The International AIDS Society 2019 Conference on HIV Science convened with new and updated information on treatment, prevention, cure, and vaccine research, along with research into the fundamentals of HIV science and how to bring that science to the people at highest risk for HIV.
Track A – Basic science
On Monday, July 22, Jonathan Karn (Case Western Reserve University) presented data suggesting a relationship between estrogen and the latent reservoir. Leukapheresis samples from 12 adults on fully suppressive antiretroviral therapy (ART) were analyzed for estrogen receptor-a-1 interaction and its association with the emergence of HIV from reservoir cells. The researchers found that estrogen exposure “nearly completely blocked viral spread” in women before and after menopause. The same wasn’t true in men.
On Wednesday, Katherine Bricker (Emory University School of Medicine, Pediatric Infectious Diseases) presented findings on whether GS-986, a Toll-like receptor 7 agonist produced by Gilead Sciences, could reverse cell latency in simian immunodeficiency virus-infected and virally suppressed infant rhesus macaques. The team found that GS-986 was associated with no adverse clinical events and increased immune activation in IL-6 and I-TAC, and that the macaques remained virally suppressed. Gilead Sciences plans to study the agonist in combination with a vaccine in the effort to find a way to clear viral reservoir and cure HIV.
Track B – Clinical science
IAS 2019 saw several HIV antiretroviral trials that showed that new drugs durably suppressed HIV and served those most in need. On Monday, Max Lataillade (ViiV Healthcare) presented 96-week data on the entry inhibitor fostemsavir in patients with resistance to several classes of HIV drugs. The drug binds to the HIV envelope gp120, preventing HIV from entering cells. By week 96, 60% of participants with 1 or 2 HIV drug classes remaining and baseline viral load of 400 copies/mL achieved viral suppression. That’s an increase of 6% from week 48.
Also on Monday, Rebecca Zash (Botswana Harvard AIDS Institute Partnership) provided an update on the rate of neural tube defects in pregnancies among women taking dolutegravir at conception. At AIDS 2018, Zash presented data showing that the rate of neural tube defects was 0.93% in women on dolutegravir, compared with 0.8% in women without HIV. The new data showed that the neural tube defect rate had dropped to a rate of 0.30% for women on DTG at conception.
Then on Wednesday, 2 trials of 2-drug regimens were presented. Jean-Michel Molina (St-Louis Hospital and University, Paris) presented a phase 2b, randomized, double-blind dose escalation trial of 121 treatment-naive people living with HIV. The patients received either Merck’s investigational ARV islatravir (ISL) plus doravirine (DOR) or DOR/lamivudine/tenofovir disoproxil fumarate. At 48 weeks, 89.7% of ISL/DOR participants achieved viral suppression with 0.25 mg of ISL plus 100 mg of DOR. Five people on ISL/DOR experienced treatment failure, vs one in the DOR/3TC/TDF arm.
Track C – Prevention
Islatravir also made an appearance on the prevention stage. Randolph Matthews (MSD) presented a 16-participant phase 1 pilot trial of the drug as preexposure prophylaxis (PrEP) and delivered in a polymer implant, similar to the contraceptive implant the company makes. At 12 weeks, participants receiving the 54 mg implant had drug levels above 0.05 pmol/106, the concentration at which the company thinks it will protect people from HIV. The drug was well-tolerated, with minor side effects, including headache.
The HOPE OLE trial also presented its final phase 3 data on the dapivirine vaginal ring for prevention. In 2016, the ring was found to be 27% effective in protecting women from HIV. In 2018, women receiving the ring had an HIV incidence of less than 2%; the HOPE trial wasn’t designed to determine efficacy. This year, Jared Baeten (Global Health, University of Washington Seattle) reported that the long-term follow-up of the trial ended with an HIV incidence rate of 2.7 per 100 person-years, compared with an expected incidence rate of 4.4 per 100 person-years.
Track D – Social, behavioral, and intervention science
In an attempt to reengage men who have sex with men in HIV care and reach viral suppression, Chris Beyrer (Johns Hopkins Bloomberg School of Public Health, Epidemiology) presented data from HPTN 078, a randomized trial using enhanced case management vs standard of care. 154 MSM living with HIV and out of care were enrolled in Birmingham, AL; Atlanta, GA; Baltimore, MD; and Boston, MA. But when they looked at who reached viral suppression by 12 months, there was no difference in viral suppression between groups; rates were 48% across groups.