Stem cell-based therapies novel strategy that may substitute conventional corneal transplantation

Major advances in medicine are currently being made in regenerative medicine for cornea. Stem cell-based therapies represent a novel strategy that may substitute conventional corneal transplantation, albeit there are many challenges ahead given the singularities of each cellular layer of the cornea.

A recent study in Science Advances aimed to treat unilateral limbal stem cell (LSC) deficiency, Ula V. Jurkunas and the team of researchers, developed cultivated autologous limbal epithelial cells (CALEC) using an innovative xenobiotic-free, serum-free, antibiotic-free, two-step manufacturing process for LSC isolation and expansion onto human amniotic membrane with rigorous quality control in a good manufacturing practices facility.

The current study if successful, will be the first to use of CALEC in the United States will serve as a steppingstone for establishing cellular therapy products as viable options for patients with LSCD.

The clinical hallmarks of LSC deficiency (LSCD) include conjunctivalization, neovascularization, recurrent or persistent epithelial defects, inflammation, and corneal scarring. These changes lead to loss of vision, pain, and impaired quality of life.

Limbal biopsies were used to generate CALEC constructs, and final grafts were evaluated by noninvasive scanning microscopy and tested for viability and sterility. Cultivated cells maintained epithelial cell phenotype with colony-forming and proliferative capacities. Analysis of LSC biomarkers showed preservation of “stemness.”

After preclinical development, a phase 1 clinical trial enrolled five patients with unilateral LSC deficiency. Four of these patients received CALEC transplants, establishing preliminary feasibility. Clinical case histories are reported, with no primary safety events. On the basis of these results, a second recruitment phase of the trial was opened to provide longer term safety and efficacy data on more patients.

In summary, the initial phase of this trial has established feasibility of the product manufacturing method with no immediate safety concerns, enabling a second recruitment phase to provide longer term safety and efficacy data on more patients. Use of the small biopsy carries low risk of inducing LSCD in the donor eye, as seen in one example showing the repeatability of the CALEC procedure.

Reference: urkunas UV, et al "Cultivated autologous limbal epithelial cell (CALEC) transplantation: Development of manufacturing process and clinical evaluation of feasibility and safety" Sci Adv 2023; DOI: 10.1126/sciadv.adg6470.