HIV capsid inhibitors
Antiretrovirals that bind the protein shell (capsid) around the HIV genome. Lenacapavir is the first, and it lasts long enough for injections twice a year.
What they are
The newest antiretroviral class. Lenacapavir binds the HIV-1 capsid protein, so it keeps working against virus resistant to the older classes. It is used with other antiretrovirals for treatment, and on its own to prevent HIV infection (pre-exposure prophylaxis). Its very long action allows a subcutaneous injection every six months.
Mechanism of action
The capsid is a cone-shaped shell built from many copies of the capsid protein (p24). It protects the viral genome on its way to the nucleus and is rebuilt in each new virion. Lenacapavir binds between neighbouring capsid subunits and disturbs capsid function, including the assembly of new capsids, so infectious virus is not produced.
Target: HIV-1 capsid protein (p24)
Drugs in this class
Others in the class
- Bictegravir + lenacapavir (combination)
Test yourself
Think of the answer, then tap the question to see it.
What does lenacapavir bind?
The HIV-1 capsid protein (p24), the shell that surrounds the viral genome.
Why does lenacapavir stay active against virus resistant to other antiretrovirals?
It acts on a target (the capsid) that no older class uses, so their resistance mutations do not affect it.
Why must new medicines be checked even months after the last lenacapavir injection?
The drug stays in the body for a long time, so its interactions last for months.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Lenacapavir: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Crystal structure of the HIV capsid hexamer bound to the small molecule long-acting inhibitor, GS-6207 (RCSB Protein Data Bank, 2020); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.