Assessing the “Drug Loss” and “Drug Lag” for Rare Diseases in China: A Comparative Analysis with the United States (2001–2024)

Recently, the Chinese government has prioritized enhancing access to rare disease drugs, with the initial objective of addressing the challenge of drugs being "available abroad but not domestically." The United States, a leader in the development of treatments for rare diseases, serves as a benchmark for assessing a nation's progress in this field. This study examined the progression and influencing factors of the availability gap through the application of two principal metrics: "drug loss" and "drug lag" at the indication level. We conducted a retrospective analysis of rare disease indications approved in the United States and China from 2001 to 2024, focusing on diseases listed in China's official Catalogs of Rare Diseases. Our study indicated that "drug loss" in China had continued to escalate, with the total number of unapproved indications reaching 123 by 2024. Although the growth rate had decelerated since 2017, the "drug loss" associated with novel therapies recently approved by the FDA had intensified. Conversely, the "drug lag" in China for indications approved by the FDA after 2015 had decreased in comparison to those approved before 2015, with the median delay reducing from 4,049 to 2,812 days. The principal factors influencing drug availability were the global R&D and commercial strategies of sponsors. This finding highlighted that encouraging multinational sponsors to integrate China into their initial global development plans and to incentivize domestic companies to engage in earlier and more substantial international research and development collaborations were more important for mitigating "drug loss" and "drug lag" in China.