The delay in the approval of drugs in Japan that had already received regulatory approval in Europe and the United States, known as'drug lag,'has been a significant issue. However, in recent years, an increasing number of drugs that have been approved in the West are either not expected to receive regulatory approval in Japan or are not being developed by companies. This has drawn attention as a new issue, termed'drug loss'. The increase in drug loss can be attributed to the presence of the'drug ecosystem'and significant changes in the pharmaceutical industry structure that have occurred in parallel. To address drug loss, it is crucial to promote drug development in Japan and to have industry, government, and academia collaborate to evaluate drugs developed overseas and attract foreign companies. The formation of a drug ecosystem is essential not only for sustaining the pharmaceutical industry in Japan but also as a potential measure to prevent future drug loss.