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AMSTERDAM -- No breakthrough cases of HIV infection were reported so far among HIV-negative adults -- mainly men who have sex with men (MSM) -- at high risk of acquiring HIV, using pre-exposure prophylaxis (PrEP), a researcher said here.
HIV infection incidence stood at precisely 0 per 100 person-years in patients who used daily PrEP (with 443 person-years of follow-up) and patients who used on-demand PrEP (with 506 person-years of follow-up), reported Jean-Michel Molina, MD, of the Saint-Louis Hospital in Paris.
"That's remarkable. That shows the incidence of HIV in this cohort is actually zero today," Molina said at a press conference at the
He said that results of the IPERGAY study two years ago showed high efficacy of on-demand PrEP to prevent HIV infection among MSM. Moreover, the dosing regimen was approved in Europe and endorsed by Australian, Canadian, and British guidelines, Molina added. But researchers wanted to provide "real world experience on dosing experience for PrEP" for this population, and confirm the public health impact of PrEP on the HIV epidemic.
Myron Cohen, MD, of the University of North Carolina at Chapel Hill, who was not involved with the research, said that these findings support previous research, and "reinforce the utility of these agents for prophylaxis."
"The results shine a light on the apparent 'forgiveness' of TDF/FTC, where less drug less often seems sufficient," he told 鶹ý.
The ANRS PREVENIR study started in May 2017, and is an ongoing study in the Paris region. Overall, 3,000 patients will be enrolled -- 85% of which are MSM. As of July 2018, there were 1,628 patients enrolled across 22 sites.
Patients were a mean age of 37, and about 99% were MSM. They could either opt for a daily regimen of tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) or on-demand TDF/FTC, and were allowed to switch regimens. They were followed up every 3 months with a 4th Gen ELISA HIV test, and were screened for sexually transmitted infections (STIs) at the discretion of their provider. Participants also received condoms, gels, risk reduction, and adherence counseling.
About 55% of participants used on-demand PrEP, with 45% using the daily regimen. The daily group also reported a significantly greater median number of condomless sex acts in the prior 4 weeks (3 versus 2 in the on-demand group, P<0.001) and a significantly greater median number of sexual partners in the prior 3 months (15 versus 10, respectively, P<0.001).
Molina and colleagues found that 96% of participants used PrEP correctly, which Molina characterized as "encouraging" and said that this showed that patients benefited from the counseling they received at the clinic. About 20% of patients used a combination of condoms and PrEP. They also noted that PrEP was "well-tolerated" with no patients discontinuing the drug due to an adverse event.
The authors said that a modified intent-to-treat analysis found that 85 HIV infections were averted, assuming an incidence of HIV infections of 9.17 per 100 person years, as observed in the IPERGAY study.
"This strengthens the case for the use of on-demand PrEP for people who want to use on-demand and people who are not willing to commit to a daily option," Molina said.
The primary objective of the PREVENIR study is to show a ≥15% reduction in HIV diagnoses among MSM in Paris compared with numbers from the National Surveillance Network by the study's conclusion in May 2020.
"In the future, we want to [enroll] participants from other populations, such as transgender and heterosexual men and women at high risk of HIV infection," Molina said in a statement.
Disclosures
The authors disclose support from Gilead, Merck, ViiV, and Teva.
Primary Source
International AIDS Conference
Molina J-M, et al "Incidence of HIV-infection in the ANRS Prevenir study in Paris region with daily or on-demand PrEP with TDF/FTC" IAC 2018; Abstract 13278.