Jim Pickett, director of advocacy at AIDS Foundation of Chicago and chairman of the International Rectal Microbicide Advocates, says the pre-exposure prophylaxis trial evaluated the safety and efficacy of the anti-retroviral drug TDF/FTC -- brand name Truvada -- taken once daily for HIV prevention among HIV-negative gay men, transgender women and other men who have sex with men.
The drug trial from June 2007 to December 2009 involved 2,499 individuals from Peru, Ecuador, Brazil, South Africa, Thailand and the United States. Half the men were randomized into the group that received Truvada and the other half were randomized into the placebo arm, who received a look-alike pill with no active ingredient. Study participants were tracked for an average of 14 months.
The trial, published in the New England Journal of Medicine, said there were 36 new HIV infections in participants who received Truvada and 64 in recipients who took the placebo.
The researchers calculated that the use of Truvada reduced new HIV infections by an estimated 43.8 percent overall when compared with placebo.
"The study team found that about half of the men in the active arm of the trial were in fact not taking their pills regularly, if at all," Pickett said in a statement. "It is not clear why this happened."