A potential game-changer in HIV prevention is moving closer to reality with the development of a once-a-month oral pill, MK-8527. Designed to provide 30 days of protection against HIV per tablet, the pill has shown promising results in phase 2 trials and has now advanced to phase 3 studies.
MK-8527 belongs to a class of drugs known as nucleoside reverse transcriptase translocation inhibitors (NRTTIs), which disrupt the virus’s replication cycle. Phase 2 results, presented recently at a major international AIDS conference, found the pill to be safe and well tolerated across different doses 3mg, 6mg, and 12mg and showed antiretroviral levels sufficient for HIV protection in participants’ blood.
Participants in the six-month study, conducted in South Africa, the US, and Israel, received monthly doses and were monitored afterward. None contracted HIV during the trial, although participants were considered low-risk. Importantly, side effects such as headache, nausea, and fatigue were mild and occurred at similar rates to those on placebo. Only two participants withdrew due to side effects.
Notably, the 6mg and 12mg doses maintained protective levels for over 28 days, suggesting a one-week buffer for late doses. The drug also appears to act quickly, possibly offering protection within an hour of ingestion.
Safety monitoring focused on CD4 and lymphocyte counts due to the pill’s similarity in action to Islatravir, a drug that previously showed immune-related issues at high doses. However, no significant downward trends in these counts were found, strengthening MK-8527’s safety profile.
Phase 3 trials, EXPrESSIVE-10 and EXPrESSIVE-11, are enrolling nearly 9,000 participants in multiple countries, including Kenya, Uganda, and South Africa. These trials will evaluate the monthly pill’s safety and effectiveness compared to the current standard — a daily pill containing tenofovir and emtricitabine.
If proven effective, MK-8527 could provide a discreet, convenient alternative to daily pills and long-acting injections. With the potential for generic production, experts believe it could be a more affordable and accessible prevention option, expanding the range of tools available in the fight against HIV.
