Tenofovir gel no more effective than placebo gel in preventing HIV

Nov 28 2011

Studies of different dosing regimens to continue

An independent review of the VOICE study, funded by the National Institute of Allergy and Infectious Diseases (NIAID) and conducted by the Microbicide Trials Network, determined that tenofovir gel was no more effective than placebo gel in preventing HIV. The review found no safety concerns and the VOICE study will continue to evaluate the effectiveness of the oral Truvada tablet in preventing HIV in women. It is unknown at this time why tenofovir gel did not work in this particular trial. The study will need to be completed before data can be analyzed to determine whether adherence to a daily regimen was possibly a key factor.

Use of tenofovir gel was shown to be effective in reducing HIV and herpes infections in the CAPRISA 004 study, which tested a different dosing strategy where women were asked to use the gel before and after sex. The CONRAD-sponsored FACTS 001 trial, which is currently assessing the same dosing regimen as the CAPRISA 004 trial, is ongoing in South Africa.

"Tenofovir gel is still a promising new product for women," said CONRAD Executive Director Dr. Henry Gabelnick. "Despite the disappointment of this result, VOICE will contribute important safety data toward the possible licensure of tenofovir gel. We are pleased that USAID, the Bill & Melinda Gates Foundation, and the government of South Africa are supporting the FACTS study, which will serve to provide confirmatory results for regulatory approval."

Gilead Sciences licensed tenofovir royalty-free to CONRAD, who manufactured and supplied the gel for the CAPRISA 004, VOICE and FACTS 001 trials. CONRAD and the South African Government's Technology Innovation Agency (TIA) have a license agreement that grants TIA the rights to manufacture and distribute tenofovir gel in Africa, pending regulatory approval.

If FACTS 001 can confirm CAPRISA's positive results, these combined effectiveness data, along with VOICE's safety data on tenofovir gel, may enable the licensure of the first microbicide for women, and a powerful new tool for women to protect themselves from HIV and genital herpes.

Source: CONRAD