Eyeworld

WINTER 2024 | EYEWORLD | 65 C Relevant disclosures Jun: OcuCell Jurkunas: Ocucell Koo: Emmecell, KOWA Lee: Aurion Biotech macular degeneration is in development and stands to restore vision for another large group of patients suffering from vision loss. Cultivated autologous limbal epithelial cells (CALEC) therapy Ula Jurkunas, MD, said there are a lot of cell therapy options looking at the corneal endo- thelium, the inner layer of the cornea. "The cell therapy that we have developed is for corne- al epithelium, or the surface cells," she said. "Corneal epithelial cells get destroyed due to chemical injuries, various infections, genetic disorders, even contact lens wear." This can de- stroy the inside, or peripheral corneal epithelial cells, where the corneal stem cells reside. When there is corneal stem cell destruction, the patient develops limbal stem cell deficiency, the cornea becomes opaque, the patient can become blind, and it can be very painful, Dr. Jurkunas said. "We've developed technology where we are harvesting a small biopsy from healthy eyes. Let's say it's asymmetric disease— one eye is affected and the other is mostly healthy; we take them to a special GMP lab, and we isolate those stem cells, expand them, and make a lot more of them on a sheet." CALEC involves cells on a sheet of am- niotic membrane as a scaffold, then they are transplanted to the eye that has the injury or infection. Dr. Jurkunas noted that the first feasibility and safety study was published in Science Advances, 1 and the efficacy paper study of the Phase 2 trial has been accepted in Nature Communications. The study showed that 92% of CALEC grafts achieved partial or complete success at 18 months of follow-up. The trial was the first of this kind in the U.S., though cultivated epithelial stem cells have been used outside the U.S. in the past. "We were the first center to develop this trial, and continued on page 66 Contact Jun: CFJ3PJ@uvahealth.org Jurkunas: Ula_Jurkunas@meei.harvard.edu Koo: exk126@med.miami.edu Lee: wblee@mac.com Albert Jun, MD, PhD, also commented on the future of this field, noting that it's an exciting time for cornea and cell therapy. "I think part of what makes it so interesting is the very focused type of pathology that we sometimes see in the cornea. The accessibility of tissue also makes it appealing. It's the extension of that minimally invasive approach for everything that we do in medicine to make things better for patients, to do less but accomplish the goal that the patient needs to have restored function." Dr. Jun called the developments in corneal cell therapy a logical extension to the lamellar ker- atoplasty trend. Using technology to produce and grow cells from a source, whether it's a patient's own cells or a donor, helps with the targeted ability to treat the patient's vision loss, he said, adding that he began doing work in this area around 10 years ago. There's a general concept of putting endothelial cells back onto the cornea where they need to be to work, he said, adding that tremendous work has been done in this area by Shigeru Kinoshita, MD, PhD. "Other technologies have been developed around cell injection, taking the cells you grow, injecting them into the eye, and having them stick to the cornea and work," Dr. Jun said. The next question to look at is how well this technology works compared to current meth- ods of endothelial keratoplasty. "I think cell injection proved a lot of things," he said. "It proved you can take cells off donor corneas and grow them, they retain their function, you can process them safely and put them back into a person, and they can work. That's been proven, and that's tremendous. But what the field will determine is whether or not that approach is advantageous over the current way of doing things." Dr. Jun said it will also be important to see how this treatment works in a variety of conditions. The other issue is efficacy. "We have to see if the results are just as good as or better than DMEK, and that's something that patient experience will teach us." Dr. Jun added that cost will be a factor as well. Dr. Jun has worked with the eye bank VisionGift in Portland, Oregon, and OcuCell to develop these cell technologies. OcuCell's Endo-Tek is human-derived cultured corneal endothelial cells seeded onto a biocompatible hydrogel. "Our approach has been to replace the mem- brane and the cell with a synthetic membrane that's a replacement for Descemet's mem- brane, and this has cells on it," he said.

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