R4P Conference Highlights

R4P Highlights
HIV Research for Prevention Conference Presents Hope and Innovation
by Chip Alfred

Over the course of four days in late January and early February, the International AIDS Society (IAS) hosted the HIV Research for Prevention (HIVR4P) Virtual Conference, the world’s only scientific meeting dedicated exclusively to biomedical HIV prevention. The biennial conference brought together 1,800 researchers, advocates, funders, and policy makers from eighty-five countries. The first two days, January 27–28, focused exclusively on HIV prevention, while a separate two-day conference on February 3–4, centered on HIV research and its intersection with the COVID pandemic. “It’s a chance for us all as a community to reflect on one of the most productive eras in HIV prevention science,” remarked one of five conference co-chairs Mitchell Warren, Executive Director of AVAC, as he welcomed conference attendees. Of course, the conference wasn’t just about looking at how far we’ve come; it also offered a deep dive into some of the latest research projects and new developments on the horizon.

Laptop monitor with nine people in a video call. Front view isolated on a white background.

There was much discussion about the results from the Phase III Antibody-Mediated Prevention (AMP) trials. The VRC01 antibody was originally discovered in the blood of a patient living with HIV and mass-produced in the laboratory as a monoclonal antibody. It is the same process being used to treat COVID-19 patients. According to trial leader Dr. Lawrence Corey, virologist and professor at Fred Hutchinson Cancer Research Center in Seattle, this study showed that just as combinations of different antiretroviral drugs are needed to treat HIV, combinations of more potent antibodies might be able to prevent it. “The trial, as a test of concept, was wonderfully successful and sets the landmark that we can use broadly neutralizing antibodies for the prevention of HIV,” Corey concluded. “That will be a new modality and a new toolbox, and it opens up the field.”

HIVR4P also hosted the presentation of interim results from HPTN 084, which was conducted on women 18-45 in seven countries in sub-Saharan Africa. Results from the study on the long-acting injectable antiretroviral drug cabotegravir for PrEP in women showed that the drug is safe and effective in women and that it is more effective than daily pills in preventing HIV acquisition in women. Principal investigator Dr. Sinead Delany-Moretlwe of the University of Witwatersrand in Johannesburg hailed the result as a major step forward for HIV prevention for young women. Cabotegravir has the potential to increase choice and overcome some of the barriers related to adherence for long-term use of biomedical HIV prevention.

Islatravir is an antiretroviral drug with a novel mode of operation that has generated a lot of interest because of its extraordinary persistence in the body. This means it may only need to be given once a week for HIV treatment, and a subcutaneous implant that releases the drug might only need to be replaced once a year when used for PrEP. Pending the results from studies of an implant, however, a study presented at HIVR4P showed that islatravir as PrEP can also be given very easily as a pill that only needs to be taken once a month. Professor Sharon Hillier of University of Pittsburgh Magee-Womens Research Institute presented the results of a Phase IIa study, which showed that the once-monthly dose “provides enough forgiveness for people to be a couple of weeks late in taking their next dose. People could go to a pharmacy once a month and either take it right there or take it home with them. This would be ideal for people who don’t want an injection but also don’t want to risk the discovery of a bottle of pills.”

As the conference was about to begin, the WHO recommended the dapivirine vaginal ring (DPV-VR) as a new choice for HIV prevention for women at substantial risk of HIV infection. The DPV-VR is worn inside the vagina, where it releases the antiretroviral drug dapivirine slowly for a period of twenty-eight days. After that time, it should be replaced by a new ring.

Two Phase III randomized controlled trials found that using the DPV-VR reduced the risk of HIV infection in women and long-term use was well-tolerated. The Ring Study demonstrated an HIV reduction of 35% among women using DPV-VR, and the ASPIRE study showed a 27% reduction in risk. Results from the open-label extension studies of the trials showed increases in ring use and modeling data suggest greater risk reduction—by over 50% across both studies—compared to the Phase III trials. Early phase studies of the DPV-VR as a Multi-Purpose Prevention Technology, combining contraception with HIV prevention by adding the hormone levonorgestrel, are encouraging but also indicate a need for reformulation.

Chip Alfred is A&U’s Editor at Large, a public speaker, and a media and public relations consultant based in Philadelphia. Follow Chip on Twitter @ChipAlfred.