Exclusion of Women from Phase I Trials: Perspectives from Investigators and Research Oversight Officials

Abstract

Over the past 30 years, progress has been made in increasing women's representation in clinical research. However, women continue to be underrepresented in phase I clinical trials—those trials that test the safety and tolerability of investigational drugs, often on healthy individuals. As sex-based differences in adverse drug reactions are often linked to drug dose, pivotal safety information in phase I trials is often insufficiently—and inequitably—captured for females. Yet there has been little attention to how clinical investigators and those charged with overseeing the ethical conduct of these trials perceive the barriers to women's inclusion in phase I trials. To address this gap, we report on 22 interviews with U.S. phase I investigators and institutional review board (IRB) members. Our findings indicate that although these investigators and IRB members acknowledged the importance of including women in clinical trials, they justified women's exclusion from phase I trials by citing the need to manage their reproductive potential. In particular, we identified four key themes that informants used to warrant women's exclusion from phase I trials: the structure of the drug-development system itself, fears about risks to potential fetuses, distrust of women to prevent pregnancy, and concerns about risks and burdens to institutions from resulting pregnancies. We argue that these rationales reflect structural and cultural barriers to women's inclusion in clinical research that ultimately fail to respect female research participants as persons, highlighting the need for broad-based solutions.