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.
Lenacapavir (brand name Sunlenca) is the first HIV capsid inhibitor, a completely new class of antiretroviral drug. What makes it unique is its dosing: after an initial loading period, lenacapavir is given as a subcutaneous injection just once every six months. This is the longest-acting HIV treatment currently available.
How Does Lenacapavir Work?
HIV’s capsid is the protein shell that surrounds the virus’s genetic material. The capsid plays a role in multiple stages of HIV’s life cycle, including entry into the cell nucleus, assembly of new viral particles, and release from the cell. Lenacapavir disrupts all of these processes by binding to the capsid protein, making it a multi-stage inhibitor.
Because it targets a completely different part of the virus from existing drugs (NRTIs, NNRTIs, PIs, INSTIs), lenacapavir is effective against HIV strains that are resistant to other drug classes.
Who Is Lenacapavir For?
Lenacapavir is currently approved for treatment-experienced adults with multi-drug resistant HIV who cannot construct an effective regimen from other available drugs. It’s combined with an optimised background regimen (other drugs chosen based on resistance testing).
It’s also being studied for:
- PrEP: Twice-yearly lenacapavir injections for HIV prevention showed remarkable efficacy in the PURPOSE 1 trial (100% efficacy among women in Africa). Regulatory submissions for PrEP use are underway.
- First-line treatment: Trials combining lenacapavir with other long-acting drugs for broader treatment use.
How Is It Given?
- Day 1: Oral tablets (loading dose) + subcutaneous injection
- Day 2: Oral tablets
- Day 8: Oral tablets
- Week 4: Subcutaneous injection (second injection, at clinic)
- Every 6 months thereafter: Single subcutaneous injection at clinic
The injections are given in the abdomen by a healthcare professional at an HIV clinic.
Side Effects
- Injection site reactions (nodules, swelling, pain) — the most common side effect
- Nausea
- Diarrhoea
Read more: What is HIV? | Injectable HIV treatment | HIV drug resistance
Frequently Asked Questions
Can anyone with HIV get lenacapavir?
Currently, lenacapavir is only approved for treatment-experienced patients with multi-drug resistant HIV. It may become available more broadly if PrEP and first-line treatment trials are successful.
Is lenacapavir available on the NHS?
Yes, for patients who meet the criteria (multi-drug resistant HIV without other viable treatment options). Access is through specialist HIV clinics.
How does twice-yearly dosing work?
Lenacapavir has an extremely long half-life due to its crystalline structure at the injection site. The drug slowly dissolves and releases into the bloodstream over months, maintaining therapeutic levels between injections.
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.
