An investigational vaginal gel intended to prevent HIV infection in women has demonstrated encouraging signs of success in a clinical trial conducted in Africa and the United States.
Findings of the recently concluded study, funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, were presented at the Conference on Retroviruses and Opportunistic Infections in Montreal.
The study investigators found the microbicide gel-known as PRO 2000 (Indevus Pharmaceuticals, Inc., Lexington, Mass.)-to be safe and approximately 30 percent effective (33 percent effectiveness would have been considered statistically significant). This is the first human clinical study to suggest that a microbicide-a gel, foam or cream intended to prevent the sexual transmission of HIV and other sexually transmitted infections when applied topically inside the vagina or rectum-may prevent male-to-female sexual transmission of HIV infection.
“Although more data are needed to conclusively determine whether PRO 2000 protects women from HIV infection, the results of this study are encouraging,” says NIAID Director Anthony S. Fauci, M.D.
The Phase II/IIb clinical trial, which enrolled more than 3,000 women, is NIH’s first large clinical study of a microbicide.
“An effective microbicide would be a valuable tool that women could use to protect themselves against HIV and one that could substantially reduce the number of new HIV infections worldwide,” Dr. Fauci adds.
“The study, while not conclusive, provides a glimmer of hope to millions of women at risk for HIV, especially young women in Africa,” adds lead investigator Salim S. Abdool Karim, MBChB, Ph.D., from the Center for the AIDS Program of Research in South Africa, who presented the findings at CROI. “It provides the first signal that a microbicide gel may be able to protect women from HIV infection.”
Currently, women make up half of all people worldwide living with HIV. In sub-Saharan Africa, women represent nearly 60 percent of adults living with HIV, and in several southern African countries young women are at least three times more likely to be HIV-positive than young men.