A Study to Determine the Efficacy and Safety of Tividenofusp Alfa (DNL310) vs Idursulfase in Pediatric and Young Adult Participants With Neuronopathic (nMPS II) or Non-Neuronopathic Mucopolysaccharidosis Type II (nnMPS II)

Open to people ages 2-25

• 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

• 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