Early Promise for a New Paralysis Treatment
Four months ago, Roger, a 55-year-old construction worker from Mooresville, N.C., fell out of a deer stand and was left with a damaged spinal cord and no sensation from the middle of his chest down. Patients with his condition typically have less than a 1-in-20 chance of recovering any feeling in or control over the paralyzed areas. A new kind of implant aims to change that.
At Carolinas Medical Center in Charlotte, Roger, who doesn’t want to disclose his last name to protect his privacy, allowed doctors to perform an experimental procedure that involved cutting directly into his spinal cord to insert a sort of bridge for surviving nerve cells. Within a month, he regained feeling in his abdomen, some feeling in his legs, and some bladder control. While he’s not walking, he says he’s determined to get there and is getting leg braces so he can move with a walker.
Roger was the third patient to receive the implant, made by InVivo Therapeutics in Cambridge, Mass., and the second with markedly improved bodily function. The chance of that happening was below 1 percent, according to InVivo Chief Executive Officer Mark Perrin, and it’s welcome news for the 8,000 Americans who suffer spinal cord-related paralysis each year.
Conventional treatment focuses on repairing a fractured spine with rods and screws, but it doesn’t address the spinal cord itself, which relays electrical impulses from the brain to the body. Imaging studies show that cell death in the spinal cord generally spreads even as patients recover. InVivo’s device, called the neuro-spinal scaffold, is a tiny cylindrical implant made of biodegradable plastic fibers. It supports nerve cells like a trellis, directing their growth where needed.
“You’re not just trying to stabilize the spine, but do something helpful directly at the area of the injury,” says Dom Coric, chief of neurosurgery at Carolinas Medical Center, who’s working with InVivo. “If we can preserve those cells, maybe we’ll get some function back.” The implant dissolves over several weeks, he says.
InVivo’s scaffold emerged from the MIT lab of Bob Langer, a biomedical engineering professor who’s founded some two dozen companies. More than a decade ago, Erin Lavik created a prototype scaffold for her MIT graduate thesis. As detailed in a breakthrough study she published with Langer in 2002, Lavik’s device, seeded with stem cells, helped paralyzed rats walk again. Later tests on rodents and monkeys proved similarly encouraging. (So far, human tests haven’t included stem cells.) Lavik is now a biomedical engineering professor at Case Western Reserve University.
InVivo, co-founded by Langer in 2005, licensed the technology from MIT in 2007 to commercialize it. The U.S. Food and Drug Administration initially granted the company permission to treat five patients, tracking each for three months before enrolling another. In October 2014, Jordan Fallis received the implant after a flip on a dirt bike paralyzed him from the waist down, and he regained some motor function. Patient No. 2, Jesi Stracham, has regained some sensation but no motor function in her legs since her motorcycle accident. Following those results, the FDA allowed InVivo to simultaneously enroll its last three patients, including Roger.
Langer, who’s been closely watching the patients’ progress, says he expects even better results when the company seeds the scaffold with stem cells or other growth factors to encourage regrowth of damaged nerves. InVivo has received a humanitarian use device designation, meaning it needs only proof of “probable benefit” to get FDA approval for wider use, according to CEO Perrin. He says he’s still talking with the FDA about what further tests the agency might want and wouldn’t set a target date for commercial approval.
While InVivo negotiates with the FDA, other scientists are working on new materials that could further stimulate cell growth within the spinal cord. Anthony Windebank, a neurologist at the Mayo Clinic’s Regenerative Neurobiology Laboratory, is working to develop biodegradable polymers that mimic the jello-like properties of the spinal cord. “The technology is changing, and what we can do with cells and biomaterial is revolutionary,” he says. It would be immoral, he says, “to not pursue this as hard as we can.”
The bottom line: InVivo’s neuro-spinal scaffold has led to marked improvement in two of its first three patients. FDA approval is pending.
(Updated eighth paragraph to clarify the term for InVivo's humanitarian use device designation.)