NAIROBI, 24 July 2026 – Kenya will play a dual role in the development and potential future supply of alimatravir, an investigational once-monthly oral pre-exposure prophylaxis option being studied for the prevention of HIV-1.
MSD, known as Merck in the United States and Canada, has signed a royalty-free, non-exclusive voluntary licensing agreement with UCL Kenya. The agreement is intended to allow early product development, regulatory planning and manufacturing preparations while Phase 3 clinical trials continue.
UCL Kenya is one of seven generic manufacturers selected to support potential future public- and private-sector supply across 129 low- and middle-income countries, subject to successful trials and regulatory approvals.
“Recognizing the urgent, unmet needs in HIV prevention, we are acting early to enable rapid, broad and sustainable access to alimatravir, an investigational once-monthly oral PrEP option, in low- and middle-income countries,” said Robert M. Davis, chairman and chief executive officer of Merck.
Kenya is also participating in EXPrESSIVE-10, a Phase 3 study evaluating the safety and efficacy of alimatravir among adolescent girls and young women in Kenya, South Africa and Uganda. The study, which is now enrolling, is receiving financial support from the Gates Foundation.
“People across Africa need more options to prevent HIV. A once-monthly pill could provide a different choice for people in how to protect themselves, subject to successful trials and regulatory approval,” said Jean Kaseya, director-general of the Africa Centres for Disease Control and Prevention. “We welcome this decision to engage African manufacturers early.”
Globally, approximately 1.2 million people acquired HIV in 2025, about 3,300 people each day. In 2023, 3.5 million people were using oral PrEP, compared with a global target of 20 million by 2030.
Alimatravir remains investigational and has not been approved for use. MSD has committed to supporting access for trial participants after the studies conclude, pending regulatory approval.
ENDS
About alimatravir (MK-8527)
Alimatravir (MK-8527) is being evaluated as a potential once-monthly oral prevention option for HIV-1. Alimatravir inhibits reverse transcriptase through multiple mechanisms, including:
- inhibition of reverse transcriptase translocation, resulting in immediate chain termination, and
- induction of structural changes in the viral DNA (delayed chain termination)
Alimatravir is currently being evaluated in two ongoing Phase 3 clinical trials. With financial support from the Gates Foundation, the Phase 3 EXPrESSIVE-10 trial (MK-8527-010, NCT07071623) is evaluating the safety and efficacy of alimatravir in adolescent girls and young women in Kenya, South Africa and Uganda. The Phase 3 EXPrESSIVE-11 trial (MK-8527-011, NCT07044297) is evaluating the safety and efficacy of alimatravir among people with greater likelihood of HIV-1 exposure in 16 countries. Both trials are now enrolling.
The initiation of the Phase 3 clinical trial program was supported by results of a double-blind, multicenter, Phase 2 trial (MK-8527-007, NCT06045507) examining the safety and pharmacokinetics of alimatravir. The study enrolled 350 participants, 18–65 years of age, with low likelihood of HIV-1 exposure, who were randomized 2:2:2:1 to receive alimatravir (3, 6 or 12 mg) or placebo once monthly for six months. In the trial, the rates of adverse events were similar among those in the alimatravir arms and those in the placebo arm, and no clinically meaningful changes were seen in laboratory tests, including total lymphocyte and CD4 T-cell counts. The pharmacokinetics of alimatravir and alimatravir-triphosphate, the active form of alimatravir, support the continued development of alimatravir as an oral, once-monthly option for PrEP.
Merck is committed to ensuring that the people who are participating in the EXPrESSIVE Phase 3 trials have access to alimatravir after the trials conclude, pending regulatory approval.