The secret realm of phase I trials in healthy volunteers

Phase I clinical trials in healthy volunteers aim at establishing safety, pharmacokinetics, and dosage for subsequent testing of new drugs. They are a necessary step in building the evidence for new treatments. But many view them with suspicion. Phase I trials expose humans to unproved drugs—often at plasma concentrations needed for detecting toxicity. Because volunteers are healthy, the ratio of medical risk to benefit for them is almost infinite. Another reason for suspicion is that healthy volunteers are paid—a fact that makes it likely that primary motivations for participation are misaligned with those of researchers,1 and that study participants will be drawn from underemployed people.

A few catastrophic events in phase I testing, including the death of a relatively healthy volunteer in 1999, and the occurrence of life threatening toxicities in six participants in 2006, have also fuelled concerns.2 3 Finally, there is the problem of opacity. What happens in phase I studies in healthy volunteers is largely hidden from public view.4 5 Some policies, such as the US Food and Drug Administration Amendments Act of 2007,6 exempt …