Evolving Research and Development Landscape for Rare Diseases: Growing Concerns Over Orphan Drug Lag in Japan.

Patients with rare diseases worldwide face substantial unmet therapeutic needs. In Japan, drug lag-delays in drug approval compared to other countries-has resurfaced as a pressing public health issue. This study analyzes orphan drugs (ODs) approved in the United States (US) from 2005 to 2021, examining OD lag trends, and research and development (R&D) models to streamline OD development in Japan. Despite increased OD approval in the United States since 2018, the number of unapproved ODs in Japan has substantially increased. Although OD lag decreased, it has resurged since 2017. This is largely due to changes in the R&D strategies of pharmaceutical companies, which are driven by the growing presence of US- and Europe-based small- to mid-sized enterprises (SMEs) and the evolving industry landscape. Large foreign pharmaceutical companies have shifted toward a global development strategy for Japan, aiming for more efficient development and competitive advantage. This has been propelled by a move toward in-licensing earlier-stage drug candidates with global exclusivity from SMEs. Japanese pharmaceutical companies have focused on in-licensing late-stage drug candidates for the Japanese market from SMEs without a business presence in Japan, which have not been developed locally, thereby employing a bridging strategy for Japan. With the increase in ODs developed in the United States by these SMEs, this practice has substantially exacerbated the OD lag. As these SMEs are unlikely to enter the Japanese market, it is crucial for Japanese pharmaceutical companies to proactively pursue earlier, more proactive global partnerships with SMEs.