New clinical data presented at ISSCR 2026 show that transplanted human neural progenitor cells survived for at least one year following subretinal transplantation in patients with retinitis pigmentosa, while maintaining a favorable safety profile, according to a Jul. 9 announcement.
Retinitis pigmentosa is a group of inherited retinal diseases that causes progressive vision loss and currently has no treatment for most patients. The disease can be caused by thousands of different genetic mutations, making mutation-specific gene therapies challenging to develop. Cell-based therapies are being explored as a gene-agnostic approach that could potentially benefit more patients.
The Phase 1/2a clinical study, funded by the California Institute for Regenerative Medicine, evaluated the safety and feasibility of a single subretinal injection of CNS10-NPC—a human neural progenitor cell product derived from fetal brain cortex—in 13 patients with retinitis pigmentosa. Participants received either 300,000 or 1,000,000 cells and were followed for twelve months before enrolling into a long-term follow-on protocol.
Visual acuity remained stable during the study period. Imaging with optical coherence tomography showed that transplanted cells persisted in the subretinal space for at least one year. Reported cell-related adverse events included three epiretinal membranes and one persistent subretinal bleb. Investigators concluded that the treatment was well tolerated and resulted in long-term cell engraftment.
"Our goal is to help patients maintain their vision for as long as possible," said Dr. Liao, the clinical lead on the project. "The next critical question is whether these surviving cells can slow the continued deterioration that occurs in retinitis pigmentosa." Svendsen also presented data on an induced pluripotent stem cell-derived neural progenitor product during the presentation; this iPSC-based approach could provide a more scalable therapy capable of treating substantially more patients while avoiding ethical concerns associated with fetal tissue sources.
