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Tenofovir Prevention Study: Commentary in Support
"Outside View: An HIV pill that offers hope"
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By Thomas J. Coates
Outside View Commentator
Dr. Coates is Professor of Medicine, Division of Infectious Diseases and member of the Executive Committee of the UCLA AIDS Institute, at the University of California, Los Angeles, David Geffen School of Medicine.
Los Angeles, CA, May. 6 (UPI) -- Last month, researchers in Atlanta launched a clinical trial to determine if the drug tenofovir, already in wide use to treat HIV/AIDS, also can be taken by uninfected people to protect them from HIV.
This is the strategy we use with malaria and other diseases: We take preventative medications before we encounter pathogens, so our body can repel infection. If we can use the same approach with tenofovir, millions of at-risk people might remain HIV-free.
As we have seen with tenofovir trials in Cambodia, Nigeria and Cameroon, however, ethical concerns and the complexities inherent in these types of studies could delay or even derail this urgently needed research.
As someone who has been working to stop AIDS since 1982 -- before the human immunodeficiency virus, the organism that causes AIDS, was even identified -- I know the disease's devastation all too well. I also am only too aware of the limits of our current prevention strategies, and the dire need for better ones.
My vaccine research colleagues tell me not to hope for much in that realm for another 15 years, and that is when they are feeling optimistic.
Tenofovir, on the other hand, could work to reduce new infections in as few as two years, when study results start to roll in. I, for one, would never recommend a prevention strategy -- tenofovir or anything else -- without knowing for sure that it protects a person from HIV without harming them.
Plenty of data show tenofovir, a once-a-day pill, is safe and effective in treating HIV-infected individuals, and it can delay or block infection in monkeys, but we do not know if the same is true for HIV-negative people.
The only way to find out is through a placebo-controlled trial. To this end, such studies are looking at tenofovir's prevention potential in some of the world's highest-risk populations: sexually active young adults in Botswana, injection drug users in Thailand, female sex workers in Ghana, heterosexual men in Malawi and gay men in San Francisco and Atlanta.
Men and women who volunteer for these trials need to understand that participation does not equal protection. They must be allowed to enroll only if they fully comprehend they could receive a pill with the study drug or an inactive "dummy" pill.
Most important, participants must be given every chance to stay uninfected by receiving proven interventions: intensive risk-reduction counseling, condoms, STD screening and treatment and sterile syringes or bleach kits for cleaning drug equipment. Current trials offer all these things.
Some activists have criticized the placebo design of tenofovir studies. This is understandable, stemming from the early days of the epidemic when AIDS advocates unanimously considered it unethical to deny people access to experimental therapies that might prolong their lives.
In tenofovir studies today, however, using a placebo for comparison is the only way we can ascertain whether this potential prevention strategy will be safe and effective.
I have conducted my fair share of HIV prevention trials, both in the United States and in resource-poor nations. The hardest part of this work is not identifying an approach to study or the people willing to take part in it. It is learning that a participant has become infected. At that point, my job -- and the job of all who conduct this type of research -- is to ensure the individual is linked immediately to the best available medical care. The reward for altruism must be nothing less.
Through the collaboration of researchers, participants, affected communities and study sponsors, I believe we are well on the way to ensuring tenofovir trials adhere to the highest ethical standards. I fear, however, the biggest challenge will come later.
What happens if tenofovir reduces, but does not eliminate, HIV risk? Most experts think tenofovir will prove only partially effective in preventing HIV and will need to be used together with existing behavioral interventions. Just as HIV treatment involves a combination of anti-retroviral drugs, avoiding infection through "combination prevention" is likely to the become state of the art in stopping the spread of the virus.
Looking back to 1985, when the HIV test was first introduced and I took it, people predicted that a vaccine and an end to AIDS were at hand. Now, 20 years and 60 million infections later, I know there remains a long road ahead. The HIV epidemic's severity demands we move forward with studies of tenofovir -- but always proceed with caution. Our challenge is to ensure fear does not paralyze our efforts, but instead spurs us on to ultimate success.
Millions of lives depend on it.
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