A new HIV prevention pill that only needs to be taken once a month is showing promising results in late-stage clinical trials, raising hopes of expanding options to prevent new HIV infections.
The experimental drug, called alimatravir (MK-8527), is being developed by pharmaceutical company Merck Sharp & Dohme (MSD). Unlike the daily HIV prevention pills currently used by many people, alimatravir is designed to be taken just once every month.
The medicine is not a vaccine, and it does not cure HIV. Instead, it is a form of pre-exposure prophylaxis (PrEP), medicine taken by HIV-negative people who are at high risk of infection to prevent the virus from establishing itself in the body if they are exposed.
The drug is currently in Phase Three clinical trials, the final stage of testing before regulators consider approving it for public use. At this stage, researchers are testing whether the pill is both safe and effective in thousands of volunteers.
If the trials are successful and health regulators approve the drug, it could become another important HIV prevention option alongside daily oral PrEP, injectable PrEP and condoms. Recognising the need to make the medicine available quickly if approved, MSD has already announced agreements with several generic pharmaceutical manufacturers to prepare for production.
Among the companies selected is Quality Chemicals Industries Limited (QCIL) in Uganda, alongside Aspen Pharmacare in South Africa and Universal Corporation Limited in Kenya. The partnerships are intended to enable local production for low- and middle-income countries, helping to reduce costs and improve access across Africa.
The Joint United Nations Programme on HIV/AIDS (UNAIDS) welcomed the move, saying early planning for manufacturing, financing and distribution is essential to avoid delays that have affected access to previous medical innovations.
It added that if the trials are successful, the agreement will present an important opportunity to strengthen Africa’s local pharmaceutical manufacturing capacity. It will also bring innovative HIV prevention options closer to the people who need them most, supported by sustainable market development and technology transfer.
UNAIDS Deputy Executive Director Angeli Achrekar said scientific breakthroughs can only have an impact if they reach everyone who needs them. She said that if alimatravir is proven safe and effective, governments, manufacturers and development partners must work together to ensure rapid production, affordable pricing and timely access, particularly in low- and middle-income countries from day one. “No one should have to wait years for life-saving HIV prevention.”
Globally, about 1.2 million people acquired HIV in 2025, while 570,000 people died from AIDS-related illnesses. In sub-Saharan Africa alone, around 3,100 adolescent girls and young women become infected with HIV every week, highlighting the continued need for more accessible prevention methods.
According to UNAIDS, expanding HIV prevention choices remains critical despite significant advances in treatment and prevention. The agency added that despite remarkable progress in scientific innovations in recent years, including antiretroviral-based HIV prevention options, millions of people, particularly adolescent girls and young women, marginalised populations and other people at heightened risk of HIV, still lack access to effective HIV prevention options.
Health experts say a monthly pill could improve adherence for many people who struggle to remember taking a tablet every day, potentially making HIV prevention more effective.
UNAIDS says it will continue working with governments and partners to support affordable pricing, strengthen health systems and ensure new HIV prevention technologies reach communities quickly and equitably if the new pill receives regulatory approval.
