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Comparing tividenofusp alfa to idursulfase for treating Mucopolysaccharidosis II in children and young adults

A Phase 2/3, Multicenter, Double-Blind, Randomized Study to Determine the Efficacy and Safety of Tividenofusp Alfa (DNL310) vs Idursulfase in Pediatric and Young Adult Participants With Neuronopathic or Non-Neuronopathic Mucopolysaccharidosis Type II

Phase2; Phase3 Interventional Denali Therapeutics Inc. · NCT05371613

This study is testing a new treatment called tividenofusp alfa to see if it works better than the standard treatment for children and young adults with Mucopolysaccharidosis Type II.

Quick facts

PhasePhase2; Phase3
Study typeInterventional
Enrollment63 (estimated)
Ages2 Years to 25 Years
SexAll
SponsorDenali Therapeutics Inc. Industry-sponsored
Locations32 sites (Oakland, California and 31 other locations)
Trial IDNCT05371613 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the efficacy and safety of tividenofusp alfa (DNL310), a new enzyme-replacement therapy, against the standard treatment idursulfase in pediatric and young adult patients with Mucopolysaccharidosis Type II (MPS II). The study is designed as a Phase 2/3, double-blind, randomized trial, meaning that neither the participants nor the researchers know who is receiving which treatment to ensure unbiased results. Participants will be divided into two cohorts based on age and will be monitored for safety and effectiveness over the course of the trial. There is also an option for participants to enter an open-label phase after the initial treatment period based on specific criteria.

Who should consider this trial

Good fit: Ideal candidates for this study are children and young adults aged 2 to 26 years with a confirmed diagnosis of MPS II who have not previously received enzyme replacement therapy or have been off such treatment for a specified period.

Not a fit: Patients with other genetic diagnoses causing developmental delays or those who have previously received certain gene therapies or CNS-targeted treatments may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a more effective therapy for children and young adults suffering from MPS II, potentially improving their quality of life.

How similar studies have performed: Other studies have shown promise with enzyme-replacement therapies for MPS II, but this specific approach with tividenofusp alfa is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

* Participants aged ≥2 to \<6 years (Cohort A) or ≥6 to \<26 years (Cohort B)
* Confirmed diagnosis of MPS II (for Cohort A, nMPS II; for Cohort B, nnMPS II)
* Have no history of treatment with enzyme replacement therapy (ERT) OR not have received continuous ERT for 4 months prior to screening OR be on maintenance ERT and have tolerated idursulfase for a minimum of 4 months prior to screening

Key Exclusion Criteria:

* Have a documented mutation of other genes or genetic diagnosis accounting for developmental delay
* Previously received an iduronate 2-sulfatase (IDS) gene therapy or stem cell therapy
* Received any CNS-targeted MPS ERT within 6 months prior to screening
* Have a contraindication for lumbar punctures and/or magnetic resonance imaging (MRI)
* Participated in any other investigational drug study or used an investigational drug within 60 days prior to screening or intend to receive another investigational drug during the study

Where this trial is running

Oakland, California and 31 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Mucopolysaccharidosis IIHunter SyndromeMPS IInMPS IInnMPS II
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.