PrEP in random schemes provide extra options, but adherence is much better with daily PrEP dosing

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Tim Holtz and Sharon MannheimerFor some people in some settings, less frequent PrEP regimens with therapeutic doses associated with sexual activity are feasible, with a large number of sexual acts protected by PrEP, suggest some of the studies that were presented on Monday for the 8 International AIDS Society Conference in Vancouver.

This can give people, who want to use PrEP, and their doctors, some additional options, allowing people to find a PrEP pattern that suits them best. But studies have also found that more and more people can join daily PrEP than non-daily regimens. In addition, the actual effectiveness of "random" schemes remains uncertain.

The studies presented today were in part inspired by the French study known as IPERGAY, which is, so far, the only study that demonstrates that a random Prep schedule, with pre and post dose doses, can be effective. (It was 86% lower the incidence of infections). However, IPERGAY was conducted in a population of homosexual men who tended to have sex very often. To avoid transmission during anal sex, four doses per week appear to be almost equivalent to seven doses. However, it is possible that people who deal less frequently - and therefore take pills less frequently - will have lower levels of the drug in the body, which can result in ARV concentrations that are not efficient protectors.

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Presented in Vancouver on Monday afternoon, HPTN 067 / ADAPT is a group of three randomized trials evaluating the feasibility and acceptability of different PrEP schemes with three distinct populations in Bangkok, Harlem, New York, and Cape Town. The studies provided insights into usage and adherence patterns, but were not designed to answer questions about their efficacy. Major, phase-specific, specific trials would be needed to arrive at a definitive conclusion on the subject.

The researchers found that in a group of well-educated, well-motivated Thai gay men, each of the three PrEP regimens tested were considered viable and acceptable and would probably protect against the vast majority of HIV virus exposures. Random schemes require much less tablets.

Challenging social conditions most commonly experienced by participants in Harlem and Cape Town, membership was generally worse at both locations. In addition, the daily schedule resulted in better adherence and more effective protection against HIV than likely to protect Random PrEP options.

The studies

In each of the cities, approximately 180 participants were recruited and randomly assigned to receive one of three PrEP treatments with Truvada

  • Daily dosage,

  • Twice weekly dosing + one extra dose after sex or

  • Event-driven dosages (one dose up to 48 hours before intercourse and another up to 2 hours after intercourse).

They were followed up for a period of six months. Adhesion was measured by delivering PrEP pills into enclosures that sent an electronic signal when opened. Weekly participants were called and information about recent sexual activity was collected, which was correlated with data from when the pills were taken.

The populations of the three cities mixed diverse social, cultural and demographic groups. The researchers hoped for a way to influence and verify the acceptability of different schemes - they did not expect to find a therapeutic scheme that would be appropriate for the general population.

  • Bangkok, Thailand: 176 men who have sex with men and two transgender women. Most were college students, some were unemployed, and the average age was 31. Participants had sex on average once a week.

  • Harlem, New York, United States of America: 176 men who have sex with men and three transgender women. More than two-thirds were unemployed and more than two-thirds were black. Average age was 30 years. Participants had sex on average once a week.

  • Cape Town, South Africa: 179 women. Four-fifths were unemployed, a similar proportion was single, and the mean age was 26 years.

Results

At all sites adherence was slightly higher for daily PrEP activities, rather than random doses. For example, in Bangkok, 85% of the daily doses, 79% of two weekly doses and 65% of "event-driven" doses were taken as prescribed. In Harlem, the respective figures were 65%, 46% and 41%.

The first analysis was the percentage of sexual acts that were protected by PrEP, with doses before and after sex.

In Bangkok, the daily scheme had protected 85% of sexual acts, twice the weekly scheme that had protected 84% and those of the "event-oriented" schemes had protected 74%.

  • In Harlem, the daily scheme had protected 66% of sexual acts, twice the weekly scheme that had protected 47% and those of the "event-oriented" schemes had protected 52%.

  • In Cape Town, the daily scheme had protected 75% of sexual acts, twice the weekly scheme that had protected 56% and those of the "event-driven" schemes had protected 52%.

