In a significant advancement for ophthalmology, a pioneering stem cell therapy has shown remarkable success in treating severe corneal injuries. The study, published on March 4, 2025, in Nature Communications, evaluated the safety and efficacy of cultivated autologous limbal epithelial cells (CALEC) in 14 patients over an 18-month period. This innovative treatment involves harvesting stem cells from a healthy eye, expanding them into a cellular graft, and transplanting the graft into the damaged eye. The results indicate that CALEC not only proved feasible and safe but also achieved a high rate of complete or partial success in restoring corneal surfaces, offering hope to individuals with previously untreatable conditions.
A Closer Look at the Clinical Trial
In the heart of Boston's vibrant medical community, during the spring of 2023, a team of dedicated researchers embarked on a groundbreaking clinical trial. Led by Dr. Ula Jurkunas, associate director of the Cornea Service at Mass Eye and Ear and professor of Ophthalmology at Harvard Medical School, this phase 1/2 trial explored the potential of CALEC to heal eyes damaged by chemical burns, infections, or other traumas. The procedure begins with a biopsy from a healthy eye, followed by a meticulous two-to-three-week process of cultivating the extracted stem cells into a viable tissue graft. Once ready, the graft is surgically implanted into the injured eye.
The trial's outcomes were nothing short of impressive. At the three-month mark, half of the participants experienced full restoration of their corneas. By the end of the 18-month follow-up period, 77% had achieved complete recovery, while the overall success rate—including partial recoveries—stood at 92%. Notably, three participants underwent a second transplant, one of whom reached full success by the study's conclusion. Visual acuity improved across all 14 patients, albeit to varying degrees. Moreover, the treatment demonstrated a high safety profile, with no serious adverse events reported. One minor bacterial infection occurred due to prolonged contact lens use but was promptly resolved.
Despite its promise, CALEC remains an experimental treatment, not yet available in U.S. hospitals. Additional studies are necessary before it can be submitted for federal approval. Funded by the National Eye Institute (NEI), this trial represents the first human study of a stem cell therapy for corneal injuries in the United States. Collaborations between Mass Eye and Ear, Dana-Farber Cancer Institute, and Boston Children’s Hospital played a crucial role in developing the manufacturing process for the stem cell grafts.
Looking ahead, researchers aim to expand the treatment's reach by exploring allogeneic manufacturing using donor eyes, potentially benefiting patients with damage to both eyes. Future trials will involve larger cohorts and longer follow-ups to further validate the treatment's efficacy.
From a journalist's perspective, this study underscores the transformative potential of cell therapy in addressing previously incurable conditions. It highlights the importance of continued research and collaboration among medical institutions to bring innovative treatments from the lab to the clinic. Ultimately, the success of CALEC brings us closer to a future where vision loss due to corneal injuries may become a thing of the past, offering renewed hope to countless individuals worldwide.