JR-141 for Hunter Syndrome

Enrolling by invitation at 8 trial locations

Overseen By JCR Pharmaceuticals Co., Ltd.

Age: Any Age

Sex: Any

Trial Phase: Phase 3

Sponsor: JCR Pharmaceuticals Co., Ltd.

Must not be taking: Gene therapy, NSAIDs

Disqualifiers: Gene therapy, Drug allergy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

Duration: 2 years

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to study the safety and effectiveness of JR-141, a treatment for Hunter Syndrome, a genetic disorder affecting metabolism. The research focuses on long-term outcomes for participants using this treatment. Participants should have previously taken part in an earlier study with JR-141 and completed specific assessments without switching treatments during that study. Individuals with Hunter Syndrome who meet these conditions from a prior study might be suitable candidates for this trial. As a Phase 3 trial, this study represents the final step before FDA approval, offering a chance to contribute to a potentially groundbreaking treatment.

Do I need to stop my current medications for the trial?

The trial information does not specify if you need to stop taking your current medications. However, if you are using drugs that affect bleeding or platelet function, you should stop them 14 days before a lumbar catheter insertion.

Is there any evidence suggesting that JR-141 is likely to be safe for humans?

Research has shown that JR-141, also known as pabinafusp alfa, is safe for treating Hunter Syndrome. Previous studies found that this treatment helps with both physical and brain-related symptoms. Importantly, data collected over five years showed ongoing benefits without serious safety issues.

The treatment uses a new type of enzyme that can pass through the blood-brain barrier, a protective layer around the brain. This capability is crucial for addressing brain-related symptoms, and the safety results have been positive. No major side effects were reported in these studies, suggesting that JR-141 is generally well-tolerated by patients.

Overall, the research indicates that JR-141 has a good safety record and could be a promising option for people with Hunter Syndrome. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for Hunter Syndrome?

Unlike the standard enzyme replacement therapies for Hunter Syndrome, which are typically administered intravenously, JR-141 is exciting because it utilizes a unique fusion protein that crosses the blood-brain barrier. This innovative mechanism allows the treatment to potentially address neurological symptoms of the condition, which standard treatments don't effectively target. Researchers are particularly excited about JR-141's ability to reach the central nervous system, offering hope for improved cognitive outcomes in patients.

What evidence suggests that JR-141 might be an effective treatment for Hunter Syndrome?

Research has shown that JR-141, also known as pabinafusp alfa, holds promise for treating Hunter syndrome. This special enzyme can enter the brain, a feat many drugs cannot achieve. Long-term studies indicate that it aids both brain and body symptoms of the disease. Specifically, after five years, patients using JR-141 experienced improvements in thinking skills and physical health. This suggests that JR-141 can likely help manage Hunter syndrome by addressing symptoms affecting both the brain and the body. ^{1 2 3 4 6}

Are You a Good Fit for This Trial?

This trial is for individuals with Hunter Syndrome who previously participated in the JR-141-GS31 study without safety concerns. They must be able to give consent or have a legal representative do so, agree to use effective contraception, and be capable of following the study protocol.

Inclusion Criteria

I agree to use effective birth control during and up to 90 days after the study for men, 30 days for women.

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

I (or my legal guardian) have signed the consent form to participate in the study.

Exclusion Criteria

I switched from JR-141 to idursulfase in a previous study.

[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

Refusal to sign the ICF

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive JR-141 2.0 mg/kg/week for the treatment of MPS II

2 years

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Open-label extension

An extension study to evaluate the long-term safety and efficacy of JR-141

Long-term

What Are the Treatments Tested in This Trial?

Interventions

• JR-141

Trial Overview The trial is an extension study testing the long-term safety and effectiveness of JR-141 in treating Mucopolysaccharidosis Type II (Hunter Syndrome). It's open-label and multicenter, meaning everyone knows what treatment they're getting and it's conducted at multiple sites.

How Is the Trial Designed?

Group I: JR-141 2.0 mg/kg/week Experimental Treatment 1 Intervention

JR-141 is already approved in Japan for the following indications:

Approved in Japan as IZCARGO for:

• Mucopolysaccharidosis type II (MPS II)
• Hunter syndrome

Who Is Running the Clinical Trial?

JCR Pharmaceuticals Co., Ltd.

Lead Sponsor

Trials

13

Recruited

320+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7854283/

A Phase 2/3 Trial of Pabinafusp Alfa, IDS Fused with Anti ... Pabinafusp alfa (JR-141) is a novel enzyme drug that crosses the blood-brain barrier by transcytosis via transferrin receptors.

2. biospace.com biospace.com/press-releases/jcr-pharmaceuticals-presents-long-term-clinical-data-on-pabinafusp-alfa-for-the-treatment-of-mucopolysaccharidosis-type-ii-mps-ii-at-iciem-2025

JCR Pharmaceuticals Presents Long-Term Clinical Data ... Key findings included five-year clinical data demonstrating sustained neurocognitive and somatic benefits of pabinafusp alfa (JR-141) in ...

3. clinicaltrials.gov clinicaltrials.gov/study/NCT04573023

NCT04573023 | A Phase III Study of JR-141 in Patients ... A Global Phase III multicenter, randomized, assessor-blinded, active-controlled designed to evaluate safety and efficacy of study drug for the treatment of ...

4. firstwordpharma.com firstwordpharma.com/story/5977574

JCR Pharmaceuticals Announces the Achievement of ... This novel mechanism of action is expected to make JR-141 effective against the central nervous system (CNS) symptoms of Hunter syndrome. In non ...

5. checkrare.com checkrare.com/efficacy-and-safety-of-pabinafusp-alfa-in-mps-ii-hunter-syndrome/

Efficacy and Safety of Pabinafusp-Alfa in MPS-II (Hunter ... Previous clinical trials have provided positive results suggesting pabinafusp alfa is efficacious against both somatic and neurological symptoms.

6. finance.yahoo.com finance.yahoo.com/news/jcr-pharmaceuticals-presents-long-term-170300633.html

JCR Pharmaceuticals Presents Long-Term Clinical Data ... Key findings included five-year clinical data demonstrating sustained neurocognitive and somatic benefits of pabinafusp alfa (JR-141) in ...