By InvitationPhase 3

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

United States, Argentina, Brazil80 participantsStarted 2023-02-22

Plain-language summary

An extension of Global Phase III open-label, multicenter designed to evaluate the Long-term safety and efficacy of study drug for the treatment of the MPS II.

Who can participate

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. 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 before being administered the study medication of that respective visit, and in the opinion of the principal investigator there are no safety concerns.
. 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.
. 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

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

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

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

Timeframe: [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

Timeframe: [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 VABS-II from each subject's first administration of JR-141 throughout the Parent Study (JR-141-GS31) or this study

Timeframe: [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 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

Timeframe: [B-1: Week 78, 105, 157, 209, 261] [B-2: Week 78, 105, 131, 157, 209, 261]

Trial details

NCT IDNCT05594992

SponsorJCR Pharmaceuticals Co., Ltd.

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2028-02-28

View on ClinicalTrials.gov More Mucopolysaccharidosis II trials