References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Ibalizumab (brand name Trogarzo) is a monoclonal antibody that blocks HIV from entering CD4 cells. It’s the first HIV drug in this class and is given as an intravenous infusion every two weeks. Ibalizumab is reserved for adults with multi-drug resistant HIV who have limited treatment options remaining.
How Does Ibalizumab Work?
Ibalizumab is an antibody that binds to the CD4 receptor on human immune cells. It doesn’t block HIV from first attaching to CD4, but it prevents the conformational change HIV needs to fuse with the cell membrane and enter. This stops the virus from infecting new cells.
Because ibalizumab targets a human receptor rather than a viral protein, HIV cannot easily develop resistance by mutating. This makes it particularly valuable for patients with extensively drug-resistant HIV.
Who Is Ibalizumab For?
Ibalizumab is only approved for heavily treatment-experienced adults with multi-drug resistant HIV who are failing their current antiretroviral regimen. It’s not first-line treatment. The patient’s HIV must have documented resistance to drugs from multiple classes, and they must be unable to construct an effective regimen from existing drugs.
How Is It Given?
- Loading dose: 2000mg IV infusion at the start
- Maintenance: 800mg IV infusion every 2 weeks
- Given at an HIV clinic by a healthcare professional
- Combined with an optimised background regimen
Side Effects
- Diarrhoea
- Dizziness
- Nausea
- Rash
- Infusion reactions (rare)
Read more: What is HIV? | HIV drug resistance | Lenacapavir
Frequently Asked Questions
Is ibalizumab available on the NHS?
Yes, for patients meeting the strict criteria (multi-drug resistant HIV without viable alternatives). Access is through specialist HIV centres.
Does ibalizumab replace daily HIV medication?
No. It’s given alongside an optimised background regimen of other antiretroviral drugs chosen based on resistance testing.
Related reading
- Choosing the Right PrEP Drug: Truvada vs Descovy
- Dovato for HIV: A Two-Drug Regimen
- Triumeq for HIV: A Straightforward Guide
- Efavirenz for HIV: An Older NNRTI Still in Use
- Eviplera: How This Anti-HIV Drug Works
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
