Eyeworld

78 | EYEWORLD | SPRING 2025 C ORNEA by Ellen Stodola Editorial Co-Director About the sources Albert Cheung, MD Virginia Eye Consultants Norfolk, Virginia Rajan Shukla Chief Executive Officer Brightstar Therapeutics Lexington, Kentucky Joseph Tauber, MD Chief Medical Officer Brightstar Therapeutics Leawood, Kansas B rightMEM corneal allograft (Brightstar Therapeutics) is a new treatment op- tion for ocular surface disease. Several sources discussed BrightMEM, their experience using it, and its treatment applications. Albert Cheung, MD, said that BrightMEM is a decellularized Descemet's membrane product that is used for its inherent properties in cases of ocular surface disease. The anterior aspect of Descemet's membrane contains proliferative proteins that are similar to those found in the limbal basement membrane, he said, adding that these are not typically present in the central cornea. Pre-clinical studies have demonstrated the ability of Descemet's membrane to act as a substrate for epithelial cells and limbal stem cells, to be more resistant to degradation than amniotic membrane, and to maintain greater transparency than amniotic membrane, Dr. Cheung said. Joseph Tauber, MD, said the term "BrightMEM" is used for both a product and a procedure, BrightMEM anterior keratoplasty (BMAK), in a unique way. "Descemet's mem- brane is the back layer of the cornea, and we're using it on the front of the eye, and we're doing that because of some recently discovered sci- ence from Joshua Hou, MD, at the University of Minnesota, who found that the anterior side of Descemet's membrane, the fetal banded portion of Descemet's membrane, contains proteins that are very supportive, encouraging of stem cells," he said. Why does that matter? "You have to un- derstand the normal healing process," he said, "where there are undifferentiated stem cells at the limbus. Something happens in the central cornea, there's a signal to heal, and the cells march their way across the cornea. They leave the niche, they lose their supportive protein mi- croenvironment, and they start to differentiate, and hopefully grow back over the entire surface. If those cells could grow over a membrane that maintains that regenerative capability, that would be a good thing," Dr. Tauber said. "The original development concept was to use that membrane, grow a layer of cells on it, and provide surgeons with both membrane and cells," he said. "That is a more challenging regulatory pathway for FDA approval that's on our radar. … But it turned out that the decellu- larized Descemet's membrane is wonderful just by itself." Rajan Shukla, CEO of Brightstar Therapeu- tics, has worked in front-of-the-eye therapeutics since 2014 and has previously worked with serum tears. It was this work and his interest in novel therapies for severe dry eye and ocu- lar surface disease that ultimately led him to BrightMEM. "When you look at quality of life, severe dry eye disease is comparable to hip fracture and severe angina in that it impedes patients from living their lives. In many cases, patients can suffer from both significant vision loss and constant eye pain," he said. BrightMEM helps fill a niche intended for these severe ocular surface disease patients who have impaired healing of their cornea. "All of the limbal stem cells, all of the cells in the eye that produce the clear cornea [epithelium], live in a specialized area called the limbal niche, which is in a ring around the cornea," Mr. Shukla said. "These cells produce the corneal epithelium, and when the cornea is damaged or the epithelium is removed, the limbal stem cells migrate out of the niche and start repopulating the cornea, but once they leave that niche, they lose their stem cell phenotype. What that means is that stem cells are capable of self-renewing so they can do horizontal division, making another stem cell, or they can differentiate into mature epithelial cells, which form the clear cornea. But once they leave the niche, they lose that ability, so what we saw [is] if you've lost enough stem cells, they can't do that double duty of main- taining their own population and healing the cornea. That's when you start to see… conjunc- tiva growing over [the cornea], and that ends up causing pain and photophobia. So patients are in a terrible condition where they can't see and they're in pain all the time." The company was looking for a new mem- brane that was both durable and optically clear, so it can act like the limbal niche and maintain the stem cells long term. Mr. Shukla said BrightMEM is designed to be a long-term solution for patients. It's BrightMEM corneal allograft: a new treatment for ocular surface disease

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