Stem cell therapy restores corneal function
Autologous, stem cell-derived limbal epithelial cell transplantation shows promise in restoring corneal function for patients with limbal stem cell deficiency.
Mass Eye and Ear (MA, USA) researchers have developed a technique that restores corneal function using autologous stem cells. Now, results from an expanded Phase I/II clinical trial confirm the technique’s safety and promising success rates, paving the way for further research and potential wider accessibility.
Corneal injuries, for example due to chemical burns, infection or injury, can deplete the limbal epithelial stem cells from the corneal limbus. Without these cells the corneal epithelium is unable to repair and renew itself, leaving the surface of the eye permanently damaged and unsuitable for a corneal transplant. Limbal stem cell deficiency is characterized by conjunctivalization of the corneal surface, a process where the conjunctiva – the thin, transparent membrane covering the white part of the eyeball and the inside of the eyelids – replaces the corneal epithelium. This, along with other associated processes, such as neovascularization, inflammation, scarring and opacity, leads to decreased vision and persistent pain.
To address this unmet need, researchers at Mass Eye and Ear developed a method to regenerate limbal epithelial cells. The treatment, called cultivated autologous limbal epithelial cell (CALEC) transplantation, involves harvesting limbal stem cells from a healthy eye biopsy, expanding them in vitro into a cellular tissue graft, and surgically transplanting the graft into the damaged eye.
In 2023, a Phase I clinical trial demonstrated the safety and feasibility of CALEC transplantation in four patients. Now, the results of an expanded Phase I/II clinical trial have been published with primary outcomes assessing safety and feasibility and a secondary outcome evaluating the treatment’s efficacy based on improvements in the integrity of the corneal epithelial surface.
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The clinical trial demonstrated promising results for CALEC transplantation. At three months, 50% of the 14 participants had complete corneal restoration, increasing to 79% at 12 months and 77% at 18 months. Including partial successes, the overall success rates were 93% at 12 months and 92% at 18 months. Three participants required a second transplant, with one achieving complete success by the study’s end.
Visual acuity improved to varying degrees in all 14 participants. CALEC also exhibited a strong safety profile, with no serious adverse events in donor or recipient eyes. One bacterial infection occurred due to chronic contact lens use, while other minor adverse events resolved quickly.
“We feel this research warrants additional trials that can help lead towards FDA approval,” said Principal Investigator Ula Jurkunas. “While we are proud to have been able to bring a new treatment from the lab bench to clinical trials, our guiding objective was and always will be for patients around the country to have access to this effective treatment.”
A key limitation of this autologous therapy is that it requires patients to have one unaffected eye, as a biopsy from the healthy eye is needed to obtain the starting material for treatment. To address this, the researchers hope to develop an allogeneic version of the treatment in the future, making it available to patients with damage in both eyes.
