July 24, 2018

HIV prevention research advances unveiled at AIDS 2018

Written by International AIDS Society

This press release originally appeared on AIDS 2018. Reposted with permission.

24 July 2018 (Amsterdam, The Netherlands) – The results of several important HIV prevention studies were announced today at the 22nd International AIDS Conference (AIDS 2018). This includes research confirming that “treatment as prevention” and “on-demand PrEP” are highly effective prevention strategies for men who have sex with men (MSM), and encouraging new long-term data from a major HIV vaccine study.

“This is a new era in HIV prevention, and these studies help point the way forward,” Linda-Gail Bekker, President of the International AIDS Society and International Chair of AIDS 2018, said. “If we deliver prevention advances where they’re needed most and at scale, we can greatly reduce the number of new infections worldwide.”

Today’s press conference highlighted five HIV prevention studies, selected from nearly 3,000 scientific abstracts being presented at AIDS 2018.

Note: Press summaries are based on abstracts; final data presented at the conference may change

Study confirms viral suppression prevents HIV transmission in gay male couples

The PARTNER2 study was designed to provide precise estimates of HIV transmission risk through condomless sex in “serodifferent” gay male couples (one partner is HIV positive and the other is HIV negative) in which the HIV-positive partner is virally suppressed through antiretroviral treatment. Previous studies, including PARTNER1 and Opposites Attract, found no cases of HIV transmission in these kinds of couples, but the level of evidence has remained less than for heterosexual couples.

The study enrolled 972 serodifferent gay couples in 14 European countries. Couples were eligible if they reported condomless sex, if the HIV-negative partner did not report using pre- or post-exposure prophylaxis (PrEP or PEP), and if the HIV-positive partner was virally suppressed.

The results showed that despite almost 75,000 condomless sex acts, there were zero cases of HIV transmission between the partners. Alison Rodger of University College London reported that this gives a precise rate of zero for within-couple HIV transmission, with a high degree of statistical confidence. [Summary based on submitted abstract; updated data may be presented on site.]

Abstract: Risk of HIV transmission through condomless sex in MSM couples with suppressive ART: The PARTNER2 Study extended results in gay men

Session: AIDS 2018 Co-Chairs’ Choice (Hall 12; Wednesday, 25 July, 11:00-12:30)

New evidence that on-demand PrEP is highly effective in MSM

Results from Prevenir, an ongoing observational study, provided further evidence that on-demand PrEP is an effective strategy for preventing HIV acquisition in at-risk MSM. On-demand PrEP involves taking a pill containing tenofovir plus emtricitabine (TDF/FTC) before and after sex, rather than daily.

Prevenir builds on the results of a previous study, IPERGAY, with data from a cohort of 1,435 at-risk, HIV-negative individuals, nearly all of them MSM, in the Paris region. At enrolment, 44% of participants used PrEP daily and 53% used it on demand.

Jean-Michel Molina of the University of Paris Diderot reported that, so far, the study had found no breakthrough HIV infections among men taking PrEP “on demand” or those taking it daily, supporting continuing use of both dosing regimens in this population. No study participants discontinued PrEP for drug-related adverse events. [Summary based on submitted abstract; updated data may be presented on site.]

Abstract: Incidence of HIV-infection in the ANRS Prevenir study in Paris region with daily or on-demand PrEP with TDF/FTC

Session: PrEP: Work in progress (Elicium 1; Wednesday, 25 July, 14:30-16:00)

Feminizing hormone therapy may reduce PrEP efficacy among transgender women

Concerns about potential interactions between feminizing hormone therapy and PrEP have hampered PrEP uptake among transgender women. The iFACT study in Thailand studied PrEP use in 20 transgender women who had never undergone orchiectomy (removal of the testicles) and had not received injectable feminizing hormone therapy within six months. Study volunteers started taking feminizing hormone therapy at the beginning of the study, and began taking PrEP in week three.

Akarin Hiransuthikul of the Thai Red Cross AIDS Research Centre reported the study results, which showed lower plasma tenofovir exposure in the presence of feminizing hormone therapy. These data suggest that feminizing hormone therapy may affect PrEP efficacy among transgender women. Further studies are warranted to determine whether these reductions in tenofovir are clinically significant. [Summary based on submitted abstract; updated data may be presented on site.]

Abstract: Drug-drug interactions between the use of feminizing hormone therapy and pre-exposure prophylaxis among transgender women: the iFACT study

Session: PrEP in the real world: What are we learning? (Hall 11B; Tuesday, 24 July, 13:00-14:00)

Innovative research on “digital PrEP”

Researchers reported positive results from a study of “digital PrEP,” a novel formulation of the PrEP pill that has a tiny, embedded, ingestible sensor.

Once the sensor reaches the stomach, it transmits a signal to a patch worn by the patient, and a digital record is sent to an app on the patient’s mobile device. With the patient’s permission, this data would be accessible to healthcare providers, allowing for near real-time remote confirmation and adherence support.

The single-arm, open-label study, presented by Sara H Browne of the University of California San Diego, enrolled 60 HIV-negative men who wished to take PrEP. Results showed that digital PrEP was pharmacokinetically equivalent to regular PrEP, and 92% of participants reported having a positive experience with the system. [Summary based on submitted abstract; updated data may be presented on site.]

Abstract: Digital Pre-Exposure Prophylaxis (PrEP): near real-time remote capture of medication ingestion for clinical use in trials and adherence support

Session: Poster exhibition (Tuesday, 24 July, 10:00)

Positive new long-term data from APPROACH HIV vaccine study

Researchers presented encouraging new long-term data from APPROACH, a Phase 1/2a study evaluating the safety and immunogenicity of several different HIV vaccine regimens. The study enrolled nearly 400 HIV-negative adults in the United States, East Africa, South Africa and Thailand.

Frank Tomaka of Janssen Research & Development reported the study results, which showed that participants who received the most promising regimen achieved high and persistent immune responses that were maintained until week 78 (30 weeks after the fourth dose).

Data from APPROACH have already helped lead to a proof-of-concept efficacy study in women at risk for HIV. That study, known as Imbokodo, is now taking place in sub-Saharan Africa. [Summary based on submitted abstract; updated data may be presented on site.]

Abstract: Long-term data from APPROACH: Phase 1/2a randomized, double-blind, placebo-controlled study evaluating safety/tolerability and immunogenicity of vaccine regimens using combinations of Ad26.Mos.HIV, MVA-Mosaic and gp140 envelope protein

Session: From conception to delivery: The vaccine discovery pipeline (E105-108; Tuesday, 24 July, 11:00-12:30)