A Study of ELAPRASE in Treatment-naïve Participants With Hunter Syndrome (Mucopolysaccharidosis [MPS] II)

NCT ID: NCT05494593

Last Updated: 2025-12-09

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

WITHDRAWN

Clinical Phase

PHASE4

Study Classification

INTERVENTIONAL

Study Start Date

2023-02-28

Study Completion Date

2025-08-29

Brief Summary

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The main aim of this study is to evaluate the ability of a prophylactic immune tolerizing regimen (ITR) to prevent or reduce the development of high titer anti-idursulfase antibodies in treatment-naïve participants with Hunter syndrome.

In this open label, single arm study, all participants will receive ELAPRASE treatment and a prophylactic ITR.

Participants will be treated with ELAPRASE for up to 104 weeks. The prophylactic ITR will start 1 day prior to the start of ELAPRASE. The prophylactic ITR will consist of a 5-week cycle of: Rituximab (intravenously \[IV\], weekly for 4 weeks); Methotrexate (oral, 3 times per week for 5 weeks) and intravenous immunoglobulin (IVIG) (IV, every 4 weeks of the cycle).

Following the completion of 1 cycle, an assessment will be made at Month 6, 12, and 18 regarding the need for administering another 5-week cycle of the ITR.

Participants will be in the study for approximately 112 weeks (including 6 weeks for screening, up to 104 weeks for treatment, and 2 weeks for follow-up).

Detailed Description

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Conditions

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Mucopolysaccharidosis (MPS) Hunter Syndrome

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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ITR + ELAPRASE

Participants will receive prophylactic ITR which consist of rituximab, methotrexate and IVIG in a 5-week cycle. Following the completion of 1 cycle and at the Month 6, 12, and 18 study visits, an assessment will be made regarding the need for administering another 5-week cycle of the ITR depending on the trend of the participants anti-idursulfase antibody titers and lymphocyte quantitation and CD19 percent (%) recovery.

Elaprase treatment (IV, weekly) will start 1 day after the initiation of the first cycle of ITR and continue for 104 weeks.

The dose of ELAPRASE will be calculated based on the participant's weight at each visit.

Group Type EXPERIMENTAL

ELAPRASE

Intervention Type DRUG

Participants will receive 0.5 milligram per kilogram (mg/kg) of body weight of ELAPRASE, intravenous, infusion for 104 weeks.

Rituximab

Intervention Type DRUG

Participants will receive 375 milligram per square meter per dose (mg/m\^2/dose) of intravenous rituximab weekly for 4 weeks in 5-week cycle.

Methotrexate

Intervention Type DRUG

Participants will receive 0.4 mg/kg of methotrexate by mouth (PO) 3 times per week for 5 weeks in each cycle.

Intravenous Immunoglobulin (IVIG)

Intervention Type DRUG

Participants will receive 500 mg/kg of IVIG every 4 weeks in 5-week cycle.

Interventions

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ELAPRASE

Participants will receive 0.5 milligram per kilogram (mg/kg) of body weight of ELAPRASE, intravenous, infusion for 104 weeks.

Intervention Type DRUG

Rituximab

Participants will receive 375 milligram per square meter per dose (mg/m\^2/dose) of intravenous rituximab weekly for 4 weeks in 5-week cycle.

Intervention Type DRUG

Methotrexate

Participants will receive 0.4 mg/kg of methotrexate by mouth (PO) 3 times per week for 5 weeks in each cycle.

Intervention Type DRUG

Intravenous Immunoglobulin (IVIG)

Participants will receive 500 mg/kg of IVIG every 4 weeks in 5-week cycle.

Intervention Type DRUG

Other Intervention Names

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Idursulfase

Eligibility Criteria

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Inclusion Criteria

* Participant is male.
* Participant is ELAPRASE-naïve at study entry.
* Participant must have a documented diagnosis of MPS II. The following combination will be accepted as diagnostic of MPS II:

* Participant has a deficiency in iduronate-2-sulfatase (I2S) enzyme activity of less than or equal to (\<=) 10 percent (%) of the lower limit of the normal range as measured in plasma, fibroblasts, or leukocytes (based on the reference laboratory's normal range). The participant has a normal enzyme activity level of at least 1 other sulfatase as measured in plasma, fibroblasts, or leukocytes (based on the reference laboratory's normal range).
* Participant has a documented mutation in the IDS gene; additionally, participants must have a severe mutation (example, large deletion or complex gene rearrangement), which is predicted to lead to development of a persistent anti-idursulfase antibody response.
* Participant will be less than (\<) 6 years of age at enrollment.
* Participant has a negative test result for serum anti-idursulfase antibodies.

Exclusion Criteria

* Participant has received treatment with any investigational drug within the 30 days prior to study entry.
* Participant has received or is receiving treatment with idursulfase-IT.
* Participant has received growth hormones, a cord blood infusion, or a bone marrow transplant at any time.
* Participant has received blood product transfusions within 90 days prior to screening.
* Participant is unable to comply with the protocol as determined by the investigator.
* Participant has known or suspected intolerance or hypersensitivity to the investigational product(s), closely related compounds, or any of the stated ingredients, including the prophylactic ITR.
* Participant has current or recurrent disease that could affect the action, absorption, or disposition of the investigational product, or clinical or laboratory assessments.
* Participant has current or relevant history of physical or psychiatric illness, or any medical disorder that may require treatment or make the participant unlikely to fully complete the study, or any condition that presents undue risk from the investigational product or procedures.
* Participant has current use of any medication (including over-the-counter, herbal, or homeopathic preparations) that could affect (improve or worsen) the condition being studied, or could affect the action, absorption, or disposition of the investigational product(s), or clinical or laboratory assessment (Current use is defined as use within 30 days).
* Within 30 days prior to the first dose of investigational product, the participant has been enrolled in a clinical study (including vaccine studies) that, in the investigator's opinion, may impact this study.
Maximum Eligible Age

6 Years

Eligible Sex

MALE

Accepts Healthy Volunteers

No

Sponsors

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Takeda Development Center Americas, Inc.

INDUSTRY

Sponsor Role collaborator

Takeda

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Study Director

Role: STUDY_DIRECTOR

Takeda

Locations

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Phoenix Childrens Hospital

Phoenix, Arizona, United States

Site Status

Children's Hospital and Research Center at Oakland

Oakland, California, United States

Site Status

Rady Childrens Hospital San Diego - PIN

San Diego, California, United States

Site Status

The Lundquist Institute for BioMedical Innovation at Harbor-UCLA Medical Center

Torrance, California, United States

Site Status

Ann and Robert H Lurie Childrens Hospital of Chicago

Chicago, Illinois, United States

Site Status

Children's Hospitals and Clinics of Minnesota

Minneapolis, Minnesota, United States

Site Status

NewYork-Presbyterian Morgan Stanley Children's Hospital

New York, New York, United States

Site Status

The Cleveland Clinic Foundation

Twinsburg, Ohio, United States

Site Status

Countries

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United States

Related Links

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Other Identifiers

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TAK-665-4003

Identifier Type: -

Identifier Source: org_study_id

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