Treatment for young boys with Hunter Syndrome using ELAPRASE

An Open-label, Multicenter, Phase 4 Study to Assess the Effects of a Prophylactic Immune Tolerizing Regimen in MPS II Treatment-Naïve Patients Planned to Receive ELAPRASE Who Are at Risk of Developing Persistent Neutralizing Antibodies

This study is testing if a new treatment plan using ELAPRASE and other medications can help young boys with Hunter Syndrome without their bodies fighting against the treatment.

Quick facts

• Phase: Phase 4
• Study type: Interventional
• Enrollment: 5 (estimated)
• Ages: N/A to 6 Years
• Sex: Male
• Sponsor: Takeda (Industry-sponsored)
• Drugs / interventions: Rituximab, Methotrexate
• Locations: 8 sites (Phoenix, Arizona and 7 other locations)
• Trial ID: NCT05494593 on ClinicalTrials.gov

What this trial studies

This study evaluates the effectiveness of a prophylactic immune tolerizing regimen (ITR) combined with ELAPRASE treatment in treatment-naïve boys diagnosed with Hunter Syndrome. Participants will receive ELAPRASE for up to 104 weeks, starting with a 5-week cycle of Rituximab, Methotrexate, and intravenous immunoglobulin (IVIG) to prevent the development of antibodies against the treatment. The study will assess the need for additional ITR cycles at 6, 12, and 18 months after the initial treatment. The goal is to reduce the risk of immune response that could hinder the effectiveness of ELAPRASE.

Who should consider this trial

Good fit: Ideal candidates for this study are male children under 6 years old who are treatment-naïve and have a documented diagnosis of Hunter Syndrome with specific genetic and enzyme activity criteria.

Not a fit: Patients who are older than 6 years or have previously received ELAPRASE treatment will not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could significantly improve treatment outcomes for boys with Hunter Syndrome by minimizing immune responses that reduce the efficacy of ELAPRASE.

How similar studies have performed: While this specific approach is novel, similar studies have shown promise in managing immune responses in enzyme replacement therapies.

Eligibility criteria

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.

Where this trial is running

Phoenix, Arizona and 7 other locations

• Phoenix Childrens Hospital — Phoenix, Arizona, United States (Recruiting)
• Children's Hospital and Research Center at Oakland — Oakland, California, United States (Recruiting)
• Rady Childrens Hospital San Diego - PIN — San Diego, California, United States (Recruiting)
• The Lundquist Institute for BioMedical Innovation at Harbor-UCLA Medical Center — Torrance, California, United States (Recruiting)
• Ann and Robert H Lurie Childrens Hospital of Chicago — Chicago, Illinois, United States (Recruiting)
• Children's Hospitals and Clinics of Minnesota — Minneapolis, Minnesota, United States (Recruiting)
• NewYork-Presbyterian Morgan Stanley Children's Hospital — New York, New York, United States (Recruiting)
• The Cleveland Clinic Foundation — Twinsburg, Ohio, United States (Recruiting)

Study contacts

• Study coordinator: Takeda Contact

Conditions Mucopolysaccharidosis; Hunter Syndrome