People at high risk of contracting HIV can significantly lower their chances of getting the virus with a daily pill known as PrEP, or pre-exposure prophylaxis, medicine. While this innovation has led to lower rates of new HIV cases among some, others can’t stick to the once-a-day regimen, prompting scientists to search for a low-effort, long-term way for people to take PrEP on schedule.
To help develop a long-term solution, the Bill and Melinda Gates Foundation is investing up to $140 million (about K105 billion) in the creation of a subdermal (under the skin) implant that can continuously release PrEP for up to one year before needing to be replaced.
The device, which is called the Medici drug delivery system, is being developed by Boston-based Intarcia Therapeutics Inc. Because strong adherence is key to effective HIV prevention, this device could be crucial in helping people stick to a regimen without having to worry about how to acquire and store pills or having to remember to take medicine every day.
HIV prevention medicine, which usually takes the form of a single daily pill, has revolutionized the way the world controls the spread of the incurable and potentially deadly virus. However, research shows that its effectiveness among different high-risk groups is mixed ― not for any biological reasons but because of social and cultural factors that get in the way of people and their medicine.
For instance, daily PrEP pills have an almost 100 percent effectiveness rate among gay men in California, while trials testing PrEP’s effectiveness among women in Africa showed it doesn’t significantly reduce HIV infections.
Experts hypothesize that women may have trouble preventing HIV in general because of their status in a male-dominated society. Adhering to a daily pill regimen, or even insisting on condom use, over the objections of a partner can be difficult barriers for these women. Discreet devices like a skin implant, or a vaginal ring, which the National Institutes of Health tested in 2016, could help eliminate roadblocks for women who need protection from HIV but cannot store conspicuous pills in their homes or be seen at clinics picking up medicine. However, an implant that goes under the skin of the abdomen wouldn’t be noticeable to a sexual partner, wouldn’t require interruption of sexual intimacy to activate and would need to be replaced only infrequently.
Other people who might benefit from some kind of long-term HIV prevention tool include anyone for whom PrEP is recommended: those who are in a relationship with someone with HIV, those who aren’t in mutually monogamous relationships, people who use injectable drugs or people who have unprotected sex with partners of unknown HIV status.
Intarcia’s device isn’t the only implant in development. Scientists from the University of California, San Francisco are trying to develop a biodegradable implant that releases PrEP and needs replacement every 90 days, while the nonprofit Oak Crest Institute of Science is working on an implant that also shows promise.—Additional material from Huffpost.com