Abstract TUPE040.
9. ViiV Healthcare. A Single-Center Randomized, Open-Label, Study to Assess the Relative Bioavailability of New Formulations of GSK1265744 LAP in Healthy Adult Subjects. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on December 17, 2012. NLM Identifier: NCT01754116. Last accessed April 24, 2013.
10. ViiV Healthcare. A Phase IIb, Dose Ranging Study of Oral GSK1265744 in Combination With Nucleoside Reverse Transcriptase Inhibitors for Induction of Human Immunodeficiency Virus -1 (HIV-1) Virologic Suppression Followed by an Evaluation of Maintenance of Virologic Suppression When Oral GSK1265744 is Combined With Oral Rilpivirine in HIV-1 Infected, Antiretroviral Therapy Naive Adult Subjects. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on June 28, 2012. NLM Identifier: NCT01641809. Last accessed April 24, 2013.
Last Reviewed: May 29, 2013
Last Updated: May 29, 2013