(RxWiki News) Last summer, a breakthrough in AIDS prevention was announced: A trial of a vaginal gel had successful results. But a new trial has been scrapped after the gel was found to be ineffective.
The cancelation of the trial is being called a major setback for AIDS research. It's not yet clear why the gel did not work in this trial. Researchers were surprised that the gel was shown to be less effective than a placebo.
"An AIDS-preventing vaginal gel is not yet available."
Creating a safe and effective vaginal gel has long been a goal for AIDS researchers. It's intended primarily for use in Sub-Saharan Africa, where many women risk refusal or violence if they ask their male partners to wear a condom. A gel could be applied in secret, allowing them to protect themselves from AIDS and violence.
The first trial of the vaginal gel, which contains the drug tenofovir, had encouraging results. It protected 39 percent of the women who used it, and women who used it regularly reduced their chances of infection by 59 percent.
Researchers were optimistic that the new trial would confirm the previous trial's results. Five thousand women in South Africa, Uganda, and Zimbabwe were enrolled in the new trial, called VOICE (Vaginal and Oral Interventions to Control the Epidemic).
VOICE was reviewed by an independent data and safety monitoring board during the trial. The board found that the gel was less effective than a placebo – meaning, no prevention. Six percent of women on the gel became infected, which was as many as became infected with the placebo.
The independent review caused the cancellation. The VOICE trial also involved a tenofovir pill, which has also been scrapped for similar reasons. However, part of the trial is still continuing, so researchers are unable to survey the participants to search for reasons why the trial may not have worked.
Sharon L. Hillier, a lead researcher for the Microbicide Trials Network, said she was surprised and disappointed by the cancellation. She emphasized that there could be human factors that could have produced bad results. The participants' adherence to the regimen, dosing strategy, inflammation or other factors could explain the lack of effectiveness.
Sub-Saharan Africa is considered the epicenter of the current AIDS epidemic. A majority of all HIV infections occur in the region. But progress is being made in the fight against AIDS. In South Africa, the rate of new infections continues to drop.