Of the 180,000 corneal transplants carried out annually, greater than 20% occur in patients at a high risk for transplant rejection. Neovascularization, or new blood vessel formation, can contribute to this risk, since the main reason for graft failure is irreversible immunological rejection. In a study carried out in a high-risk rabbit model, researchers have demonstrated safe transplantation of an engineered donor cornea designed to prevent new blood vessel formation.
The study, titled “Safety and Efficacy of OXB-202, a Genetically Engineered Tissue Therapy for the Prevention of Rejection in High-Risk Corneal Transplant Patients,” comes from research teams at the Cullen Eye Institute, Baylor College of Medicine and Oxford BioMedica (UK) Ltd. Their work is published in Human Gene Therapy and is available for free download until May 12, 2018.
As described in the paper, “OXB-202 (previously known as EncorStat®) is a donor cornea modified prior to transplant by ex vivo genetic modification with genes encoding secretable forms of the angiostatic human proteins, endostatin and angiostatin.” The modification is carried out using lentiviral vector. The treatment showed significantly reduced corneal neovascularization and a reduced, dose-dependent rate of corneal rejection. No adverse toxicity was observed up to 13 weeks post surgery.
"The work from [authors] Drs. Stout and Ellis and their colleagues represents yet another example of how gene therapy for disorders of the eye has led the way in clinical translation. Gene modification of corneal transplants could provide a unique approach to filling a pressing unmet medical need," said Dr. Terence R. Flotte, Human Gene Therapy editor-in-chief and Dean, Provost, and Executive Deputy Chancellor, University of Massachusetts Medical School.
Image: A full thickness corneal transplant. Image courtesy of the National Eye Institute.
Source: Mary Ann Liebert Inc.