Final HIV Prevention & Treatment Research Highlights from CROI 2021

NIAID Now | March 12, 2021

Hillary Hoffman interviews NIAID's Dr. Carl Dieffenbach about research from the final day of CROI 2021.

Credit: HIV.gov

Cross-posted from HIV.gov

As the 2021 virtual Conference on Retroviruses and Opportunistic Infections (CROI) concluded, NIH’s Dr. Carl Dieffenbach joined HIV.gov for a conversation about the latest HIV prevention and treatment research presented there. Dr. Dieffenbach is the Director of the Division of AIDS at NIH’s National Institute of Allergy and Infectious Diseases (NIAID). In his conversation with colleague Hillary Hoffman, he highlighted research into new forms of biomedical HIV prevention, advances in monoclonal antibodies for prevention of both COVID-19 and HIV, and findings on HIV treatment regimens for pregnant women. Watch the conversation with Dr. Dieffenbach:

Some highlights of Dr. Dieffenbach’s conversation follow.

Advances in HIV Prevention

Dr. Dieffenbach highlighted the Tuesday, March 9, plenary session by Dr. Linda-Gail Bekker of South Africa’s Desmond Tutu HIV Foundation that reviewed the variety of long-acting HIV prevention options under research. Safe and effective forms of long-acting HIV prevention could provide alternatives to currently available daily oral pre-exposure prophylaxis (PrEP), which many people find challenging to adhere to. She highlighted a number of options that would require less frequent and alternate forms of dosing, including a monthly insertable vaginal ring; injections that could provide HIV prevention lasting one, two, or six months; implants that slowly release an HIV prevention drug for up to one year; or an oral pill that could provide protection for 30 days. This expanded range of choices would better meet the HIV prevention needs of more people, Dr. Bekker observed.  

Dr. Dieffenbach also discussed new findings on research into a long-acting form of the HIV drug cabotegravir injected once every eight weeks. Last year, investigators reported that this long-acting injectable is safe and more effective than daily oral Truvada at preventing HIV acquisition among cisgender men who have sex with men and transgender women who have sex with men. At CROI, Dr. Raphael Landovitz of UCLA shared analyses conducted to better understand the HIV acquisitions that occurred among the 4,566 study participants during the trial. They revealed that 37 of 39 participants in the Truvada group who acquired HIV during the study had levels of the drug in their blood that were not consistent with daily use. Of the 12 HIV acquisitions in the cabotegravir group, only four occurred among participants who received on-time cabotegravir injections that achieved targeted drug concentrations. These results further underscore that both Truvada and long-acting cabotegravir are highly effective for HIV prevention. Dr. Dieffenbach noted that in a companion study, HPTN 084, long-acting cabotegravir was shown to also be safe and more effective among cisgender women.

Monoclonal Antibodies for Prevention of COVID-19 and HIV

Dr. Dieffenbach also briefly touched on studies of monoclonal antibodies for prevention of both HIV and COVID-19.  He discussed findings that monoclonal antibodies are effective at preventing severe COVID-19 and death. Dr. Dieffenbach emphasized that NIH also is supporting studies of monoclonal antibodies for HIV prevention, noting that tools honed over many years to develop monoclonal antibodies for HIV enabled rapid studies of such antibodies for COVID-19. He explained that as researchers continue the HIV antibody studies, they are exploring how combinations of several antibodies might serve as a long-acting HIV prevention or treatment tool.

HIV Treatment Research of Note

At CROI, there also were multiple presentations on research into lenacapavir, a potential long-acting drug for treatment and prevention of HIV. A study presented by Dr. Sorana Segal-Maurer of New York-Presbyterian Queens found that among heavily treatment-experienced people with HIV whose current treatment regimen was failing, a subcutaneous injection of lenacapavir delivered every six months as part of a complete HIV treatment regimen was safe, well tolerated, and resulted in viral suppression. Data from an animal study also provided a proof of concept for further exploration of the use of lencapavir for HIV prevention. Dr. Dieffenbach observed that these developments are examples of how drug discovery for both HIV prevention and treatment continues.

In addition, investigators from the NIH-supported IMPAACT 2010 study reported additional results of their evaluation of three HIV treatment regimens initiated in pregnancy. Two of the three regimens contained dolutegravir and the third contained efavirenz. Previously, at CROI 2020, the researchers had reported that dolutegravir-containing regimens were more effective for maternal viral suppression through time of delivery. The new data presented by Dr. Lameck Chinula of the University of North Carolina Project-Malawi provide insights into the safety and efficacy of the three regimens for both mother and baby through the first postpartum year. Infant mortality was higher among mothers using the efavirenz regimen. One year postpartum, maternal viral suppression rates were similarly high for all three regimens, but more women on the efavirenz regimen experienced virologic failure and had to change regimens. Additional details on these findings from the IMPAACT study team are available here

About CROI

CROI is an annual scientific meeting that brings together top researchers from around the world to present and discuss the latest studies and other developments that can help accelerate global progress in the response to HIV/AIDS and other infectious diseases, including COVID-19. More than three thousand HIV and infectious disease researchers gathered virtually this year for this forum for translating laboratory and clinical research into progress against these diseases. Among the studies that were presented were many that were conducted or supported by NIH, CDC, and other federal agencies.

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