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Several children with Angelman syndrome from the Angelman outpatient clinic of the ENCORE expertise center participated in the TANGELO study. This study has now been completed, and the results have been published in the medical journal Nature Medicine.

The full article is available here .

Thanks to the parents and children who participated, it was possible to achieve this result, many thanks for that!

Angelman Syndrome: New Treatment Studied in Children

Angelman Syndrome (AS) is a serious hereditary condition that affects brain development. Children with AS often have difficulty speaking, moving, and learning. Currently, there is no treatment that addresses the underlying cause of the condition.

The disease develops because a specific gene in the brain, the UBE3A gene, malfunctions. A new drug, rugonersen, aims to reactivate this gene. This drug is specifically designed to reactivate the father's "deactivated" gene.

An initial study (phase 1) was conducted with 61 children between the ages of 1 and 12. The goal was to determine whether the drug is safe and well-tolerated. The children received varying doses of the drug, and the study was conducted at multiple sites.

The main finding was that the drug appears to be safe for children. The study also examined how the drug works in the body and whether there were any changes in brain activity and behavior. The results showed that the drug could partially improve some abnormalities in the brain waves of children with AS. There were also signs that some children made progress in their development.

These initial results are positive and give hope that rugonersen can be further developed as a treatment for Angelman Syndrome.

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The company Hoffmann-La Roche has previously sold the drug Rugonersen to another company: Oak Hill Therapeutics (see Oak Hill Bio Enters into Exclusive License Agreement with Roche to Obtain Global Rights for a Phase 3-Ready, Potential Best-in-Class Treatment for Individuals with Angelman Syndrome – Apr 15, 2025 and  Oak Hill Bio Announces Publication of Rugonersen Phase 1 Study Results in Nature Medicine)

They are setting up follow-up studies and making this medication available to participants in the Tangelo study who wish to continue treatment. We are very curious to see what this will mean for all children with Angelman syndrome.