An Extension Study of JR-141 to Evaluate the Long-term Safety and Efficacy in Mucopolysaccharidosis Type II (Hunter Syndrome) Subjects

• Register: ClinicalTrials.gov
• Last refreshed on: 26 May 2025
• Main ID: NCT05594992
• Date of registration: 06/10/2022
• Prospective Registration: Yes
• Primary sponsor: JCR Pharmaceuticals Co., Ltd.
• Public title: An Extension Study of JR-141 to Evaluate the Long-term Safety and Efficacy in Mucopolysaccharidosis Type II (Hunter Syndrome) Subjects
• Scientific title: An Extension Study of JR-141 to Evaluate the Long-term Safety and Efficacy in Mucopolysaccharidosis Type II (Hunter Syndrome) Subjects
• Date of first enrolment: February 22, 2023
• Target sample size: 80
• Recruitment status: Enrolling by invitation
• URL: https://clinicaltrials.gov/ct2/show/NCT05594992
• Study type: Interventional
• Study design: Allocation: N/A. Intervention model: Single Group Assignment. Primary purpose: Treatment. Masking: None (Open Label).
• Phase: Phase 3

Countries of recruitment

Argentina, Brazil, France, Germany, Italy, Spain, United States

Key inclusion & exclusion criteria

Inclusion Criteria:

1. A subject who participated in the Parent Study (JR-141-GS31) and completed the
assessments at Week 105 in Cohort A or Week 53 in Cohort B, and in the opinion of
the principal investigator has no safety concerns to enter this study.

2. A subject from whom an IRB or IEC-approved written informed consent can be obtained,
which is voluntarily signed. If the subject is aged under 18 years (aged under 16
years in the UK) at the time of enrollment or willingness to participate in the
study cannot be confirmed due to MPS II-related intellectual disability, the
subject's legally acceptable representative (e.g., his parents or guardians) may
sign the ICF on behalf of the subject. Written informed assent should be obtained
from the subject, wherever possible.

3. Female subject of child bearing potential or male subject whose female partner is of
child-bearing potential, i.e., fertile, following menarche and until becoming
post-menopausal unless permanently sterile, agrees to use a medically accepted,
highly effective method of contraception from the time of signing the ICF. The
method of contraception must be used during the study until 90 days for male
subjects, and 30 days for female subjects after the final study drug administration.

Exclusion Criteria:

1. A subject who has received gene therapy treatment at any point.

2. Refusal to sign the ICF.

3. A subject who is judged by the principal investigator or sub-investigator as being
unable to undergo lumbar puncture, including those who have difficulties in
attaining the required position for lumbar puncture due to joint contracture or
those who are likely to experience breathing difficulties during the lumbar puncture
process.

4. A subject who changed treatment from JR-141 to idursulfase during the treatment
period in the Parent Study (JR-141-GS31).

5. A subject who is unable to comply with the protocol (e.g., is unable to return for
safety evaluations or is otherwise unlikely to complete the study) as determined by
the principal investigator or sub-investigator.

6. A subject who is judged by the principal investigator or sub-investigator to be
ineligible to participate in the study due to a history of serious drug allergy or
sensitivity including to anesthesia or hypersensitivity to any component of JR-141.

7. A subject who has a known or suspected local or general chronic infection or is at
risk of abnormal bleeding due to medical conditions* or therapies the investigator
classifies as causing the patient to be ineligible to participate in the study.

8. A subject who otherwise is judged by the principal investigator or sub-investigator
to be ineligible to participate in the study .

9. [Only in France] Persons deprived of their liberty by a judicial or administrative
decision, according to article L. 1121-6 of the Public Health Code (Code de la santé
publique, CSP) adults who are the subject of a measure of legal protection or unable
to express their consent according to article L. 1121-8 of the CSP.

Medical Conditions:

1. Clinically significant multiple or severe drug allergies, intolerance to topical
corticosteroids, or severe post-treatment hypersensitivity reactions (including, but
not limited to, erythema multiforme major, linear IgA, toxic epidermal necrolysis,
and exfoliative dermatitis)

2. Evidence or history of significant active bleeding or coagulation disorder or use of
non steroidal anti-inflammatory drugs or other drugs that affect coagulation or
platelet function within 14 days prior to lumbar catheter insertion

3. Allergy to lidocaine (Xylocaine®) or its derivatives


Age minimum: N/A
Age maximum: N/A
Gender: All

Health Condition(s) or Problem(s) studied

Mucopolysaccharidosis II

Intervention(s)

Drug: JR-141

Primary Outcome(s)

Change in neurocognitive testing, calculated by the VABS-II from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study [Time Frame: [A-1: Week 157, 209, 261] [A-2: Week 131, 157, 183, 209, 261] [A-3: Week 131, 157, 209, 261 ] [A-4: Week 131, 157, 183, 235, 287][B-1: Week 78, 105, 157, 209, 261] [B-2: Week 78, 105, 131, 157, 209, 261]]

Change in heparan sulfate concentrations in cerebrospinal fluid from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study to each time point [Time Frame: [A-1, A-2, A-3: Week 157, 209, 261] [A-4: Week 131, 183, 235, 287]]

Change in neurocognitive testing, calculated by the BSID-III or KABC-II, from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study [Time Frame: [A-1: Week 157, 209, 261] [A-2: Week 131, 157, 183, 209, 261] [A-3: Week 131, 157, 209, 261 ] [A-4: Week 131, 157, 183, 235, 287]]

Change in neurocognitive testing, calculated by the Wechsler, from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study [Time Frame: [B-1: Week 78, 105, 157, 209, 261] [B-2: Week 78, 105, 131, 157, 209, 261]]

Secondary Outcome(s)

Change in 6-minute walk distance from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study [Time Frame: [B-1: Week 105, 157, 209, 261] [B-2: Week 78, 105, 157, 209, 261]]

Change in liver and spleen volume from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study [Time Frame: [A-1, A-3: Week 157, 209, 261] [A-2: Week 131, 157, 209, 261] [A-4: Week 131, 183, 235, 287] [B-1: Week 105, 157, 209, 261] [B-2: Week 78, 105, 157, 209, 261]]

Secondary ID(s)

JR-141-GS32

Source(s) of Monetary Support

Please refer to primary and secondary sponsors