David A. Kessler, M.D., Commissioner of Food and Drugs, opened the workshop. He noted that while the proportion of women participating in clinical drug studies generally reflected the prevalence of the condition under study in the general population, the safety and efficacy data from those clinical trials were not analyzed routinely for the specific influence of gender. He encouraged workshop participants to clarify critical and methodological questions aimed at improving and expediting the drug development process and to draw on FDA’s 1993 "Guideline for the Study and Evaluation of Gender Differences in the Clinical Evaluation of Drugs" as a means of producing the safest and most effective medical therapies possible.
Janet Woodcock, M.D., Director of FDA’s Center for Drug Evaluation and Research, then presented the formal workshop charge. She acknowledged that scientific knowledge and societal shifts have led to an understanding that the role of gender, coupled with other individual patient factors, should be evaluated during the drug development process. Dr. Woodcock noted that appropriate clinical trial enrollment in early drug studies, followed by rigorous data analysis, enhance substantially the ability to predict whether or not certain interactions are likely to be important to specific population groups. These predictions can then be examined in the overall database.
While the FDA’s interest in assessing the effects of gender during drug development has been applauded in some quarters, it has also raised concern that too little is currently known about drug effects in women and the importance of those differences. Dr. Woodcock said that a substantial body of data about gender effects already exists, pointing out that in her own field of rheumatology, where a range of medical conditions predominantly affect women, most of the participants in clinical drug trials are women. However, she acknowledged that unanswered questions about how to assess gender effects in clinical trials remain.
Drug development sponsors and other researchers have raised concern about the practical and methodological consequences of assessing drug effects by gender. It has been suggested, for example, that the cost of clinical drug development could double if it were necessary to conduct parallel trials among men and women, each powered separately and each enrolling half as quickly as a less restricted trial. According to Dr. Woodcock, that concern has been fueled by the erroneous idea that information about drug effects derives solely from randomized trials. She pointed out that if every question about drug effects had to be answered via controlled trials designed specifically to answer that question, medical progress would slow dramatically. Rather, the goals of drug development science - to understand sources of variable response and causes of adverse reactions in order to allow more effective and safer treatments are supported by various kinds of data, including data on pharmacokinetics, metabolism, and drug and hormonal interactions, among others. A further approach is to pool data from multiple studies for demographic subgroup analyses. Appropriate clinical trial enrollment in early drug studies and rigorous data analysis greatly enhance the ability to predict when given interactions are likely to be important to specific population groups and, just as crucial, when they are not likely.
Dr. Woodcock cautioned conference participants that the deliberations of the workshop should not result in a rigid set of instructions for uncovering gender-related effects during drug development. Because the science is not yet mature, important questions remain about how best to detect those differences. She noted, for example, that under certain circumstances, early clinical pharmacology studies may be appropriately employed to elucidate gender differences, while in other instances large, simple trials that enroll many subjects with disparate characteristics may be more appropriate. The challenge is to determine the factors that may differentiate these cases to guide appropriate study design.
In outlining the structure and goals of the conference, Dr. Woodcock said that workshop findings are intended to assist both the FDA and drug developers to apply state-of-the- art scientific knowledge to the investigation of gender-related differences. She expressed the hope that further research and additional initiatives would result from the workshop and suggested that additional FDA recommendations may be forthcoming to guide sponsors on how to study gender effects during medical product development.