Keio University School of Medicine
Keio University Regenerative Medicine Research Center
Hideyuki Okano and Masaya Nakamura of Keio University, along with their research team, have continued the long-term follow-up study of participants enrolled in the clinical study, "Regenerative medicine for spinal cord injury at subacute stage using human induced pluripotent stem cell-derived neural stem/progenitor cells." Okano is Director and Professor of the Keio University Regenerative Medicine Research Center; Nakamura is Professor and Chair of the Department of Orthopaedic Surgery at Keio University School of Medicine. The team has now compiled follow-up results of up to four years after transplantation. No tumor formation or serious adverse events attributable to the transplanted iPSC-NS/PCs were observed, providing further support for the long-term safety of this therapy.
This study was the world's first clinical transplantation of iPSC-NS/PCs into the injured human spinal cord. The present findings provide additional evidence supporting the safety of this therapeutic approach. Furthermore, improvements in motor function and the proportion of patients achieving improvement in AIS grade at 52 weeks exceeded those observed in a historical control cohort. These findings support the further development of spinal cord cell transplantation using iPSC-NS/PCs for patients with severe spinal cord injury and may also contribute to the future development of regenerative therapies for a broad range of central nervous system disorders.
These findings, integrating the results of the initial one-year clinical study and the subsequent long-term follow-up study, were published online in Nature Medicine on July 21, 2026 (British Summer Time).
For further information, please refer to the following PDF file.