About The Study

This study tested to see if the pill TDF/FTC (Truvada®) can offer protection against HIV infection if taken on an intermittent or ‘on demand’ basis as pre-exposure prophylaxis (PrEP). The medication has been shown to have some effectiveness as a tool for preventing HIV when taken on a daily basis, but the effectiveness of daily PrEP is very much dependent on adherence to treatment. When compared to daily use, on-demand PrEP could have significant benefits such as easier adherence that would make the treatment more effective, as well as lower costs.


Risk of HIV infection continues to be a serious health concern. In Quebec, the rate of HIV infection rose between 1997 and 2002. Study researchers have noted that in 2009 men who have sex with men accounted for the highest population with new HIV diagnoses in Quebec. Current prevention strategies such as the use of condoms have been shown to be effective but also limited in a context of at-risk sexual behaviour. Study researchers seek to identify an additional approach to the prevention of HIV infection that can work with current measures such as the use of condoms.

Study Approach

Adult men who have sex with men, who are HIV-negative but who are exposed by their sexual relations to the risk of HIV infection, were recruited. The study was double-blind so neither participants nor researchers knew who was receiving the study drug or a placebo. Community representatives were directly involved in the implementation of the study and were consulted at all stages of the project.

Participants were randomly selected to either join the study drug arm or the placebo arm of the study. In addition to the placebo controlled study drug, all participants were asked to schedule regular visits to a clinic and be offered a complete prevention package to reduce risk (individual support, counselling, screening for HIV and sexually transmitted infections, condoms, lube, and vaccinations for hepatitis A and B).

This study was sponsored by the French National Agency for AIDS Research (ANRS) and was conducted in France and Quebec. In Canada, the study recruited 53 men without HIV infection into the study, the rest of the 400 participants were enrolled in France. Participants, who were randomized to receive the drug, took two pills in the 24-hour period before anticipated sexual intercourse and two separate single-pill doses in the two days following sex.


After a median follow-up of 9.3 months, there was a reduction of 86 percent in the incidence of HIV with on demand PrEP. Sixteen participants acquired HIV-infection after enrolment, 14 in the placebo arm and 2 in the Truvada arm. Participants used a median of 15 pills/month. Adverse responses to Truvada were minimal, the most common complaints being gastrointestinal and kidney issues. Overall, the researchers found that on demand PrEP with oral Truvada is highly effective to reduce the incidence of HIV-infection in high-risk men who have sex with men and has a good safety profile. Further CTN-supported analysis showed that this ‘on demand’ PrEP strategy ranges from cost saving to largely cost-effective. The government of Canada approved the use of Truvada as daily PrEP in February of 2016.

During a presentation at the AIDS 2016 Conference in Durban, South Africa, the results of the long-term follow-up portion of the study were presented. Participants in the long-term arm of the IPERGAY trial were followed for a median length of 11.7 months. The long-term use of Truvada as ‘on demand’ PrEP was found to be as effective at preventing HIV transmission as in the short-term study. The study found that, although condom use declined slightly, it did not have an effect on the ability of the drug to prevent HIV transmission rates. Only one participant (of 362), who had stopped taking PrEP as recommended, acquired HIV during the course of the study.

Principal Investigators

Here’s who is leading this study.

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