HIV researchers have announced that a vaginal ring containing an antiretroviral (ARV) drug called dapivirine, helped protect against HIV in a large-scale trial involving more than 2,600 women in Africa.
The results announced on Monday at the Conference on Retroviruses and Opportunistic Infections (CROI) in Boston, US, revealed that the vaginal ring prevented about a third of HIV infections among the women who used it in the research. But for those older than 25 years, there was 61% reduction in HIV acquisition risk.
"About 1 in 3 women who would have acquired HIV did not," said Dr. Jared Baeten of the Microbicide Trials Network (MTN) and University of Washington. He was accompanied by Dr. Annalene Nel of the International Partnership for Microbicides (IPM).
The study asked volunteers to insert a ring that slowly releases dapivirine into the vagina and its walls to prevent HIV in the case of unprotected sex with a man who is HIV positive. The dapivirine ring reduced the risk of HIV infection by 27% overall.
But women who were older than 25 years old received a 61% risk reduction. Intrigued by this significant age-related protection difference, researchers conducted additional analyses which revealed that women older than 25 were 56% better protected than those between the age of 18 and 21.
The study (ASPIRE comes from A Study to Prevent Infection with a Ring for Extended Use) was carried out in Uganda, Malawi, South Africa and Zimbabwe. 253 Ugandans volunteered at Makerere University-Johns Hopkins (MU-JHU) Research Collaboration in Mulago, Kampala, as part of the total 2,629 HIV-negative women, aged 18 to 45, in the four countries. The study, which began in August 2012 until June 2015, was funded by the US National Institutes of Health.
The results were published online in the New England Journal of Medicine.
Dr. Flavia Matovu Kiweewa, who was the principal investigations officer at the study hosted by Makerere University - Johns Hopkins University Research Collaboration in Mulago, called it a very big achievement.
"To understand the impact, consider that about 400 people get HIV daily in Uganda. Over 50% of these are women. If all the 200 women used the ring, at a protection of one in every three women, we would save about 66 women per day. In a year, these are over 24,000 women! And if the women are above 25 years of age, at 61%, we would save 122 women per day, which makes it 44,530 women a year! That is a recommendable product!" she said.
Matovu also said the ring was well accepted. The women who participated in the study found it easy to use.
"Many told us they forgot it was even there and their partners did not feel it during sexual intercourse," she said.
A similar study, known as The Ring Study, is going on in Uganda and South Africa by IPM. 197 HIV negative women are volunteering in Masaka, under Dr Anatoli Kamaali, who is the principal investigator. Preliminary analysis so far shows a reduction of HIV infection risk of 31% overall, and 37% amongst participants older than 21.
The study, which began in April 2012 with 1,959 HIV-negative women, is expected to close in December 2016. However, following the positive results in ASPIRE, South Africa regulatory authority, IPM has decided to close the Ring Study and provide all women enrolled with the dapivirine ring for the remainder of their participation. IPM is seeking similar approval in Uganda.
Matovu said ASPIRE and The Ring study have made important strides in the fight against HIV in women and opened the door to developing next-generation products as well. The ring's development demonstrates how investments in scientific innovation and public-private partnerships can advance global health.
"Because women are often not empowered to have sex on their own terms, especially demanding for condom use, this will become the only tool so far that a woman can use without needing permission to protect herself from HIV infection. She only needs to replace the ring once a month, as a discreet and easy-to-use new method of protection," said Dr Clemensia Nakabiito, a consultant gynecologist with MU-JHU Research Collaboration, who is also the co-investigator for the ASPIRE study.
With these results, IPM also announced that it will submit an application for the licensure of the product.
"We hope that the ring will be available on the market very soon," said Nel. "IPM will use all efforts to fast track the process including getting World Health Organisation to prequalify it especially in countries where the studies were done," she said.
Women are at higher risk for HIV infection than men. More than half of the more than 36.9 million people living with HIV, are women. They account for nearly 60% of adults with HIV in sub-Saharan Africa. Girls 15-24 are especially vulnerable, twice as likely as boys to have HIV.
Experts and activists still advise that abstinence, monogamy and the use of male condoms are the best interventions. However, they have neither done enough to stop the HIV epidemic nor are they realistic methods in many settings. Women still lack practical and discreet tools they can use to protect themselves from HIV infection.
Vaginal rings are flexible products that fit comfortably high inside the vagina and provide sustained delivery of drugs over a period of time. Women in many countries already use vaginal rings designed to deliver contraceptive hormones.
The dapivirine ring, which women insert and leave in place for one month, is the first long-acting ARV-based product to be tested for efficacy.