Results of two large-scale clinical trials in Africa show promise for a potential HIV/Aids prevention option for women: a vaginal ring.
The flexible silicone ring contains Dapivirine, a highly- potent antiretroviral drug which prevents HIV/Aids from replicating its genetic material after the virus enters a healthy cell. Once inserted through the vagina, the ring settles in the cervix where it releases the drug.
The trials, ASPIRE and Ring Study, found a 27 and 31 per cent efficacy of the ring, respectively, among women aged between 18 and 45 years. The ASPIRE study was conducted through the National Institutes of Health’s Microbicide Trials Network and enrolled 2,629 uninfected women in 15 sites around Malawi, South Africa, Uganda and Zimbabwe. Of these, 253 were Ugandan.
Over the study duration that started in 2012, each woman was given either a dapivirine or placebo ring (without the drug) at random, which was replaced every four weeks. The ASPIRE findings, published in the New England Journal of Medicine, found that the dapivirine ring reduced the risk of acquiring HIV/Aids by 27 per cent.
This implies that there were 27 percent fewer women who acquired HIV in the group assigned to use the dapivirine ring than in the group assigned to use a placebo ring containing no active drug. Overall, 168 women in the study acquired HIV; 97 in the placebo group and 71 in the dapivirine ring group.
“Benefits of using the ring are many. It is discreet, can safely provide protection against HIV/Aids for a month or longer and is the first long-acting HIV/Aids prevention method to show efficacy,” Dr Flavia Matovu Kiweewa, the principal investigator for the ASPIRE study in Uganda, told journalists at a recent press conference in Kampala.
When researchers included only women over 25 years, they found that the ring reduced the infection rate by 61 per cent. However, this figure tremendously dropped to 10 per cent in women less than 25 years. Dr Matovu attributes the ring’s decreased efficacy among the younger participants to them using it less consistently.
“The researchers will continue to study the ring and its efficacy, particularly trying to establish how they can increase its effectiveness among younger women,” she said.
In the Ring Study, overall reduction was 31 per cent (31 of every 100 women were protected from acquiring the virus). As with the ASPIRE study, efficacy for the Ring Study was substantially higher, at 37 per cent, among the subset of women who were over 21 years and kept the ring in consistently throughout the month.
The International Partnership for Microbicides (IPM), which developed the monthly dapivirine ring, is conducting The Ring Study in South Africa and Uganda among 1,959 women.
Although the ring is by no means a complete protection from HIV/Aids transmission, Dr Clemensia Nakabiito said it provides an extra line of defense for women especially in light of inconsistent condom use.
She is the head of microbicides research at Makerere University John Hopkins University research collaboration
Today, daily oral PrEP (pre-exposure prophylaxis), female condoms, a vaginal film and gel are the prevention options available for women. If licensed, the dapivirine vaginal ring might become an additional option and will cost about $5 (Shs 17,500).