An additional requirement for safety and efficacy is that the ring must not trigger immune defenses, and their associated inflammation, as that could encourage HIV infection by compromising the integrity of the mucosal barrier, as well as by recruiting and activating immune cells that are the virus's targets. And in fact, the immune system, and the vaginal microbiome were undisturbed.
Baum notes that the pig-tailed macaque model is an ideal surrogate for humans. "The model has similarities with the human menstrual cycle, vaginal architecture and vaginal microbiome, and the ability to conduct efficacy studies with simian-human immunodeficiency virus," he says.
"Macaques cannot be infected with HIV, so scientists have developed a hybrid virus, simian-human immunodeficiency virus, that infects the monkeys and leads to a disease much like AIDS," Baum explains. This virus contains parts of the human immunodeficiency virus, and is susceptible to many HIV drugs, he says. "This is the state of the art for studying HIV/AIDS in vivo."
The two drug combinations tested include Truvada, which consists of emtricitabine and tenofovir disoproxil fumarate, and Truvada plus maraviroc, which works by blocking the chemokine receptor, CCR5, which is a target entryway of HIV.
|Contact: Jim Sliwa|
American Society for Microbiology