Angelman SyndromePhase 3NCT07782827
CHAMPION: A Study to Evaluate the Efficacy and Safety of Obudanersen (ION582) in Children and Adults With Angelman Syndrome (AS)
A Phase 3 study testing obudanersen in people with Angelman Syndrome, run by Ionis Pharmaceuticals, Inc. at 1 site in United States.
Trial summary
The primary purpose of the study is to evaluate efficacy of obudanersen in participants with AS due to uniparental disomy or imprinting defects (UPD/ID) as measured through expressive communication. Read more about this study
- Who is it for?
- Ages 2 to 50 years
- Conditions the study is for
- Angelman Syndrome
- What is being tested?
- obudanersen
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Sep 2026to May 2031
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 50 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Clinical diagnosis of AS with molecular result indicating either paternal UPD of 15q11.2-q13 or ID of the maternal 15q11.2-q13 region, provided by the Investigator and confirmed by either a qualified central vendor or a qualified local geneticist at the site.
- The participant's caregiver(s)/legally-authorized representative (LAR) must have given written informed consent and any authorizations required by local law and be able and willing to comply with all study requirements.
- Medically stable and can undergo sedation and/or general anesthesia without intubation.
- Male or female between 2 and ≤ 50 years of age, depending on the specific cohort, at the time of the in-clinic Screening visit.
- If applicable, is currently receiving stable doses of concomitant medications typically prescribed for AS, such as anti-epileptic medication, behavioral management medications, sleep medications, gabapentin, cannabidiol, and special diets, supplements, or nutritional support for at least 8 weeks prior to the Baseline visit. If recent changes (< 8 weeks stable) in medications, the participant may be allowed per Investigator judgment if the change is not expected to have an impact on the signs and symptoms of AS.
- LAR/caregiver(s) agree(s) not to post any of the participant's personal medical data or information related to the study on any website or social media site (e.g., Facebook, Instagram, X, YouTube, TikTok, WhatsApp) from the time of enrollment until they are notified that the study is completed.
Who cannot join
- Participant has a clinical diagnosis of AS with molecular confirmation of a UBE3A deletion or UBE3A mutation.
- Any clinically significant abnormalities in medical history (e.g., major surgery within 3 months of Screening), or on physical examination for which treatment with an antisense oligonucleotide (ASO) would be contraindicated or which, in the opinion of the Investigator, could confound the results of this study.
- Known brain or spinal disease that would interfere with the lumbar puncture (LP) procedure, cerebrospinal fluid (CSF) circulation, or presence of other factors that would affect the safety of the LP procedure, including tumors or abnormalities by MRI or computed tomography (CT), subarachnoid hemorrhage, suggestion of raised intracranial pressure (ICP) on magnetic resonance imaging (MRI) or ophthalmic examination, Chiari malformation, obstructive hydrocephalus, syringomyelia, tethered spinal cord syndrome, or connective tissue disorders such as Ehlers-Danlos syndrome and Marfan syndrome.
- Any laboratory abnormalities or any other clinically significant abnormalities that would, as assessed by the Investigator, at Screening or Baseline, render a participant unsuitable for inclusion.
- Previous treatment with an oligonucleotide (including small interfering ribonucleic acid [siRNA] and ASOs) or gene therapy or gene editing. This exclusion criterion does not apply to approved nucleic acid-based vaccines, including messenger Ribonucleic Acid (mRNA) vaccines, which are allowed.
- Other inclusion/exclusion criteria may apply
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of North Carolina at Chapel Hill School of Medicine
Carrboro, North Carolina, 27510
About this study
Official title: Phase 3 Study of the Efficacy and Safety of ION582 in Children and Adults With Angelman Syndrome Due to Paternal Uniparental Disomy or Imprinting Defects
The primary purpose of the study is to evaluate efficacy of obudanersen in participants with AS due to uniparental disomy or imprinting defects (UPD/ID) as measured through expressive communication.
Read the detailed description
This is a Phase 3, open-label, single treatment arm, multi-center study in participants with Angelman syndrome due to paternal uniparental disomy or imprinting defects. The study will consist of 4 periods: a screening period of up to 28 days, an approximate 60-week Treatment Evaluation Period, followed by 101 weeks of Long-Term Extension (LTE) period, and an 8-month Post-Treatment Follow-up Period. There will be two age-based Cohorts enrolled in this study: Cohort 1 (pediatric participants (aged 2 to <18 years old)) and Cohort 2 (adult participants (aged 18 to ≤50 years old). More individuals will be enrolled in Cohort 1 than in Cohort 2.
