Once-promising HIV drug trial called off
A large trial of the drug Truvada, hoped to be a successful HIV-preventing treatment for women, has been halted after it was found to be ineffective.
The HIV research community suffered a setback on Monday with the news that a large-scale trial of an HIV-preventing drug for women has been halted. The trial, which involved taking a daily oral dose of the combination drug Truvada, was called off after it was found to be ineffective.
“At this time, it cannot be determined whether this drug works to prevent HIV infection in women in the FEM-PrEP trial. Other ongoing HIV-prevention studies may be able to shed further light on the effectiveness of Truvada among women,” said Dr Khatija Ahmed of the Setshaba Research Centre in Pretoria. Ahmed led the research at one of four sites in which the female pre-exposure prophylaxis (Fem-Prep) trial was carried out.
The other sites were in Bloemfontein, Bondo in Kenya, and Arusha in Tanzania. These sites were chosen because women in southern African countries are disproportionately affected by HIV. In some countries in the region, young women are over three times more likely than young men to be infected with HIV.
Ahmed said that though the trial would be brought to a close, researchers would continue to monitor the women for side effects over the next few months. An in-depth analysis of the data will also be done.
One year on
The trial involved 1 951 HIV-negative women between the ages of 18 and 35 who were at high risk of HIV exposure. All of the women involved received monthly counseling on how to reduce their risk of contracting HIV and were encouraged to use a condom every time they had sex. The women were also treated for sexually transmitted infections and provided with contraception and a regular supply of condoms. Half of the participants were given the active drug, Truvada, while the other half took a placebo.
Over the course of the year in which the trial was conducted, there were 56 new HIV infections, with an equal number of those on the drug and those on the placebo contracting the virus. Those who became HIV-positive during that time continued to be monitored, received counseling, and were referred to medical and social services in the community.
It was hoped that Truvada, which has shown some success when used in the form of a vaginal gel for women and as a daily oral drug when taken by men who have sex with men, would prove to reduce the risk of HIV infection when taken as a daily oral drug by women.
But this was not the case.
“It shows that you can’t extrapolate that what happens in one population group will give you the same results in another population group,” said Ahmed. She pointed out that despite the disappointing result, the data gathered from this study would help in future trials.
One unexpected finding of the trial was that women who took Truvada as well as an oral contraceptive were slightly more likely to become pregnant than those who took the placebo or those who used an injectable contraceptive. Further research would need to be done to find out why this was so. “We’re not sure whether it was because the women forgot to take the oral contraceptive as well as the Truvada, or whether there was some interaction between the two drugs that we’re unaware of,” said Ahmed.
Ahmed added that it was important that research into drugs that could help prevent HIV infection continues. “There is still a very high HIV prevalence in sub-Saharan Africa and women need more options for HIV prevention,” she said.