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.
To learn more about investigational drugs, read the AIDSinfo What is an Investigational HIV Drug? fact sheet.
Lefitolimod is an investigational drug that is being studied as part of a strategy to cure HIV infection.2
Currently, there is no cure for HIV infection. One of the main obstacles to curing HIV infection is that the virus can remain hidden and inactive (latent) inside certain cells of the immune system (such as resting CD4 T cells) for many months or even years. While HIV is in this latent state, the immune system cannot recognize the virus, and antiretroviral therapy (ART) has no effect on it. (ART is the recommended treatment for HIV infection and involves using a combination of different antiretroviral [ARV] drugs to prevent HIV from replicating.)5,6
Lefitolimod belongs to a general class (group) of HIV drugs called latency-reversing agents. There are different types of latency-reversing agents. Lefitolimod is a type of latency-reversing agent called a toll-like receptor agonist.2
Latency-reversing agents reactivate (turn back on) latent HIV within resting CD4 T cells. When latent HIV is reactivated, it is once again able to produce new virus and multiply (replicate). It is hoped that after latent HIV is reactivated, the CD4 T cells in which the virus was hiding are more likely to die off on their own or be recognized and killed by the body’s immune system.6,7
In addition, any new virus that is produced during reactivation can then be prevented from infecting other cells with the use of ongoing ART.6,7 Recent research has shown that additional therapies, together with latency-reversing agents, may be needed to fully eliminate latent HIV from the body.7
Beyond its potential as a possible HIV latency-reversing agent, lefitolimod may also improve the body’s immune response to HIV.8
Clinical trials are conducted in phases. Each phase has a different purpose and helps researchers answer different questions.9
In most cases, an investigational drug must be proven effective and must show continued safety 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.9 (Some clinical trials are categorized as “a” or “b,” such as “Phase Ia” or “Phase IIb.” These different sublevels typically mean that a study is researching certain types of information or using a certain type of participant population.)
Lefitolimod is currently being studied in a Phase Ib/IIa clinical trial as a treatment for HIV.2
Study Names: TEACH study; NCT02443935
Sponsor: University of Aarhus
Purpose: The purpose of this study is to investigate whether lefitolimod can reactivate latent HIV hiding inside cells and improve immune responses in HIV-infected participants.8
For more details on this study, see the Health Professional version.
Early results from the TEACH study (NCT02443935) were reported in a press release from the company that manufactures lefitolimod. According to this early report, lefitolimod appears to be safe for people infected with HIV.8,10
Because lefitolimod is still being studied, information on possible side effects of the drug is not complete. As testing of lefitolimod continues, additional information on possible side effects will be gathered.
More information about lefitolimod-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.9
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: November 22, 2016