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  • U.S. researchers developed a text messaging service to increase PrEP adherence.
  • Healthcare providers used PrEPmate to send messages and reminders to PrEP users.
  • Recipients were more likely to take PrEP as prescribed and attend appointments.

Clinical trials have demonstrated that pre-exposure prophylaxis (PrEP) can significantly reduce the risk of HIV infection. A key aspect of PrEP involves taking a fixed-dose combination of two drugs—tenofovir DF and FTC—sold under the brand name Truvada. It is also available in generic formulations. In Canada, regulatory authorities have approved taking daily PrEP for people at high risk of HIV infection. However, some doctors prescribe intermittent PrEP (so-called “on-demand”) to gay, bisexual and other men who have sex with men (MSM), as clinical trials have found that this schedule also reduces the risk of HIV infection in this group. PrEP also involves regular screening for HIV and other sexually transmitted infections (STIs), as well as other assessments, done prior to starting PrEP and usually every three months thereafter.

A problem that has emerged both in clinical trials and in clinics is that some people have difficultly remembering to take PrEP exactly as directed, maintaining regular visits to their healthcare providers and going for lab tests.

In the United States, research has found that young gay, bisexual and other men who have sex with men (MSM) are at heightened risk for HIV infection. Furthermore, at least two studies with adolescents and young men in that country have found reduced rates of adherence to PrEP. In an attempt to find ways to improve the ability of youth to take PrEP exactly as directed (and thereby maintain protection from HIV), researchers in San Francisco and Chicago have developed an intervention that works on mobile telephones. The intervention, code-named PrEPmate, centres on text messages that can be sent between healthcare professionals and PrEP users. Researchers tested it in a randomized clinical trial with young men living in Chicago. They found that PrEPmate users were significantly more likely to maintain timely medical appointments and have high levels of tenofovir DF in their blood than participants who did not use PrEPmate.

The premise for PrEPmate

The idea for PrEPmate was based on Canadian adherence research. About a decade ago, Canadian scientists developed a pill-taking reminder using a simple text message for mobile telephones for use by HIV-positive people in East Africa. This was tested in a randomized clinical trial in Kenya among people taking HIV treatment (ART) and was found to help improve the ability of people to achieve and maintain a suppressed viral load.

Subsequently, researchers in San Francisco developed PrEPmate based on the Kenyan study as well as data from PrEP users in a pilot study.

According to the developers of PrEPmate, the intervention is “grounded in the information, motivation and behavioural theory of behaviour change.” PrEPmate includes text messages and an online presence, all designed to enhance adherence to PrEP among young MSM. The program sent out “check-in” messages as well as daily reminders about pill-taking accompanied by what the researchers called “fun facts and trivia.” The daily reminders were sent out for the first two weeks after participants initiated PrEP, “with the option to continue to receive reminders throughout the study.” Pill-taking reminders were sent at a time chosen by the participants.

Participants using PrEPmate who sought support from the study staff were contacted by text or telephone. The online component of PrEPmate included information about PrEP as well as videos by young people who had taken PrEP outside of the study. The researchers stated that there was also a password-protected user forum that was moderated by staff where participants could “discuss PrEP-related issues with other participants using PrEPmate.”

PrEPmate was compared to the standard of care associated with PrEP-taking, which researchers stated has the following components:

  • “HIV risk assessment”
  • “brief adherence and risk reduction counselling”
  • “clinical evaluation and medical management”
  • “access to a pager to reach a clinician whenever needed”
  • viewing a video “explaining how PrEP works in the body”
  • “receiving reminders for clinic visits via phone calls per the local clinic standard”

Researchers excluded volunteers who could not commit to the regular clinic and laboratory visits that are needed to accompany the use of PrEP.

Study details

Participants were randomized in a 2:1 ratio to receive either PrEPmate (81 men) or the standard of care (40 men) for 36 weeks. All participants received free PrEP from the study clinic. To try to simulate conditions in the world outside of a clinical trial, participants still had to pay for clinic visits and laboratory services.

