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More on Trials

Many questions are asked about the ethics of clinical trials. Below are some Q and A which begin to explain how these trials take place.

Why do we need to test microbicides in humans?
How well-informed are participants in the trials?
Why do so many trials take place in developing countries (in Africa)?

Why do we need to test microbicides in humans?

Each new drug, not just a candidate microbicide must go through sets of tests by humans before we can call them truly safe and effective. If a country is to make a new drug available to their population, the drug regulatory board in that country must have information on how the drug affects human beings. This can only be made available if humans are allowed to test the product. Testing of a microbicide candidate by humans is therefore a necessary part of microbicides development.

How well-informed are participants in the trials?

Potential volunteers are often required to give informed consent at pre-screening (to see if they are suitable for the trial), at screening and again at enrolment once they are found to be eligible to participate in a trial. This means that they must understand exactly what is happening and make a decision about whether or not they would like to participate in the pre-screening for a trial (which will typically include preliminary questions and explanation of the trial), screening (which will include an HIV test) and finally actually enrolling in a trial. These processes will take place on different days in order to give potential volunteers time to think about what trial participation involves and give them the opportunity to change their minds. In addition to this, women are allowed to leave studies when they wish, providing they return any microbicide or comparison gel samples they may have.

The UNAIDS/WHO 2007 Ethical Considerations in Biomedical HIV Prevention Trials contains explicit guidance on how to monitor informed consent in trials, and each government must also regulate the conduct of clinical trials within their country. Many governments and research trial networks have also developed guidance on this issue. (For an example of the informed consent process, you can see the Population Council’s video developed for the Carraguard Microbicides trial. It can be viewed at http://www.popcouncil.org/microbicides/micro_vignettes.asp

Why do so many trials take place in developing countries (in Africa)?

So far only candidate vaginal microbicides have been moved forward to efficacy trials. Given that a vaginal microbicide has to be tested by large numbers of women at high risk of sexually transmitted HIV in order to determine its effectiveness, the location in which Phase III trials are conducted must have:

  • High incidence of HIV (many new infections per year)
  • Stable population so that participants can be followed up easily
  • Virtually no injecting drug use or other sources of HIV risk among the participants

Conditions like these exist in parts of sub-Saharan Africa and in some communities in India and Southeast Asia. Communities where HIV incidence is high among women in the North America and Europe also tend to have high rates of injecting drug use, which could confuse the trial results by introducing other sources of exposure to HIV.