- Conditions
- Angelman Syndrome
- Being tested
- obudanersen
- Keywords
- Paternal Uniparental Disomy, ION582, imprinting defects
- Medical subject headings
- Angelman Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
obudanersenDrug
Also called ION582
ION582 will be administered by IT injection.
| Study group | Role | What they receive |
|---|---|---|
| obudanersen 80 mg | Experimental | Participants in Cohorts 1 and 2 will be administered obudanersen via intrathecal (IT) bolus injection every 12 weeks during the Treatment Evaluation and LTE periods. Receives: Drug: obudanersen |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Performance on the Expressive Communication Domain Raw Score Without Caregiver Input of the Bayley Scales for Infant and Toddler Development-4 (Bayley-4) in Cohort 1
Measured: Baseline and Week 52
Secondary outcomes (7)
Change From Baseline in Bayley-4: Cognition Scale Raw Score Without Caregiver Input
Measured: Baseline and Week 52
Change From Baseline in Aberrant Behavior Checklist - Second Edition - Community Version (ABC-2-C): Hyperactivity
Measured: Baseline and Week 52
Change From Baseline in (ABC-2-C): Irritability
Measured: Baseline and Week 52
Change From Baseline in Vineland Adaptive Behavior Scale-3 (Vineland-3): Receptive Communication Domain Raw Score
Measured: Baseline and Week 52
Change From Baseline in Vineland-3: Daily Living Skills, Personal Domain Raw Score
Measured: Baseline and Week 52
Change From Baseline in (Bayley-4): Fine Motor Domain Raw Score Without Caregiver Input
Measured: Baseline and Week 52
Change From Baseline in Observer-Reported Communication Ability (ORCA): Overall Emerging and Mastery T Score
Measured: Baseline and Week 52
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Aug 2026
- Study start30 Sep 2026
- Primary completionMay 2028 (estimated)
- Study completionMay 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Angelman SyndromeStudies of the same condition, open and under way.
- More trials run by Ionis Pharmaceuticals, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ionis Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07782827
- Sponsor's protocol ID
- ION582-CS3
- Status last verified
- Oct 2026
- First submitted
- 20 Aug 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Ionis may share anonymized individual participant data, aggregated clinical data, and other types of data that support the results in this study. Data requests from qualified researchers will be considered once all three of the following criteria are met: (1) 12 months from marketing approval of the study drug in both the United States and European Union; (2) 18 months from conclusion of the study; and (3) 6 months from publication of study article. Access would be via a secure environment and is contingent upon approval of a research proposal and entry into an appropriate data use agreement. Requests to access data can be submitted via the website https://vivli.org/ourmember/ionis/.
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Phase 3 Study of the Efficacy and Safety of ION582 in Children and Adults With Angelman Syndrome Due to Paternal Uniparental Disomy or Imprinting Defects
- ClinicalTrials.gov ID
- NCT07782827
- Acronym / sponsor ID
- ION582-CS3
- Conditions
- Angelman Syndrome
- Keywords
- Paternal Uniparental Disomy, ION582, imprinting defects
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Ionis Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 30 Sep 2026 (actual)
- Primary completion
- May 2028 (estimated)
- Study completion
- May 2031 (estimated)
- First posted
- 24 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary purpose of the study is to evaluate efficacy of obudanersen in participants with AS due to uniparental disomy or imprinting defects (UPD/ID) as measured through expressive communication.
Detailed description
This is a Phase 3, open-label, single treatment arm, multi-center study in participants with Angelman syndrome due to paternal uniparental disomy or imprinting defects. The study will consist of 4 periods: a screening period of up to 28 days, an approximate 60-week Treatment Evaluation Period, followed by 101 weeks of Long-Term Extension (LTE) period, and an 8-month Post-Treatment Follow-up Period. There will be two age-based Cohorts enrolled in this study: Cohort 1 (pediatric participants (aged 2 to <18 years old)) and Cohort 2 (adult participants (aged 18 to ≤50 years old). More individuals will be enrolled in Cohort 1 than in Cohort 2.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| obudanersen 80 mg | Experimental | Drug: obudanersenParticipants in Cohorts 1 and 2 will be administered obudanersen via intrathecal (IT) bolus injection every 12 weeks during the Treatment Evaluation and LTE periods. |
Who may qualify
- Ages
- 2 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (6 listed)
- Clinical diagnosis of AS with molecular result indicating either paternal UPD of 15q11.2-q13 or ID of the maternal 15q11.2-q13 region, provided by the Investigator and confirmed by either a qualified central vendor or a qualified local geneticist at the site.
