Intriguing Insights from CROI 2017

The poster session at CROI
CROI 2017 in Seattle, Washington.
Photo credit: CROI
headshot of Elizabeth Russell


Elizabeth Russell
Senior Advisor for Biomedical Prevention Technologies

Elizabeth Russell PhD, MSc, is a Senior Advisor for Biomedical Prevention Technologies in the Research Division of the Office of HIV/AIDS. She provides technical assistance for pre-clinical and clinical research projects supported by the U.S. Agency for International Development (USAID) for new microbicide products.

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Conferences are a time for opening up your mind to absorb the wide breadth of new scientific advances being shared and synthesizing that information to figure out how it influences strategic thinking for your little corner of this important work. The 2017 Conference on Retroviruses and Opportunistic Infections (CROI) covered multiple topics that influence USAID’s work to develop and deliver HIV prevention products for women in sub-Saharan Africa. These advances include research on new antiretroviral drugs, new technologies to deliver those drugs, and new insights on how the bacteria in the vagina are connected to HIV incidence and pre-exposure prophylaxis (PrEP) products in women. Here are some of my major takeaways from CROI 2017.

More Options for Prevention: Fewer Side Effects and Less Frequent Dosing

One CROI presentation introduced a drug, GS-CA1, in a new class of antiretroviral drugs called capsid inhibitors. This type of drug interferes with what is basically the bodyguard of the viral genome and, most importantly, can stop the HIV virus from replicating at multiple points. Because of this, a potential injection or implant would only need a small dose of the drug to protect users from HIV, limiting side effects, product size and costs. An equally exciting feature of this drug is that it stays in the body long after it’s delivered, with the potential for dosing only once a month or even less frequently. While the drug is still very early in development, it is definitely one to watch.

Long-acting HIV prevention options, particularly new ways to formulate drugs to reduce how often you have to take them, were the topic of many presentations at the conference. USAID-supported research on a long-acting biodegradable implant for HIV prevention was also presented. This research demonstrated the feasibility of a flexible device implanted beneath the skin, much like contraceptive implants on the market currently, which deliver drugs and do not require removal. Unlike other long-acting injectable prevention products being developed, antiretrovirals cleared the body within days of leaving the implant – meaning no long “tail” of residual drug remains, which could contribute to drug resistance if a woman were infected with HIV during this time – ultimately limiting her future treatment options. While the implant presented at CROI could protect against HIV for only 2–3 weeks, it’s already being tweaked back in the lab to provide protection for much longer periods of time. An effective biodegradable implant that could be delivered, for example, twice a year to coincide with every other contraceptive injection visit, has significant promise to offer women protection from HIV infection that easily integrates into their lives.

Vaginal Bacteria Does Not Stop Oral PrEP from Protecting Women

Another important session followed up on research presented last summer at the 2016 International AIDS Society Conference. At that conference, early research showed women using an antiretroviral gel for PrEP with certain bacteria in their genital tracts had increased rates of HIV infection and that possibly these bacteria had absorbed the vaginally-applied drug tenofovir, preventing it from being present if needed to stop HIV. The suggested PrEP combination with tenofovir may, therefore, be unlikely to work for the large proportion of women with these bacteria, many of whom are at higher risk for infection. At CROI, we heard research confirming this finding, but other research found that PrEP taken in pill form was effective in preventing HIV infection in women, regardless of the type of bacteria in their genital tracts when it was taken orally. More research will be needed to ensure vaginal products in development will be effective, but it is reassuring to know that oral PrEP can work for women.

New prevention products are on the horizon, which have a wide range of how often they are taken and how they are administered. As we’ve learned from the contraceptive field (and from women when they have been asked), when a woman has multiple options, she has a better chance to find a product that she can fit into her life and consistently use to stay healthy and lead her best life for herself and her family.

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