July 21, 2015 - NAM
by Roger Pebody
For some people in some settings, less frequent pre-exposure prophylaxis (PrEP) regimens with doses linked to sexual activity are feasible, with high numbers of sexual acts protected by PrEP, studies that were presented on Monday to the Eighth International AIDS Society Conference (IAS 2015) in Vancouver, Canada, show.
This may give people, who want to use PrEP, and their doctors additional options, allowing people to find a pattern of taking PrEP that best suits them. But the studies also found that more people are able to adhere to daily PrEP than non-daily regimens. Further, the actual effectiveness of non-daily regimens remains uncertain.
The studies presented today were in part inspired by the French IPERGAY study, so far the only study to demonstrate that a schedule of non-daily PrEP, with doses before and after sex, could be effective. (There were 86% fewer infections). However IPERGAY was conducted in a population of gay men who tended to have sex quite frequently. To prevent transmission during anal sex, four doses a week appear to be almost equivalent to seven doses. But it's possible that people who have sex less frequently – and therefore take pills less frequently – will have lower levels of the drug in the body that are not protective. Continue reading...