- The participant's caregiver(s)/legally-authorized representative (LAR) must have given written informed consent and any authorizations required by local law and be able and willing to comply with all study requirements.
- Medically stable and can undergo sedation and/or general anesthesia without intubation.
- Male or female between 2 and ≤ 50 years of age, depending on the specific cohort, at the time of the in-clinic Screening visit.
- If applicable, is currently receiving stable doses of concomitant medications typically prescribed for AS, such as anti-epileptic medication, behavioral management medications, sleep medications, gabapentin, cannabidiol, and special diets, supplements, or nutritional support for at least 8 weeks prior to the Baseline visit. If recent changes (< 8 weeks stable) in medications, the participant may be allowed per Investigator judgment if the change is not expected to have an impact on the signs and symptoms of AS.
Key exclusion criteria (6 listed)
- Participant has a clinical diagnosis of AS with molecular confirmation of a UBE3A deletion or UBE3A mutation.
- Any clinically significant abnormalities in medical history (e.g., major surgery within 3 months of Screening), or on physical examination for which treatment with an antisense oligonucleotide (ASO) would be contraindicated or which, in the opinion of the Investigator, could confound the results of this study.
- Known brain or spinal disease that would interfere with the lumbar puncture (LP) procedure, cerebrospinal fluid (CSF) circulation, or presence of other factors that would affect the safety of the LP procedure, including tumors or abnormalities by MRI or computed tomography (CT), subarachnoid hemorrhage, suggestion of raised intracranial pressure (ICP) on magnetic resonance imaging (MRI) or ophthalmic examination, Chiari malformation, obstructive hydrocephalus, syringomyelia, tethered spinal cord syndrome, or connective tissue disorders such as Ehlers-Danlos syndrome and Marfan syndrome.
- Any laboratory abnormalities or any other clinically significant abnormalities that would, as assessed by the Investigator, at Screening or Baseline, render a participant unsuitable for inclusion.
- Previous treatment with an oligonucleotide (including small interfering ribonucleic acid [siRNA] and ASOs) or gene therapy or gene editing. This exclusion criterion does not apply to approved nucleic acid-based vaccines, including messenger Ribonucleic Acid (mRNA) vaccines, which are allowed.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| obudanersenAlso: ION582ION582 will be administered by IT injection. | Drug | obudanersen 80 mg |
Primary outcome
Change From Baseline in Performance on the Expressive Communication Domain Raw Score Without Caregiver Input of the Bayley Scales for Infant and Toddler Development-4 (Bayley-4) in Cohort 1
Time frame: Baseline and Week 52
7 secondary outcomes
Change From Baseline in Bayley-4: Cognition Scale Raw Score Without Caregiver Input
Time frame: Baseline and Week 52
Change From Baseline in Aberrant Behavior Checklist - Second Edition - Community Version (ABC-2-C): Hyperactivity
Time frame: Baseline and Week 52
Change From Baseline in (ABC-2-C): Irritability
Time frame: Baseline and Week 52
Change From Baseline in Vineland Adaptive Behavior Scale-3 (Vineland-3): Receptive Communication Domain Raw Score
Time frame: Baseline and Week 52
Change From Baseline in Vineland-3: Daily Living Skills, Personal Domain Raw Score
Time frame: Baseline and Week 52
Change From Baseline in (Bayley-4): Fine Motor Domain Raw Score Without Caregiver Input
Time frame: Baseline and Week 52
Change From Baseline in Observer-Reported Communication Ability (ORCA): Overall Emerging and Mastery T Score
Time frame: Baseline and Week 52
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2026.
- Individual participant dataSharing planned: Yes. Ionis may share anonymized individual participant data, aggregated clinical data, and other types of data that support the results in this study. Data requests from qualified researchers will be considered once all three of the following criteria are met: (1) 12 months from marketing approval of the study drug in both the United States and European Union; (2) 18 months from conclusion of the study; and (3) 6 months from publication of study article. Access would be via a secure environment and is contingent upon approval of a research proposal and entry into an appropriate data use agreement. Requests to access data can be submitted via the website https://vivli.org/ourmember/ionis/.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing obudanersen in people with Angelman Syndrome, run by Ionis Pharmaceuticals, Inc. at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ionis Pharmaceuticals, Inc. ((844) 373-1141, Champion@clinicaltrialmedia.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change From Baseline in Performance on the Expressive Communication Domain Raw Score Without Caregiver Input of the Bayley Scales for Infant and Toddler Development-4 (Bayley-4) in Cohort 1 (time frame: Baseline and Week 52). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Oct 2026.