Challenges on Multiple Endpoints in Clinical Trials: An Industry Survey in Japan

Background: Two issues on clinical trials with multiple endpoints were surveyed: (1) the terminology of multiple endpoints, relationship between rare events and endpoints, and differences in multiplicity adjustment between regions; and (2) the current practice on multiplicity adjustment and sample size calculation. This article provides a summary of the results of a survey on the first issue. Methods: The survey was conducted among 63 members of the Japan Pharmaceutical Manufacturers Association from October to November 2017. Results: Thirty-five companies based in Japan and 12 companies based in other countries, 47 companies in total, responded to the survey. The terms co-primary endpoints, secondary endpoint, and composite endpoint were used in a variety of ways. An endpoint for a clinically most important event that is expected to occur rarely differed between regions. Although the Pharmaceuticals and Medical Devices Agency did not demand multiplicity adjustment, it was considered in clinical trials with multiple endpoints for approval in Japan. Conclusions: The use of terminology differed from the definition in the Food and Drug Administration guidance and the European Medicines Agency guideline. There remain challenges on a clinically most important event that is expected to occur rarely and multiplicity adjustment in clinical trials with multiple endpoints.