Trials enlist vaginal gel and ring in fight against HIV

Researchers are developing and studying vaginal delivery systems for antimicrobial and antiretroviral gels that could cut the levels of infection with life-threatening viruses such as HIV and HSV-2 (herpes simplex virus type 2).

Researchers at SRI International have received a grant from the National Institute of Allergy and Infectious Diseases (NIAID) to develop a gel that will deliver microbicides in the vagina. As part of the project, researchers from SRI are working on a bioadhesive gel that will deliver tenofovir and acyclovir, both antiviral drugs, based on the company's patented bioadhesive polymeric platform.

"The inexpensive and easy-to-use combination therapy in development could help contain the spread of HIV and HSV, and possibly other sexually transmitted diseases," said Gita Shankar, director of Formulations R&D at SRI Biosciences.

Two studies of a vaginal ring delivering the antiretroviral drug dapivirine over one month have started in Africa, as announced at the XIX International AIDS Conference (AIDS 2012). The first is called ASPIRE (A Study to Prevent Infection with a Ring for Extended use) and will involve 3,476 women at 17 sites in Malawi, Uganda, South Africa, Zambia and Zimbabwe. Results are expected in late 2014 or early 2015. The second, known as The Ring Study, will include around 1,650 women in South Africa and Rwanda. These are the first effectiveness trials of a vaginal ring for HIV prevention. The International Partnership for Microbicides (IPM) developed the dapivirine ring, and has access to the active drug through a royalty-free licensing agreement with Janssen R&D Ireland.

There are 22.5 million people in Africa with HIV/AIDS, and up to 80% of the female population in Africa is infected with HSV-2, which can speed up the progression of HIV/AIDS. Preventing infection using a simple-to-use vaginal gel or ring could save lives, particularly when condoms are unavailable or simply unacceptable.

The ring has the advantage that it can be inserted and left in for a month, whereas the gel has the advantage that it is only used when needed. As Jared Baeten of the University of Washington in Seattle says: "As a field, we must continue to develop new strategies for HIV prevention. No single approach will be right for every person. In the same way there is a range of effective choices when it comes to birth control, women must have multiple effective options for HIV prevention."

- read the press release from SRI International
- see the press release from the Microbicide Trials Network