A Study Of Intrathecally Administered Rugonersen In Pediatric And Adult With Angelman Syndrome

Overview

About this study

The purpose of this study is to evaluate the efficacy of rugonersen compared with placebo.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Male or female and ≥ 1 year to ≤ 50 years of age at signing of the informed consent form (ICF).

  • Independent of the age of the participant, the participant has a parent, caregiver or legal representative (herein after referred to as caregiver) who is reliable and competent in the Investigator’s judgement. The caregiver is:

    • Able to consent for the participant according to International Council for Harmonisation (ICH) and local regulations,

    • At least 18 years of age,

    • Willing and able to accompany the participant to clinic visits and be available to the investigational site by telephone, email, or other electronic form as needed,

    • Is, and will likely remain, sufficiently knowledgeable of participant’s condition throughout the study to be able to respond to queries, and is willing and able to complete caregiver assessments and inform the site personnel about the participant’s condition as requested.

  • Clinical diagnosis of Angelman syndrome.

  • Pre-existing medical records confirm the clinical diagnosis of AS and the molecular diagnosis with genotypic classification of either:

    • Mutation in the UBE3A gene, and the pathogenic or likely pathogenic variant identified,

    • Deletion on the maternally inherited chromosome 15q11-q13 that encompasses the UBE3A gene.

  • Able to comply with all study requirements.

  • Able to tolerate blood draws

  • Able to undergo LP and IT injection, under sedation or anesthesia as deemed appropriate.

  • Has stable medical status for at least 4 weeks prior to screening and at the time of enrolment

  • Bodyweight > 7 kg

  • Legally authorized representative/caregiver(s) agree(s) not to share any of the participant’s personal medical data or information related to the study on by any means, including, e.g., a website or a post on a social media site (e.g., Facebook, Instagram, Twitter, YouTube, TikTok, etc.) from the time of enrollment until they are notified that the study is completed.

  • Stable permitted medications (including cannabidiol [CBD]) for epilepsy for 12 weeks prior to screening and at the time of enrolment, with the exception of age/weight-based or blood level (toxicity) dose adjustments.

  • Stable concurrent psychotropic medications for 4 weeks prior to screening and at time of enrolment.

  • Complies with the requirements regarding contraception as described below and is confirmed by caregiver consent:

    • Female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies:

      • Women of non-childbearing potential,

      • Women of childbearing potential (WOCBP) who agree to remain abstinent or use a highly effective method of contraception such as: bilateral tubal occlusion/ligation, male sexual partner who is sterilized, established proper use of hormonal contraceptives that inhibit ovulation, hormonereleasing intrauterine devices and copper intrauterine devices.

      • Note: Female participants who reach menarche after enrollment in the study must agree thereafter to regular pregnancy testing as defined in the SoAs and must agree to either remain completely sexually abstinent or comply with the same contraceptive requirements as outlined above for WOCBP from first menses until at least 6 months after the final dose of rugonersen.

    • Male participants must consent during the treatment period and for at least 6 months after the final dose of rugonersen, to agree to:

      • Remain abstinent or use contraceptive measures such as condom, with a female partner of childbearing potential or pregnant female partner.

    • The reliability of sexual abstinence for male and/or female enrolment eligibility needs to be evaluated in relation to the duration of the clinical study and the preferred and usual lifestyle of the participant. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or post-ovulation methods) and withdrawal are not acceptable methods of preventing drug exposure.

Additional Inclusion Criteria for Part 2 (OLE):

  • Any individual with a clinical and molecular diagnosis of AS who previously received rugonersen (or previously named RO7248824) as part of the Phase 1 TANGELO study OLE, or the planned EAP, but not as part of this clinical study, and who has not received any other cellular therapy, or gene therapy, or gene editing, or any other gene expression modulating clinical trial, such as an ASO treatment, other than rugonersen

Exclusion Criteria:

  • Molecular diagnosis of AS with genotypic classification of:

    • Uniparental paternal disomy (UPD) of 15q11-q13,

    • Imprinting center defect (ICD) within 15q11-q13,

    • A partial molecular diagnosis of AS, that cannot exclude UPD or ICD despite appropriate genetic testing.

