The latest status of regenerative medicine in Japan – 2025

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In 2025, Japan’s regenerative medicine sector continues to be at the forefront of global innovation. Over the past year, there have been significant advancements across basic research, clinical applications, regulatory frameworks, and societal implementation. Notably, the development of retinal pigment epithelium (RPE) sheet transplantation by the joint team from RIKEN and Osaka University, the clinical achievements in iPS cell-based therapies for Parkinson’s disease, and the announcement of the “YOKOHAMA Declaration 2025” by the Japanese Society for Regenerative Medicine have all had a profound impact on the progress of regenerative medicine in Japan. This article focuses on the latest developments since spring 2024, providing a detailed overview of the current state and future prospects of regenerative medicine in Japan.

Advances in iPS Cell Technology and Expansion of Clinical Applications

Japan has been a global pioneer in induced pluripotent stem cell (iPS cell) research, consistently achieving outstanding results. By 2025, the clinical application of iPS cell-based therapies has made remarkable progress.

Of particular note is the “retinal pigment epithelium (RPE) sheet transplantation” developed by the joint research team of RIKEN and Osaka University. This technique involves differentiating iPS cells, derived from the patient’s own skin cells, into sheet-like retinal pigment epithelial cells, which are then transplanted. In February 2025, it was announced that the tenth such transplantation in Japan had been successfully performed on patients with intractable retinal diseases such as age-related macular degeneration and retinitis pigmentosa. In all cases observed for more than one year post-surgery, the stability of the transplant site and maintenance or improvement of visual acuity were confirmed, demonstrating significant progress in both safety and efficacy.

Furthermore, iPS cell-based therapy for Parkinson’s disease has also yielded notable results. A research group at Kyoto University conducted clinical trials in which dopamine-producing neurons, differentiated from iPS cells, were transplanted into patients’ brains. The final results, published in April 2025, involved seven patients aged 50 to 69. Over two years of follow-up, dopamine production derived from the transplanted cells was confirmed in six patients, and four patients showed clear improvement in motor function. No serious adverse events were reported. Based on these outcomes, the collaborating companies have begun preparations for applications aimed at commercial production.

Such iPS cell-based therapies, which utilize the patient’s own cells, offer a low risk of immune rejection and significantly contribute to the realization of personalized medicine. Additionally, the progress of the iPS Cell Stock Project by the CiRA Foundation at Kyoto University has established a system for the stable supply of high-quality, clinical-grade iPS cells to research institutions both in Japan and abroad.

New Therapeutic Fields and Progress in Industrialization

Beyond iPS cells, various regenerative medicine technologies have evolved in Japan in 2025. For example, clinical research on therapies utilizing extracellular vesicles (EVs), such as exosomes, is progressing ahead of the rest of the world. The Japanese Society for Regenerative Medicine has developed clinical application guidelines for EVs, leading the establishment of international standards in this field.

In addition, new therapies such as immune cell treatments (including CAR-T cells), tissue regeneration using 3D bioprinting, and the combination of regenerative medicine with gene therapy are moving toward practical application. These advances are supported by funding and strengthened industry-academia collaboration from the government and the Japan Agency for Medical Research and Development (AMED). Although the 2024 fiscal year budget for regenerative medicine was approximately JPY 20 billion, which was still modest compared to other major countries, efficient research promotion and social implementation are steadily progressing.

On the industrial side, commercialization and export of regenerative medicine products are also accelerating. By 2025, the number of regenerative medicine products approved in Japan exceeded 20, and technology transfer and joint development with Europe, the United States, and Asian countries are expanding.

The YOKOHAMA Declaration 2025 and a New Framework for Regenerative Medicine in Japan

In March 2025, the Japanese Society for Regenerative Medicine (JSRM) announced the “YOKOHAMA Declaration 2025.” This is an important statement aimed at the sound development of regenerative medicine and the establishment of international credibility.

The most significant feature of the YOKOHAMA Declaration 2025 is the clear distinction it draws between scientifically validated therapies (Explorative Therapy) and therapies that have not undergone sufficient scientific validation (Uninvestigated Therapy). Explorative therapies are required to register clinical data in an independent third-party registry and to conduct explorative studies before and after treatment, ensuring transparency and reliability. This framework enables patients and healthcare professionals to accurately assess the efficacy and safety of treatments (JSRM, 2025).

The declaration also specifically addresses essential issues for the social implementation of regenerative medicine, such as strengthening dialogue and information disclosure with patients and the public, establishing ethical and legal frameworks aligned with international standards, developing data driven evaluation methods, and building sustainable medical economic models. As a result, a system has been established that allows both domestic and international patients to choose regenerative medicine with confidence.

Furthermore, the declaration states the intention to actively collaborate with AMED and the Ministry of Health, Labour and Welfare to review the Act on the Safety of Regenerative Medicine (ASRM) and make policy recommendations. This approach aims to maintain a balance between regulatory frameworks and scientific progress, promoting flexible system design that does not hinder innovation.

International Leadership and Future Prospects

Japan maintains global leadership in regenerative medicine, particularly in iPS cell technology. As of 2025, the number of clinical trials using iPS cells is rapidly increasing both domestically and internationally, with overseas companies and research institutions following Japan’s strategy. Moreover, in new therapeutic fields such as extracellular vesicles, immune cell therapies, and 3D bioprinting, Japanese-developed guidelines and standardized protocols are influencing the international community.

On the other hand, challenges remain regarding the maintenance of international competitiveness, including research funding, workforce mobility, and the strengthening of industry-academia collaboration. Among researchers and policymakers, there is a growing call for reforms from a global perspective, such as utilizing private capital, conducting joint research with overseas institutions, and revising intellectual property strategies.

Conclusion

Over the past year, Japan’s regenerative medicine sector has undergone multifaceted evolution, from basic research to clinical practice and regulatory frameworks. The achievements in RPE sheet transplantation by RIKEN and Osaka University, as well as iPS cell-based therapy for Parkinson’s disease, have opened new doors for personalized medicine and the treatment of intractable diseases. The YOKOHAMA Declaration 2025 presents a new societal framework based on scientific rigor, ethics, and transparency, serving as a guiding principle for Japan to continue leading the world in regenerative medicine.

Going forward, Japan will continue to pioneer the future of medicine by implementing safe and reliable regenerative medicine centered on patient needs, while sharing its expertise with the international community.

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