Early treatment with anti-HIV drugs stops transmission between partners – Study

May 18, 2011 News

---

Even as Guyana and the rest of the Caribbean gear to realise the elimination of mother-to-child transmission of the Human Immunodeficiency Virus (HIV), researchers have reported yet more tantalizing data that the antiretroviral drugs doctors currently used to treat HIV infection could also be effective in preventing transmission of the virus.
The notion that the Caribbean needs to take collective action against mother-to-child transmission of HIV was one of the issues that secured consensus among Ministers of Health of the Region when the 21st meeting of the Council for Human and Social Development (COHSOD) concluded in April.
And this achievement, according to Minister of Health, Dr Leslie Ramsammy, is in fact very realistic. He pointed out that over the years he had spoken of moving away from the trajectory of reduction to the trajectory of elimination.
“I believe it is possible because in a short period we have demonstrated that. We have demonstrated that in Guyana, as an example, 10 years ago about 150 to 200 babies were born with HIV and in more recent years it is three or four.”
However, the most recent auspicious development, whereby HIV transmission could be prevented among sexual partners, was detailed in a recent article – Early Treatment with Anti-HIV Drugs stops Transmission between partners – By Alice Park http://www.healthland.time.com). It was revealed that in a large randomized trial involving more than 1,700 heterosexual couples — in which one person was HIV-positive and the other was not — infected people who took the anti-HIV drugs reduced their risk of transmitting the virus to their partners by 96 percent, compared with those who did not immediately start treatment.
The results were so stark that Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID), which sponsored the trial, elected to release them early and stop the global study four years before its scheduled end.  All study participants are now being offered antiretroviral therapy.
These results come not long after another large-scale landmark trial that found evidence that using antiretroviral drugs could be an effective prevention measure. The trial included nearly 2,500 HIV-negative men in six countries, who were at high risk of contracting HIV.  Those who took a combination anti-HIV pill called Truvada (a combination of the drugs tenofovir and emtricitabine) were anywhere from 44 percent to 73 percent less likely to acquire HIV – depending on how faithfully they took their medication during the study’s three-year follow-up – than participants who took a placebo.  The findings add weight to the “treatment as prevention” strategy that some AIDS scientists increasingly believe, if broadly implemented, can help slow the spread of HIV and AIDS.
The latest study was carried out in 13 countries including Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand and the United States, and mostly involved heterosexual couples.  Infected partners were randomly assigned to begin receiving antiretroviral drugs immediately at the start of the study, or to wait to start treatment until their disease had progressed, signaled by a drop in the infected partner’s immune cell count below a certain threshold.  All participants were also counselled on how to protect against HIV transmission and were given free condoms.
In the group that waited to start treatment, there were 27 cases of HIV transmission from the infected person to his or her partner – all occurred when the patients were not taking antiretroviral drugs.
By comparison, in the group that started treatment immediately, only one such transmission occurred.
Antiretroviral drugs work by lowering patients’ “viral loads” — the amount of HIV in the body — which means they have less virus to transmit.
“The latest study really is very encouraging, and indicates that earlier therapy provides additional benefits to the treated person as well as to the patients,” says Dr. Robert Grant, a professor of medicine at the University of California, San Francisco, who was not involved in the current trial but chaired the group that designed the Truvada study in gay men.
In a statement, Fauci said, “This new finding convincingly demonstrates that treating the infected individual — and doing so sooner rather than later — can have a major impact on reducing HIV transmission.” However, because the trial’s population was 97 percent heterosexual couples, the findings are not applicable to homosexual couples.
As encouraging as the data are, though, AIDS experts aren’t quite ready to start doling out antiretroviral drugs as a prevention strategy like condoms. For one thing, the drugs require strict adherence and must be taken daily for life in order to work.
Also, they don’t work for everyone. In a follow-up to the study in high-risk, healthy gay men, scientists tested the preventive benefit of Truvada in high-risk women.
That trial was also halted early because it found no benefit in using the drug prophylactically in women. But some pointed out that the women in that study may not have been reporting accurately how regularly they took their medications.
That doesn’t mean the anti-HIV drugs won’t be helpful in HIV prevention. It just means that these studies are only the first in what will certainly be a long line of trials that will help scientists figure out exactly when and how the medications should be used.
And, as Grant says, anti-HIV drugs are just one in a growing list of ways to prevent HIV transmission — including male circumcision and antimicrobial vaginal gels. As these strategies are increasingly implemented, allowing more people to lower their chances of acquiring infection, the overall community viral load will drop, much the way that vaccinations reduce the circulation of contagious bacteria and viruses.
That makes it possible for HIV scientists to shift their efforts from blocking transmission of HIV back to finding a cure. And studies like this one are critical to accomplishing that goal.
“Now we can look forward to winning the war on HIV,” says Grant. “This is a turning point in the epidemic. There is no question in my mind about that.”

---

---