Thursday, 28 March, 2024
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Some HIV drug resistance in PrEP users

A case note review from 56 Dean Street, the largest HIV and STI clinic in Europe, has found that former PrEP users who get HIV are more likely to have a certain type of drug resistance than people who have never taken PrEP. However, says an Aidsmap report this had little if any impact on their response to HIV treatment once they were diagnosed and started antiretroviral therapy.

The report says the Dean Street Collaborative Group of researchers reviewed notes for all patients testing HIV positive between July 2015 and January 2019. After excluding 47 people with no HIV resistance test recorded at diagnosis, they found 22 clinic attendees who were diagnosed HIV positive and mentioned having taken PrEP within the previous year, and compared them with 917 not known to have taken PrEP.

The patients were overwhelmingly gay men (there were 13 women and 26 exclusively heterosexual men, none of whom had taken PrEP) with an average age of around 32. This case note review has some limitations. It features a small group of PrEP takers who may not be typical of ones who started it more recently; it doesn’t compare treatment success rates with people who had not taken PrEP; and it doesn’t estimate the time of HIV acquisition.

According to the report it also can’t say whether people developed M184V due to taking PrEP while already having HIV – or whether they caught HIV that already had that drug resistance mutation in the first place, which was why their PrEP failed. Emtricitabine reaches high levels in rectal tissues much faster than tenofovir does, so could be offering the sole protection against HIV early on after a first dose of PrEP. This might make intermittent PrEP, especially, less effective in people exposed to HIV with the M184V mutation.

[link url="http://www.aidsmap.com/news/feb-2020/does-prep-cause-more-hiv-drug-resistance-yes-some"]Full Aidsmap report[/link]

[link url="https://www.thelancet.com/journals/lanhiv/article/PIIS2352-3018(19)30404-7/fulltext"]The Lancet HIV correspondence[/link]

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