Exploratory Analysis of Drug Lag in New Oncology Drugs Between Japan and the US.

Abstract

Drug lag in Japan has greatly decreased over the past decades; however, new instances of drug lag have appeared along with changes in the circumstances of oncology drug development. We aimed to investigate the factors associated with the approval lag for new oncology drugs between Japan and the United States (US) over the past decade by comparing approval dates and modalities, lead indications, approval types, and phase I strategies for earlier approval in Japan. We descriptively evaluated the characteristics of 117 new oncology drugs approved in either Japan or the US from January 1, 2011, to December 31, 2020. Seventy-one drugs were approved in Japan, 112 in the US, five only in Japan, and 46 only in the US. Interestingly, new oncology drugs were predominantly developed by the top 20 pharmaceutical companies in Japan; however, the opposite was true for drugs that were not yet approved in Japan. However, no clear trend was observed in the relationship between drug lag and the studied factors, except for the phase I strategy. There was a numerical but clear trend in which a higher percentage of phase I multiregional clinical trials (MRCTs) in the drug development strategy was observed for drugs with earlier approval in Japan. Participation in global drug development during the early stages, such as during phase I MRCTs, is one of the keys to successfully minimizing this new instance of drug lag in Japan.