An Empirical Analysis of Japan's Drug Development Lag Behind the United States

The “drug lag” (ie, the approval lag for new drugs) hinders patients’ access to innovative new medicines. The drug lag was heavily debated in Japan from the late 2000s to the early 2010s. It consists of “development lag” (ie, the submission date lag for new drug applications) and “review lag” (ie, the difference in review periods). As the 2 lags have different causes and display significantly different recent trends in Japan, we focus on the development lag—in contrast with most previous literature—between Japan and the United States, based on a database we created for all new drugs from 2008 to 2018 using publicly available data sources. First, we found that Japan's development lag relative to the United States did not shrink in terms of the overall distribution rather than the median, which was the focus of most prior studies. Second, we examined the factors (product characteristics) that significantly affected the development lag and found that products that underwent multiregional clinical trials and those that were certified as “breakthrough therapies” in the United States had significantly shorter development lags with high robustness, whereas products receiving price premiums did not. Finally, we discussed the policy implications of these results. For instance, innovative new drugs that are presumed to receive price premiums require enhanced policy support for early application from the initial stages of clinical trials. It is also essential to promote information sharing regarding evaluations by foreign reviewing authorities for efficient use in the home country.