Research into the Background to Delays in New Drug Development in Japan

Abstract

The present study aimed at analyzing the factors that were associated with delays in the development of new drugs in Japan by investigating the approval status and timing of new drugs in the US, EU, and Japan, including unapproved drugs in Japan, and discussing measures to prevent such delays. We studied new active substances (NASs) that were approved in both the US and EU between 2010 and 2020, and were approved in Japan later than both country/region or were not yet approved at the end of 2020. Cox regression analysis was conducted using the time from the approval in the US and EU to the approval in Japan as a response variable (unapproved drugs in Japan at the end of 2020 were handled as censored data), and eight explanatory variables such as the availability of similar drugs and whether the drug was antineoplastic. The analysis suggested delays in development in Japan for new drugs for which no similar drug existed or the marketing-authorization holder in the US or EU did not have a Japanese subsidiary. The analysis based on drugs approved in Japan suggested that there might be delays in approval in Japan for NASs for which the originator and the marketing-authorization holder were different, or the expected sales in Japan was small. Based on the result, it is important to consider measures to deal with the issue of drug lag from multiple perspectives including pharmaceutical regulations and drug price system.