A promising new approach that could slow, stop or prevent nerves from dying may get its first test in patients next year.
Nura Bio, a startup based in South San Francisco, has developed an oral small molecule inhibitor of the enzyme SARM1, which neuroscientists believe is involved in many neurological conditions such as ALS.
On Tuesday, the startup said it recently finished testing its drug, NB-4746, in healthy volunteers. The company also announced that it raised $68 million in an extension of its Series A financing, bringing its total funding to $141 million since launching in 2020.
The new funds are expected to help Nura begin a Phase 1b/2 trial in patients in 2025. Shilpa Sambashivan, who was previously the company’s chief scientific officer and has now been promoted to CEO, told Endpoints News that she believes the drug “has very broad therapeutic potential.” Her team is still deciding which disease to test the drug in first.
Eli Lilly is also developing a SARM1 inhibitor, which it got from its acquisition of Disarm Therapeutics in 2020 for $135 million upfront and up to $1.225 billion in milestone payments. Lilly is testing the drug’s safety in a large Phase 1 study of healthy volunteers that’s expected to wrap up in June 2025. But the pharma company also hasn’t said which disease it will test the drug in first.
Picking the right test case for the drug will be key. The neurodegenerative disease space is littered with compounds that looked promising in preclinical studies but have failed to meaningfully stall disease in humans.
Sambashivan said that Nura has tested its drug in models of ALS, multiple sclerosis and traumatic brain injury. She also envisions a role for the drug in treating eye diseases like glaucoma and preventing peripheral neuropathies caused by chemotherapy. To get a read on how well the drug is working, Nura will look at levels of a protein called neurofilament light, which is shed as neurons die, she added.
Nura Bio, which has fewer than 20 employees, was partly based on research from Marc Freeman, a scientist at Oregon Health & Science University who discovered genetic mutations in SARM1 that protected against axon degeneration. Scientists initially suspected the protein was part of the immune system, but soon realized it was an enzyme that breaks down a molecule called NAD, which is important for the proper functioning of many other enzymes.
Much of the work at Nura has focused on unraveling the inner workings of the enzyme to create a drug that can inhibit it. Yet in many ways, the enzyme still remains a mystery. It doesn’t chew up the ends of neurons itself, and how exactly its role in breaking down NAD leads to axon degeneration is unknown.
“We don’t completely understand the connection,” Sambashivan said. What is clear is that the enzyme is shut down in healthy people, she added. “It’s very tightly regulated. There are checks and balances that keep it turned off. Because when it turns on, it’s catastrophic in the degenerative loss that it drives.”
Nura’s new funding round was led by The Column Group, the startup’s founding investor. Prior investors Samsara BioCapital and Euclidean Capital and newcomer Sanofi Ventures chipped in, too.
“We’ve been very fortunate to have our investors stay with us,” Sambashivan said. “The science hasn’t been easy, and sometimes, as you know, you can’t expedite the science by throwing a whole lot of money or resources at it.”