CROI 2014Monthly injections of the long-acting investigational antiretroviral GSK744 given to pigtail macaques prevented vaginal acquisition of SIV, which is the simian cousin of HIV. The study raises hopes that HIV-negative women may eventually have an alternative to taking daily pills for pre-exposure prophylaxis (PrEP) to prevent the spread of HIV, and one that would help address the critical issue of drug adherence. Investigators from the Centers for Disease Control and Prevention (CDC) presented their findings at the Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.

The researchers gave injections of GSK744 to six macaques every four weeks and gave injections of a placebo to another six primates on the same schedule. All the monkeys were exposed to SIV vaginally twice a week, totaling 22 exposures in all.

All six of the primates that received the placebo injections acquired SIV, following a median of four exposures to the virus. None of the six macaques that received injections of the ARV were infected during the 22 exposures, nor did they show signs of the virus 20 weeks after the final injection of GSK744.

The study’s results, the researchers find, support human trials to study GSK744’s potential as a form of PrEP for women.