Does Evidence-Based Medicine Serve Everyone? Representation, Reward and Risk In Phase I Clinical Trials
Summary
Evidence-based medicine is a vast industry created around supporting the testing of new
therapies before they are prescribed in the general population. Previous researchers have been
concerned with the representativeness of these trials, citing concerns of external validity for
female patients and racial minorities. However, Phase I trials, where the therapy is tested on a
small group of healthy volunteers, have not been studied as extensively. Recent work suggests this
group of participants may be disproportionately Black and Hispanic in the United States, reflecting
a phenomenon of serial participation. These participants are often unfairly disadvantaged in the
labor market, often facing unemployment, and are attracted to Phase I participation for the
payment. These findings have not been replicated with a systematic review, as the original
researchers relied on self report data, recruiting at trial centers themselves. This methodology is
prone to selection bias, as it relies on permission. The present study was a systematic review of
publicly available Phase I trials with the goal of clarifying factors which affect female enrollment as
well as determining if enrollment by race is affected by whether or not the participants receive
therapeutic benefit. A total of 300 articles reporting on 384 trials were included in this analysis. I
found overall low female enrollment, except for in trials which were conducted in more than one
global region (p < .001). Pharmacokinetic studies, pharmacodynamic studies, and studies
conducted in Africa were also less likely to enroll female participants (p < .001). Within the United
States, Black and Hispanic participants were found to be overrepresented as compared to their
share of the population according to Census data, however this was not predicted by whether or
not they participated as healthy volunteers as opposed to patients (p > .05). Most of the trials in
the sample were conducted on healthy volunteers, however (76%). Future researchers may
consider investigating a larger sample of trials with participant benefit for a more fair comparison.