More Evidence Daily Pill Can Prevent HIV Transmission

This preventative treatment should be routinely offered to gay men at high risk, researchers say

By Mary Elizabeth Dallas

Wednesday, September 9, 2015

WEDNESDAY, Sept. 9, 2015 (HealthDay News) -- There's more data showing that a daily HIV medication called Truvada may prevent HIV-negative gay men at high-risk for infection from contracting the AIDS-causing virus.

The treatment, known as pre-exposure prophylaxis (PrEP), is very effective at preventing new HIV infections and should be added to the HIV prevention toolkit for gay men at risk of HIV infection, British researchers reported in the Sept. 9 issue of The Lancet.

Previous studies have shown that Truvada (tenofovir-emtricitabine) can reduce the risk of HIV infection. But it was unclear if the benefits of this preventive treatment would be offset by an increase in risky behavior among those who believed the medication protected them from the virus, the study authors explained in a journal news release.

A team of researchers led by Sheena McCormack, of the Medical Research Council clinical trials unit at University College London, sought to investigate this issue in the PROUD study.

The randomized trial, which was conducted at 13 sexual health clinics in England, involved HIV-negative gay men who had had anal sex at least once without a condom within 90 days.

The researchers randomly assigned 275 of the men to receive Truvada right away. Another 269 men received the treatment after a delay of one year. The researchers conducted a follow-up with the men every three months. The participants and the researchers were aware of their assigned treatment group.

Based on early findings suggesting that PrEP is highly effective, the trial steering committee recommended in October 2014 that all participants in the delayed-treatment group be offered the preventive treatment.

Among the men who received treatment right away, three HIV infections occurred, compared to 20 in the delayed-treatment group, the study found. The researchers calculated those in the immediate-treatment group had an 86 percent relative reduction in their risk for infection with the virus compared to the group that received delayed treatment.

Meanwhile, the prevalence of sexually transmitted infections, such as syphilis, gonorrhea or chlamydia, was similar in both treatment groups.

"This finding is highly encouraging for PrEP implementation, although quantifying the likely demand in the U.K. remains challenging. The impressive reduction in HIV incidence in people taking PrEP, without a measurable increase in other sexually transmitted infections, is reassuring for clinical, community, and public health stakeholders," McCormack and colleagues concluded.

In a linked commentary, two U.S. researchers endorsed the study authors' call for using the preventive treatment widely.

"The PROUD results show that PrEP should be part of the range of services offered by any clinical program that focuses on sexual health," wrote Dr. Kenneth Mayer, of Fenway Health and Harvard Medical School in Boston, and Dr. Chris Beyrer, from the Bloomberg School of Public Health at Johns Hopkins University in Baltimore.

"The time for cautionary speculation is over: HIV prevention services should be expanded worldwide by offering PrEP routinely to those who could benefit," Mayer and Beyrer concluded.

SOURCE: The Lancet, news release, Sept. 9, 2015

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