The doses that were missed were more often missed by those who were instructed to perform PrEP after sex (both in the twice weekly regimen and in the event-driven regimens). Participants are often in a situation that makes it difficult to take this dose when they are still with a sexual partner or when away from home. Translator's note: The text does not say, but it is clear that casual sex can happen and not all people, to say nothing, would walk with a 'utility belt' like Batman's, that would bring the face to perform an operation of PrEP and there is still the risk of the partner inquiring what the "tablet" would look like.

The researchers also tested blood samples twice during the study to see if tenofovir could be detected, restricting the analysis to participants who reported having had sex the week before. In Bangkok, more than 90% of participants in each arm of the study had detectable tenofovir in the bloodstream, with no significant differences between study arms.

In contrast, participants from Harlem and Cape Town were more likely to have Tenofovir detected when they had been asked to take PrEP daily.

Six people for whom the PrEP prescription had become HIV-positive (five in Cape Town, one in Harlem) but each had low or insignificant levels of Truvada in their body.

An expected advantage with randomized regimens would be to reduce the number of tablets taken so that the side effects could be less frequent. However, the data so far collected did not show statistically significant differences in the experience of side effects between arms of the study. This may be partially due to the limited number of people in each arm of the study and the short follow-up period. The side effects that were reported (dizziness, headache, nausea, diarrhea, etc.) were mild and experienced mainly during the first two months of PrEP.

But random schemes do not require Truvada in a statistically significantly lower number, which could make PrEP more accessible. Sexual behavior did not differ in the different therapeutic regimens of PrEP.

Conclusions

Introducing the Bangkok data, Timothy Holtz summed up several advantages of daily regimens: It has been clearly proven that they are more effective, they can offer more protection, more forgiving of missed doses, and help people develop habits of taking daily pills. But he said that a random PrEP could be an option for those men who have few and rare sexual relationships as long as they know in advance when they are likely to do so. The results suggest some flexibility in how PrEP can be prescribed.

Robert Grant, who conducted the HPTN 067 / ADAPTAR studies, told a press conference that PrEP needs to be adaptable to different circumstances in life. And "non-daily use" is happening anyway: "People choose how they want to use Prep when they take it, and when not to take it," he said.

Written by Roger Pebody

Translated by Cláudio S. de Souza from the original published on 21º day July of 2015 in Non-daily PrEP regimens provide extra options, but adherence is often better with daily dosing (olink opens in another browser tab \. Mara Macedo

Editor's Note: Although PrEP is proving to be a breakthrough, and I must acknowledge that I know of a couple who remain in this ballad since long before the studies started and they already had two children who were born without HIV, I feel obliged to say that although it is said, nowadays, that the condom is only 98% effective, I have had sex with people who are divergent on a number of occasions, and there was never one that would "sink in" as long as we maintained a relationship; all this before my current marriage, to avoid that some people lend wings to their imaginations (...), I recommend that even using PrEP, make use of a condom, including you, a sex professional who eventually reads to me, since the condom does not protects "only HIV"; protects against syphilis, which is a disease on the rise, against gonorrhea, which has shown itself to be aggressive and resistant to almost, if not all, known antibiotics (yes, it can become an incurable disease and could even kill), protects against vaginosis, HPV, discharge and, what is very serious, prevents unplanned or unwanted pregnancies, which almost always lead to abortion, which I do not see as a solution (except in very specific cases) where even the mother of the pregnant woman is at risk of life .

PrEP? Yes!

No walks? No!!!!!!!!!!!

References

Holtz TH et al. HPTN 067 / ADAPTAR study: a comparison of the daily and non-daily prophylaxis pre-exposure dosage of Thai among men who have sex with men in Bangkok, Thailand. 8 International AIDS Society conference on HIV pathogenesis, treatment and prevention, Vancouver abstract MOAC0306LB, up to 2015.

Mannheimer S et al. HPTN 067 / ADAPTAR study: A comparison of daily and intermittent pre-exposure prophylaxis (PrEP) dose of HIV prevention among men who have sex with men and transsexual women in New York City. 8 International AIDS Society conference on HIV pathogenesis, treatment and prevention, Vancouver abstract MOAC0305LB, up to 2015.

Grant R et al. HPTN 067 / ADAPTAR methods and results of women in Cape Town. 8 International AIDS Society conference on HIV pathogenesis, treatment and prevention, Vancouver abstract MOSY0103, up to 2015.

The Cape Town results had previously been presented at CROI 2015 e reported on aidsmap.com

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