• ART5803 is being developed for the treatment of anti-NMDAR autoimmune neuropsychiatric diseases, including anti-NMDAR encephalitis (ANRE)

• Preclinical data in higher animal models confirms ART5803’s therapeutic potential for rapid reversal of anti-NMDAR autoantibody pathogenicity

• Safety and pharmacokinetic data from healthy volunteers anticipated in the first half of 2025

LA JOLLA, Calif., October 10, 2024 – Arialys Therapeutics, a clinical-stage biotechnology company pioneering new precision medicines for autoimmune neuropsychiatry, today announced that it has initiated dosing of healthy volunteers in its first clinical trial of ART5803. ART5803 is a therapeutic monoclonal antibody candidate designed to specifically compete with pathogenic autoantibodies targeting the NMDA receptor (NMDAR). Pathogenic anti-NMDAR autoantibodies cause anti-NMDAR encephalitis (ANRE), a devastating and underserved rare disease for which there is currently no approved therapy. Recent findings have also implicated anti-NMDAR autoantibodies in other neuropsychiatric diseases such as schizophrenia and dementia. Arialys anticipates initiating a Phase 2a proof of concept clinical evaluation of ART5803 in ANRE in the second half of 2025.

“ART5803 is a first-in-class precision therapeutic candidate and initiation of its clinical development is an important and exciting step towards the effective treatment of anti-NMDAR autoimmune neuropsychiatric diseases,” said Peter Flynn, Ph.D., President and CEO of Arialys Therapeutics. “In parallel to our clinical development efforts in ANRE, we are evaluating autoantibody levels and ART5803’s therapeutic potential in patients suffering from a broader set of neuropsychiatric diseases such as schizophrenia and dementia.”

The ART5803 Phase 1 clinical study is designed as a double-blind, placebo-controlled, first-in-human, single-ascending dose trial in healthy volunteers (ClinicalTrials.gov Identifier: NCT06575153). The study is being conducted in collaboration with Nucleus Network in Melbourne, Australia. The study will evaluate the safety, tolerability, and pharmacokinetics (PK) of ART5803 and is expected to enroll approximately 40 subjects.

Pending safety, tolerability, and PK assessments in healthy volunteers, Arialys anticipates initiating a Phase 2a proof-of-concept clinical trial of ART5803 in the second half of 2025, initially in patients with ANRE.

About ANRE and ART5803

Anti-NMDA receptor encephalitis (ANRE) is a rare, potentially lethal, poorly managed and often misdiagnosed neurological disease. ANRE is caused by pathogenic autoantibodies that bind NMDA receptors (NMDAR), resulting in loss of function and rapid onset of a range of symptoms, including psychiatric and behavioral alterations, cognitive decline, seizures, and diminished autonomic function. A significant percentage of ANRE patients are pediatric where NMDAR specific autoantibodies can also result in neurological development deficits. Recent findings have also identified anti-NMDAR autoantibodies in other neuropsychiatric diseases such as schizophrenia and dementia. Arialys has used co-crystallographic structural analysis of the autoantibody-NMDAR interaction to design a precision medicine approach to the treatment of neuropsychiatric disease. ART5803 is a therapeutic antibody that competitively blocks the pathogenic autoantibodies and rescues NMDAR function. Arialys has generated compelling preclinical data in higher disease models confirming ART5803 rapidly reverses the behavioral symptoms caused by NMDAR autoantibody pathogenicity in the brain. Arialys has received Orphan Drug Designation from the U.S. FDA for ART5803.

About Arialys Therapeutics

Arialys was founded to meaningfully expand the treatment possibilities for neuropsychiatric disorders driven by autoimmune disease. Using a combination of highly sensitive autoantibody detection, patient sampling and receptor structural biology, Arialys has developed a first-in-class precision therapy to specifically block pathogenic autoantibodies in the brain. Arialys is headquartered in La Jolla, California. For more information, visit www.arialysrx.com.

Contacts

Company: Mathew Mitchell, Senior Vice President, Corporate Development, Arialys Therapeutics, info@arialysrx.com

Media: Jessica Yingling, Ph.D., Little Dog Communications Inc., jessica@litldog.com, +1.858.344.8091

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