A medicine injected just twice a year could transform the fight against HIV. In a 2024 clinical trial involving more than 2,000 young women in South Africa and Uganda, no participants who received lenacapavir contracted HIV.

Developed by United States pharmaceutical company Gilead Sciences, the injectable drug can be used to prevent HIV.

“It’s the most innovative tool that has reached the HIV arena for the last decade, because it’s the closest we have [to] a vaccine,” Carlota Baptista da Silva, global HIV lead at Doctors Without Borders (known by its French initials, MSF), told Al Jazeera.

The World Health Organization has recommended the long-acting injectable as an additional form of pre-exposure prophylaxis, or PrEP – medicine to reduce the risk of getting HIV.

But the arrival of the drug comes at a challenging juncture in the global fight against HIV.

International funding for HIV fell 18 percent in 2025, to $7.3bn, its lowest level in nearly two decades, according to the United Nations programme on HIV/AIDS (UNAIDS). The squeeze has already hit prevention programmes: The number of people receiving medicine to reduce risk fell from 1.4 million in 2024 to 1.1 million in 2025.

That makes the arrival of a highly effective, twice-yearly prevention option significant. The question of who can access it is now more urgent.

For MSF, the scientific question has largely been answered: lenacapavir can prevent HIV with remarkable efficacy.

The fight now is whether the rules governing manufacture, price and supply will allow that scientific breakthrough to reach the people who need it.

Why some countries are excluded In the United States, lenacapavir costs about $28,000 per person annually. Generic versions are expected to cost about $40 a year.

A generic version is a copy of the original drug made by another manufacturer after the patent holder licenses the technology. It contains the same active ingredient, but it can be produced and sold at a much lower price.

In June 2025, the US Food and Drug Administration (FDA) approved lenacapavir for HIV prevention, giving people the option of an injection twice a year. But in several low- and middle-income countries, access to cheaper versions is not expected at scale until 2027.

Gilead is supplying its own version of lenacapavir at no profit for programmes supported by the Global Fund and the US President’s Emergency Plan for AIDS Relief (PEPFAR), with rollouts under way in countries including South Africa, Kenya, Zambia, Nigeria and Eswatini.

These are not the cheaper generic versions expected to cost about $40 per person a year. Gilead has licensed six manufacturers to produce those, with large-scale generic rollout expected in 2027.

At least 26 middle-income countries are excluded from Gilead’s generics agreement, MSF says, including countries with rising HIV infections and some that helped test the drug. Among them are Brazil, Mexico, Argentina and Peru.

“People should not really help generate the evidence for breakthrough medicine and then find that their country is excluded from affordable generic access,” da Silva said.

According to MSF, countries excluded from the licence accounted for close to 23 percent of new HIV infections globally in 2023.

Gilead has since announced a separate agreement with the Pan American Health Organization, creating an access pathway for 14 Latin American and Caribbean countries outside its generic licensing territory, including Brazil, Mexico, Argentina and Peru.

MSF argues that leaves those countries dependent on Gilead rather than able to automatically buy the cheaper generics.

MSF says it still cannot buy the drug For more than a year, MSF says it has sought permission to purchase lenacapavir directly from Gilead for its medical programmes, without demanding a discounted price.

“Despite those requests, Gilead has not allowed MSF to purchase this medicine directly,” da Silva said.

That matters particularly in humanitarian emergencies, she argues. People displaced by conflict or disaster may struggle to take a prevention pill every day, while sexual violence and other vulnerabilities can increase the risk of HIV.

Daily PrEP pills are already available as an alternative to the injection. But unlike lenacapavir, they need to be taken consistently to provide protection. An injection offering six months of protection could be particularly valuable.

“People living through conflict [and] humanitarian crises cannot be the last in line for medical innovation,” da Silva said.

Gilead declined Al Jazeera’s request for an interview due to scheduling constraints. In its emailed statement, it said its access strategy combines no-profit supplies, royalty-free licensing and regional agreements. It didn’t reply to questions about why it won’t sell its drug to MSF, or why certain countries were excluded from its generics agreement.

The company plans to provide enough lenacapavir for up to three million people through 2028 as generic manufacturers scale up production, with large-scale generic rollout expected in 2027.

MSF says that is nowhere near the scale required, pointing to projections that close to 20 million people worldwide need access to PrEP to substantially reduce new HIV infections. That includes all forms of PrEP, not just lenacapavir.

But countries left outside Gilead’s generic licensing deal may have another option. Can governments bypass the patent barriers?

World Trade Organization (WTO) rules allow governments, in some cases, to bypass a drug company’s patent so cheaper versions of a medicine can be made or imported without the company’s permission.

They can also authorise government use of patents and challenge patents they consider weak or unjustified. The 2001 Doha Declaration affirmed WTO members’ right to use such safeguards to protect public health.

Brazil has used them before in the fight against HIV. In 2007, after negotiations with pharmaceutical company Merck over the price of the HIV drug efavirenz failed, Brazil issued a compulsory licence allowing it to access cheaper generic versions of the medicine.

Nearly two decades later, activists are urging Brazil to consider using those powers again for lenacapavir if patent barriers prevent affordable generic access.

MSF says governments excluded from Gilead’s licence could consider those same legal safeguards for lenacapavir, including compulsory licensing, government-use authorisations and challenges to patents.

It is also calling on Gilead to ensure its agreements with generic manufacturers do not prevent them from supplying countries where patent barriers have been removed through such measures.

For MSF, the stakes go beyond lenacapavir. The way the drug is made available could determine whether one of the greatest advances in HIV prevention in decades reaches people based on need, rather than where they live or what their health systems can afford.

“For a humanitarian medical organisation, we should not have to spend more than a year trying to find a way to buy a WHO-recommended medicine,” da Silva said.