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Controversial trials of HIV drug hit by fresh setbacksJon Cohen Clinical trials of a promising new AIDS prevention strategy, already derailed in Cambodia and Cameroon, suffered two more setbacks last week. The studies aim to test whether the drug tenofovir can thwart HIV if people at high risk of becoming infected take one pill every day. Tenofovir, an anti-HIV drug on the market since 2001, has relatively few side effects and stays in the body for an unusually long time. Citing ethical concerns, Cambodia stopped a tenofovir prophylaxis study in sex workers in August 2004; Cameroon halted a similar trial in February. Then on 11 March, Family Health International (FHI), the North Carolina-based nonprofit that organized the Cameroon trial, announced that it was pulling the plug on a Nigerian study of sex workers, this time citing technical, not ethical, concerns. Just a day earlier, critics of a study in Thailand involving injecting drug users (IDUs) held a press conference to attack a pending tenofovir study there, charging that the trial, funded by the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, "ignores international ethical standards." Trial tribulationsCriticisms of a tenofovir study in Thailand are off the mark, says Jordan Tappero, who heads the U.S. CDC program there. FHI determined that the research team running the Nigerian trial, which started enrolling participants in September 2004, "is not at this point able to comply with all of the standards that have been established for conducting this study." The study team had problems with record-keeping and other technical issues, says Ward Cates of FHI, which decided to cut its losses. "The juice wasn't worth the squeeze," Cates says. (The Bill and Melinda Gates Foundation funded FHI to conduct its tenofovir prophylaxis trials, two of which are still under way in Ghana and Malawi.) In Thailand, the Thai Drug Users' Network and other AIDS advocates blasted several aspects of the study. Approved by both U.S. and Thai authorities and run by Thai researchers, the study plans to enroll 1600 uninfected IDUs who visit 17 different methadone clinics. Critics insist that drug users who participate should receive clean needles and syringes to help prevent HIV infection. They also allege that it's "coercion" to recruit people at methadone clinics, as some fear they must join the study to receive the heroin substitute. They further worry that IDUs who test positive for HIV either during the screening process or the trial itself will not receive AIDS drugs from government programs, which they claim discriminate against them. Jordan Tappero, head of the CDC program in Bangkok, notes that both U.S. and Thai law prohibit providing sterile injection equipment, but that Thai pharmacies and convenience stores sell needles and syringes without a prescription at low cost. He also disputes the charge that Thailand does not provide anti-HIV drugs to infected drug users. "That's just a misunderstanding," he says. As for coercion, social workers, not clinic staff, will recruit people to the study, he says. Tappero and co-workers are continuing discussions with the critics, and he hopes the study can start as planned within the next 2 months. "This community needs a prevention intervention, and tenofovir could be a great tool," says Tappero. "The only way to evaluate it is a clinical trial." Volume 307, Number 5716, Issue of 18 Mar 2005, p. 1708. |
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