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

NCT ID NCT05594992

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.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

mucopolysaccharidosis type 2

As listed by the trial registrant

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

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