Jul. 23, 2019

New HIV prevention tools address realities of people’s lives

New HIV prevention tools address realities of people’s lives

New vaccine trial and early results from first human trial of PrEP implant revealed

23 July 2019 (Mexico City, Mexico) – New studies released at the 10th IAS Conference on HIV Science (IAS 2019) place the spotlight on progress that could completely change the HIV prevention landscape. These include advancements in oral pre-exposure prophylaxis (PrEP) delivery, long-acting implants and vaccines.

Providing additional context, a special issue of the Journal of the International AIDS Society (JIAS) shared results suggesting that while new HIV prevention technologies create an opportunity to improve HIV control, they must be rolled out with well-designed and managed campaigns to create an environment where people are empowered to protect themselves from HIV.

Implantable PrEP shows promise

Notably, researchers shared early but promising news about a potential implantable form of PrEP. A double-blind placebo-controlled Phase 1 trial assessed results from a single MK-8591(a novel nucleoside reverse transcriptase translocation inhibitor) or a placebo implant placed in subjects for 12 weeks (two doses: 54mg and 62mg).

The study found that the implant was well tolerated and effectively delivered the required level of MK-8591, which the authors project to be sufficient for at least one year. These early findings are promising and should encourage continued trials to assess longer-term results.

Abstract: First-in-human trial of MK-8591-eluting implants demonstrates concentrations suitable for HIV prophylaxis for at least one year

Session: Hot off the press: What’s new in HIV prevention (Tuesday, 23 July, 16:30 – 18:00; Palacio de Valparaíso 2)

“An implant offers another choice for those who might in the future also have pills and injectables available. It could also offer a promising solution to those who face challenges adhering to a daily PrEP regimen,” Anton Pozniak, International AIDS Society President and IAS 2019 International Scientific Chair said. “Taken together, the HIV prevention studies presented at IAS 2019 show that we are creating new tools to address the realities of people’s lives.”

Announcement of a new HIV vaccine trial

Although “treatment as prevention” and PrEP are transforming the prevention landscape, there is still a clear and urgent need for a preventative vaccine. IAS 2019 also featured analysis from the ASCENT trial, designed to assess safety and tolerability and Env-specific antibody responses of two different mosaic-based vaccine regimens.

This closely watched vaccine trial is a randomized, placebo-controlled Phase 2a study of healthy, low-risk, HIV-negative adults in Kenya, Rwanda and the United States. The study found that both regimens were well tolerated and immunogenic (26 clade C, 100 bivalent and 26 placebo).

Stemming from these results, the National Institutes of Health and partners last week announced plans to conduct a new Phase 3 HIV vaccine efficacy trial, “Mosaico”, at multiple clinical research sites in North America, South America and Europe.

Abstract: ASCENT: Phase 2a, randomized, double-blind, placebo controlled study evaluating safety and immunogenicity of two HIV-1 prophylactic vaccine regimens comprising Ad26.Mos4.HIV and either clade C gp140 or bivalent gp140

Session: Hot off the press: What’s new in HIV prevention (Tuesday, 23 July, 16:30 – 18:00; Palacio de Valparaíso 2)

“These are very promising times in HIV vaccine research, with multiple efficacy clinical trials ongoing, new approaches in development, and a growing sense that we may be getting closer to an effective vaccine,” said Roger Tatoud, Director of the Global HIV Vaccine Enterprise, which issued a statement on the new study today. “Beyond the scientific challenges ahead, however, the field continues to face the critical need to sustain and expand support for HIV vaccine research, plan for a range of possible study outcomes, and prepare the way for a potential future approval and use of an effective vaccine.”

Findings from the DISCOVER trial

Researchers presented updates from DISCOVER, a trial designed to determine the safety and efficacy of tenofovir alafenamide (TAF) in combination with emtricitabine (FTC).

The trial compared this to the already approved PrEP regimen of tenofovir (TDF) together with FTC. The study reported its primary outcomes earlier this year, finding that F/TAF was non-inferior to F/TDF as PrEP among the more than 5,000 participants in the trial.

There were no differences in HIV risk, STIs or adherence seen between the two arms of the study. However, a higher proportion of people on F/TAF – 98% – had intracellular drug concentrations above the threshold thought to confer protection from HIV (compared with 65% for people on F/TDF). The authors also estimated duration of protection using a range of trial and historic data, estimating that F/TAF provided a 60% longer duration of protection.

Abstract: DISCOVER study for HIV pre-exposure prophylaxis (PrEP): F/TAF has a more rapid onset and longer sustained duration of HIV protection compared with F/TDF
Christoph D. Spinner, University Hospital rechts der Isar, Germany

Session: Hot off the press: What’s new in HIV prevention (Tuesday, 23 July, 16:30 – 18:00; Palacio de Valparaíso 2)

New evidence from Latin America on same-day PrEP access

Specifically, researchers analysed the safety and benefits of offering same-day PrEP access to men who have sex with men in Brazil, Mexico and Peru.

Men who have sex with men account for most new HIV infections in Latin America, yet the use of PrEP remains very limited. In this large-scale demonstration study, men who have sex with men and transgender women were screened and, if eligible, enrolled on the same day and offered a 30-day supply of PrEP with TDF/FTC.

The researchers found the programme to be feasible and safe. Among men who have sex with men, the vast majority continued taking PrEP in the first 120 days and a high percentage adhered to their medications.

Abstract: Safety, early continuation and adherence of same day PrEP initiation among MSM and TGW in Brazil, Mexico and Peru: the ImPrEP Study

Session: Hot off the press: What’s new in HIV prevention (Tuesday, 23 July, 16:30 – 18:00; Palacio de Valparaíso 2)

“Despite the successful scale up of antiretroviral treatment in Latin America, our roll out of PrEP and other prevention tools has been slow,” Brenda Crabtree Ramirez, IAS 2019 Local Scientific Chair, said. “The evidence is clear: we need better and more tailored interventions to meet the needs of key and vulnerable communities, including trans people, women and girls, young people, sex workers and people who inject drugs."

Insights into how HIV is spread across sexual networks

A study used phylogenetic analysis to identify 180 probable transmission pairs and applied an individual-based model to predict changes in the HIV epidemic.

Both the model and phylogenetics analysis found that HIV transmission peaked in 25-29-year-old men and 20-24-year-old women. Modelling the prevention of all transmissions among men and women of the same age group projected that HIV transmission could be reduced by 20% and 19%, respectively.

These results confirm that young people contribute disproportionately to HIV transmission in sub-Saharan Africa, especially 25- to 29-year-old men, suggesting an urgent need to scale up testing and treatment programmes aimed at this demographic.

Abstract: Quantifying the Contribution of Different Aged Men and Women to Onwards Transmission of HIV-1 in Generalised Epidemics in Sub-Saharan Africa: A Modelling and Phylogenetics Approach from the HPTN071 (PopART) trial

Session: Thinking and doing: Novel conceptual and methodological approaches (Tuesday, 23 July, 13:00 – 14:00; Palacio de Valparaíso 1)

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