Study explores self-initiated HIV post-exposure prophylaxis

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  • One effective option for HIV prevention after an exposure is post-exposure prophylaxis (PEP)
  • Toronto researchers offered advance prescriptions to allow individuals to self-initiate PEP
  • Over seven years, none of the 111 study participants acquired HIV

Two highly effective means of preventing HIV are:

  • pre-exposure prophylaxis (PrEP)
  • post-exposure prophylaxis (PEP)

PrEP involves taking a pill that consists of two anti-HIV medicines (tenofovir + FTC), usually on a daily basis. Tenofovir is available in two formulations: the original version is called TDF (tenofovir disoproxil fumarate) and the newer version is called TAF (tenofovir alafenamide). An alternative schedule to daily pill-taking is called “on-demand” PrEP; in this case, PrEP is taken before and after potential exposure to HIV. PrEP requires visits to a clinic and a lab every three months for screening for sexually transmitted infections (STIs), HIV and other tests. You can find out more about PrEP here.

PEP involves initiating a regimen of three anti-HIV drugs within 72 hours of potential exposure to this virus. PEP needs to be taken for 28 consecutive days. After initiation of PEP, medical appointments and lab tests, including screening for STIs and HIV, are required. You can find out more about PEP here.

Although both methods of prevention are highly effective when used as directed, there are barriers to their use. For instance, with PrEP, some people may have difficulty taking pills every day. The on-demand schedule of PrEP requires the ability to predict future potential exposures to HIV; some people may not be able to accurately forecast such exposures. Cost is another barrier, as medicines to treat and prevent HIV are expensive and not always fully subsidized. Although generic formulations of PrEP exist, some people may find them expensive.

People in need of PEP must usually visit the emergency room of a hospital or urgent care centre to get a prescription. After that initial visit, further appointments are needed for STI and HIV screening. Research has found that some people are unable to attend these follow-up appointments.

PEP in Pocket

A team of researchers at two large HIV prevention clinics in Toronto has developed and deployed what they call PEP in Pocket (PIP).

According to the researchers, during clinic visits, patients were asked about possible future HIV exposure. This served as a starting point for discussion about HIV prevention and which form of prevention would be best for them. For patients who anticipated few (up to four per year) episodes of potential HIV exposure, doctors would discuss the possibility of PIP. If a patient was interested and a suitable candidate, a doctor or nurse would counsel them about how to effectively use PIP and the importance of initiating it within 72 hours of potential exposure. They would also inform the patient that a course of PIP lasts for 28 consecutive days and they would stress the importance of taking their PIP pills every day. Following agreement with the patient, doctors would then provide the following:

  • a prescription for 28 days of PIP, which consists of three anti-HIV drugs
  • instructions on when to initiate PIP
  • information about when to return to the clinic for appointments once PIP is initiated

PIP regimens typically prescribed at the clinics were as follows:

  • Biktarvy – TAF + FTC + bictegravir
  • dolutegravir (Tivicay) and TDF + FTC (Truvada; also available in generic formulations)

Doctors encouraged patients to fill the prescription and have the medicine readily accessible.

For people who did not have private insurance, social workers at the clinics provided support to help them access a government drug subsidy program.

As mentioned earlier, patients and healthcare providers discussed potential future HIV exposure. After this discussion, some patients opted to switch from PIP to PrEP and vice versa.

Patients were also screened for mental health and substance use disorders and connected to care if necessary.

People who were prescribed PIP had regular clinic visits (every five or six months).

What the researchers found

The researchers reviewed information in their database collected between February 2016 and December 2022. During this time, PIP was prescribed to 111 people. Their average age was 37 years and 96% were assigned male at birth.

Although PIP was prescribed to 111 patients, only 35 people initiated it, and 69 courses of PIP were completed during the study period (some people took more than one course).

All courses of PIP were initiated because of condomless sex, though the researchers had counselled participants that use of non-sterile equipment for injecting drugs was also a reason for initiating PIP.

The most commonly used regimen was dolutegravir and TDF + FTC.

PIP was discontinued prematurely in five cases. In four of those cases, discontinuation occurred because doctors judged that the potential exposure carried a low risk of infection. In the fifth case, the patient discontinued PIP because of side effects.

None of the people who used PIP became HIV positive.

Switching prevention

Over the course of the study, 34 people switched from PIP to PrEP and 33 other people changed from PrEP to PIP. The researchers stated that these changes in prevention modalities were “seamless” and were “based on shared decision-making between patients and their [care] providers.” The researchers stated that the most commonly reported reasons for switching were “changes in relationship status and/or the number of current or anticipated sexual partners.”

Why consider PIP?

The researchers stated that PIP “may be an appropriate alternative to daily or on-demand PrEP for some individuals.” Furthermore, they acknowledged that “on-demand PrEP requires 2 to 24 hours of foresight to initiate medications before a potential exposure, which is not always possible in situations of condoms breaking, sexual assault, some injection drug exposures, or more spontaneous sexual encounters.”

The researchers added that “PIP facilitates healthcare engagement for people at risk for HIV with routine HIV and STI testing every five to six months.” They noted that “some individuals using PIP do not want to use PrEP and may not otherwise be seen by a health care professional on a routine basis.”

The researchers also stated that PIP helps to provide people with “autonomy and agency over their care.”

For the future

In the present analysis, the researchers found that most of the people who used PIP were gay, bisexual and other men who have sex with men. They stated that “further studies are needed to ascertain whether PIP is beneficial for other populations.”

By Sean R. Hosein


HIV pre-exposure prophylaxis (PrEP) resources – CATIE

HIV post-exposure prophylaxis (PEP) resources – CATIE

HIV prevention with postexposure prophylaxis-in-pocket (PIP) —BMJ


Billick MJ, Fisher KN, Myers S, et al. Brief Report: Outcomes of individuals using HIV postexposure prophylaxis-in-pocket (“PIP”) for low-frequency, high-risk exposures in Toronto, Canada. JAIDS. 2023 Nov 1;94(3):211-213.


Source : CATIE

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