Casey Begins First Gene Therapy Study for Usher Syndrome
Michelle Kopf was a third grader at the Washington School for the Deaf when teachers noticed she was having problems with her vision. Doctors suspected the young girl had Usher syndrome, a devastating genetic disorder that not only causes impaired hearing at birth, but progressive vision loss by young adulthood.
No treatments exist for Usher syndrome, which affects as many as 50,000 people in
the United States and Europe. However, as the first study center in the world to test a gene therapy for the disease, OHSU Casey Eye Institute is giving hope to those facing a life not only deaf but blind.
Now 29-years old and losing her peripheral vision, Michelle is the first patient to participate in the two-year study, designed to halt vision loss in people with defects in the MYO7A gene, one of at least nine identified genes linked to Usher syndrome. Four other adults and three children from the Pacific Northwest – all of whom were previously seen and tested for the MYO7A gene at Casey – also are considered possible candidates for the study, which is evaluating the safety and effectiveness of the experimental treatment UshStat.
“This clinical trial is the first to correct the basic molecular defect and is a major milestone in the history of Usher syndrome. We are hopeful the treatment will enable these patients to retain eyesight, enhancing the quality of their lives,” said Richard Weleber, M.D., the study’s lead investigator. The trial is using visual field software Dr. Weleber designed that for the first time allow researchers to more precisely monitor peripheral vision in the retina, the area most affected by inherited retinal diseases such as Usher syndrome.
Casey has become an international leader in gene therapy research, developing technological capabilities essential to this new generation of eye research, such as the enhanced visual field test and genetic testing. In addition to the Usher syndrome study, Casey is the only center in the United States testing a gene therapy for Stargardt disease and also a lead research site for a gene therapy study of Leber congenital amaurosis (LCA). Both are severe retinal disorders that usually appear in childhood. A fourth study, for age-related macular degeneration, is expected to begin later this year.
“Gene therapy, which targets a specific biological function, is becoming a new way to treat disease and has the potential to be quite revolutionary,” said David Wilson, M.D., Casey Eye Institute chairman. “The human eye is ideal for testing novel treatments, because it is accessible yet segregated from the rest of the body. It is also easier to introduce medications into the eye than in other organs and to objectively measure whether the experimental treatment is working. Moreover, since only one eye is treated, the fellow untreated eye serves as a valuable control.”
Developed by Oxford BioMedica, a British-based biopharmaceutical company, the UshStat treatment is delivered to the eye via a non-active virus, where healthy copies of the gene penetrate eye cells. The hope is that a single application of UshStat to the retina will stabilize vision over a long period of time or even permanently.
In April, Casey surgeons injected a healthy version of the MY07A gene beneath Michelle’s retina in an outpatient procedure. A second patient, a 22-year old Portland man, received the treatment in June. One eye of each patient will be injected with the study medication.
Michelle, who spoke through a sign-language interpreter, said she never thought a study for Usher syndrome would become a reality. Being the first patient in the world to get the treatment doesn’t worry her a bit. “It’s given me a glimmer of hope,” said Michelle, who has an 11-month old son. “It would be a miracle if it works.”
Foundation Fighting Blindness shares results of preliminary safety review for Stargardts and Ushers gene therapy.