An Overview of Valproic Acid
August 10, 2017
Other Names: Depakene, Depakote, Depakote ER, Epival, VPA, divalproex sodium, valproate
Valproic acid is in Phase II development as a latency-reversing agent for HIV.
(Compound details obtained from ChemIDplus Advanced,1 NIAID Therapeutics Database,2 Treatment Action Group website,3 and Depakote ER full prescribing information4)
What Is an Investigational Drug?
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.
What Is Valproic Acid?
Valproic acid is a drug that has been approved by FDA for the treatment of certain symptoms of bipolar disorder (a type of mental illness), the treatment of some types of seizures, and the prevention of migraine headaches.4 It has been studied as part of a strategy to cure HIV infection.5,6
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 cells) for many months or even years. The cells where latent HIV hides are known as the latent HIV reservoir. 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.)7,8
Valproic acid belongs to a general class (group) of HIV drugs called latency-reversing agents.3 There are different types of latency-reversing agents. Valproic acid is a type of latency-reversing agent called a histone deacetylase (HDAC) inhibitor.9
How Do Latency-Reversing Agents Work?
Latency-reversing agents reactivate (turn back on) latent HIV within resting CD4 cells.8,9 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 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.8,9
In addition, any new virus that is produced during reactivation can then be prevented from infecting other cells with the use of ongoing ART.8,9 Recent research has shown that additional therapies, together with latency-reversing agents, may be needed to fully eliminate latent HIV from the body.9
How Are Clinical Trials of Investigational Drugs Conducted?
Clinical trials are conducted in phases. Each phase has a different purpose and helps researchers answer different questions.10
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.10
Some clinical trials are categorized as "a" or "b," such as "Phase Ia" or "Phase IIb." These different subphases typically mean that a study is researching certain types of information or using a certain type of participant population.
In What Phase of Testing Is Valproic Acid?
The use of valproic acid to reduce latent HIV has been studied in Phase II clinical trials.2
What Are Some Studies on Valproic Acid?
Study Names: CTN-205; NCT00289952
Purpose: The purpose of this study was to determine whether valproic acid in combination with ART could reduce the amount of latent HIV.
Purpose: The purpose of this study was to determine whether adding valproic acid and the HIV medicine raltegravir to a participant's current ART regimen could reduce the amount of latent HIV.
For more details on the studies listed above, see the Health Professional version.
What Side Effects Might Valproic Acid Cause?
During the CTN-205 study (NCT00289952) discussed under the previous question, some participants dropped out of the study because of side effects they experienced when they were receiving valproic acid. As treatment time on valproic acid increased, the number of participants dropping out of the study also increased.5,11
During the study that looked at adding valproic acid and raltegravir to ART (NCT00614458), no significant side effects related to valproic acid were reported.6,12
Information on possible side effects of the drug is not complete. If testing of valproic acid continues, additional information on possible side effects will be gathered.
Where Can I Get More Information About Clinical Trials Studying Valproic Acid?
More information about valproic acid-related research studies is available from the AIDSinfo database of 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.
How Can I Find More Information About Participating in a Clinical Trial?
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.10
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.
This article was provided by AIDSinfo. Visit the AIDSinfo website to find out more about their activities and publications.