Actively Recruiting
A Phase 2a, Open-label Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of ART5803 in Participants With Anti-NMDAR Encephalitis and Anti-NMDAR Autoantibody-Associated Psychiatric Disease
Led by Arialys Australia Pty Ltd · Updated on 2026-05-12
30
Participants Needed
1
Research Sites
26 weeks
Total Duration
On this page
Sponsors
A
Arialys Australia Pty Ltd
Lead Sponsor
A
Arialys Therapeutics
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are studying adults diagnosed with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis (ANRE) or anti-NMDAR autoantibody-associated psychiatric disease to evaluate the safety, tolerability, preliminary effectiveness, and how the body processes a drug called ART5803. This condition involves the immune system attacking parts of the brain, leading to loss of receptor function, and may be linked to psychiatric symptoms. The study is a Phase 2a, open-label trial led by Arialys Australia Pty Ltd. Participants will receive ART5803, a specialized antibody designed to bind the NMDAR receptor without interfering with its normal activity, while blocking harmful autoantibodies. The treatment is given by intravenous infusion: initial participants receive 30 mg/kg, and later participants may receive up to 60 mg/kg. The schedule includes weekly infusions for 4 weeks, followed by infusions every two weeks for 8 weeks, totaling 8 doses. The study groups include adults with chronic, subacute, or acute ANRE, as well as those with anti-NMDAR autoantibody-associated psychiatric disease. During the 26-week study period, participants will undergo safety and tolerability assessments, patient-reported outcomes, neuropsychological tests, and evaluations of neurological and behavioral changes. Blood and cerebrospinal fluid samples will be collected to study how ART5803 is processed in the body. Participants will be monitored for changes in mobility, daily living activities, and psychiatric symptoms. The study aims to carefully track effects over time while ensuring participant safety.
CONDITIONS
Brief Title
A Study in Participants With Anti-NMDAR Encephalitis and Anti-NMDAR Autoantibody-Associated Psychiatric Disease
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Participants must be male or female aged 18 to 65 years (age may vary slightly by country).
- Must provide written informed consent or have a legally authorized representative if unable.
- Ability and willingness to comply with study procedures as determined by the investigator.
- Diagnosis of anti-NMDAR encephalitis or anti-NMDAR autoantibody-associated psychiatric disease per study definitions.
- Positive test for CSF anti-NMDAR IgG autoantibody within specified timeframes depending on cohort.
- Completion of prior treatments such as IVIG or immunotherapy with stable doses as required.
- Stable psychiatric medication regimen for at least 4 weeks before study start and during early study weeks.
- Adequate disease burden based on cognitive, psychiatric, or functional assessments relevant to each cohort.
- No active malignancy or residual teratoma; prior teratoma must be fully resected before study.
- Use of highly effective contraception during study and for specified periods after last dose.
- Negative pregnancy test for females of childbearing potential and agreement to additional testing.
- Agreement not to donate sperm or eggs during and after the study as specified.
- Compliance with all these restrictions documented and confirmed throughout the study.
You will not qualify if you...
- Pregnancy, breastfeeding, or planning pregnancy during the study.
- Use of investigational products within 30 days or five half-lives prior to screening.
- Use of NMDAR modulators other than the study drug within specified timeframes.
- Previous exposure to ART5803 or similar NMDAR-targeting antibodies.
- Any condition compromising safety, study participation, or result interpretation as judged by the investigator.
- Coexisting central nervous system demyelinating disorders or other significant psychiatric or neurological disorders unless approved case-by-case.
- Positive hepatitis B or C infection at screening.
- Known allergy or severe reaction to ART5803 or biologic therapies.
- History of moderate or severe substance use disorder or recent alcohol or drug addiction as defined in the protocol.
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 12 weeks
Participants receive the study drug ART5803 by intravenous infusion once a week for 4 weeks, then every 2 weeks for 8 weeks, for a total of 8 doses. Sentinel participants receive 30 mg/kg and additional participants may receive up to 60 mg/kg based on Safety Review Committee guidance.
8 visits (in-person) over 12 weeks
Duration - Up to 14 weeks
Participants are monitored for safety, tolerability, and effects on neurological, psychiatric, and functional outcomes after completing treatment.
Periodic visits for up to 14 weeks
Trial Site Locations
Total: 1 location
1
Seoul National University Hospital
Seoul, South Korea, 03080
Actively Recruiting
Research Team
A
April Purcell
M
Mari Maurer
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
4
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