The Israeli biotech trying to make damaged nerves grow again
NurExone is developing an exosome-based therapy that aims to repair spinal cord and optic nerve injuries, an area where modern medicine has long had few answers.
"Our goal is to bring to market a therapy that could help people regain function after spinal cord injuries or restore vision following damage to the optic nerve," says Dr. Lior Shaltiel, CEO of Haifa-based startup NurExone, which was founded on research conducted at the Technion and Tel Aviv University.
It is an ambitious goal. NurExone is attempting to tackle one of medicine's most difficult challenges: repairing the central nervous system, where damaged nerves have long been considered largely incapable of regeneration. While doctors have learned to treat many of the complications associated with spinal cord and optic nerve injuries, they have had little success in reversing the damage itself. Patients with severe spinal cord injuries typically do not regain the ability to walk, while damage to the optic nerve often leads to permanent vision loss.
"The moment a spinal cord injury occurs - whether in a car accident or from a partial or complete severing of the cord, for example as the result of a gunshot wound - a secondary injury begins to spread," explains Dr. Jacob Blumenthal, head of the BrainTech department at the Ehrlich Group, who was involved in the early research conducted at the Technion. "Cells in the affected area begin to die, effectively interrupting communication between the brain and the parts of the body it controls."
Unlike the peripheral nervous system, where damaged nerves can regenerate, the central nervous system contains biological mechanisms that actively prevent damaged nerve fibers from regrowing.
"If I cut my hand and damage a peripheral nerve, it can regenerate," explains Yoram Drucker, serial entrepreneur and chairman of NurExone. "But the central nervous system contains molecules that block the rehabilitation of damaged nerves."
The company's central question became straightforward: can those biological brakes be temporarily switched off?
Blocking the blocker
One of the key molecules responsible is a protein known as PTEN. Under normal circumstances, PTEN plays a critical role in protecting the body by preventing uncontrolled cell growth, helping suppress cancer. Following a nerve injury, however, the same protein also inhibits the regeneration of damaged nerve cells.
"We know there are inhibitors that prevent nerve growth," says Drucker. "So the idea was simple: let's inhibit the inhibitor. If we block the blocker, we allow nerves to regrow."
The challenge is delivering such treatment directly into damaged nervous tissue without invasive surgery.
NurExone's approach relies on exosomes, microscopic particles naturally secreted by cells to communicate with one another throughout the body.
"We use exosomes because they can do three things," Drucker explains. "They naturally migrate toward injured tissue, they help reduce inflammation and promote healing, and they serve as delivery vehicles. We load them with the therapeutic molecule we need, they enter the damaged tissue, release their cargo, and that's what produces the therapeutic effect."
The therapeutic cargo consists of a genetically engineered small interfering RNA (siRNA) molecule that temporarily suppresses PTEN activity.
"By temporarily switching off PTEN, we remove the brake on nerve regeneration," says Shaltiel. "Importantly, we do this only for a short period - roughly two to three weeks after the injury."
From engineered tissue to exosomes
NurExone's origins trace back to research led by Prof. Shulamit Levenberg of the Technion and Prof. Daniel Offen of Tel Aviv University, who later became co-founders of the company.
Initially, Levenberg's team focused on implanting engineered tissue directly into damaged spinal cords.
"We suddenly saw the rats walking," she recalls. "We expected to see some improvement, but instead they got up, stood on their own, bore weight and walked almost normally. It was an incredibly exciting moment."
The next challenge was translating those results into a treatment suitable for people.
Performing spinal cord transplants through invasive surgery would be difficult to apply widely, prompting the researchers to ask whether they could use only the biologically active components released by the cells rather than transplanting the cells themselves.
The answer was exosomes.
"We administered only the exosomes through the nose, and again the rats recovered," says Levenberg. "The animals began walking again. At that point we realized this could become a practical, non-invasive clinical therapy."
Manufacturing billions of biological delivery vehicles
Producing exosomes at clinical scale presents another technological challenge.
"We grow the cells in bioreactors at 37 degrees Celsius," explains Dr. Tali Kizhner, NurExone's vice president of research and development. "The cells grow on tiny carriers inside the bioreactor and continuously secrete exosomes, allowing us to scale production."
Founded in 2020, NurExone has raised approximately $20 million and is publicly traded on the Toronto Stock Exchange.
Part of the company's strategy is to pursue regulatory pathways for orphan diseases, which can provide development incentives and potentially accelerate regulatory review.
"This is an extremely active field because there are still no effective treatments," says Blumenthal. "The first company to successfully commercialize a therapy in this area could gain a significant competitive advantage. Strong patent protection also substantially increases the company's value."
The commercial opportunity could also be considerable. Drucker notes that roughly 50,000 new spinal cord injury patients are diagnosed annually across the Western world. The company is also developing treatments targeting optic nerve damage, including glaucoma, which affects an estimated 80 million people worldwide.
NurExone remains in the advanced preclinical stage and is preparing regulatory submissions to the U.S. Food and Drug Administration. The company expects to begin its first human clinical trial in Israel and the United States around 2027, subject to regulatory approval.
But Shaltiel believes the long-term vision extends beyond hospitals.
"Eventually, we'd like to move treatment from the emergency room to the ambulance," he says. "Someone injured in a car accident could receive the therapy immediately from a paramedic to prevent the loss of nerve cells before they even arrive at the hospital."
Levenberg shares a similar vision.
"I imagine this becoming available in every emergency department," she says. "A patient arrives with a spinal cord injury, receives exosome treatment immediately, and we prevent further deterioration while giving the tissue the opportunity to regenerate. If that becomes possible, we could prevent many of the lifelong consequences that spinal cord injuries cause today."
The vision remains several years away from being tested in humans. But if NurExone's approach proves successful in clinical trials, it could challenge one of neuroscience's longest-standing assumptions: that damage to the central nervous system is largely irreversible.
