What Is Long-acting PrEP and Why Is It Needed?
Long-acting pre-exposure prophylaxis, or PrEP, refers to potential new long-lasting forms of HIV prevention being studied by researchers that would be an alternative to taking a daily pill.
Currently, PrEP is a way for people who are at high risk for HIV infection to prevent it by taking a pill every day. When taken daily, the medications in the pill provide a high level of protection against HIV. Studies have shown that PrEP reduces the risk of getting HIV from sex by more than 90% when used consistently. Among people who inject drugs, PrEP reduces the risk of getting HIV by more than 70% when used consistently. However, many studies of PrEP indicate that PrEP is much less effective if it is not taken consistently, and that taking a daily pill can be challenging for some people.
Recognizing the challenges that having to take a pill every day poses for some people, researchers are working to create new forms of PrEP that do not require a daily dose of HIV prevention medicines. This may make it easier for more people to get very high levels of protection from PrEP. To generate new biomedical HIV prevention options that may be more desirable than a daily pill, the National Institutes of Health (NIH) funds the design and testing of new, long-acting forms of PrEP. Scientists are studying various drugs, drug formulations, and delivery mechanisms to determine which, if any, may be at least as effective as the daily oral pill. These long-acting products are being designed for people who are committed to using PrEP on an ongoing basis and may work for a month or as long as a year. The goal of this research is to provide people with a variety of acceptable, discreet, and convenient choices for highly effective HIV prevention. None of the research on these possible HIV prevention options has been completed, so they are not yet approved by the FDA and are not available for use outside of a clinical trial.
What Types of Long-acting PrEP Are Under Study?
Four forms of long-acting PrEP are in design and testing in research studies: intravaginal rings, injectable drugs, implants, and antibodies.
Intravaginal rings for women. Long-acting PrEP intravaginal rings are polymer-based products that are inserted into the vagina, where they release one or more HIV antiretroviral drugs over time. The intravaginal ring at the most advanced stage of research is the dapivirine ring that was tested in two large clinical trials, including the NIH-funded ASPIRE study. The ring is undergoing further evaluation in the HOPE open-label extension trial. NIH also is funding the human testing of two more long-acting PrEP intravaginal rings and supporting the design of several others.
Injected PrEP. Long-acting PrEP injectables are select long-acting antiretroviral drugs that are injected into the body. The first large-scale clinical trial of a long-acting PrEP injectable began in December 2016. Called HPTN 083, the NIH-sponsored study—a partnership with ViiV Healthcare and the Bill & Melinda Gates Foundation—is examining whether a long-acting form of the investigational antiretroviral drug cabotegravir, injected once every 8 weeks, can safely protect men and transgender women from HIV infection at least as well as daily PrEP. Results are expected in 2021. A related study called HPTN 084 will test whether injectable cabotegravir safely prevents HIV infection in young women. NIH also is funding the design and early clinical testing of additional long-acting PrEP injectable drugs.
Implanted PrEP. Long-acting PrEP implants are small devices that are implanted in the body and release an antiretroviral drug over time. NIH is funding the development of several long-acting PrEP implants, which will undergo laboratory testing before being studied in human trials.
Antibodies. Scientists have begun to test whether giving people periodic infusions of powerful anti-HIV antibodies can prevent HIV infection. The antibodies involved can stop a wide variety of HIV strains from infecting human cells and thus are described as “broadly neutralizing antibodies” (bNAbs). Two NIH-funded clinical trials testing the hypothesis that bNAbs can prevent HIV infection recently completed enrollment. These trials are assessing whether giving infusions of bNAbs to healthy men and women at high risk for HIV protects them from acquiring the virus. If proven safe and effective, periodic infusions of bNAbs also may be a potential alternative to daily antiretroviral therapy.
For a visual illustration of NIH’s long-acting PrEP research, see this infographic.
Can I Use Long-acting PrEP to Prevent HIV Now?
At this time, some forms of long-acting PrEP are being tested in clinical trials. The effectiveness of long-acting PrEP has not yet been proven, and it has not been considered for approval by the Food and Drug Administration (FDA). So it is not available for your doctor to prescribe yet. However, NIH-supported clinical trials may be seeking volunteers to participate in some studies on long-acting PrEP. You may be eligible to participate in one of these trials, if one is taking place near you. Information about NIH clinical trials can be found at https://www.clinicaltrials.gov/.
It will probably be a number of years before long-acting PrEP is available to the general public. In the meantime, the best forms of prevention against sexual transmission of HIV continue to be:
- HIV testing—so that you know your own HIV status and your partner’s too.
- Antiretroviral therapy for people who have HIV, to protect their health and prevent transmitting the virus to their sexual partners. This is called treatment as prevention.
- Daily oral PrEP for people who do not have HIV but are at very high risk of getting it.
- Using condoms consistently and correctly.
- Choosing less risky sexual behaviors.
- Reducing the number of people you have sex with.
- Post-exposure prophylaxis, or PEP, meaning taking antiretroviral medicines very soon after being potentially exposed to HIV to prevent becoming infected.
The more of these actions you take, the safer you will be. To learn more about steps you can take now to prevent getting or transmitting HIV, read other pages in this section.
This page was developed in collaboration with NIH’s National Institute of Allergy and Infectious Diseases.