A vaginal ring could soon offer women 3 months of HIV protection
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Key takeaways:
- It is feasible to offer the dapivirine vaginal ring as HIV PrEP where it is available.
- A 3-month version of the ring performed at least as well as the existing 1-month version.
Lima, PERU — Choice, long-lasting protection and HIV prevention in women were three major themes of this week’s HIV Research for Prevention conference.
All three overlapped in two studies assessing demand for the dapivirine vaginal ring and whether a longer lasting version of the ring could offer the same level of protection against HIV for women who choose to use it, cutting costs and reducing health care visits.
The silicone ring is one of several long-lasting options for HIV PrEP that are either already available in some regions or in late-stage development.
Worn inside the vagina, the current version of the ring lasts for around a month, slowly releasing the antiretroviral drug dapivirine over the course of 28 days, after which it must be replaced with a new ring to maintain protection.
“It’s like an on-off switch — when it’s there, it does its job,” Linda-Gail Bekker, MBChB, PhD, director of the Desmond Tutu HIV Centre at the University of Cape Town in South Africa, explained to reporters here.
The ring is authorized for use in 11 African countries and has demonstrated modest effectiveness against acquiring HIV. WHO recommended the ring in 2021 as an HIV prevention option for women at high risk for infection.
‘Choosing a method that works for them’
An ongoing study of more than 3,900 HIV-negative adult women in five sub-Saharan African countries found that, when offered their choice of HIV prevention methods, the women preferred daily oral PrEP to the dapivirine ring by a rate of around 2 to 1, according to results presented by Elizabeth Irungu, MBChB, PhD, MPH, regional technical advisor for implementation science at Jhpiego, an international health nonprofit.
Nearly half of the women in the study were aged 24 years or younger, around a quarter of them reported sex work, and most — 68% — had never used HIV PrEP before, Irungu said. Nine percent were pregnant, and 12% were breastfeeding.
At enrollment, 66% of participants chose oral PrEP, 30% chose the vaginal ring, and 4% chose neither option. The ring was less popular among pregnant women and those who were breastfeeding, who preferred it over oral PrEP just 15% and 21% of the time, respectively.
Among those who chose oral PrEP, 59% said it was because it was easy to use and 32% noted its effectiveness. Women who chose the ring also did so mostly because they thought it was easy to use (59%), or because they did not like to swallow pills (53%).
The takeaway, Irungu said, is that it is feasible to offer the vaginal ring at public health facilities in Africa that are already set up to offer PrEP and where the ring has been authorized for use.
“Women are taking advantage of choice and are choosing a method that works for them,” she said at a press conference announcing the findings. “For some, the ring is their choice despite its modest efficacy ... but many women are still choosing to use PrEP.”
A second stage of the study is underway and is offering women a choice of oral PrEP, the vaginal ring or dolutegravir, according to Irungu.
Expanding choice for women
There was interest in developing a longer acting version of the ring to lessen the burden for women who choose it by reducing their visits to a clinic and the number of times the ring has to be inserted, potentially increasing adherence, according to Jeremy Nuttall, MSc, senior director of preclinical sciences at the nonprofit Population Council.
“It’s becoming increasingly clear that the HIV prevention field is focusing on expanding choice for women and on long-acting technologies,” Nuttall told reporters.
Nuttall and colleagues conducted a clinical trial of a 3-month version of the ring that is
identical to the existing ring in every way — including material, look and feel — but contains 100 mg of dapivirine instead of 25 mg.
The phase 1 trial included 104 women who either used three 1-month rings over the course of 3 months, then switched to the 3-month ring, or the other way around. Nuttall and colleagues collected plasma and vaginal fluid samples throughout the trial to measure participants’ dapivirine levels.
Based on plasma levels, they found that the 3-month ring was both noninferior and superior to the 1-month ring in the level of protection it offered, Nuttall said. Specifically, dapivirine levels in vaginal fluid were slightly higher when using the 3-month ring compared with the 1-month ring during the first month of use, and were similar in the second and third months. Additionally, the trial found that both versions were well tolerated.
“From these data,” Nuttall said, “we conclude that the efficacy of the 3-month ring should be at least equal to that of the 1-month ring [with] important benefits over the 1-month ring.”
One of those benefits, he said, would be a reduction in cost of around 60%.
“Four rings a year and it’s starting to look more affordable,” said Bekker, who was not involved in either study.
References:
- Irungu E, et al. Abstract PRC157. Presented at: HIV Research for Prevention; Oct. 6-10; Lima, Peru.
- Nuttall J, et al. Abstract PRC019. Presented at: HIV Research for Prevention; Oct. 6-10; Lima, Peru.
- WHO recommends the dapivirine vaginal ring as a new choice for HIV prevention for women at substantial risk of HIV infection. https://www.who.int/news/item/26-01-2021-who-recommends-the-dapivirine-vaginal-ring-as-a-new-choice-for-hiv-prevention-for-women-at-substantial-risk-of-hiv-infection. Published Jan. 26, 2021. Accessed Oct. 8, 2024.
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