September 12, 2023

Arialys Therapeutics Launches to Lead the Development of New Precision Medicines for Autoimmune Neuropsychiatric Diseases

Arialys Therapeutics Launches to Lead the Development of New Precision Medicines for Autoimmune Neuropsychiatric Diseases

– Arialys was founded on the breakthrough understanding that immune cells – not only in the body’s periphery but especially in the brain – can produce autoantibodies that cause severe neurological and psychiatric diseases
– The company plans to file an Investigational New Drug (IND) application with the U.S. FDA in 2024 for its lead candidate, ART5803, for the treatment of anti-NMDA receptor encephalitis (ANRE) and autoimmune psychosis
– Arialys has shown that ART5803 blocks NMDA receptor autoantibodies and reverses encephalitis and behavioral symptoms in a nonhuman primate model of the disease

LA JOLLA, Calif., September 12, 2023 – Arialys Therapeutics, a biotechnology company pioneering new therapeutics for autoimmune neuropsychiatry, today announced the close of $58 million in seed financing. The investors in the financing included the company’s founding investors, Avalon BioVentures, Catalys Pacific, and MPM BioImpact, along with Johnson & Johnson Innovation – JJDC, Inc. and Alexandria Venture Investments. The proceeds of the financing will be used to advance new precision medicines that specifically block pathogenic autoantibodies in the central nervous system (CNS) and meaningfully expand the treatment possibilities for neuropsychiatric diseases driven by autoimmunity.

“Recent scientific discoveries have implicated abnormal autoimmune activity in a number of neuropsychiatric diseases, pointing us in a new direction to develop precision medicines for CNS disorders,” said Jay Lichter, PhD, President and CEO of Arialys and Managing Partner of Avalon BioVentures. “With the ability to isolate and characterize pathogenic autoantibodies in the CNS, we can now develop novel therapeutics and diagnostics to help millions of people who suffer from neuropsychiatric disorders driven by autoimmune disease.”

Anti-NMDA receptor encephalitis (ANRE), one of the most common forms of autoimmune encephalitis, is a rare, potentially lethal, and poorly managed neurological disease because it is often misdiagnosed. ANRE is caused by autoantibodies that crosslink and drive internalization of NMDA receptors (NMDAR), resulting in psychosis. Arialys’ lead therapeutic ART5803 is a therapeutic antibody designed to treat ANRE by blocking NMDAR autoantibodies. Arialys has generated promising preclinical data in a nonhuman primate disease model confirming ART5803 reverses encephalitis and decreases the behavioral symptoms caused by NMDAR autoantibody pathogenicity in the brain. Arialys has received orphan drug designation from the U.S. Food and Drug Administration for ART5803 for the treatment of ANRE. Arialys purchased ART5803 from Astellas Pharma.

Mitsuyuki “Mickey” Matsumoto, PhD, Scientific Founder and Chief Scientific Officer of Arialys, who previously served as an Executive Director and Head of the Neuroscience Research Unit and Virtual Venture Unit Psychiatry at Astellas Pharma, said, “Precision medicine approaches have led to tremendous successes in oncology, and now we have the insights to be at the forefront of developing precision medicines to transform the treatment landscape for neuropsychiatry. Leveraging a depth of expertise and breakthrough scientific research, the team has already generated validating preclinical proof-of-concept data, and we are excited to file an IND next year and advance ART5803 into the clinic for the treatment of ANRE and autoimmune psychosis.”

About Arialys Therapeutics

Founded to explore the latest discoveries in autoimmune neuropsychiatry, Arialys Therapeutics is developing new precision medicines to specifically block pathogenic autoantibodies in the brain and meaningfully expand the treatment possibilities for neuropsychiatric disorders driven by autoimmune disease. Arialys is headquartered in the Avalon BioVentures Accelerator on the Torrey Pines Mesa, in La Jolla, California. For more info, visit


Company: Mathew Mitchell, Vice President, Corporate Development, Arialys Therapeutics,

Media: Jessica Yingling, Ph.D., Little Dog Communications Inc.,, +1.858.344.8091