Analysis of the success rates of new drug development in Japan and the lag behind the US

Objectives: The launch delay of new drugs has been a major public concern in Japan. Although it is recognized that the delay results from industrial R&D behaviors and regulatory conditions in the global market, the specific mechanisms underlying the significant delay have been unexplained. This study analyzed the association between the success rates of clinical development programs of new molecular entities in Japan and the development lag behind the US and provides clues for policy planning. Methods: The association between the success rates of clinical development and the development time lag between Japan and the US was estimated using the Cox proportional hazard model. Results: The phase II transition success rates in Japan were positively associated with the lags behind US development. Cox regression analysis results of phase III success rates were similar to phase II success rate results but were not statistically significant. Conclusions: The advantageous effect of lags on development success in the latter country (i.e., Japan) appears to explain the persistent delays in development and launch. The government's countermeasures to reduce the access gap of new drugs must consider this mechanism and the influence on both the industry and the target population. (C) 2011 Elsevier Ireland Ltd. All rights reserved.