Nura Bio will use the series B financing to carry two neuroprotective drug candidates through early- to mid-stage clinical studies, one targeting ALS and the other for a broader neurological profile.
Nura Bio, a neuroscience-focused biotech with a novel approach to treat disorders like amyotrophic lateral sclerosis (ALS), pulled in $73.8 million in a series B funding round to support two clinical programs that could potentially address neurological conditions with high unmet need.
ALS, in particular, has been a daunting challenge for drugmakers. Only a select few, including Biogen’s Qalsody, have broken through to the market, leaving patients with limited options to treat a devastating and uniformly fatal disease. Nura is part of a revived hunt for more drugs as the biotech tackles ALS via an early- to mid-stage neuroprotective approach that targets the protein SARM1.
“There’s always a quest to identify novel neuroprotective therapies,” Nura CEO Shilpa Sambashivan told BioSpace. “We homed in on SARM1 as our flagship program . . . with the hypothesis that pharmacologic inhibition of the protein should prevent axon degeneration and should also ultimately preserve neurons.”
Axon degeneration has been documented as an early event in ALS pathology that contributes to motor neuron loss and loss of neuromuscular junction integrity, she explained.
Nura’s lead candidate, a small-molecule, oral brain-penetrant SARM1 inhibitor dubbed NB-4746, is being studied in a Phase 1b/2a trial of patients with ALS. The company also has another SARM inhibitor in the works called NB-9402, for which dosing began in a first-in-human study in healthy volunteers last week. Nura has not declared a therapeutic target for NB-9402.
This financing round was structured to deliver proof of biology data, Sambashivan said, which Nura intends to do within the next 18 to 24 months.
Sambashivan, who served as the founding chief scientific officer at Nura when the company launched more than eight years ago, stepped into the CEO role in 2024 when the biotech closed a series A financing round worth $68 million. That round brought Nura’s total raised at the time to $140 million.
Comprising a small team of 20 people, Nura is supported in the series B round by financing lead The Column Group, as well as Euclidean Capital, Samsara BioCapital and Sanofi Ventures.
A biological foothold
The basic biological mechanisms of SARM1 inhibition were discovered by Nura’s academic co-founders Marc Freeman and Steve McKnight, of Vollum Institute OHSU and UT Southwestern Medical Center, respectively. Their preclinical work found the protein played a role in axon degeneration in fly and mammalian models, Sambashivan said.
SARM1, according to McKnight’s early work, was in fact an enzyme that broke down the metabolite NAD, which conducts biological processes that protect neurons from degrading either by age or disease.
“Where our biology began was from an understanding that if you were able to knock down the enzymatic function of SARM1, preventing it from hydrolyzing NAD, then SARM1 also no longer broke down axons,” Sambashivan said. “From there, the therapeutic hypothesis was born that pharmacologic inhibition of SARM1 should be neuroprotective and ultimately preserve neurons.”
In preclinical models of diseases of the peripheral, central and ocular nervous systems, including ALS, traumatic brain injury and multiple sclerosis, “SARM1 knockdown confers significant neuroprotection, preserving axons and neurons with functional benefit,” Sambashivan continued.
While SARM1 is present across all organisms, activation of the enzyme is what causes it to begin breaking down axons and neurons. Nura’s first-generation inhibitor NB-4746 is designed to bind to an active site on the SARM1 molecule, preventing this breakdown from occurring.
The ongoing Phase 1b/2a program includes a 28-day dose range-finding study, followed by a 12-week placebo-controlled study where ALS patients are given a single dose of NB-4746, and an open label extension.
In this trial, Nura will be assessing safety, tolerability and exploratory biomarkers such as neurofilament length, which is associated with improvement in functional benefit.
ALS is an ambitious target on its own, but niether Nura nor SARM-1 were done there. Another window opened up.
“As we watched our understanding of this target evolve, our conviction around the broad therapeutic potential grew, and so we wanted one more shot on goal and ideally a differentiated mechanism,” Sambashivan said. “Typically, you’re lucky if you find one druggable pocket, but SARM gave us a few.”
The biotech’s next SARM-1 inhibitor, NB-9402, came about as a follow-up to the flagship program with a different binding mechanism. Rather than binding to the active site like NB-4746, NB-9402 binds to an inactive site on SARM1 to prevent it from activating in the first place.
“Biology has a way of surprising you, and when the second program came around, in many ways we were primed and ready to go,” Sambashivan said.
“We’ve made tremendous progress in just 12 months to get that into humans.”
The ambition for Nura is to tackle ALS and other neurological conditions in earlier stages, before patients face irreversible symptoms.
“Having worked in neurodegenerative diseases for the longest time, our goal is always to try and intervene as early as possible,” Sambashivan said. “Because the concern is, you don’t want too little too late.”
