NCT06753955

Phase 1 Study of ART5803 Safety and PK After IVIG in Healthy Participants

A Phase 1, Open-label Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of a Single-dose of ART5803 Following IVIG Administration in Healthy Participants

• Status: Active Not Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 6 (estimated)
• Sponsor: Arialys Therapeutics · Industry
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

This study will evaluate the safety, tolerability, and pharmacokinetics (PK) of ART5803 following IVIG administration in healthy participants to investigate the potential interactions between ART5803 and IVIG

Detailed description

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most common causes of autoimmune encephalitis. The disease is caused by the development of autoantibodies against the amino (N)-terminal domain (NTD) of the NMDAR subunit 1 (NR1) that bind and cross link the receptors, leading to receptor internalization and loss of function. Arialys has developed a monovalent (one-armed) antibody, ART5803, that binds to the NTD of the NMDAR NR1 subunit without causing NMDAR inhibition, activation, or receptor internalization, while simultaneously blocking the ability of the pathogenic anti-NMDAR autoantibodies to bind to the receptor. In treating anti-NMDAR encephalitis, intravenous immunoglobulin (IVIG) is commonly administered in conjunction with corticosteroids. Consequently, it is anticipated that IVIG may be administered to the target population prior to ART5803. IVIG has a long half-life and competitive binding of IVIG to the neonatal fragment crystallization receptor (FcRn) may result in FcRn saturation. This can potentially lead to increased clearance and/or impaired tissue distribution of ART5803 and decrease the cerebrospinal fluid (CSF) exposure to ART5803 through competition on FcRn at the blood-brain barrier (BBB).

Conditions

• Autoimmune Encephalitis Caused by N-Methyl D-Aspartate Receptor Antibody
• Autoimmune Encephalitis Caused by N-Methyl D-Aspartate Receptor Antibody (Disorder)
• Autoimmune Encephalitis

Interventions

Type	Name	Description
DRUG	ART5803	A monovalent (one-armed) antibody, that binds to the NTD of the NMDAR NR1 subunit without causing NMDAR inhibition, activation, or receptor internalization, while simultaneously blocking the ability of the pathogenic anti-NMDAR autoantibodies to bind to the receptor.
DRUG	Intravenous immunoglobulin (IVIG)	Administered as background treatment prior to the investigational product

Timeline

• Start date: 2025-03-18
• Primary completion: 2025-08-19
• Completion: 2025-12-24
• First posted: 2024-12-31
• Last updated: 2025-09-25

Locations

1 site across 1 country: Australia