An Overview of Ibalizumab
November 3, 2017
Other Names: Hu5A8, IBA, TMB-355, TNX-355
(Compound details obtained from ChemIDplus Advanced1 and NIAID Therapeutics Database2)
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 Ibalizumab?
Ibalizumab is an investigational drug that is being studied for the treatment and prevention of HIV infection.4
Ibalizumab belongs to a class (group) of HIV drugs called entry and fusion inhibitors.2 Entry and fusion inhibitors block HIV from getting into and infecting certain cells of the immune system. This prevents HIV from multiplying and can reduce the amount of HIV in the body.
Ibalizumab works by attaching to a protein on the surface of the immune cells. The protein is called the CD4 receptor. When ibalizumab attaches to the CD4 receptor, HIV cannot attach to, enter, or infect the cell.5
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.5
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.5 (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 Ibalizumab?
Ibalizumab is currently being studied in a Phase III clinical trial.2
What Are Some Studies on Ibalizumab?
Study Name: TNX-355.03; NCT00089700
Purpose: The purpose of this study was to determine the safety and effectiveness of ibalizumab when compared to a placebo. (A placebo is an inactive drug that is identical in appearance to the active drug being studied.)7,8
Study Names: TMB-202; NCT00784147
Sponsor: TaiMed Biologics Inc.
Status: This study has been completed.
Location: United States and Puerto Rico
Purpose: The purpose of this study was to look at the safety, tolerability, and antiviral activity of 2 different dosing regimens of ibalizumab and to determine the best dose.9,10
Note: Participants who had a successful antiviral response to ibalizumab in Study TMB-202 could choose to extend their treatment regimen of ibalizumab plus an optimized background regimen beyond 24 weeks under a separate study protocol (NCT01056393). (An optimized background regimen is a combination of drugs that are not being studied as the investigational drug in the clinical trial but are given to help control a participant's HIV infection. The drugs in an optimized background regimen are chosen on the basis of a person's resistance test results and treatment history.)11
Purpose: The purpose of this study was to look at the safety and effectiveness of ibalizumab.12
Purpose: The purpose of this study is to investigate the safety and tolerability of ibalizumab. The study will also provide access to ibalizumab for people with multidrug-resistant HIV who have previously taken ibalizumab.13
For more details on the studies listed above, see the Health Professional version.
A subcutaneous (SC) injection form of ibalizumab was studied in a Phase I trial (NCT01292174). (An SC injection is placed under the skin.) This study looked at the safety and drug properties of ibalizumab given by SC injection to adults without HIV who were at risk of becoming infected with HIV. Results from the study support further research of SC ibalizumab for HIV treatment or as prevention medicine.14,15 An intramuscular(IM) form of ibalizumab was studied in a Phase I/II trial. The study looked at the drug properties, safety, and effectiveness of IM ibalizumab in participants with HIV.16
What Side Effects Might Ibalizumab Cause?
One goal of HIV research is to identify new drugs that have fewer side effects. The following side effects were observed in studies of ibalizumab discussed under the previous question.
In this Phase IIb study, the most common side effects reported were the following: rash, diarrhea, headache, and nausea. Most side effects were considered mild to moderate.9,17
During the first 2 weeks of this Phase III study, side effects included dizziness, weakness, fatigue, nausea, vomiting, and rash. At the end of the study (Week 24), researchers reported that most of the side effects were mild to moderate in intensity. One participant had immune reconstitution inflammatory syndrome (IRIS), which was related to ibalizumab and caused the participant to stop the study early.12,18,19
Where Can I Get More Information About Clinical Trials Studying Ibalizumab?
More information about ibalizumab-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.
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.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.
This article was provided by AIDSinfo. Visit the AIDSinfo website to find out more about their activities and publications.
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