An antiretroviral drug currently used to treat people with HIV has now been found to offer some protection against HIV infection in HIV-negative people. A new study has revealed that taking the ARV, Truvada, once a day reduces the risk of HIV infection by nearly 44% in gay men.
"In a finding with the potential to fundamentally change strategies to slow the global HIV epidemic, a new study called iPrEx shows that individuals at high risk of HIV infection who took a single tablet containing two widely used HIV medications, emtricitabine and tenofir (FTC/TDF also called Truvada), experienced an average of 43.8% fewer HIV infections that those who received a placebo pill," reads a statement by the research group responsible for the study, Prexposure Prophylaxis Initiative. The study was reported in the New England Journal of Medicine.
Truvada yielded "positive results" when administered to 2,499 gay men and transgendered women between the ages of 18 and 67, the Medical Research Council said in a statement. Half of the men took Truvada, while the other half took a placebo. In all, 64 HIV infections were recorded among the group who received a placebo pill, while 36 HIV infections were recorded in the group taking the study drug.
The results were the first showing that oral use of anti-retroviral drug among HIV negative gay men could provide protection from the virus.
SA component of the trial
The Desmond Tutu HIV Foundation, based at the University of Cape Town Health Science Faculty, was selected as one of 11 international sites to participate in this groundbreaking HIV prevention trial. The trial study was conducted in South Africa, Brazil, Ecuador, Peru, Thailand and the United States between July 2007 and December 2009.
The Medical Research Council's Gita Ramjee said the results gave hope for the successful use of new biomedical technologies, together with current options such as condoms and male circumcision, for HIV prevention.
"This has been a good year in terms of HIV preventions," said Prof Linda-Gail Bekker from the Desmond Tutu HIV Foundation at the launch of the results. Apart from the positive results achieved in this study, in July 2010, a study known as CAPRISA 004 found evidence that a topical gel containing 1% tenovofir helped reduce HIV negative women's risk of HIV infection via vaginal sex.
However, the antiretroviral pill is available by prescription in many countries right now, while the microbicide gel is made only in small amounts for clinical trials. Putting the power to protect themselves in the hands of patients and their clinicians.
The protection, known as “pre-exposure prophylaxis” or “PreP,” is also the first new form available to men, especially men who cannot use condoms because they sell sex, are in danger of prison rape, are under pressure from partners or lose their inhibitions when drunk or high.
The iPrEx study found that the prophylaxis was more protective among those who reported taking the pill more regularly. Among participants who used the tablet on 50% or more of days, risk of HIV infection fell by 50.2%; among those who used the pill on 90% or more of days, it reduced infection risk by 72.8%.
No serious side effects to the drugs were reported in the trial. Side effects included a small number of reports of low-grade transient nausea, which dissipated after several weeks - such symptoms are relatively common after initiation antiretroviral therapy. In addition, isolated mild elevations of creatinine, a naturally occurring molecule filtered by the kidneys, occurring in a small number of individuals receiving the active drug, resolved spontaneously or with discontinuation of the pill. Slight increases were also detected in headache and unintentional weight loss among participants in the study arm that received FTC/TDF.
More about the trial
In addition to the medication (Truvada or the placebo), all study participants received a comprehensive package of prevention services designed to reduce their risk of HIV infection throughout the trial, including HIV testing, intensive safer sex counselling, condoms and treatment and care for sexually transmitted infections.
"iPrEx proves that PrEP provides important additional protection against HIV when offered with other prevention methods such as HIV testing, counselling, condom use and management of sexually transmitted infections," said iPrEx Protocol Chair Robert Grant, MD, MPH of the Gladstone Institutes and the University of California and San Francisco. "As with other prevention methods, the greatest protection comes with consistent use. I hope this finding inspires a renewed commitment from communities, industry, and government to stop the spread of HIV."
The iPrEx study is a double-blind, placebo controlled Phase III clinical trial that began in 2007. It is the first human efficacy study of PrEP to report data.
Meanwhile, the HIV Prevention Research Unit was undertaking another trial called Vaginal and Oral Intervention to Control the Epidemic.
The study is conducted among HIV negative women among several communities in Durban, with results expected in 2013. -(Wilma Stassen/Health24/Sapa, November 2010)