HIV prevention research was in the spotlight yesterday at the second full day of presentations at the 10th International AIDS Society Conference on HIV Science (IAS 2019). To share some highlights from those studies, Carl Dieffenbach, Ph.D., Director of the Division of AIDS at NIH’s National Institute of Allergy and Infectious Diseases (NIAID), and his colleague Anne Rancourt joined us for a Facebook Live session. They discussed research about a new experimental implantable form of HIV pre-exposure prophylaxis (PrEP), additional analysis of a drug combination being considered for PrEP, and findings from two studies that looked deeper into population characteristics and transmission dynamics to better inform HIV prevention and treatment interventions.
Here’s additional information on the issues and study findings that Dr. Dieffenbach highlighted:
- PrEP implant trial: Investigators presented results of a small phase 1 trial of a long-acting implantable form of PrEP. This first-in-human study tested the safety, tolerability, and pharmacokinetics of a matchstick-sized device that is implanted below the skin of the upper arm and that slowly releases a new anti-HIV drug, islatravir. After 12 weeks, researchers found that the implants were generally well tolerated and drug concentrations in the body were above target levels anticipated to be needed for protection. They then conducted modeling studies to predict drug concentrations over longer periods of time and found that the implant could potentially deliver a protective drug level for one year. Dr. Dieffenbach explained that the next steps in evaluating this experimental new form of PrEP include further discussions with regulators and design of larger, next-phase studies to assess safety, efficacy, and durability. He noted that having multiple forms of PrEP delivery is important for providing options in the future to people who want protection from HIV but find adherence to a daily pill to be challenging. Read the abstract, “First-in-human trial of MK-8591-eluting implants demonstrates concentrations suitable for HIV prophylaxis for at least one year.”
- Potential new form of daily oral PrEP: Researchers presented updates from DISCOVER, a trial designed to determine the safety and efficacy of tenofovir alafenamide (TAF) in combination with emtricitabine (FTC) for HIV prevention. The trial compared this new medication, known as F/TAF and marketed as Descovy, to the approved PrEP regimen of tenofovir (TDF) together with FTC (known as F/TDF and marketed as Truvada). 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. Based on those findings, the manufacturer has submitted a supplemental new drug application to the U.S. Food and Drug Administration requesting approval for use of the drug as PrEP. Dr. Dieffenbach explained that among the additional findings about F/TAF presented at IAS 2019 were that it takes effect more quickly and protective levels of the drug last longer. Read the 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.”
- Analysis of HIV transmissions by age and sex to inform interventions: Researchers also presented new data from the PopART study that provided insights into how HIV is spread across sexual networks in Zambia and South Africa. The results highlighted the significant contribution of young people under 35, especially 25- to 29-year-old men, in onward transmission of HIV in southern Africa and the need to tailor prevention and treatment engagement efforts accordingly. Dr. Dieffenbach underscored the study finding that men ages 25 to 30 transmitted HIV to younger women at twice the rate that younger women transmitted the virus to older men. Engaging young people in HIV prevention and treatment services that work for them, Dr. Dieffenbach observed, is a universal need applicable to all countries and communities. Read the 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.” Another session shared lessons learned from the PoPART trial.
- Insights on engaging hardly reached populations: Dr. Dieffenbach also discussed an NIH-funded study that evaluated strategies to identify and support men who have sex with men and transgender women with unsuppressed HIV in the United States. Dr. Dieffenbach described these individuals as “hardly reached” by HIV services, rather than “hard to reach,” noting that the new language more accurately describes the fact that effective HIV services were not reaching them. He noted that researchers found a high number of individuals who knew their HIV status but were not engaged in HIV care because they had found that the healthcare system didn’t meet their needs and/or they had many other social, economic, or health conditions that interfered with their ability to enter and remain in HIV care. But once they were reached, most of this population could be engaged in care, and half of the study participants had achieved viral suppression after one year. View the abstract “HPTN 078: primary results of a randomized study to engage men who have sex with men (MSM) living with HIV who are virally unsuppressed in the US.” Read the related NIAID press release, “Connection to HIV Care Helps Hardly Reached U.S. Populations Suppress the Virus.”
Final Research Update on Wednesday
Many of the scientific research advances behind today’s successful HIV treatment regimens and prevention interventions were first presented at conferences such at this. These advances are the foundation of Ending the Epidemic: A Plan for America, the once-in-a-generation opportunity to end the epidemic. HIV.gov will share one more update on the latest HIV research from the conference on Wednesday, July 24. Follow HIV.gov on Facebook or Twitter for schedule updates and reminders.
About the Conference
The biennial IAS Conference on HIV Science is the largest open scientific conference on HIV and has assembled more than 5,000 participants from more than 140 countries. This conference presents the latest critical advances in basic, clinical, and operational research that move science into policy and practice. Findings from research supported by the NIH as well as the Centers for Disease Control and Prevention and USAID are among the more than 1,000 abstracts being presented.
Read more about Long-Acting HIV Prevention Tools.