Study suggests PEP-in-pocket is another HIV prevention option

  • by Liz Highleyman, BAR Contributor
  • Wednesday November 1, 2023
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Dr. Isaac Bogoch of the University of Toronto studied Prep-in-pocket, or PIP, as a feasible HIV prevention option. Photo: Courtesy Canadian HIV Trials Network
Dr. Isaac Bogoch of the University of Toronto studied Prep-in-pocket, or PIP, as a feasible HIV prevention option. Photo: Courtesy Canadian HIV Trials Network

Having antiretrovirals on hand to take as post-exposure prophylaxis after potential HIV exposure, an approach known as PEP-in-pocket, or PIP, is a feasible prevention option, especially for people who have sex infrequently, according to study results presented at the recent IDWeek conference in Boston.

"I really think PIP is a strong additional tool for patients and providers and gives more options — and a more granular approach — for HIV prevention," presenter Dr. Isaac Bogoch of the University of Toronto told the Bay Area Reporter.

Pre-exposure prophylaxis (PrEP) pills taken every day or injections administered every other month reduce the risk of HIV acquisition by around 99% for gay and bisexual men and transgender women. Taking PrEP pills on demand before and after sex is also an effective option, especially for people who can anticipate when they're likely to have sex.

Another prevention tool, post-exposure prophylaxis (PEP), involves taking a monthlong course of antiretrovirals after sex or other types of exposure. Although the two-drug combination pills used for PrEP can prevent HIV from taking hold in the body, PEP — which is essentially very early treatment — uses a stronger three-drug regimen taken for 28 days.

Traditionally provided on an emergency basis, PEP should be started within 72 hours after a potential exposure, but sooner is better. This can be difficult, since exposures may occur when it's not easy or convenient to access the medications, such as over a weekend or while traveling.

PEP-in-pocket may be a good alternative for some people, for example, those who have unplanned condomless sex only a few times a year or who infrequently share needles to inject drugs. The benefits of PIP over PrEP include less total time on antiretrovirals, which lowers medication cost and reduces the duration of side effects, although PrEP is generally well tolerated. On the other hand, the more intensive PEP regimen could cause worse side effects for a shorter period of time compared with continuous PrEP.

Bogoch and his team evaluated the PEP-in-pocket approach at two HIV clinics in Toronto, it was reported at the conference October 14. After counseling, individuals who have infrequent (zero to four times per year) but high-risk exposures of any type were prescribed a course of antiretrovirals to have on hand if needed.

This analysis included 112 people, mostly gay and bi men, who were prescribed PEP-in-pocket between February 2016 and December 2022. During follow-up, 35 people self-initiated antiretrovirals following sexual exposure, including 19 who did so more than once, for a total of 69 courses of PIP. Five people discontinued the drugs early, one due to side effects and four after a more in-depth risk assessment found they weren't necessary.

There were no new cases of HIV during follow-up, the researchers reported. However, there were 22 cases of bacterial sexually transmitted infections among 13 people, suggesting that some of them might also be candidates for doxycycline post-exposure prophylaxis (doxyPEP).

Participants fluidly transitioned between different HIV prevention methods as circumstances warranted, with nearly a third switching from PEP-in-pocket to PrEP and a similar proportion doing the reverse.

"PrEP (injectable, daily, and on-demand) and PEP are fantastic, but still leave significant gaps in care. PIP fills that gap nicely and enables people with a low frequency of high-risk (and occasionally unanticipated) exposures to have agency and autonomy over their HIV prevention care," Bogoch said. "People do not take a linear path through life, and HIV risk is dynamic. We work with patients to adapt their HIV prevention modality to best suit their current and future needs."

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