A Phase 23 Study Comparing Tividenofusp Alfa DNL310 and Idursulfase for Children and Young Adults With Neuronopathic or Non-Neuronopathic Mucopolysaccharidosis II

What this Trial Is About

Researchers are evaluating the efficacy and safety of tividenofusp alfa DNL310, an investigational enzyme-replacement therapy that can penetrate the central nervous system, compared with the standard enzyme replacement treatment idursulfase in children and young adults with mucopolysaccharidosis type II MPS II, which includes neuronopathic and non-neuronopathic forms. This Phase 23, double-blind, randomized, controlled study also allows some participants to enter an open-label treatment phase based on specific criteria. The study includes two main groups Cohort A with participants aged 2 to under 6 years who have neuronopathic MPS II, and Cohort B with participants aged 6 to under 26 years who have non-neuronopathic MPS II. Both tividenofusp alfa and idursulfase are given by repeated intravenous doses. Participants who meet certain criteria may continue treatment in an open-label phase with either DNL310 or idursulfase. Participants will be closely monitored through various assessments during the study, including measurements of cerebrospinal fluid heparan sulfate levels, adaptive behavior scales, developmental tests, walking distance tests, and imaging for liver and spleen volume. Caregiver impressions of change are also collected. The primary outcomes are assessed at 24 and 96 weeks, with additional secondary outcomes measured up to 48 or 96 weeks. The study is designed to last until December 2027, ensuring thorough evaluation of safety and treatment effects.

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)