Merck has unveiled an early global access strategy for Alimatravir, an experimental once-monthly pill designed to help prevent HIV. If the medicine receives regulatory approval, the pharmaceutical company plans to make it available quickly and at affordable prices in low- and middle-income countries.
Known as MSD outside the United States and Canada, Merck said the initiative is intended to improve access to HIV prevention, particularly in regions where infection rates remain high and healthcare resources are limited.
Alimatravir, also referred to as MK-8527, is being developed as an oral pre-exposure prophylaxis (PrEP) medicine for preventing HIV-1 infection. Unlike current oral PrEP treatments, which usually require daily use, the new medication is designed to provide protection with just one pill each month.
The drug is currently undergoing evaluation in two large international clinical trials. The EXPrESSIVE-10 study, conducted in partnership with the Gates Foundation, is assessing the medicine’s safety and effectiveness among women and adolescent girls in sub-Saharan Africa. Meanwhile, the EXPrESSIVE-11 trial is enrolling participants considered at higher risk of HIV exposure across 16 countries.
Early research indicates that Alimatravir may begin working within an hour of being taken and could continue providing protection for up to one month. Researchers also believe the medicine offers a “forgiveness window,” meaning its protective effect may last for about an additional week even if a scheduled monthly dose is delayed.
Before the clinical trial results are released, Merck has already signed royalty-free licensing agreements with seven generic drug manufacturers. These companies will be permitted to manufacture and distribute the medicine across 129 low- and lower-middle-income countries if regulatory approval is granted.
The participating manufacturers include three companies based in sub-Saharan Africa and four in India. Merck said this marks the first time African manufacturers have been included from the beginning of a global access programme for an HIV prevention medicine.
The development could have a major impact in regions most affected by HIV. Around 40.9 million people were living with HIV worldwide in 2025, with more than half residing in sub-Saharan Africa.
Experts believe a once-monthly pill could improve treatment adherence, making HIV prevention more convenient for people who struggle with daily medication. Clinical trial results are expected next year, while Merck is already expanding production capacity to support rapid global distribution if Alimatravir receives approval.