  • Clinically significant vital signs or laboratory abnormalities during screening including:

    • Abnormal coagulation profile demonstrated by platelet count at or below lower limit of normal (140 × 109 /L), or by abnormal international normalized ratio (INR) and/or prothrombin time (PT), or activated partial thromboplastin time (aPTT),

  • Presence of clinically relevant electrocardiogram (ECG) abnormalities prior to dosing such as QT interval corrected for heart rate using Fredericia's formula (QTcF) > 460 ms, personal or family history of congenital long QT syndrome indicating safety risk in the Investigator’s opinion. First-degree atrioventricular block or isolated right bundle branch block is allowed.

  • Clinically relevant disease or condition, including hematological, hepatic, cardiac or renal disease or abnormality, that would in the judgement of the Investigator pose an unacceptable risk to the participant or interfere with the conduct of the study

  • Any concomitant condition that might interfere with the clinical evaluation of AS and that is not related to AS.

  • Known history of human immunodeficiency virus (HIV), hepatitis B, C, or E virus. • Any condition that increases the risk of meningitis.

  • History of bleeding diathesis or coagulopathy.

  • Medical history of brain or spinal disease that would interfere with the LP process, CSF circulation or safety assessment, including:

    • Tumors or abnormalities detected by magnetic resonance imaging (MRI) or computed tomography (CT),

    • Subarachnoid hemorrhage,

    • Clinical suggestion of raised intracranial pressure confirmed by MRI or ophthalmic examination,

    • Spinal stenosis or curvature (considered sufficient to prohibit LP),

    • Chiari malformation, o Hydrocephalus,

    • Syringomyelia,

    • Tethered spinal cord syndrome and connective tissue disorders such as Ehlers-Danos syndrome and Marfan syndrome.

    • Radiculopathy or radiculitis

  • Ventriculoperitoneal (VP) shunt for the drainage of CSF or an implanted CNS catheter.

  • Medical history of brain or spinal injury, of traumatic, hemorrhages or any other origin that may result in symptoms interfering with AS.

  • History of clinically significant post LP headache of moderate or severe intensity and/or blood patch that would in the judgement of the Investigator pose an unacceptable risk to the participant or interfere with the conduct of the study.

  • Malignancy within 5 years of screening.

  • Hospitalization for any major medical or surgical procedure involving general anesthesia planned during the study, or within 4 weeks prior to screening, that – in the opinion of the Investigator – may pose a risk to the participant.

  • Prohibited use of antiplatelet or anticoagulant therapy for 2 weeks prior to screening and at the time of enrolment.

  • Have any other conditions which would make the participant unsuitable for inclusion or could interfere with the participant participating in or completing the study, including any contraindication to administration of IT therapy.

  • Extremely or very preterm birth complications which, in the opinion of the Investigator, may interfere with study outcomes.

  • Birth complications, confirmed or suspected asphyxia before, during, or after birth.

  • Ascertained or presumptive hypersensitivity to the investigational medicinal product (IMP) or its excipients.

  • Participated in a clinical trial and received an IMP within 90 days or 5 half-lives (whichever is longer) or tested an investigational medical device within 90 days prior to dosing or if the device is still active.

  • Concurrent or planned concurrent participation in any clinical trial (including observational, non-drug or non-interventional).

  • Previous participation in cellular therapy, or gene therapy, or gene editing, or any other gene expression modulating clinical trial, such as an ASO treatment.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 01/13/2026. Questions regarding updates should be directed to the study team contact.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Khoon Ghee Queenie Tan, M.D., Ph.D.

Contact us for the latest status

Contact information:

Bradley Jorde

5072933609

jorde.bradley@mayo.edu

More information

Publications

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CLS-20610669

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