• Tue. Feb 27th, 2024

Gene therapy eyedrops restored a boy’s sight

Gene therapy eyedrops restored a boy’s sight

Miami: Two photos of Antonio Vento Carvajal’s eyes by Dr. One showed cloudy patches covering both eyelids. Another, months later after gene therapy administered through eyedrops, found that both eyes were scar-free.

Antonio, who has been legally blind for 14 years, regains his sight.

The teenager was born with dystrophic epidermolysis bullosa, a rare genetic condition that causes blisters on the body and eyes. But his skin improved when he joined a clinical trial to test the world’s first topical gene therapy. That gave Sabater an idea: What if Antonio’s eyes could match it?

This insight not only helped Antonio, but also opened the door to similar treatments that could treat millions of people with other eye diseases, including common ones.

Antonio’s condition is caused by a mutation in a gene that helps produce collagen 7, a protein that holds the skin and cornea together. The treatment, called Vijuvec, uses an inactivated herpes simplex virus to deliver functional copies of that gene. The eye drops use the same liquid as the skin version, without the added gel.

Antonio’s mother, Unielquis “Uni” Carvajal, cried at the thought of what Sabater had done for her son.

“He was there for everything,” she said in Spanish during a visit to the University of Miami Health System’s Bascom Palmer Eye Institute. “He is not only a good doctor, but a good man, who gave us hope. He never gave up.”

Dr. Alfonso Sabater, of the University of Miami Health System’s Bascom Palmer Eye Institute, examines Antonio Vento Carvajal’s eye under blue light after applying a stain to check for further ulceration before a gene therapy treatment.

Image credit: A.P

The family came to the U.S. from Cuba in 2012 on a special visa to receive treatment for Antonio’s condition, which affects about 3,000 people worldwide. Surgery was done to remove the scar from the eye, but it grew back. Antonio’s vision continued to deteriorate and eventually he no longer felt safe walking.

Sabator then had no answer and tried to comfort the boy: “I’ll find a solution, I just need some time. I’m working on it.”

“‘Yes, I know you’ll do it,'” Sabater recalled Antonio saying, “and that gave me the energy to keep going.”

At one point, Carvajal tells Sabater about an experimental gene therapy gel for Antonio’s skin lesions. He contacted drugmaker Crystal Biotech to see if it could be modified for the boy’s eyes.

Suma Krishnan, co-founder and president of research and development at the Pittsburgh-based company, said the idea made sense and “it didn’t hurt to try it.”

Antonio’s condition is caused by a mutation in a gene that helps produce collagen 7, a protein that holds the skin and cornea together. The treatment, called Vijuvec, uses an inactivated herpes simplex virus to deliver functional copies of that gene. The eye drops use the same liquid as the skin version, without the added gel.

After two years, including testing the drug in mice, the team received “compassionate use” approval from the US Food and Drug Administration and approval from university and hospital review boards. Last August, Antonio underwent surgery on his right eye, after which Sabater began treating him with eyedrops.

Krishnan said they were cautious and checked frequently to see if it was safe.

At the University of Miami Health System’s Bascom Palmer Eye Institute, Dr. Alfonso Sabater uses a syringe to apply gene therapy eyedrops to Antonio Vento Carvajal’s eyes.

Image credit: A.P

Antonio’s eye recovered from the surgery, the scars didn’t return, and there was significant improvement each month, Sabater said. Doctors recently measured Anthony’s vision in his right eye at 20/25.

This year, Sabater began treating Antonio’s left eye, which had more scar tissue. It’s also improving steadily, measuring closer to 20/50, which Sabater said is “good vision.”

Antonio comes to the eye institute about once a week for a check-up and once a month for eye drops. During the visit, Antonio must wear protective clothing that covers his hands, arms, legs, and feet. Like other children with the condition – sometimes called “butterfly children” – his skin is so fragile that even a touch can injure him.

Antonio still uses the skin gel, which was approved by the FDA in May and can be used off-label on the eyes. It does not alter DNA, so it is not a one-time treatment like many gene therapies.

Sabater, director of the Corneal Innovation Lab at the Eye Institute, said gene therapy eyedrops could be used for other diseases by altering the gene carried by the virus. For example, another gene could be used to treat Fuchs’ dystrophy, which affects 18 million people in the US and accounts for half of the country’s corneal transplants.

The prospect of treating more conditions this way is “exciting,” said Dr. Aimee Payne said. “This approach provides gene therapy that really addresses the root cause of the disease.”

With his sight restored, Antonio enjoyed a typical teenage pastime he’d been wanting to do for some time: playing video games with his friends. He finally feels safe walking around.

Sabater said the two-year journey to seek government and hospital approvals was worth it. For Antonio, it’s worth it … and also because it opens up the space to treat other patients in the future.



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