A vaginal ring that emits an HIV- fighting drug protected monkeys from getting a version of the AIDS-causing virus, according to a study that suggests the same approach may help women whose partners won’t wear condoms.
Macaques that received the drug-laced rings were 83 percent less likely to become infected with simian HIV than those that got placebo rings, researchers from the New York-based Population Council wrote in a study published today in the journal Science Translational Medicine.
Scientists have been trying to develop tools for women that would reduce the risk of contracting HIV. While a 2010 study of a vaginal gel showed it prevented infections in a large trial in Africa, researchers stopped a similar trial in November because it wasn’t working, possibly because the women weren’t using the gel often enough. Rings, similar to those now used for contraception, may avert that problem.
“This proof-of-concept study confirms that the investment in vaginal rings as a delivery system for HIV prevention is paying off,” Naomi Rutenberg, vice president and director of the Population Council’s HIV and AIDS program, said in a statement.
The rings, made either of silicone or ethylene vinyl acetate, released an experimental drug called MIV-150, an antiviral developed originally by Huddinge, Sweden-based Medivir AB (MVIRB) and licensed to the Population Council in 2003. The approach is designed to ward off infection by preventing HIV from gaining a foothold in the body.
The researchers inserted the devices either 24 hours or two weeks before exposing the monkeys to simian HIV, a virus that combines genes from the human and monkey versions of the infection, and removed them immediately before or two weeks after the exposure.
Among 17 macaques that got the drug rings, two became infected, compared with 11 of 16 animals who got plain rings. While the timing of the insertion didn’t make a difference, animals whose rings were removed just before the exposure were more likely to become infected than those whose rings remained in place.
The Population Council is working on a ring that women could leave in place for as long as three months, and that might also prevent other sexually-transmitted diseases and unplanned pregnancies, it said in the statement.
The U.S. National Institutes of Health said in July it’s starting a trial of a ring that may involve almost 3,500 women in five countries.
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