Antiviral Drug Used to Treat AIDS to Be Tested as Vaccine
San Francisco Chronicle
Sabin Russell
DECEMBER 1, 2004
The US arm of an international drug trial will enroll 400 gay men in San Francisco and Atlanta to determine whether the properties that allow tenofovir (Viread) to suppress HIV among infected patients might also prevent HIV among the uninfected. Researchers believe tenofovir is a good candidate because it is deemed the least toxic AIDS drug and is taken just once daily.
"There are 150,000 HIV-infected people who have been on tenofovir, and the safety profile looks very good," said Dr. Lynn Paxton, who is coordinating the US and overseas studies for CDC. "We want to look at it, to see if it’s safe for HIV-negative people."
Participants in the trial will be randomly assigned to take either tenofovir or placebo every day for two years. At the international study’s end, researchers will compare the results. Researchers want to know if the drug is safe for preventing HIV, and whether such a pill could cause an undesirable increase in unsafe sex. The study would also determine if any participants who acquire HIV have tenofovir-resistant virus.
The researchers must ensure that participants are fully educated about potential risks. Researchers are ethically bound to dissuade all participants from engaging in risky sexual behavior and offer counseling on proper condom use and safer sex practices. Subjects will be warned there is no way for them to know if they are receiving the active pill or a placebo, and that even if they receive the drug, it may not protect them.
A proposed tenofovir trial among Cambodian prostitutes - designed by University of California-San Francisco and to be funded by the Bill & Melinda Gates Foundation - was called off this summer after the nation’s prime minister objected to the study’s design. Similar trials have begun without incident in Nigeria, Cameroon and Ghana.
CDC is sponsoring trials among 1,200 HIV-negative men and women ages 18-29 in the Botswanan cities of Gabarone and Francistown. In Bangkok, CDC-supported researchers are enrolling 1,600 uninfected IV drug users. "These trials first got started among heterosexuals in the developing world, because [heterosexual sex] is what’s driving the worldwide epidemic," said Paxton.