September 28, 2013
New Intravaginal Ring Proves Effective At Preventing HIV
April Flowers for redOrbit.com - Your Universe Online
The HIV/AIDS epidemic often has a woman's face because the proportion of women infected with HIV has been on the rise for a decade. For example, in sub-Saharan Africa, women constitute 60 percent of people living with disease. Preventative drugs are available, but they are often ineffective, especially in light of financial and cultural barriers in developing nations.The answer, according to a new study published in the Proceedings of the National Academy of Sciences, could be a new intravaginal ring filled with an anti-retroviral. Northwestern University visiting associate professor Patrick Kiser developed the ring with support from the National Institute of Allergy and Infectious Diseases. The ring is easy to use, long lasting, and has demonstrated a 100 percent success rate protecting primates from the simian immunodeficiency virus (SIV). Kiser says the device will soon undergo its first human trials.
“After 10 years of work, we have created an intravaginal ring that can prevent against multiple HIV exposures over an extended period of time, with consistent prevention levels throughout the menstrual cycle,” said Kiser, an expert in intravaginal drug delivery who joined Northwestern from the University of Utah, where the research was conducted.
Prior research had shown that antiviral drugs can prevent HIV infection, however existing methods of delivery fall short: pills require high daily doses, vaginal gels are inconvenient as they have to be applied prior to each sex act. Both yield poor usage rates.
The new ring, known as a TDF-IVR (tenofovir disoproxil fumarate intravaginal ring), is inserted easily and stays in place for 30 days. The ring delivers a smaller dose than pills because it is at the site of transmission.
The retroviral drug used by the ring is powdered tenofovir. Tenofovir is taken orally by 3.5 million HIV-infected people globally, but has never before been studied topically. The strength of the ring, however, is its unique polymer construction. The elastomer swells in the presence of fluid, delivering 1,000 times more of the drug than the current intravaginal ring technology. Such products, like the NuvaRing, are made of silicon and have release rates that decline over time.
The upcoming clinical trial will evaluate the ring in 60 women over 14 days at the Albert Einstein College of Medicine in New York in November of this year. The trial is meant to assess the ring’s safety and measure how much of the drug is released and the properties of the ring after use.
Kiser sees potential for the ring to be used to deliver other drugs, such as contraceptives or antiviral drugs to prevent other sexually transmitted infections — a feature that could increase user rates.
“The flexibility to engineer this system to deliver multiple drugs and change release rates is extraordinary and could have a significant impact on women’s health,” he said.
Image Below Credit: Patrick Kiser/Northwestern University