What is the mechanism of action of this treatment?

Hunter Syndrome, or Mucopolysaccharidosis II (MPS II), is treated primarily through Enzyme Replacement Therapy (ERT) and Gene Therapy. ERT involves infusing a synthetic version of the deficient enzyme iduronate-2-sulfatase (I2S) to help break down glycosaminoglycans (GAGs) and reduce their harmful accumulation in tissues. Gene Therapy, on the other hand, introduces a functional I2S gene into the patient's cells, potentially enabling the body to produce the enzyme naturally. These treatments are vital as they address the underlying enzyme deficiency, thereby alleviating symptoms, slowing disease progression, and significantly improving the quality of life for patients.

What side effects are associated with this type of intervention?

Hunter Syndrome, also known as Mucopolysaccharidosis II (MPS II), is commonly treated with Enzyme Replacement Therapy (ERT) or Gene Therapy. ERT, such as idursulfase, aims to replace the deficient enzyme iduronate-2-sulfatase. Common side effects of ERT include infusion-related reactions like fever, headache, rash, and hypertension. More severe reactions can include anaphylaxis. Gene therapy, which targets the underlying genetic cause, is still under investigation but may present risks such as immune responses to the viral vector used for gene delivery, potential insertional mutagenesis, and long-term effects that are not yet fully understood.

What prior FDA approvals exist?

Hunter Syndrome, or Mucopolysaccharidosis II (MPS II), has seen FDA approval for enzyme replacement therapies (ERT) such as idursulfase (brand name Elaprase). Elaprase is designed to replace the deficient iduronate-2-sulfatase enzyme in patients with MPS II, helping to reduce the accumulation of glycosaminoglycans. Gene therapy approaches are also being explored, but as of now, ERT remains the primary FDA-approved treatment for managing the symptoms and progression of Hunter Syndrome.

What other types of research exist?

Promising novel alternatives for Hunter Syndrome (MPS II) patients in 2024 include gene editing technologies such as CRISPR/Cas9, which aim to correct the genetic mutations causing the enzyme deficiency. Additionally, substrate reduction therapies (SRTs) that decrease the accumulation of glycosaminoglycans (GAGs) and small molecule chaperones that stabilize the defective enzyme are also being explored. These approaches offer potential improvements in targeting the root cause of the disease and enhancing patient outcomes.

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Enzyme Replacement Therapy

JR-141 for Hunter Syndrome

Phase 3

Recruiting

Research Sponsored by JCR Pharmaceuticals Co., Ltd.

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

Patients with confirmed diagnosis of MPS II

Timeline

Screening 3 weeks

Treatment Varies

Follow Up baseline to week 13, 26, 53, 78, 105

Awards & highlights

Study Summary

This trial is testing a new drug for MPS II, a disease that causes problems with the nervous system and organs. The trial will compare the new drug to the current standard of care to see if it is safe and effective.

Who is the study for?

This trial is for patients with Hunter Syndrome (MPS II). Eligible participants include those diagnosed with MPS II, either treatment-naïve or on stable enzyme therapy. They must agree to use effective contraception and sign consent forms. There are specific age-related cognitive criteria for two separate cohorts: Cohort A includes children aged 36-71 months with certain developmental scores, while Cohort B includes individuals aged 6 years or older with an IQ of 70 or higher.Check my eligibility

What is being tested?

The STARLIGHT Phase III trial is testing the safety and effectiveness of a drug called JR-141 compared to Idursulfase in treating MPS II. Participants will be randomly assigned to receive either JR-141 alone, JR-141 combined with Idursulfase, or only Idursulfase in a blinded manner where assessors do not know which treatment each participant receives.See study design

What are the potential side effects?

While the specific side effects of JR-141 are not listed here, similar treatments often cause reactions at injection sites, allergic responses, headaches, fever and chills. Side effects can vary from person to person based on individual health conditions.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

Select...

I have been diagnosed with MPS II.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ through study period

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~through study period

This trial's timeline: 3 weeks for screening, Varies for treatment, and through study period for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.

Primary outcome measures

Change in levels of cerebrospinal fluid heparan sulfate from baseline (Cohort A)

Change in the raw scores of cognitive testing measured from baseline (BSID-III) (Cohort A)

Secondary outcome measures

Change in the age equivalent scores of adaptive behavior measured from baseline (VABS-II) (Cohort A)

Change in the growth scores of cognitive testing measured from baseline (BSID-III) (Cohort A)

Relative change in distance walked using the 6-minute walk test from baseline to Week 53 (Cohort B)

+2 more

Other outcome measures

Absolute change in the Forced Expiratory Volume from baseline (Cohort B)

Absolute change in the Forced Vital Capacity from baseline (Cohort B)

Absolute change in the percent predicted Forced Vital Capacity from baseline (Cohort B)

+50 more

Trial Design

3Treatment groups

Experimental Treatment

Group I: administered as the standard of care: idursulfase (ELAPRASE®)Experimental Treatment1 Intervention

standard of care-controlled study

Group II: Rescue armExperimental Treatment1 Intervention

Group III: JR-141 2.0 mg/kg/weekExperimental Treatment1 Intervention

Treatment

First Studied

Drug Approval Stage

How many patients have taken this drug

JR-141

2018

Completed Phase 3

~60

Idursulfase

2012

Completed Phase 4

~160

0 / 1Eligibility criteria met

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.

Mechanism Of Action

Side Effect Profile

Prior Approvals

Other Research

Hunter Syndrome, or Mucopolysaccharidosis II (MPS II), is treated primarily through Enzyme Replacement Therapy (ERT) and Gene Therapy. ERT involves infusing a synthetic version of the deficient enzyme iduronate-2-sulfatase (I2S) to help break down glycosaminoglycans (GAGs) and reduce their harmful accumulation in tissues. Gene Therapy, on the other hand, introduces a functional I2S gene into the patient's cells, potentially enabling the body to produce the enzyme naturally. These treatments are vital as they address the underlying enzyme deficiency, thereby alleviating symptoms, slowing disease progression, and significantly improving the quality of life for patients.