Treating the infected partner in heterosexual HIV discordant couples with triple-drug therapy reduced HIV transmission by 96% compared with no treatment, new study finding reveal.
“This is a crucial development because we know that sexual transmission accounts for about 80% of new infections,” WHO Director-General Margaret Chan, MD, MSc, said in a press release.
Although findings from previous observational studies have suggested that antiretrovirals have potential as HIV prophylaxis, National Institute of Allergy and Infectious Diseases director Anthony Fauci, MD, said this is the “first, rather dramatic, randomized trial in discordant couples,” during a telephone press conference.
Conducted by the HIV Prevention Trials Network and funded by the National Institutes of Health, the study, which began in 2005, was expected to run until 2015, but was stopped ahead of schedule when the study’s data safety monitoring board saw the dramatic results during an interim review.
Myron Cohen, MD, of the University of North Carolina Chapel Hill, and colleagues, enrolled 1,763 couples, 97% of whom were heterosexual, from 13 sites in nine countries to participate in the trial, dubbed HPTN 052.
All participants with HIV (890 men and 873 women) were immunocompetent and had CD4-positive T-cell counts between 350 and 550 per cubic millimeter, but were ineligible to receive HIV treatment based on local guidelines.
The researchers randomly assigned patients to either an immediate treatment group or a delayed therapy group in which treatment was withheld until a patient’s CD4 counts fell to 250, or the patient experienced an AIDS-defining event. Treatment regimens varied by site and involved 11 different antiretroviral drugs in various combinations.
A total of 39 previously uninfected partners developed HIV during the study period, of which 28 transmissions were genetically linked to the HIV-positive partner. All but one of these transmissions occurred among couples in the deferred treatment group (P<0.0001).
All participants in the deferred treatment group are now being offered triple-drug therapy regardless of CD4 count, Cohen said during the conference.
Despite efforts to include men who have sex with men in the trial, very few agreed to take part; therefore, the findings cannot be extrapolated to this population the researchers warned.
Other findings include fewer cases of extrapulmonary tuberculosis in the early treatment group compared with the delayed treatment group, 3 vs. 17 (P=0.0013). Overall 23 deaths occurred, 10 in the immediate treatment group vs. 13 in the deferred treatment group, but the difference was not statistically significant.