Sudden sensorineural hearing loss, in which hearing in one ear suddenly disappears, often does not recover if early treatment is missed, but there is currently no therapy. Patients who do not respond to steroid treatment in reality have no choice but to rely on hearing aids or cochlear implants.
Korea-based biotech company Neuracle Science has thrown its hat into the ring to develop a hearing-loss therapy. The company is targeting not only hearing loss but also degenerative neurological diseases such as dementia with a new approach that revives "consolidation (synapse, Synapse)" between nerve cells. A synapse is a structure like a "network" that connects nerve cells and transmits signals. When this consolidation is cut off, information transfer is blocked, leading to declines in hearing or cognitive function.
On the 1st at Korea University in Seongbuk-gu, Seoul, Seong Jae-young, CEO of Neuracle Science (professor at Korea University College of Medicine), who met with ChosunBiz, said, "Our main goal is to prove with clinical data an innovative principle that restores synapse consolidation, so domestic technology can lead the global market and result in the commercialization of a 'first-in-class' therapy."
CEO Seong Jae-young, who founded Neuracle Science in 2015, is a neuroendocrinologist and an expert in discovering drug target proteins. After earning a bachelor's in zoology and a Ph.D. in molecular biology at Seoul National University, he served as a postdoctoral researcher at the Medical School of Göttingen in Germany and as a professor at Chonnam National University College of Medicine. He is currently a professor at Korea University College of Medicine.
◇ Discovered a "novel target" with no papers... Entered the clinic after more than 10 years of research
Seong's research ramped up after the human genome map was completed in 2003. He said, "There are 20,000 human genes, and only about 1,000 of them were drug targets—just 5%," adding, "The remaining 95% was an area nobody knew."
Through bioinformatics, he narrowed the list to about 50 candidates, and the target he viewed as most promising was FAM19A5. This protein suppresses the formation of synapses, which are the consolidation sites between nerve cells, and promotes their degradation. Neuracle Science's core pipeline, NS101, inhibits the activity of this protein to maintain and restore synapses.
The criteria for target selection were clear: it must be expressed only in the nervous system (central and sensory), be secreted outside the cell, and be evolutionarily conserved. These may seem simple, but they are key conditions that determine the likelihood of success in drug development.
To reduce drug side effects, the target protein should not exist in other organs, and for a drug to act easily, it should be outside the cell. The explanation is that the more evolutionarily conserved a protein is, the more important a role it plays in sustaining life, and thus the fewer mutations it has.
In particular, the decisive point was that the amino acid sequences are 100% identical between humans and mammals (monkeys, mice, rats, dogs, cats). This provides scientific grounds that the therapeutic effects seen in animal studies (synapse restoration) are highly likely to be reproduced in humans.
However, choosing such an unprecedented "novel target" itself was a major challenge. Seong said, "At the time, there was not a single paper on this protein," adding, "We had to elucidate everything from its function to its mechanism of action and experimental methods from scratch."
He recalled, "Generally, you form a hypothesis by referring to prior studies, but we had to start with a completely blank slate," adding, "We went through a lengthy process of hypothesizing and validating, and if it was wrong, repeating from the beginning."
Because of this, he said he prioritized securing patents over disclosing research results. Seong said, "Publishing a paper first could affect patents, so we delayed external disclosure for a long time," adding, "We discovered the protein in 2007, but full-fledged paper publications came much later, and the key paper was published in 2025." Neuracle Science has secured 232 registered patents and 110 patent applications related to FAM19A5.
◇ "Confirmed synapse restoration effect... phase 2 is progressing smoothly"
NS101 is an antibody therapy that suppresses the activity of FAM19A5, a protein involved in synapse loss. FAM19A5 binds to LRRC4B, a protein important for synapse formation, and acts to reduce consolidation between nerve cells. By blocking this binding, NS101 prevents synapses from disappearing and induces the recovery of damaged consolidation.
