A Phase 1 interventional study of α-Syn H21 Monoclonal Antibody in Multiple System Atrophy, sponsored by Ruijin Hospital. Not yet recruiting at 1 site in China. Open to participants aged 45 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-08-19.
Sponsored by Ruijin Hospital · Phase 1, Interventional, and Treatment
Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by autonomic dysfunction, parkinsonism, and cerebellar ataxia. Abnormal aggregation of alpha-synuclein is believed to play an important role in disease progression. The α-Syn H21 monoclonal antibody is designed to selectively bind pathological alpha-synuclein aggregates and may reduce their spread and related neuroinflammation.
This single-center, prospective, exploratory study will evaluate the safety, tolerability, and preliminary efficacy of the α-Syn H21 monoclonal antibody in patients with MSA. Participants will receive intravenous infusions of H21 every 4 weeks for 3 doses and will be followed for 12 weeks. Clinical symptoms, laboratory tests, imaging findings, and adverse events will be assessed to determine whether H21 may provide clinical benefit and support future larger studies.
207 studies on the registry are indexed under Multiple System Atrophy; 73 are open to participants now.
This study's planned enrollment of 3 is below the median of 41 across 134 interventional studies indexed under Multiple System Atrophy.
Browse Multiple System Atrophy studies →Ruijin Hospital is the lead sponsor of 679 studies on the registry; 387 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biological: α-Syn H21 Monoclonal Antibody
The α-Syn H21 monoclonal antibody is a humanized monoclonal antibody designed to selectively bind pathological alpha-synuclein aggregates. Participants will receive the study drug by intravenous infusion once every 4 weeks for a total of 3 doses during the 12-week study period.
Incidence of treatment-emergent adverse events
Incidence, severity, and relationship of adverse events (AEs) and serious adverse events (SAEs) to study treatment.
Time frame: From first dose through Week 12
Change from Baseline in Unified Multiple System Atrophy Rating Scale (UMSARS) Total Score (Parts I-IV)
Change from baseline in the total score and subscale scores of the Unified Multiple System Atrophy Rating Scale (UMSARS Parts I-IV). The UMSARS is a clinician-administered scale used to assess disease severity in patients with multiple system atrophy. Total scores are derived from Parts I-IV, with higher scores indicating greater disease severity and worse clinical status. The total score ranges from 0 to 249, with higher scores indicating more severe impairment.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from baseline in DAT-PET/MRI measures of striatal dopamine transporter uptake and brain structural changes
Change from baseline in DAT-PET/MRI imaging parameters, including brain metabolic and structural changes.
Time frame: Baseline and Week 12
Change from Baseline in Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Total Score
Change from baseline in the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS Parts I-IV) total and subscale scores. The MDS-UPDRS is a clinician-administered scale used to assess the severity and progression of Parkinsonian symptoms. The total score ranges from 0 to 260, with higher scores indicating greater disease severity and worse motor and non-motor impairment.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change in Patient Global Impression of Improvement (PGI-I) Score
The Patient Global Impression of Improvement (PGI-I) is a patient-reported measure assessing overall perceived improvement following treatment. Scores range from 1 (very much improved) to 7 (very much worse), with lower scores indicating better perceived improvement.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from Baseline in Mini-Mental State Examination (MMSE) Score
Change from baseline in the Mini-Mental State Examination (MMSE) score. The MMSE is a widely used clinician-administered screening tool for global cognitive function, assessing domains including orientation, attention, memory, language, and visuospatial abilities. Scores range from 0 to 30, with higher scores indicating better cognitive function and lower scores indicating greater cognitive impairment.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from Baseline in Hamilton Depression Rating Scale (HAMD) Score
Change from baseline in the Hamilton Depression Rating Scale (HAMD) score. The HAMD is a clinician-administered scale used to assess the severity of depressive symptoms. Scores range from 0 to 52 (17-item version), with higher scores indicating more severe depressive symptoms and lower scores indicating less severe depression.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from Baseline in Hamilton Anxiety Rating Scale (HAMA) Score
Change from baseline in the Hamilton Anxiety Rating Scale (HAMA) score. The HAMA is a clinician-administered scale used to assess the severity of anxiety symptoms. Scores range from 0 to 56, with higher scores indicating more severe anxiety symptoms and lower scores indicating less severe anxiety.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from Baseline in Parkinson's Disease Sleep Scale-2 (PDSS-2) Score
Change from baseline in the Parkinson's Disease Sleep Scale-2 (PDSS-2) score. The PDSS-2 is a patient-reported scale used to assess the severity of nocturnal disturbances and sleep-related symptoms in patients with Parkinson's disease. Scores range from 0 to 60, with higher scores indicating more severe sleep disturbances and poorer sleep quality.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from Baseline in Parkinson's Disease Questionnaire-39 (PDQ-39) Score
Change from baseline in the Parkinson's Disease Questionnaire-39 (PDQ-39) score. The PDQ-39 is a patient-reported questionnaire used to assess health-related quality of life in patients with Parkinson's disease across eight domains, including mobility, activities of daily living, emotional well-being, and social support. Scores range from 0 to 156, with higher scores indicating poorer health-related quality of life and greater disease impact.
Time frame: Baseline, Week 4, Week 8, and Week 12
Number of Participants With Clinically Significant Abnormal Laboratory Values
The number of participants with clinically significant abnormal laboratory values following H21 administration, including abnormalities in hematology, urinalysis, liver function, and renal function tests, as assessed by the investigator.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change from baseline in electrocardiogram parameters including heart rhythm, PR interval, QRS duration, and QTc interval
Standard 12-lead electrocardiograms will be performed at scheduled visits to assess changes from baseline in cardiac conduction and rhythm parameters, including heart rhythm, PR interval, QRS duration, and corrected QT (QTc) interval, following H21 administration.
Time frame: Baseline, Week 4, Week 8, and Week 12
Change in Blood Pressure After Infusion
Change in blood pressure measured before each H21 infusion and at 10 minutes and 30 minutes after infusion to evaluate short-term hemodynamic changes associated with study drug administration.
Time frame: Pre-dose and 10 minutes and 30 minutes after each infusion through Week 12
Change in Heart Rate After Infusion
Change in heart rate measured before each H21 infusion and at 10 minutes and 30 minutes after infusion to evaluate short-term cardiac responses associated with study drug administration.
Time frame: Pre-dose and 10 minutes and 30 minutes after each infusion through Week 12
Change in Respiratory Rate After Infusion
Change in respiratory rate measured before each H21 infusion and at 10 minutes and 30 minutes after infusion to evaluate short-term respiratory changes associated with study drug administration.
Time frame: Pre-dose and 10 minutes and 30 minutes after each infusion through Week 12
Serum Concentration of H21
Serum concentrations of H21 will be measured at prespecified time points following administration to characterize the concentration-time profile of H21.
Time frame: During treatment through Week 12
Maximum Observed Serum Concentration (Cmax) of H21
The maximum observed serum concentration (Cmax) of H21 following administration.
Time frame: During treatment through Week 12
Time to Maximum Observed Serum Concentration (Tmax) of H21
The time to reach the maximum observed serum concentration (Tmax) of H21 following administration.
Time frame: During treatment through Week 12
Area Under the Serum Concentration-Time Curve (AUC) of H21
The area under the serum concentration-time curve (AUC) of H21 following administration.
Time frame: During treatment through Week 12
Terminal Elimination Half-life (t1/2) of H21
The terminal elimination half-life (t1/2) of H21 following administration.
Time frame: During treatment through Week 12
Plan to share: No
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.