Can new intra-vaginal ring prevent HIV in women

Written by PTI | Washington | Updated: Sep 29 2013, 20:37pm hrs
Vaginal RingThe new ring is easily inserted and stays in place for 30 days. (Thinkstock)
A new easy-to-use intra-vaginal ring filled with an anti-retroviral drug could be extremely effective at preventing the deadly HIV in women, a new study has found.

The ring is easy to use, long lasting, and recently has demonstrated a 100 per cent success rate protecting primates from the simian immunodeficiency virus (SHIV).

The device will soon undergo its first test in humans, researchers said.

"After 10 years of work, we have created an intra-vaginal ring that can prevent against multiple HIV exposures over an extended period of time, with consistent prevention levels throughout the menstrual cycle," said Patrick Kiser, an expert in intra-vaginal drug delivery.

Previous studies have demonstrated that antiviral drugs can prevent HIV infection, but existing methods for delivering the drug fall short.

Pills must be taken daily and require high doses; vaginal gels that must be applied prior to each sex act are inconvenient, yielding poor usage rates.

The new ring is easily inserted and stays in place for 30 days. And because it is delivered at the site of transmission, the ring - known as a TDF-IVR (tenofovir disoproxil fumarate intravaginal ring) - utilises a smaller dose than pills.

The device contains powdered tenofovir, an anti-retroviral drug that is taken orally by 3.5 million HIV-infected people worldwide, but that has not previously been studied topically, researchers said.

The ring's strength stems from its unique polymer construction: its elastomer swells in the presence of fluid, delivering up to 1,000 times more of the drug than current intra-vaginal ring technology, such as NuvaRing, which are made of silicon and have release rates that decline over time.

The upcoming clinical trial, to be conducted in November at Albert Einstein College of Medicine in New York, will evaluate the ring in 60 women over 14 days.

The trial will assess the ring's safety and measure how much of the drug is released and the properties of the ring after use.

Other drugs could potentially be integrated into the ring, such as contraceptives or antiviral drugs to prevent other sexually transmitted infections - a feature that could increase user rates, said Kiser, who joined Northwestern University from the University of Utah, where the research was conducted.

The study was published in the journal Proceedings of the National Academy of Sciences (PNAS).