A stem cell therapy designed to restore function by repairing damaged nerve pathways is moving closer to clinical testing for people with chronic spinal cord injury (SCI), according to research presented at the International Society for Stem Cell Research (ISSCR) 2026 Annual Meeting
The work, presented by Hideyuki Okano, MD, PhD, of Keio University in Japan, builds on more than a decade of research into regenerative therapies for SCI. Okano’s team pioneered the development of induced pluripotent stem cell (iPSC)-derived neural stem/progenitor cells and launched the world’s first clinical study of the approach in patients with subacute SCI
In March 2025, the researchers announced one-year follow-up results from that four-patient first-in-human study, reporting no serious treatment-related adverse events and neurological improvements in two participants, including one who regained the ability to stand independently and begin gait training. Although those findings have not yet been published in a peer-reviewed journal, they provided the safety foundation for expanding the program to chronic SCI
The physician-initiated trial, expected to begin recruiting patients in 2027, will enroll individuals with chronic, incomplete SCI who retain inactive but demyelinated nerve fibers. Unlike patients treated soon after injury, these individuals often have surviving nerve pathways that have lost the myelin insulation needed for efficient signal transmission
“We have already successfully completed a world-first, first-in-human clinical study targeting patients in the subacute phase, which demonstrated a promising safety profile,” Okano said. “Our shift to the chronic phase is the next logical milestone, built upon that solid foundation. Since the cellular environment changes over time, we are evolving our strategy from just establishing safety to actively overcoming the stubborn, long-standing barriers of chronic paralysis.”
The biology of chronic injury also required a different cell therapy. While the earlier program used neural stem/progenitor cells capable of generating neurons, the new approach uses clinical-grade gliogenic neural stem/progenitor cells (gNS/PCs), which preferentially develop into astrocytes and oligodendrocytes—the support cells responsible for maintaining neurons and restoring myelin around surviving nerve fibers. Rather than attempting to regenerate entirely new neural circuits, the therapy aims to repair and restore the function of existing ones. Earlier preclinical studies demonstrated that these gliogenic cells promoted remyelination, preserved host axons, and improved locomotor recovery in animal models, providing the rationale for advancing the therapy toward human testing.
The latest preclinical findings further support that strategy. The researchers reported that the clinical-grade gNS/PCs efficiently differentiated into neurons, astrocytes, and oligodendrocytes in laboratory studies. Following transplantation into animal models of chronic SCI, the cells promoted behavioral recovery without evidence of tumor-like tissue formation while remodeling the injured spinal cord microenvironment
News & FeaturesAnimal modelsClinical trialInduced pluripotent stem cellsRegenerative medicineSpinal cord injuryStem cell therapies
