It is with profound sadness that we announce the passing of Professor Masafumi Fukagawa on November 9, 2024, due to injuries sustained in an accidental fall while attending a scientific meeting. His demise occurred just one day after his 66th birthday and coincided with the MBD-21 Research Meeting (formerly the ROD-21 Research Meeting), an event he was instrumental in establishing. Prof. Fukagawa had recently retired in March 2024 from his position as Professor in the Division of Nephrology, Endocrinology and Metabolism at Tokai University and was actively leading the revision of the Clinical Practice Guideline for the Management of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) for the Japanese Society for Dialysis Therapy (JSDT). His untimely departure remains difficult to comprehend.

Reflecting on Prof. Fukagawa’s life, he made remarkable contributions to the fields of nephrology and bone metabolism. After graduating from the University of Tokyo in 1983, he trained under Prof. Kiyoshi Kurokawa in the First Department of Internal Medicine. He gained recognition in secondary hyperparathyroidism research by publishing on the effects of oral active vitamin D pulse therapy in the New England Journal of Medicine. In 1992, he continued his research at Vanderbilt University, and upon returning to Japan in 1995, he had the distinct honor of serving as an Imperial Household Physician to the Emperor of Japan.

In 2000, he joined Kobe University as an Associate Professor in the Second Department of Internal Medicine, where he dedicated himself to strengthening the nephrology group. In 2008, he suffered an acute aortic dissection while at work but made a remarkable recovery. The following year, as the Division of Nephrology—spun off from the Second Department of Internal Medicine—continued to grow under the leadership of Prof. Fukagawa, he was appointed Professor of the Division of Nephrology, Endocrinology and Metabolism at Tokai University.

Prof. Fukagawa devoted his life to the study of CKD-MBD. Previously known as renal osteodystrophy (ROD), the concept of CKD-MBD was introduced at the Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference in 2005. Recognizing its significance, he played a key role in promoting this concept in Japan. In 2006, he led the development of the world’s first clinical guideline incorporating the CKD-MBD concept—The JSDT Guidelines for the Management of Secondary Hyperparathyroidism in Chronic Dialysis Patients. He was also the only Japanese member of the Work Group for the KDIGO CKD-MBD Guideline published in 2009 and updated in 2017.

Beyond his work with KDIGO, Prof. Fukagawa served on the editorial boards of international journals, including Kidney International, American Journal of Kidney Diseases, Clinical Journal of the American Society of Nephrology, JBMR Plus, and Journal of Bone and Mineral Metabolism. Through these roles, he provided Japan with timely updates on international research. He actively supported young Japanese researchers in establishing a global presence and introduced Japan’s high-standard CKD-MBD clinical practices to the world, offering valuable insights into their background. In doing so, he served as a vital bridge between Japan and the international CKD-MBD community.

Above all, Prof. Fukagawa was deeply committed to mentoring the next generation. He tirelessly created opportunities for young investigators to collaborate beyond institutional boundaries. One of his notable initiatives was the ROD-21 Research Meeting, established in 2000. In 2017, he founded the Japan CKD-MBD Forum as its first president, which later evolved into the Japanese Society for CKD-MBD Research. Through these organizations, he fostered both collaboration and competition among young researchers, significantly advancing their careers.

Perhaps the most poignant aspect of his passing is that the revision of the JSDT CKD-MBD Guideline, which he chaired, was in its final stages but remains unfinished. It is heartbreaking that he did not live to see its publication. As I reflect on the long and arduous journey to this point, I deeply wish we could have completed it together. His expertise and leadership were still needed for its dissemination and implementation. To honor his legacy, we, the remaining committee members, will work together to complete this vital task.

Prof. Fukagawa, thank you for your extraordinary contributions to nephrology and bone metabolism research, as well as for mentoring young investigators in Japan. As one of your many mentees, I am forever grateful for your guidance and support. With profound respect and gratitude for all that you have given, may you rest in peace.