Den här översättningen är inte klar ännu. Den här sidan är just nu på engelska.

Gå till den engelska sidan

Hunter syndrome drug JR-141 tested for Long-Term safety

NCT ID NCT05594992

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only This study
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study is an extension of a previous trial testing JR-141, a drug given weekly by IV, for people with Hunter syndrome (a rare genetic disorder). It aims to see if the drug remains safe and effective over a longer period. About 80 participants who completed the earlier study will continue receiving JR-141, and researchers will track changes in spinal fluid markers, thinking skills, and physical abilities.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
JR-141 (a drug given by IV infusion weekly)
What this could lead to
If successful, this could confirm that JR-141 safely controls Hunter syndrome symptoms long-term, offering a continued treatment option for patients.
What could go wrong
This is an extension study, so it builds on earlier results but is still open-label (no placebo). Long-term benefits are not guaranteed, and side effects may emerge over time.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

About 80 people

The number the study aims to enrol. It can still change while the study runs.

Started

Feb 2023

Expected to finish

Feb 2028

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

Children (under 18), adults (18 to 64) and older adults (65 and over)

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. A subject who participated in the Parent Study (JR-141-GS31) and completed the assessments at Week 105 in Cohort A or Week 53 in Cohort B before being administered the study medication of that respective visit, and in the opinion of the principal investigator there are no safety concerns. 2. A subject from whom an IRB or IEC-approved written informed consent can be obtained, which is voluntarily signed. If the subject is aged under 18 years (aged under 16 years in the UK) at the time of enrollment or willingness to participate in the study cannot be confirmed due to MPS II-related intellectual disability, the subject's legally acceptable representative (e.g., his parents or guardians) may sign the ICF on behalf of the subject. Written informed assent should be obtained from the subject, wherever possible. 3. Female subject of child bearing potential or male subject whose female partner is of child-bearing potential, i.e., fertile, following menarche and until becoming post-menopausal unless permanently sterile, agrees to use a medically accepted, highly effective method of contraception from the time of signing the ICF. The method of contraception must be used during the study until 90 days for male subjects, and 30 days for female subjects after the final study drug administration. Exclusion Criteria: 1. A subject who changed treatment from JR-141 to idursulfase during the treatment period in the Parent Study (JR-141-GS31). 2. A subject who is unable to comply with the protocol (e.g., is unable to return for safety evaluations or is otherwise unlikely to complete the study) as determined by the principal investigator or sub-investigator. 3. \[Only in France\] Persons deprived of their liberty by a judicial or administrative decision, according to article L. 1121-6 of the Public Health Code (Code de la santé publique, CSP) adults who are the subject of a measure of legal protection or unable to express their consent according to article L. 1121-8 of the CSP.

Get updates

Get notified about this study

Sign up to get updates when this study changes or when new studies for Mucopolysaccharidosis ii are added.

Vår säkerhetsrekommendation!

Genom att skicka in godkänner du våra Användarvillkor

Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

How to take part

Only the study team decides who joins. These are the ways to reach them.

  1. The places running it

    10 sites in 8 countries. The list below names each one and where it is.

  2. The official record

    The full official record for this study. This one lists no contact details, but it is the first place any would appear.

    Open the record ↗

  3. A doctor treating you

    A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

  • Children's Hospital of Philadelphia

    Philadelphia, Pennsylvania, 19104, United States

  • Hospital Sant Joan de Déu

    Barcelona, Spain

  • Hospital Universitario Austral

    Buenos Aires, Argentina

  • Hospital de Clínicas de Porto Alegre

    Porto Alegre, Brazil

  • Hôpital Femme Mère Enfant

    Bron, France

  • Instituto de Genética e Erros Inatos do Metabolismo

    São Paulo, Brazil

  • Osp. Pediatrico Bambino Gesù, IRCCS

    Rome, Italy

  • UCSF Benioff Children's Hospital Oakland

    Oakland, California, 94609, United States

  • Universitätsklinikum Hamburg-Eppendorf

    Hamburg, Germany

  • Uniwersytecki Szpital Dziecięcy

    Krakow, Poland

More trials for these conditions

Other studies related to the condition(s) this trial covers.