Arialys Therapeutics is a biotechnology company that develops treatments for autoimmune neuropsychiatric disorders. The company creates precision medicines to block harmful autoantibodies in the brain. This expands treatment possibilities for a range of autoimmune neuropsychiatric conditions. Arialys Therapeutics is headquartered in La Jolla, California, within the Avalon BioVentures Accelerator.
Targeted Conditions
Arialys Therapeutics concentrates on conditions where autoantibodies, immune system proteins, mistakenly attack the brain. Historically, autoimmune activity focused on peripheral tissues. However, autoantibodies can target the brain, leading to severe neurological and psychiatric diseases.
One primary condition Arialys addresses is anti-NMDA receptor encephalitis (ANRE), a rare but potentially life-threatening neurological disease. ANRE is caused by autoantibodies that disrupt NMDA receptors, important for brain functions like cognition, learning, and memory. This disruption can lead to severe psychosis and other neurological deficits.
Beyond ANRE, Arialys explores autoantibodies in other neuropsychiatric conditions, including autoimmune psychosis and certain forms of dementia. Anti-NMDAR autoantibodies have been detected in patients with schizophrenia, schizoaffective disorder, and cancer-related cognitive impairment.
Current treatments for conditions like ANRE often use non-specific immunological modulators. These therapies can have a slow onset, may not be effective, and carry risks of infectious complications. Arialys aims to address these unmet medical needs by developing highly targeted treatments.
Innovative Scientific Approach
Arialys Therapeutics’ scientific approach focuses on counteracting pathogenic autoantibodies in the brain. This approach is based on discoveries that immune cells, even in the brain, can produce autoantibodies causing severe neurological and psychiatric diseases.
Their strategy involves designing precision medicines to block these harmful autoantibodies. This approach differs from traditional broad immunosuppression by targeting specific molecular interactions responsible for the disease. By directly interfering with autoantibody function, Arialys develops therapies with improved efficacy and reduced side effects.
Their methodology includes structural analysis of autoantibody-target interactions, like with the NMDA receptor. This detailed molecular understanding allows Arialys to design therapeutic agents that competitively block the binding of pathogenic autoantibodies. This mechanism aims to rescue the function of critical brain receptors.
Current Research and Development
Arialys Therapeutics’ lead candidate, ART5803, is in clinical development. This therapeutic antibody is designed to competitively block pathogenic autoantibodies that target the NMDA receptor. The goal of ART5803 is to restore NMDA receptor function, which is impaired in conditions like anti-NMDA receptor encephalitis (ANRE).
Preclinical data for ART5803 in disease models is compelling. Studies have shown ART5803 can rapidly reverse behavioral symptoms caused by NMDAR autoantibody pathogenicity in the brain. The company is investigating ART5803’s clinical potential in ANRE and other neuropsychiatric diseases where NMDAR autoantibodies are present.
ART5803 has received Orphan Drug Designation from the U.S. Food and Drug Administration for ANRE treatment. The company initiated MAD (Multiple Ascending Dose) cohorts in a Phase 1 study for ART5803 in February 2025, having completed all planned SAD (Single Ascending Dose) cohorts.
Arialys Therapeutics acquired ART5803 from Astellas Pharma. Beyond ANRE, Arialys explores whether ART5803 could treat other common illnesses, such as certain forms of schizophrenia and dementia linked to Alzheimer’s disease. The company also intends to identify additional autoantibodies that drive neuropsychiatric diseases and develop new drugs to block them.