The next generation of medications and preventative treatments for HIV/AIDS continues to look promising. New research released Tuesday suggests that people can safely wear a vaginal ring-based treatment meant to prevent HIV infection for as long as three months. A monthly version of the same drug is already being weighed for approval in African countries and elsewhere.
The treatment is called dapivirine. Like other antiretroviral drugs, it works by inhibiting HIV’s ability to replicate inside cells. Since 2014, the International Partnership for Microbicides (IPM)—a nonprofit organization focused on developing HIV prophylactics for women in lower-income countries—has owned the rights to dapivirine and has been trying to secure an approval for the drug as a first-of-its-kind intravaginal ring that can lower a person’s risk for infection. This would make the drug a form of pre-exposure prophylaxis, or (PrEP). Currently, the only available form of PrEP is a pill that has to be taken daily.
In late 2019, following the completion of two Phase III trials in Africa, a monthly formulation of dapivirine was submitted for approval by the European Medicines Agency (EMA). Last year, the EMA gave a positive review of the clinical trial data, which found that women on dapivirine were around 27% to 35% less likely to contract HIV than those in the control group. Earlier this January, the World Health Organization recommended dapivirine as a treatment that should be included as one of several options for HIV prevention. The IPM has said that they are applying for approval of dapivirine in several countries in sub-Saharan Africa, where rates of HIV among women continue to be very high. Last week, they also applied for the drug’s approval from the U.S. Food and Drug Administration.
While this process has been going on, the IPM, in partnership with the U.S. National Institutes of Health, has been testing out whether a longer-lasting version of the ring might be better for women to use once it’s likely made available to the public. Their preliminary results, detailed Tuesday at the (virtual) Conference on Retroviruses and Opportunistic Infections, do seem to point in that direction.
The Phase I study involved 49 healthy HIV-negative women and individuals assigned female sex at birth in the U.S. Two groups of volunteers either wore a ring containing 100 milligrams or 200 milligrams of dapivirine for 90 days, while a third wore the monthly form of the ring, which contained 25 milligrams of dapivirine, for the same length of time. Then they were watched for 13 weeks.
All three groups appear to tolerate their rings well, with no serious health risks found during the study. But those who wore the 90-day version had higher levels of dapivirine in their blood and cervical tissue. That indicates that the drug could be more potent and effective at preventing HIV when used in this longer-lasting form.
The results are still preliminary, it should be noted. And Phase I trials are expressly designed to test the safety of an experimental treatment, not its effectiveness. But if the monthly form of the dapivirine ring is approved as expected later this year, it wouldn’t be much of a hurdle to bring a 90-day version to the public eventually, assuming this research continues to show promise. The IPM is also testing out a version of the ring that would contain dapivirine and a long-lasting contraceptive.
“Regulatory approval of the monthly ring would be an incredible milestone for women, who have been the face of the HIV epidemic in much of the world and need and deserve to have a range of safe and effective methods. Hopefully, an extended duration dapivirine ring that women replace every three months can be yet another option available to women in the not-too-distant future,” study author Albert Liu, clinical research director at the San Francisco Department of Public Health, said in a statement released by the Microbicide Trials Network, a project funded by the U.S. National Institutes of Health to study and help develop preventative treatments for sexually transmitted diseases like HIV.
There’s been lots of encouraging news in the HIV research world recently. Aside from the vaginal ring approach, there’s work ongoing in developing other longer-lasting versions of PrEP, taken as an injection or a pill, for people at higher risk of infection. And in February, the first longer-lasting HIV treatment—a series of two injections, taken monthly—was approved by the FDA, called Cabenuva. Recent research has since suggested that Cabenuva can be taken as little as six times a year, and the drug’s maker, ViiV Healthcare, has now filed for an updated approval on the bi-monthly version.