MPS IIPhase 3NCT07344376
An Extension Study to Assess the Long-term Safety and Efficacy of Hunterase (Idursulfase Beta)
A Phase 3 study testing Hunterase in people with MPS II and Hunter Syndrome (MPS II), run by GC Biopharma Corp at 1 site in South Korea.
Trial summary
The objective of this study is to assess the long-term safety and efficacy of Hunterase for approximately 1 year in subjects who completed the end of study (EOS) visit (Visit 54) tests in the Phase 3 Hunterase study and patients who received Hunterase for more than 6 months Read more about this study
- Who is it for?
- Any age, men only
- Conditions the study is for
- MPS II, Hunter Syndrome (MPS II), Hunter Syndrome
- What is being tested?
- Hunterase
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteSouth Korea
- Study dates
- 23 May 2018to 30 Dec 2022
- Phase
- Phase 3
- Are there results?
- None posted in the registry
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 Any age
- Men only
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Subject diagnosed with Hunter syndrome (MPS II) who completed activities at the EOS visit (Visit 54) in the GC1111_P3 study
- (Subject who did not participate in the GC1111_P3 study) Subject diagnosed with Hunter syndrome (MPS II) who received Hunterase for more than 6 months
- (Subjects who did not participate in the GC1111_P3 study) Males aged ≥ 5
- Informed consent form voluntarily signed by the subject or by a legally acceptable representative
- Subject who agrees to use contraception
Who cannot join
- Subject with hypersensitivity to any of the ingredients of the investigational product
- Subject impossible to perform follow-up observation of the safety
- Subject who received the treatment with another investigational product within 14 days prior to the start of study drug
- Subject who plans to be treated with another investigational product during the study period
- Subject who has history of tracheostomy, bone marrow transplant, or cord blood transplant
- Any other inappropriate conditions for study participation at the investigator's discretion
Trial locations and contacts
1 site in 1 country.
About this study
Official title: An Extension Study to Assess the Long-term Safety and Efficacy of Hunterase (Idursulfase Beta) in Patients With Hunter Syndrome
The objective of this study is to assess the long-term safety and efficacy of Hunterase for approximately 1 year in subjects who completed the end of study (EOS) visit (Visit 54) tests in the Phase 3 Hunterase study and patients who received Hunterase for more than 6 months
- Conditions
- MPS II, Hunter Syndrome (MPS II), Hunter Syndrome, Hunterase, GC1111
- Being tested
- Hunterase
- Keywords
- Hunterase, GC1111, GC Biopharma, Long-term study, extension study
- Medical subject headings
- Sudden Infant Death, Mucopolysaccharidosis II
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HunteraseDrug
Also called GC1111
0.5mg/kg weekly IV administration
| Study group | Role | What they receive |
|---|---|---|
| Hunterase | Other | Single arm Receives: Drug: Hunterase |
What is being measured
The primary outcome is the main question the study is designed to answer.
Laboratory tests (CBC, Chemistry, Urinanalysis)
Abnormality of Laboratory tests results
Measured: Every visit until 12months
Physical examination
Abnormality of physical examination
Measured: Every visit until 12months
Adverse Event
occurence, grade
Measured: Every visit until 12months
Electrocardiography
Abnormality of ECG results
Measured: Every 6 months until 12months
Secondary outcomes (2)
6-minute walk test
Mean, Change and percent change of 6-minute walk test
Measured: Every 4months until 12months
Urine GAG (Heparan sulfate, Dermatan sulfate)
Mean, Change and percent change of Urine HS/DS
Measured: Every visit until 12months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jan 2026
- Study start23 May 2018
- Primary completion30 Dec 2022
- Study completion30 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for MPS IIStudies of the same condition, open and under way.
- More trials run by GC Biopharma CorpThe 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
- Model description
- Phase 3 Extension study
- Masking
- None (open label)
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- GC Biopharma Corp
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Samsung Medical Center
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07344376
- Sponsor's protocol ID
- GC1111_P3_Ex
- Status last verified
- Nov 2025
- First submitted
- 17 Nov 2025
- Last updated
- 15 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Im M, Song A, Park H, Kim J, Kim C, Noh ES, Bae GY, Sung J, Hwang J, Ahn YJ, Kim H, Oh Y, Kim B, Cho SY. Sustained clinical benefit of idursulfase beta in mucopolysaccharidosis II: two-year experience from a phase 3 extension study including patients switched from idursulfase. Orphanet J Rare Dis. 2026 Jul 9. doi: 10.1186/s13023-026-04492-2. Online ahead of print.
