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Something could soon change in HIV prophylaxis: A new dapivirine vaginal ring is intended to protect against HIV infections. Read more here.
Young women and girls are the cohort most at risk from HIV worldwide. Between the ages of 15 and 24, they are more than twice as likely to become infected with HIV as young men. Women are often not self-determined in their sexuality and therefore have no decision-making authority over whether their sexual partner uses a condom to protect them or not. Many people are denied access to oral PrEP. A vaginal ring that once inserted offers protection against HIV could be a good and discreet way for women to at least reduce the risk of HIV infection.
One month with dapivirine
The vaginal ring used consists of a silicone matrix containing 25 mg of the non-nucleoside reverse transcriptase inhibitor (NRRTI) dapivirine. It must be worn for 24 hours before it reduces the risk of HIV infection. The ring should remain intravaginally throughout the month and should not be removed during sex. It can be used with most contraceptives, but should not be used with vaginal rings, diaphragms, menstrual cups or cervical caps. The recommendation is to combine the ring with a condom, also to prevent the transmission of other STDs.
The effectiveness has already been examined in two large phase 3 studies, the ASPIRE and the RING study. The effectiveness in preventing HIV infection was reported to be around 30%. The ring was well tolerated and there was no evidence of an increase in resistance to NNRTIs. The low preventive effect has been associated with inadequate treatment adherence. This was particularly evident in the group of 18-21 year old women, in whom the ring was able to prevent almost no infection.
Regular aftercare
This hypothesis has now been further investigated in the DREAM study. HIV-negative women from the RING study were included in the study. The study was conducted in 5 centers in South Africa and one study center in Uganda. The women were followed up every three months, which included HIV testing, interviews, and measurements of remaining dapivirine doses from the vaginal rings. By measuring the remaining dose, the researchers were able to monitor treatment adherence. The women were also examined gynecologically for adverse local reactions. Expected HIV incidence was simulated using data from the RING study. Between July 2016 and January 2019, 941 study participants were included. The follow-up period was at least 12 months.
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Follow
Only 9% of enrolled participants dropped out of the study early, with the most common reasons being HIV seroconversion and work-related circumstances. Side effects attributed to the ring were primarily vaginal discomfort. 8% of the study participants became infected with HIV. This result was 62% lower than expected based on the simulations. Of the 17 individuals who demonstrated HIV-1 seroconversion in DREAM and had a genotypic resistance result, an NNRTI resistance-associated mutation was identified in five (29.4%) of 17. The study authors advise that this fact should be viewed with caution as the virological profile of the transmitting partner was unknown and resistance to NNRTIs in South Africa is reported to be up to 13%.
Safety for pregnant and breastfeeding women
The ring is currently not approved for use in pregnant and breastfeeding women. However, a recent study in which 207 healthy pregnant women used the ring found that the rate of complications in the last trimester of pregnancy was similar to the background rate of these events in the communities where the study was conducted. Another study found that the ring posed no safety concerns in 148 women who were breastfeeding their babies, confirming the ring’s favorable safety profile as an HIV prevention method.
The dapivirine vaginal ring has now received regulatory approval or approval for use in 11 countries in eastern and southern Africa. The ring is currently being offered to women through more than 30 implementation and pilot studies in six countries, including Eswatini, Kenya, Lesotho, South Africa, Uganda and Zimbabwe. A strategic partnership is being negotiated with manufacturer Kiara Health to reduce costs and make the product available to more women. Local production capacities are to be built up over the next few years in order to significantly reduce the costs of the product. The company is also already working on a successor product that will only have to be changed every three months, which should make it easier to use and reduce costs further. Development of this longer-acting ring will be completed and submitted for regulatory approval in the next 12-18 months, according to the Population Council.
Sources
Jared M. Baeten, Thesla Palanee-Phillips, Elizabeth R. Brown, Katie Schwartz, et al. Use of a dapivirine-containing vaginal ring for HIV-1 prevention in women. N Engl J Med 2016; 375:2121-2132. DOI: 10.1056/NEJMoa1506110
Annalene Nel, Neliëtte van Niekerk, Saidi Kapiga, Linda-Gail Bekker et al. Safety and effectiveness of a dapivirine vaginal ring for HIV prevention in women. N Engl J Med 2016; 375:2133-2143. DOI: 10.1056/NEJMoa1602046
Annalene Nel, Neliëtte van Niekerk, Ben Van Baelen, Mariëtte Malherbe et al. Safety, adherence and HIV-1 seroconversion in women using the dapivirine vaginal ring (DREAM): an open-label extension study. Lancet HIV. 2021 Feb;8(2):e77-e86. DOI: 10.1016/S2352-3018(20)30300-3
Bunge, Katherine; Balkus, Jennifer; Fairlie, Lee; Mayo, Ashley J et al. SUPPLY: A safety study of a dapivirine vaginal ring and oral PrEP for HIV prevention during pregnancy. JAIDS Journal of Acquired Immune Deficiency Syndromes 95(1):S. 65-73, January 1, 2024. DOI: 10.1097/QAI.0000000000003312
Microbicide Trials Network. A study suggests that the dapivirine vaginal ring can be safely used for HIV prevention during breastfeeding. Press release from February 21, 2023.
Image source: National Cancer Institute, Unsplash
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