Krystal is among dozens of companies seeking innovative ways to deliver replacement genes to more locations in the human body, including hard-to-reach organs like the brain.
“Delivery is the most important factor in genetic medicine,” says Maxx Chatsko, founder of Solt DB, a publisher and investment analysis company, who also buys and sells shares in biotech companies (including Krystal). “I think this could eventually be the first gene therapy people dose at home.”
Gene delivery usually involves placing a DNA strand inside a virus naturally equipped to enter a human cell and drop off the gene. In Krystal’s case, the company is using herpes simplex virus, the same one that causes cold sores.
HSV-1, as the virus is known, is very common—about half the people in the world are infected by it. That means it is fairly safe, but it also has the advantage that it naturally evades the immune system. Krishnan says that feature is what permits the drug to be used repeatedly, without causing negative reactions.
While the startup has been successful, Chatsko says there has also been some controversy over how it hit upon its strategy. In 2022, Krystal agreed to pay up to $75 million to another startup, PeriphaGen, which accused Krishnan and the company of pilfering its ideas and technology.
Whether or not this is a case of a stolen “Eureka,” Krystal has already demonstrated the versatility of its approach by developing an eye-drop version of the drug at the request of Anthony’s ophthalmologist, Alfonso Sabater, director of the Corneal Innovation Lab at the University of Miami’s medical school.
“When I learned he was in the skin trial, I thought, why don’t we try that on the eye,” says Sabater, who reached a special agreement with the FDA to test the idea on a single patient, Anthony. First, Sabater surgically removed a layer of scar tissue that had built up on Anthony’s eyes. After that, he says, monthly use of the eye drops appears to have stopped those injuries from returning.
“I think this is also the first time there’s a gene therapy for the cornea, and the first time it’s in an eye drop,” says Sabater.