PubMed 42421116
Study at a glance
From the registry record, last updated by the sponsor on 15 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Extension Study to Assess the Long-term Safety and Efficacy of Hunterase (Idursulfase Beta) in Patients With Hunter Syndrome
- ClinicalTrials.gov ID
- NCT07344376
- Acronym / sponsor ID
- GC1111_P3_Ex
- Conditions
- MPS II, Hunter Syndrome (MPS II), Hunter Syndrome, Hunterase, GC1111
- Keywords
- Hunterase, GC1111, GC Biopharma, Long-term study, extension study
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- GC Biopharma CorpIndustry (pharma, biotech, devices)
- Collaborators
- Samsung Medical Center
- Study start
- 23 May 2018 (actual)
- Primary completion
- 30 Dec 2022 (actual)
- Study completion
- 30 Dec 2022 (actual)
- First posted
- 15 Jan 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 objective of this study is to assess the long-term safety and efficacy of Hunterase for approximately 1 year in subjects who completed the end of study (EOS) visit (Visit 54) tests in the Phase 3 Hunterase study and patients who received Hunterase for more than 6 months
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Phase 3 Extension study
| Arm | Type | Receives |
|---|---|---|
| Hunterase | Other | Drug: HunteraseSingle arm |
Who may qualify
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (5 listed)
- Subject diagnosed with Hunter syndrome (MPS II) who completed activities at the EOS visit (Visit 54) in the GC1111_P3 study
- (Subject who did not participate in the GC1111_P3 study) Subject diagnosed with Hunter syndrome (MPS II) who received Hunterase for more than 6 months
- (Subjects who did not participate in the GC1111_P3 study) Males aged ≥ 5
- Informed consent form voluntarily signed by the subject or by a legally acceptable representative
- Subject who agrees to use contraception
Key exclusion criteria (6 listed)
- Subject with hypersensitivity to any of the ingredients of the investigational product
- Subject impossible to perform follow-up observation of the safety
- Subject who received the treatment with another investigational product within 14 days prior to the start of study drug
- Subject who plans to be treated with another investigational product during the study period
- Subject who has history of tracheostomy, bone marrow transplant, or cord blood transplant
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 |
|---|---|---|
| HunteraseAlso: GC11110.5mg/kg weekly IV administration | Drug | Hunterase |
Primary outcome
Laboratory tests (CBC, Chemistry, Urinanalysis)
Time frame: Every visit until 12months
Abnormality of Laboratory tests results
Physical examination
Time frame: Every visit until 12months
Abnormality of physical examination
Adverse Event
Time frame: Every visit until 12months
occurence, grade
Electrocardiography
Time frame: Every 6 months until 12months
Abnormality of ECG results
2 secondary outcomes
6-minute walk test
Time frame: Every 4months until 12months
Urine GAG (Heparan sulfate, Dermatan sulfate)
Time frame: Every visit until 12months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jan 2026.
- Derived from this study: PubMed 42421116Im M, Song A, Park H, Kim J, Kim C, Noh ES, Bae GY, Sung J, Hwang J, Ahn YJ, Kim H, Oh Y, Kim B, Cho SY. Sustained clinical benefit of idursulfase beta in mucopolysaccharidosis II: two-year experience from a phase 3 extension study including patients switched from idursulfase. Orphanet J Rare Dis. 2026 Jul 9. doi: 10.1186/s13023-026-04492-2. Online ahead of print.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
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 Hunterase in people with MPS II and Hunter Syndrome (MPS II), run by GC Biopharma Corp at 1 site in South Korea.
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 5 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: finished, as of the sponsor's last update on 15 Jan 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 South Korea. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Laboratory tests (CBC, Chemistry, Urinanalysis) (time frame: Every visit until 12months). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07344376, which also lists 1 linked publication.
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 15 Jan 2026.