While condoms and preventative drugs are effective at blocking HIV transmission, for women in developing regions like sub-Saharan Africa, such methods can be too expensive or impractical for continual use. A new treatment, which provides patients with a more long-term protective solution in the form of a drug-releasing vaginal ring, has proved partially effective in a new study.

More than half of the 25.8 million people living with HIV in sub-Saharan Africa are women. The vaginal ring, which is central to the US National Institutes of Health-funded ASPIRE study, provides a sustained release of the antiretroviral drug dapivirine, providing a new way of combating the risk of contracting the virus. We've seen very similar devices in the past, including the Northwestern University-developed TDF-IVR. Researchers believe that the technology could make a big difference in preventing transmission of the virus.

The ASPIRE study, which is also known as MTN-020, is a collaborative project led by researchers at South Africa's Wits Reproductive Health and HIV Institute, and the University of Washington in Seattle. The team worked to test the effectiveness of the drug-releasing ring, which is designed to be replaced once every four weeks.

The project began in 2012, and saw more than 2,600 women without HIV take part, with ages ranging from 18 to 45 years old. The patients were split into two groups, one receiving the drug-releasing ring, and one being given a placebo ring.

At the end of the study, the researchers found that the dapivirine ring had reduced transmission risk by 27 percent across all women taking part in the study. But delving a little deeper into the data revealed that its effectiveness was likely understated by the research.

For example, once the data from women at two test sites, where it was obvious to the researchers that the participants were not using the ring as consistently as requested, was excluded, the results improved. Under those conditions, the ring was found to reduce risk of infection by 37 percent.

Looking more closely still, the researchers noticed that for women aged 25 and older, use of the device reduced risk by an impressive 61 percent, but for those under 25, it provided no statistically significant protection. Analyzing blood from participants revealed that younger participants weren't using the ring as much as older patients, once again suggesting that the device, when used properly, reduced risk significantly more than the blanket 27 percent figure indicates.

Overall, the ASPIRE study represents the first practical evidence that sustained drug delivery, as provided by the ring, can indeed offer significant protection from the risk of contracting HIV.

"To help bring about an end to the HIV/AIDS epidemic, women – especially those in sub-Saharan Africa – need multiple options for HIV preventions," said study co-lead Jared Baeten. "The ASPIRE study was an important step towards determining whether the dapivirine ring could become one such option."

The findings of the research are published online in the New England Journal of Medicine.

Source: NIH