A New Stem Cell Approach Offers Hope for Those with Chemical Eye Burns

A new type of stem cell treatment has potential to restore the eye’s corneas, according to a study published August 18 in Science Advances. A phase 1 trial of cultivated autologous limbal epithelial cell transplantation (CALEC) was found to be safe and well-tolerated by four patients with chemical burns in one eye.

The cell therapy was able to restore cornea surfaces; two patients were able to undergo a corneal transplant and two reported significant improvements in vision without additional treatment.

Ula Jurkunas, M.D.

“Our early results suggest that CALEC might offer hope to patients who had been left with untreatable vision loss and pain associated with major cornea injuries,” principal investigator and lead study author Ula Jurkunas, M.D., associate director of the Cornea Service at Mass Eye and Ear and an associate professor of ophthalmology at Harvard Medical School, said in a press release.

Chemical burns can lead to a loss of cells surrounding the cornea — called limbal stem cells — making them ineligible for corneal transplants. Despite much research to develop a cell therapy for this type of injury, no manufacturing process has met the quality control tests required by the FDA or showed any clinical benefit.

Researchers at Mass Eye and Ear, a member of Mass General Brigham, along with researchers at Dana-Farber Cancer Institute, developed the CALEC technique. CALEC is a two-stage cell manufacturing process that aims to ensure stability and consistency of the limbal stem cells. The system used is serum- and antibiotic-free, and the cells are first grown on plastic and then transferred to BioTissue’s AmnioGraft for continued growth until transplant. After several weeks, the cells are transplanted into the eye with corneal damage.

“It was challenging to develop a process for creating limbal stem cell grafts that would meet the FDA’s strict regulatory requirements for tissue engineering,” Jerome Ritz, M.D., executive director of the Connell and O’Reilly Families Cell Manipulation Core Facility at Dana-Farber and professor of medicine at Harvard Medical School, said in the press release.

In this study, the first patient to be transplanted using the CALEC method was able to undergo an artificial cornea transplant. The second patient experienced a complete resolution of symptoms with vision improving from 20/40 to 20/30. The third had his corneal defect resolved and his vision improved from hand motion to 20/30 vision. The fourth patient initially did not have a successful biopsy that resulted in a viable stem cell graft. After re-attempting CALEC three years later, he underwent a successful transplant and his vision improved. He then received an artificial cornea.

The trial is ongoing, and investigators plan to provide more data on a larger cohort of patients from an 18-month follow-up for efficacy end points and correlation of these outcomes with marker and potency assay data. This study was funded by the National Eye Institute (NEI), a part of the National Institutes of Health (NIH) and is the first stem cell study funded by the NEI.