The average profile of participants upon entering the study was as follows:

  • age – 24 years
  • 95% identified as male and the remaining participants identified as “transgender or gender queer”
  • major ethno-racial groups: 36% Hispanic, 28% Black, 26% white
  • 73% disclosed problematic levels of drinking
  • 21% tested positive for chlamydia, gonorrhea or syphilis
  • symptoms of depression were relatively common among all participants; after randomization, such symptoms were found in 40% of participants who were assigned to receive PrEP and 22% of participants who were assigned to receive the standard of care


Overall, researchers found that participants who used PrEPmate compared to people who used the standard of care were significantly more likely to have the following:

  • completed more of the required clinic visits –  86% vs. 71%
  • high protective concentrations of tenofovir in their blood – 72% vs. 57%

These differences remained significant after researchers took into account whether or not a person had symptoms of depression. Furthermore, factors such as race/ethnicity, income, education level and having private insurance coverage had no impact on the study’s results.

Although these results are very encouraging, toward the end of the study (around week 36) the researchers found the following disappointing trends: More participants from both study groups missed clinic visits and “only 57% of PrEPmate participants had protective tenofovir [levels in their blood], suggesting that additional efforts may be required to sustain long-term adherence.”

Adverse events

The unfortunate events that can occur in a clinical trial are called “adverse events” by researchers. These can be caused by study drugs, pre-existing health problems or other issues such as accidents. In the present study, only one serious adverse event occurred: One young man developed severe depression and thoughts of suicide. He was in the standard of care group. Although investigation revealed that his illness was not caused by the study drugs, his doctor removed him from the study so that his depression could be treated.

Sexually transmitted infections

No participants developed HIV infection.

Over the course of the study, researchers found that rates of other STIs fell among participants.

Views and use of PrEPmate

Researchers surveyed participants who used PrEPmate and found that it was viewed favourably, as follows:

  • 88% reported that it was “very/somewhat helpful”
  • 83% reported that they wanted to continue using PrEPmate after the study ended
  • 92% would recommend PrEPmate to other people

The majority (61%) of requests for assistance via PrEPmate during the study were for help securing clinic appointments. Only 14% of requests were for counselling and the remainder of requests were for a wide variety of issues.

Bear in mind

Adherence is a problem for many people who have to take medicines daily, whether because of high blood pressure, abnormal cholesterol, type 2 diabetes or the treatment or prevention of HIV infection, and there is no simple and perfect adherence support intervention. In this context, the development and testing of an adherence and support tool such as PrEPmate is useful. This multi-component smartphone intervention was found to be generally effective at keeping a majority of young participants engaged in medication-taking and regular clinic visits. PrEPmate is a good step forward in helping to maintain adherence to Truvada, at least over the short term. However, given the decrease in adherence over the long-term, PrEPmate likely requires further refinement.

Smartphones are widely used, particularly by young people. Therefore, it is likely that there will be an increased focus on adherence interventions that involve smartphones for PrEP in the future.


Oral pre-exposure prophylaxis (PrEP) – Fact sheet

Canadian guidelines on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis – Biomedical HIV Prevention Working Group of the CIHR Canadian HIV Trials Network (CTN)

La prophylaxie préexposition au virus de l'immunodéficience humaine : Guide pour les professionnels de la santé du Québec – Ministère de la Santé et des Services sociaux du Québec (French only)

Guidance for the use of Pre-Exposure Prophylaxis (PrEP) for the prevention of HIV acquisition in British Columbia  – B.C. Centre for Excellence in HIV/AIDS

8 Questions About PrEP for Guys – Client resource available online and in print

PrEP for understudied populations: Exploring questions about efficacy and safetyPrevention in Focus

Pre-exposure prophylaxis (PrEP) resources

—Sean R. Hosein


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