Küleon LLC, a preclinical-stage biotechnology company building a best-in-class library of selective, G-protein-biased serotonergic medicines, today announced it has been awarded a $2 million grant from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) within the National Institutes of Health (NIH), to advance one of its novel serotonin 5-HT2C agonists, KB-128, as a potential treatment for alcohol-use disorder (AUD). KB-128 is a “trifunctional” ligand that is a full 5-HT2C serotonin receptor agonist with little to no functional activity or agonism at the 5-HT2A/2B serotonin receptors. KB-128 also exhibits a significant bias for Gq-based signaling. KB-128 is designed to deliver non-hallucinogenic modulation of key serotonergic circuits relevant to addiction, impulse control, and reward. In pilot studies, KB-128 has shown high efficacy in reducing self-administration of alcohol in rodent models designed to simulate human alcohol abuse.

This non-dilutive grant will now support IND-enabling activities for KB-128, including toxicology, and performing advanced studies in AUD rodent models, as well as clinical-readiness efforts to advance the program into first-in-human evaluation in AUD. The development plan is intended to confirm KB-128’s differentiated pharmacology and to establish a clear path toward clinical proof of concept in AUD.

KB-128’s profile is engineered to address limitations seen with many serotonergic agents. KB-128 was designed specifically to exhibit a strong G-protein signaling bias with little to no β-arrestin recruitment at 5-HT2C—an attribute associated with preserving efficacy and reducing receptor desensitization over time. KB-128 represents a potential pivotal advance in the fight against alcohol abuse and relapse, as an effective, durable, and safe treatment. According to the NIAAA, over 29 million Americans suffer from AUD, and AUD claimed the lives of more than 175,000 Americans in 2025. Küleon's novel approach also mitigates the known cardiovascular risks typically associated with other serotonergic ligands that are agonists at the 5-HT2B receptor, potentially revolutionizing the treatment of AUD.

“Receiving this award from NIAAA underscores the promise of our GPCR-biased, non-hallucinogenic 5-HT2C approach in multiple indications, including AUD,” said Allen Barbieri, CEO of Küleon. “It is also an important endorsement of Küleon’s scientific rigor and commitment to addressing one of the most pressing public health crises of our time. AUD is a major public-health challenge with limited pharmacological treatment options. KB-128’s unique pharmacology and safety-first design give us a compelling opportunity to deliver an entirely new therapeutic class for patients and clinicians.”

Küleon continues to engage with academic and industry collaborators to accelerate KB-128 into clinical development for AUD and other neuropsychiatric indications.

About Küleon Bioscience

Küleon Bioscience is a privately held biotechnology company based in Seattle, Washington focused on discovering and advancing selective, non-hallucinogenic, serotonin-receptor modulators for neuropsychiatric disorders. Leveraging AI/ML-guided design and in silico modeling, Küleon has built one of the industry’s largest libraries of G-protein-biased serotonergic ligands and is advancing multiple programs through IND-enabling development.

The company’s broader pipeline includes multiple proprietary serotonergic agents, including selective 5-HT2A agonists, mixed 5-HT2A/2C agonists, and functionally selective 5-HT2C agonists, for treating a variety of neuropsychiatric disorders, including anxiety/depression, addiction, obesity, and rare seizure disorders. These assets are in varying stages of pre-clinical validation and IND-enabling testing in partnership with multiple universities, contract research organizations, and the National Institute of Drug Addiction (NIDA). Learn more at www.kuleonbio.com.

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awarded a $2 million grant from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) within the National Institutes of Health (NIH), to advance one of its novel serotonin 5-HT2C agonists, KB-128, as a potential treatment for alcohol-use disorder