Increasing orphan drug loss in Japan: Trends and R&D strategy for rare diseases.

Rare disease (RD) patients face significant unmet therapeutic needs worldwide. However, orphan drugs approved in the United States, but not approved or developed in Japan, have increased rapidly with recently increasing US approvals, indicating greater RD drug loss in Japan. US/EU-based startups have become key players in RD drug R&D, significantly contributing to this drug loss trend. They successfully develop drugs in the United States by combining in-licensing with in-house drug discovery. Out-licensing to Japanese companies or large pharma is critical for expansion into Japan, with successes attributed to drug innovation, target indications, and transactional capabilities. These findings highlight the need to foster partnerships with startups and cultivate an ecosystem in Japan that nurtures local startups, to address drug loss and ensure access to promising drugs.