Weekly HIV Pill Matches Daily Therapy in 600-Patient Study After 48 Weeks

Q: What happens to a patient's viral load if they forget to take the groundbreaking weekly HIV pill?

If a patient forgets the once-weekly HIV pill once, their viral load would not be expected to jump immediately, but protection can start to weaken if the dose is missed for more than seven days. The reason is that the investigational regimen — islatravir plus lenacapavir — is designed to keep drug levels in the body for about a week. Researchers involved in the study said that if a dose is missed, it only lasts in the body for a further week, so sticking closely to weekly dosing is important. If the gap goes beyond that, the treatment may stop working effectively, giving the virus a chance to start replicating again and, over time, raising viral load. The available evidence suggests viral rebound is not usually instantaneous. In HIV treatment more broadly, it often takes days to weeks for viral load to rise after treatment interruption, especially in people who have been undetectable for a long time. But the concern is not just rebound — repeated or prolonged missed doses can also increase the risk of drug resistance. For this weekly pill in particular, researchers noted that if it is missed for more than seven days, patients may need another loading dose to restore effective drug levels. That is one reason doctors are stressing that people should not adjust or restart this regimen on their own. The weekly pill is still experimental, so the exact missed-dose instructions will depend on future regulatory guidance and a patient’s doctor.

2 articles · Updated · Queerty · Aug 18

More than 600 virally suppressed adults in 12 countries maintained the same HIV suppression rates after 48 weeks whether they stayed on daily pills or switched to a once-weekly islatravir-lenacapavir regimen.
Queen Mary University of London researchers said the weekly option could ease treatment fatigue and stigma tied to daily dosing, potentially helping patients stick with lifelong therapy.
Modern HIV drugs already let undetectable patients avoid transmitting the virus and live near-normal lifespans, but alternatives to daily pills remain limited.
Long-acting injectables approved in 2021 are given every two months, yet uptake has stayed low—about 3% of treated patients in 2023—suggesting a weekly pill may appeal to more people.
The trial, published in the New England Journal of Medicine, is continuing to 96 weeks, so patients are not being advised to switch treatment yet.