UAB Callahan Eye Hospital Performing Cutting-Edge Genetic Therapy for Eye Disease

Sep 13, 2022 at 08:19 pm by steve

The UAB Callahan Eye Hospital has been named as one of only 14 treatment sites for Spark® Therapeutics' LUXTURNA®, the first FDA-approved gene therapy treatment for Leber congenital amaurosis, an eye disease that results from mutations in both copies of the RPE65 gene. This condition, which can only be confirmed by genetic testing, causes patients to begin losing vision in their first five years of life and gets worse as they age.

Drs. Jason Crosson and Richard Feist Jr. of Retina Consultants of Alabama will perform the procedure for Callahan. The surgeons insert a functioning copy of the RPE65 gene under the retina via a non-lethal virus. It is a precise operation, requiring one surgeon to position the needle and hold it in place while the other surgeon injects the virus containing the gene.

Leber congenital amaurosis is an extremely rare condition, occurring in two to three per 100,000 newborns. It was chosen because the RPE65 mutation occurs naturally in a breed of dog called Briard, making it easier to conduct animal studies.

UAB Callahan is the only location in the southeast. The two nearest locations are Bascom Palmer Eye Institute in Miami and Baylor in Houston. Dawn DeCarlo, OD, PhD, who serves as the Director of the UAB Center for Low Vision Rehabilitation, has several patients who traveled to get the treatment before Callahan was chosen as a site.

"I had two sisters from Alabama who traveled to Texas," she said. "Their visual ability has basically doubled since the procedure. Before the treatment, as soon as it started to get dark they would go inside because they couldn't see. Now they can stay out at night. They recently saw fireworks for the first time. They're cheerleaders and now they can go to cheer practice even when it's getting dark. They can now go to Friday night football games.

"Another patient of mine was one of the first people treated after it was FDA approved. He was 15. He couldn't get a driver's license before this, but he qualified after the treatment. I had been seeing him since he was around five years old. These three people describe this as nothing less than life-changing."

All these patients got the treatment when they were in their teens, which is helpful because this is a degenerative condition. "It is too late when you don't have any cells left to treat," DeCarlo said. "It is also too early if you are not at least one year of age because the retina is still developing."

At this point, clinicians don't know for certain whether the results of the treatment will last a lifetime, but there was good longevity in the animal models and people from the early treatments are still are doing well, which is vital because it surgeons would probably not be able to re-treat because of a number of complexities involved.

Now that UAB Callahan is an approved site, the hospital has several patients in the pipeline for treatment. "We have screened potential patients and the surgeons thought there was enough viable tissue to make them candidates," DeCarlo said. "However, it takes months to get the insurance approval. The surgery costs is over $400,000 per eye. Fortunately, Spark® Therapeutics drug has an entire department dedicated to working with insurers for approval.

"Even preparation for the surgery requires training. The Callahan pharmacy had to be trained in how to handle it because it's frozen at -80 degrees, it has to be thawed and then reconstituted. So the procedure involves a big team.

Thanks to the success of this treatment, and with other gene therapies for vision in phase two and phase three clinical trials, UAB Callahan now has free genetic testing eye disease. "In the past, we weren't genetically testing everybody and the genetic testing for eyes is not covered under insurance," DeCarlo said. "With these free inherited retinal disease panels, we can now make sure we don't miss any of these patients. We can help them find a treatment and give them information about relevant clinical trials. They may or may not want to participate, but we can help them make an informed decision.

So our message to doctors is if you have a patient with a retinal disorder and they haven't been genetically tested, UAB Callahan has free testing. We can't guarantee we will find the genetic cause of a person's eye disease with this test. A lot we do, but some we don't. But in the future, we may get a report from the genetic testing company that says we have reclassified this gene for your patient. So it's valuable information."

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