Conclusions
DISEASE, RARE DISEASES
Our results indicated that the presence or absence of RCT data in the clinical data package for NDA in the US was associated with three factors: severity of disease outcome, type of drug usage, and type of primary endpoint. Due to the small population of rare diseases, discussion on the necessity of RCT data tends to focus on the feasibility of conducting the clinical trials. While it is an unavoidable nature of orphan drug development, our results indicated the importance of selecting a target disease and potential efficacy variables to be used in the clinical trials to examine the need for RCT data for NDA. We hope that the results of this study will contribute to improving the predictability of the need for RCT data, optimizing investment in new drug development, and enhancing strategic collection of relevant information to establish efficacy variables for potential orphan drug development.