グローバル試験の問題と克服すべき課題

抄録

Drug loss, defined as the absence of clinical development in Japan despite regulatory approval in overseas, have become significant concerns in the Japanese clinical research environment. Although Japan has transitioned toward participation in global clinical trials since the implementation of revised Good Clinical Practice regulations in 1997, its role in international development remains limited in certain therapeutic areas, including amyotrophic lateral sclerosis (ALS). As of March 2023, 143 drugs approved in the United States or Europe were unapproved in Japan, more than half of which were developed by emerging biotechnology companies. Limited financial resources, high operational costs, and Japan's relatively small market size reduce its attractiveness as a trial site. In ALS, approximately 50 trials are conducted globally, whereas only around five are active in Japan. Japanese sites are recognized for high data quality, strong compliance with electronic data capture systems, and low protocol deviation rates. However, challenges remain in patient enrollment speed and cost efficiency. Contributing factors include fragmented trial sites, limited outpatient infrastructure for infusion therapies, administrative complexity related to Japan's healthcare reimbursement system, and language or time–zone barriers in global collaboration. In addition, feasibility assessments are sometimes conducted after eligibility criteria are fixed, resulting in impractical study designs that hinder enrollment. Despite these limitations, Japan has demonstrated strengths in ALS development, including low discontinuation rates and successful completion of pivotal trials. Leveraging efficient infrastructure, telemedicine, and platform–based trial models may enhance competitiveness and help mitigate drug loss in rare diseases.