Seong compared nerve cells to "entities with contact lists." He explained, "You can think of one nerve cell as having about 1,000 contacts (consolidations). As we age or develop disease, these consolidations are severed one by one, and when they fall below a certain level, function declines and eventually the cells die," adding, "If we increase the severed consolidations again, cell function can be restored."
This hypothesis was confirmed in preclinical studies. When NS101 was administered in animal experiments, damaged synapses reformed, neural consolidation recovered, and cognitive function and hearing metrics improved significantly.
Similar safety and pharmacokinetic characteristics were confirmed in a phase 1 study in humans. A phase 2a study is underway in 95 patients with sudden hearing loss, and key data are expected to be released after June.
Seong said, "Synapses are the common foundational structure of all neurological diseases," adding, "We can expand not only to hearing loss but also to dementia, ophthalmic diseases, and motor dysfunction."
The reason "hearing loss" was chosen as the first disease group (indication) is that the company viewed it as the condition that can most objectively and quickly prove the innovative principle (mechanism) of synapse restoration.
The sound of Beethoven's Symphony No. 5 ("Fate") heard with normal hearing and the sound heard by cochlear implant recipients are very different. Seong said, "The sound heard with a cochlear implant is not majestic music but reduced to signals like 'chik-chik-chik,'" adding, "Information is transmitted, but the quality is completely different."
He went on to explain, "Before the hair cells in the ear die completely, neural consolidation is cut first, and if we just revive the consolidation at that point, functional recovery is possible."
He said, "With hearing loss, we can immediately quantify a drug's efficacy through hearing tests, so even if the number of patients is not large, we can secure statistically meaningful data. Compared with dementia, which takes a long time to confirm cognitive improvement, it is advantageous for proving the mechanism (PoC)," adding, "The fact that it is an 'untapped market' with no clear therapy is also a major reason."
Global pharmaceutical companies are also jumping into developing hearing-loss therapies, but their strategies differ from this company's. U.S. drugmakers such as Eli Lilly and Company and Regeneron are targeting specific hereditary hearing loss based on gene therapy, while Neuracle Science is first developing for sudden sensorineural hearing loss and plans to expand indications to noise-induced hearing loss, ototoxic hearing loss, and presbycusis.
Seong said, "Gene therapy has limited eligible populations and a relatively small market," adding, "By contrast, we target general hearing loss caused by aging or environmental factors, so the market is much larger."
◇ First step toward global expansion: aiming for technology export
The industry expects the phase 2 results of NS101 to be a watershed for technology export (license-out). Seong also said, "After securing the data, we will move in earnest to collaborate with global pharmaceutical companies."
Seong described the research and development process so far as "a succession of luck." New drug development is structured so that attrition is decided at each stage. If a toxicity study fails, development stops, and if serious adverse events occur in clinical trials, a retry is virtually impossible.
Seong said, "From discovering the FAM19A5 target and researching NS101 to passing gates such as nonclinical toxicity studies and a phase 1 study in patients, we had strokes of luck five or six times so far," adding, "Despite being an untraveled path, the scientific evidence confirmed through multiple gates enabled us to continue developing the drug."
Neuracle Science plans to first commercialize NS101 in sudden sensorineural hearing loss and then expand indications to neurotology diseases and neurodegenerative diseases such as dementia. That is because synapses act commonly across all neurological diseases. Seong said, "For frontotemporal dementia, the clinical trial already completed first patient enrollment in Dec. last year and is progressing smoothly."
Financing will proceed in parallel. The company plans to raise a pre-IPO investment of about 30 billion won this year and, after confirming top-line data from the hearing-loss clinical trial, to start with a technology evaluation application and pursue a KOSDAQ listing next year. It recently completed a rights offering of 21.3 billion won.
Seong said, "In the long run, our goal is to grow into corporations that, like global pharmaceutical companies, in-license external technologies and develop them," adding, "We will set a new standard for treating neurological diseases with domestic technology."