AIDS Meeting Spotlights Pills to Prevent Infection

NEWS p983 Dig deep: p986 Root of all bias: p988 Climate control: Cell phones are Should scientists Paul Epstein tracks set to help find be barred from the effect of arsenic-free water financial conflicts warmer weather in Bangladesh. of interest? on diseases. AIDS meeting spotlights pills to prevent infection Gels, creams and pills that can prevent HIV think about it, what is more female-controlled infection are the most promising new tools in the than taking a pill in the morning that can 38.6 million Number fight against HIV/AIDS: that was the recurring protect you from getting infected?” infected with HIV worldwide th theme at the 16 international AIDS conference 4.1 million Number of new in Toronto in August. Trials and tribulations infections in 2005 Faced with growing numbers of HIV The concept of using antiretroviral drugs is infections and the dim prospects of a vaccine to not new. Drugs such as AZT and nevirapine 1.65 million Number of prevent them, researchers are pinning their hopes have been used in HIV-positive pregnant individuals on antiretroviral on circumcision, microbicides and antiretroviral women to prevent transmission of the virus therapy drugs taken to thwart HIV infection. to their children. Members of some high-risk 8,000 Number of deaths Trials of 16 microbicides, championed by the groups, such as men who have sex with men, each day from AIDS-related http://www.nature.com/naturemedicine Bill & Melinda Gates Foundation and others, are already thought to take AIDS drugs as illnesses are under way in Africa and India. Five of those prevention. are in advanced trials and results are expected If rigorous trials back the use of these pills 9% Proportion of adults at next year. One large trial last year showed that for preventing infections, several questions risk with access to condoms circumcision can reduce HIV infections by up follow: who would pay to provide the pills, to 60% (Nat. Med. 11, 1261; 2005). and to whom? What about the potential for 33% Proportion of US But antiretroviral drugs are only just beginning misuse and for resistance to the drug? Is it funds for prevention set to get attention as a means of prevention. safe to give these potentially toxic medicines aside for abstinence In his keynote speech, Bill Gates said his to otherwise healthy individuals? foundation would dedicate funds for drugs that A few concerns arose even before the trials prevent HIV infection. “Oral prevention has began. Activists asked whether the drug would be Against abstinence Nature Publishing Group Group Nature Publishing 6 not gone as fast as it should,” he said. “We blame available to participants after the trial ended and Solutions to the many other ethical concerns are ourselves for not pushing that more.” whether those who become infected during the starting to emerge. Tenofovir is long-lasting and 200 An early trial, funded by the foundation and trial would be cared for long term. The intense safe. Other antiretroviral drugs, such as 3TC, © led by the nonprofit Family Health International, media scrutiny that followed shut down studies have been available longer and are known to be has shown that the antiretroviral drug tenofovir in Cambodia and Cameroon. safe even after long-term use. (Viread) is safe when given to healthy people. Trials since then have taken these concerns To combat the potential problems with Because too few people became infected during into account, says Peterson. For instance, she resistance, ideally some companies would reserve the trial, however, it is not yet clear whether the says, researchers negotiated to provide treatment specific drugs for prevention, says Lange. Despite drug can protect against HIV, says Leigh Peterson, for at least 15 years to trial participants in Ghana all the hurdles that remain, he says, “I still think lead investigator of the trial. who became infected. it’s far easier in the end to do this than to put 30 Other trials of the approach are million people on therapy.” under way in Thailand, Botswana, Peru Researchers at the meeting also and the US, testing either tenofovir or discussed the use of cervical barriers, Truvada, a combination of tenofovir and such as diaphragms, and suppressing emtricitabine. Results from the Thai trial, herpesvirus infections, which increase expected next year, should clarify whether HIV risk by up to three times. the approach works. For the first time, world leaders also These studies are testing the method in loudly criticized the US government’s sex workers, men who have sex with men emphasis on abstinence. President and drug users—high-risk groups for Bush’s $15 billion AIDS program whom the drugs are likely to be the most earmarks 33% of its prevention funds effective. Oral drugs would also allow for abstinence-based programs. women to protect themselves without the “On balance, this program has knowledge or cooperation of their partners, done a lot more good than harm,” said notes Joep Lange, an AIDS specialist at the former President Bill Clinton. But “an University of Amsterdam. Jorge Uzon/Agence France Presse abstinence-only program is going to “There’s an enormous need for female- Safety first: New tools for prevention and the US policy on fail.” controlled methods,” Lange says. “If you abstinence were hot topics at the AIDS meeting in Toronto. Apoorva Mandavilli, Toronto NATURE MEDICINE VOLUME 12 | NUMBER 9 | SEPTEMBER 2006 981.

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