Utilisation of Foreign Clinical Data in Japanese New Drug Approval Review

Objective: Foreign clinical evidence for efficacy and safety of new pharmaceutical drugs was utilised in decisions for marketing approval in Japan without specific regulatory guidelines until a new internationally harmonised guidance for bridging strategy was introduced in 1998. We examined how foreign clinical studies were used in recent marketing approval decisions and also how the new guidelines affected the trends of foreign data acceptance. Methods: New drug applications (NDAs) approved between 1999 and 2003 with review reports issued by the regulatory authority available on the official website were scrutinised. Focusing on critical clinical trials including dose response studies in phase II and confirmatory studies in phase III, we classified the type of utilisation of foreign clinical data into several groups. Results: Of the 171 NDAs approved during this period, 55 (32%) contained foreign studies as formally submitted data. Twenty NDAs (12%) were approved based on the bridging strategy. In 24 NDAs (14%) important foreign data were used as references, but not as formally submitted materials. NDAs that were given orphan drug status or priority review status were more likely to be submitted and approved on the basis of foreign clinical data. The number of bridging-based NDAs successfully approved increased from three in 2000 to ten in 2002, although confusion about the application of the new guidelines was observed after the guidelines’