NCT05494593

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

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

• Status: Withdrawn
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 0 (actual)
• Sponsor: Takeda · Industry
• Sex: Male
• Age: 6 Years
• Healthy volunteers: Not accepted

Summary

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).

Conditions

• Mucopolysaccharidosis (MPS)
• Hunter Syndrome

Interventions

Type	Name	Description
DRUG	ELAPRASE	Participants will receive 0.5 milligram per kilogram (mg/kg) of body weight of ELAPRASE, intravenous, infusion for 104 weeks.
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.
DRUG	Methotrexate	Participants will receive 0.4 mg/kg of methotrexate by mouth (PO) 3 times per week for 5 weeks in each cycle.
DRUG	Intravenous Immunoglobulin (IVIG)	Participants will receive 500 mg/kg of IVIG every 4 weeks in 5-week cycle.

Timeline

• Start date: 2023-02-28
• Primary completion: 2025-08-29
• Completion: 2025-08-29
• First posted: 2022-08-10
• Last updated: 2025-12-09

Locations

8 sites across 1 country: United States

Regulatory

• FDA-regulated drug study