Gene Therapy Halts Vision Loss from Retinitis Pigmentosa

Wilfong, of Lincolnton, NC, was 8 years old when his parents noticed he was having trouble finding a toy on the floor. Doctors diagnosed him with retinitis pigmentosa (RP), which over time damages the retinal layers and causes vision loss. According to Lejla Vajzovic, MD, a retina specialist at the Duke Eye Center, the first signs of RP are loss of night vision, and then loss of peripheral vision, which narrows the field of vision. Eventually, RP leads to tunnel vision and central vision loss.

Wilfong, now 36, described his world as darker as he grew up. “Everything was really blurry. In low-light situations, it was like blindness. I couldn’t play high school football because I couldn’t see under the lights. Everything in the gym is brown, dark brown hardwood, dark brown bleachers. It was hard to see.”

While he had a driver’s license for about three years and never had an accident, Wilfong eventually had to stop driving. He could do some carpentry work, but had to stop that, too. “I felt like I was losing my independence. It had gotten to the point where I couldn’t walk around the grocery store. What’s bright to other people wasn’t bright to me.”

As the condition worsened, Wilfong said he was afraid “I was going to lose my sight.”

Because the disease is inherited, Wilfong underwent genetic testing in Winston-Salem to determine if his family members were affected. While none had RP, the testing uncovered that Wilfong’s mother and father carried a specific mutation in the gene referred to as RPE65. His local eye doctor knew that people with this gene mutation could qualify for gene therapy treatment.

The eye doctor referred Wilfong to Duke, one of the few eye centers in the country to offer the gene therapy known as Luxturna (voretigene neparvovec). Wilfong had the procedure on his left eye in 2023.

A healthy, artificially engineered RPE65 gene is packaged into a harmless virus that cannot cause disease and acts as a delivery vehicle. The virus is surgically injected precisely into the area of damaged cells responsible for vision loss. “The new healthy gene helps decrease the degeneration of those cells and helps stop the process that causes them to die slowly,” explained Dr. Vajzovic.

While every patient’s response is different, Dr. Vajzovic said clinical trials show the therapy can decrease the progression of disease and improve vision.

The first thing Wilfong noticed in the days after the procedure was how many fingers he held up on his hands. Eventually, the world became brighter, and he could see more details in low-light situations. “Before, if there were no lights on, I couldn’t see inside the house.”

Now, he can find his new baby’s pacifier when it drops, see his baby’s mouth to feed him a bottle, and change his baby’s diaper without help. So far, his baby’s vision appears unaffected. “It’s been life-changing,” Wilfong said. “Duke really came through. I’m looking forward to getting the other eye done.”

Only a few centers can perform gene therapy for RP because of the complexities involved. The virus with the RPE65 gene must be formulated in a specialty pharmacy. It must be thawed, mixed appropriately, and used within hours by surgeons specially trained to perform the procedure.

Because inherited retinal diseases are so rare, it’s important to go to an eye center like Duke, where experts examine and diagnose people with RP and other rare inherited retinal diseases. The team includes genetic counselors who help diagnose the disorder and provide counseling on the implications of having certain genetic mutations. Being seen at a center like Duke also ensures access to advanced treatments and research.

As one of the leading eye centers in the country, Duke is involved in several clinical trials looking at other mutations that may be solved with gene therapy.