PrEP, HIV Treatment, and Social Determinants: Key Highlights from CROI 2016

By Sean Dickson March 8, 2016

The 2016 Conference on Retroviruses and Opportunistic Infections (CROI) provided a bevy of exciting updates in HIV prevention and treatment, with important developments in new Pre-Exposure Prophylaxis (PrEP) modalities and sobering modeling of the current state of the epidemic. Below, NASTAD outlines some of the most exciting developments from the conference. Additional summaries of specific studies can be found at the National AIDS Treatment Advocacy Project (NATAP) website, and full conference presentations are available at the CROI website.

PrEP: New Modalities, Effectiveness, and STI Considerations

PrEP was a significant focus at CROI 2016. Presentations demonstrated important advances in evaluating long-acting injectable (LAI) cabotegravir as a PrEP modality: in one study, LAI cabotegravir was well-tolerated among men who have sex with men (MSM) at low-risk for HIV infection and preferred relative to daily oral PrEP; in another study, LAI cabotegravir showed significant efficacy in macaque models designed to study the efficacy of PrEP for people who infect drugs. Two trials of the dapivirine vaginal ring demonstrated very strong efficacy in preventing HIV infection in heterosexual African women, though the effect was more pronounced among women over age 22 (who also demonstrated greater uptake). F/TAF, Gilead’s proposed replacement for Truvada, showed substantial efficacy in preventing rectal SHIV infection in a macaque model (demonstrating equivalent efficacy as previous Truvada trials). Maraviroc, a potential oral PrEP agent, showed promising results in a study among MSM, though it may need to be combined with FTC or TDF to achieve desirable levels of protection. A rectal microbicide formulation of TDF demonstrated acceptability similar to oral PrEP when administered when anal sex was anticipated, but daily administration was less acceptable.

Among CROI’s most sensational reports was a case study of one man acquiring multi-class resistant HIV in spite of demonstrated adherence to daily PrEP. Two sets of presentations discussed the impact of PrEP on renal function, both demonstrating mild impacts that resolved once PrEP was discontinued. Viewed holistically, these reports reiterate that PrEP is safe, well-tolerated, and exceptionally effective, but that physicians need to implement appropriate protocols to monitor individual renal function and for breakthrough infections.

Two important presentations on Sexually Transmitted Infections (STIs) both recommended increased screening frequency relative to Centers for Disease Control (CDC) guidelines. The presentations, from San Francisco and New York, both showed significant amounts of asymptomatic STIs at three-month screening intervals that would have gone undetected following CDC’s routine and symptomatic screening recommendations.

Treatment: New Modalities and Resistance and Early Treatment Implications

Both four and eight week dosing schedules of long-acting injections of cabotegravir+rilpivirine showed comparable antiviral activity to daily oral therapy. Transitions from dolutegravir to once-daily raltegravir showed comparable viral suppression, supporting a more patient-friendly regimen. Switching patients from F/TDF (Truvada) to F/TAF, Gilead’s planned replacement for Truvada, showed improvements in renal function and bone mineral density, though there remain questions as to clinical significance. In a Canadian cohort, trends show decreasing resistance to NRTIs, NNRTIs, and PIs, but resistance to integrase inhibitors increased (though still remained rare).

Early treatment of HIV during the hyperacute phase of infection appears to promote a lower viral set point and an improved response to therapeutic vaccines. In South Africa, same-day initiation of ART was found to significantly increase viral suppression.

Social Determinants: Modeling Incidence in Black and Latino MSM, Averting New Infections, and Addressing Transgender Health

The CDC released a scathing assessment of HIV incidence in Black and Latino MSM, modeling that current trends indicate that 1 in 2 Black MSM and 1 in 4 Latino MSM will acquire HIV during their life, compared to 1 in 11 White MSM. CDC also modeled, however, that over 185,000 infections could be averted by 2020 through increases in testing, treatment, and PrEP access.

In an important move, CROI highlighted transgender health in a plenary presentation calling for increased attention to transgender health and research on HIV prevention and treatment that responds to the unique needs of transgender persons.

Did you attend CROI 2016? What were your key takeways? Tell us by leaving a comment below.