A Phase I/II Trial of JR-446 in Mucopolysaccharidosis Type IIIB (MPS IIIB)

June 8, 2026 updated by: JCR Pharmaceuticals Co., Ltd.

A Global, Open-Label, Phase I/II Trial, to Evaluate Safety, Tolerability, Pharmacodynamic and Preliminary Efficacy of JR-446 in Mucopolysaccharidosis Type IIIB (MPS IIIB)

This is a global, open-label, Phase I/II, interventional trial in participants younger than 6 years of age with Mucopolysaccharidosis Type IIIB (MPS IIIB), designed to assess the safety and tolerability of JR-446, determine its pharmacodynamic effects, and explore its potential to demonstrate early clinical effects on disease-relevant outcomes.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Germany
      • Hamburg, Germany, 20246
        • University Medical Center Hamburg-Eppendorf
        • Contact:
          • Nicole Maria Muschol
          • Phone Number: +49 (0) 40 7410 53714
          • Email: muschol@uke.de
  • United Kingdom
      • London, United Kingdom, WC1N 3JH
        • Great Ormond Street Hospital For Children
        • Contact:
  • United States
    • California
      • Oakland, California, United States, 94609
        • Children's Hospital Oakland Research Institution, Attn: 2900 Wing
        • Contact:
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15224
        • UPMC Children's Hospital of Pittsburgh
        • Contact:
    • Virginia
      • Fairfax, Virginia, United States, 22030
        • Lysosomal and Rare Disorders Research and Treatment Center (LDRTC)
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patients with confirmed MPS IIIB with a phenotype of MPS IIIB that is not classified as slowly progressive (i.e., not attenuated).
  2. A chronological age <6 years.
  3. Ability to complete and achieve a Standard score ≥55, using either Bailey Scale of Infant Development-4 (BSID-4) Cognitive domain or Kaufman Assessment Battery for Children-II (KABC-II) Non-Verbal Index, whichever tool is most appropriate for the participant's chronological age.

Exclusion Criteria:

  1. Contraindication for lumbar puncture or MRI.
  2. A participant who has a medical condition or extenuating circumstance that, in the opinion of the principal investigator or sub-investigator, might compromise the participant's ability to comply with protocol requirements, the participant's well-being or safety, or the interpretability of the participant's clinical data.
  3. A participant who has received any other investigational drug product (including but not limited to, tralesinidase alfa enzyme replacement therapy [TA-ERT], Genistein, KINERET [anakinra], ambroxol, miglustat) within 4 months (or 5 half-lives, whichever is longer) before the time of providing informed consent.
  4. A participant who has received gene therapy treatment or hematopoietic stem cell transplantation (HSCT) with successful engraftment.
  5. Serious drug allergy or hypersensitivity to any components of JR-446 or medications likely prescribed during the trial.
  6. A participant has a history of bleeding disorder or current use of medications that, in the opinion of the investigator, place them at risk of bleeding following lumbar puncture.
  7. A patient with recurrent epileptic seizures not adequately controlled with anti-seizure medication, and which, in the clinical judgment of the principal investigator, would preclude safe participation in the trial.
  8. Serology consistent with human immunodeficiency virus (HIV) exposure or consistent with active hepatitis B (HepB) or hepatitis C (HepC) infection.
  9. A participant/family, who, in the opinion of the investigator, may not be able to comply with protocol requirements and cooperate fully with the trial assessments, procedures, and scheduling for JR-446 IMP dose administrations.
  10. Study participants for whom informed consent is unable to be provided by a parent or legal guardian; or when applicable for a study participant who is unable to provide assent with respect to study participation in conjunction with parental or legal guardian consent for participation on study.

The above information is not intended to contain all considerations relevant to a patient's potential participation in this clinical trial.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: JR-446
Arm: 1
Drug: JR-446
IV infusion

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
To establish the safety and tolerability of JR-446 in MPS IIIB patients following repeated dose administration
Time Frame: Up to 1 year (multiple visits)
Incidence and severity of treatment-emergent adverse events; Incidence and severity of infusion-associated reactions; Incidence of clinically significant changes/abnormalities in safety laboratory tests, vital signs, and electrocardiogram.
Up to 1 year (multiple visits)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Change From Baseline in Cerebrospinal Fluid Heparan Sulfate Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Absolute Change From Baseline in Serum Heparan Sulfate Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Percent Change From Baseline in Serum Heparan Sulfate Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Absolute Change From Baseline in Urine Heparan Sulfate Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Percent Change From Baseline in Urine Heparan Sulfate Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Absolute Change From Baseline in Serum Neurofilament Light Chain Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Percent Change From Baseline in Serum Neurofilament Light Chain Concentration
Time Frame: Through Week 53 (up to 1 year; multiple visits)
Through Week 53 (up to 1 year; multiple visits)
Change in Cognitive Function Assessments From Baseline
Time Frame: Through Week 53 (up to 1 year)
Through Week 53 (up to 1 year)
Change in Brain MRIs From Baseline
Time Frame: Through Week 53 (up to 1 year)
Through Week 53 (up to 1 year)
Change in Height Standard Deviation Score (SDS) From Baseline (using WHO child growth standards)
Time Frame: Through Week 53 (up to 1 year)
Through Week 53 (up to 1 year)
Change in Weight SDS From Baseline (using WHO child growth standards)
Time Frame: Through Week 53 (up to 1 year)
Through Week 53 (up to 1 year)
Change in Body Mass Index (BMI) SDS From Baseline (using WHO child growth standards)
Time Frame: Through Week 53 (up to 1 year)
Through Week 53 (up to 1 year)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
JCR Pharmaceuticals Co., Ltd.

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
MEDIPAL HOLDINGS CORPORATION

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 18, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 30, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 14, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 11, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • JR-446-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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