Surgeon meets challenges of performing gene therapy
Audina M. Berrocal, MD, of Bascom Palmer Eye Institute, performed the 1-hour surgery in a Florida boy with Leber congenital amaurosis.
On March 22, a Florida boy underwent gene therapy with Luxturna for treatment of inherited retinal disease at the Bascom Palmer Eye Institute, a first for the institution.
“Of course there were challenges,” the boy’s surgeon, Audina M. Berrocal, MD, told Healio.com/OSN.
Luxturna (voretigene neparvovec-rzyl, Spark Therapeutics) was FDA approved in December 2017 for individuals with biallelic RPE65 mutation-associated retinal dystrophy, and the first treatment was done March 20 at Massachusetts Eye and Ear.
Creed Pettit, a 9-year-old from Mount Dora, Florida, was diagnosed at age 2 with Leber congenital amaurosis and was legally blind due to biallelic mutation of the RPE65 gene.
A challenging procedure
In this case, Berrocal, a pediatric retina surgeon and professor of clinical ophthalmology at Bascom Palmer Eye Institute, needed to first perform vitrectomy, locate the appropriate subretinal space for the injection, and then, using a hair-thin needle, inject the modified virus directly under Pettit’s retina in his right eye during the hour-long surgery.
The medication is only viable for 4 hours before it can be injected, she said, so Pettit was put under anesthesia and the vitrectomy quickly completed. A typical vitreous in a normal 9-year-old child is thick and gelatinous, Berrocal said, but Pettit’s was more atrophic so it was easier to remove.
After removing the vitreous, Berrocal used an OCT-integrated microscope to find the subretinal space and inject the medication. As it is injected, the medication detaches the macula.
“Finding the subretinal space where we actually inject the medication is quite difficult,” she said. “We had two syringes with the medication. With the first syringe, I could not find the right space, and we lost it; we could not inject it in the right space.”
It took a second attempt with the second syringe to place the treatment. An air-fluid exchange was then performed to remove any medication that may have been left on the retina to deter inflammation, she said.
“I’ve been texting with [Pettit’s mother] since the surgery, and both she and grandma already see changes in his vision. He’s been doing things he’s never done before. The amount of lighting he needs to look at things has changed dramatically. It amazes me,” Berrocal said. “I’ve watched many children with this disorder lose vision, but I’ve never seen the regaining of vision. If that’s what we’re seeing here, that’s going to be amazing.”
An amazing journey
Pettit’s mother was interested in enrolling him in clinical trials with Luxturna for years, but he either “could not or would not navigate the maze test used in the trial,” Berrocal said, adding that after the FDA approval, Pettit’s mother chose Bascom Palmer, part of the University of Miami Miller School of Medicine, for treatment because the procedure could be done sooner than at University of Iowa, where the trials were done.
Being able to see a patient regain vision with this disease, rather than slowly losing vision over time, has been an amazing experience, she said.
“The more we do the surgery, the better we’re going to become at this,” Berrocal said. “To me, being part of this bench to bedside story is probably the most amazing thing I’ve experienced in my career to this day. Being part of this boy’s story will simply be unforgettable. Everyone who was in the operating room with me that day, will never forget it. It was magical.”
Pettit was scheduled to undergo treatment in his left eye on March 28. – by Robert Linnehan
Florida boy with inherited blindness first to receive FDA-approved gene therapy at Bascom Palmer. https://news.umiamihealth.org/en/boy-with-inherited-blindness-receives-fda-approved-gene-therapy/. Published March 23, 2018. Accessed March 23, 2018.
For more information:
Audina M. Berrocal , MD, can be reached at Bascom Palmer Eye Institute, 900 NW 17th St., Miami, FL 33136; email: email@example.com.
Disclosure: Berrocal reports no relevant financial disclosures.