Conditions: Mucopolysaccharidosis I
Keywords: MPS I, Mucopolysaccharidosis, Hurler syndrome
Allocation: RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 7
Healthy volunteers: no

Brief summary:
The purpose of this study is to see if treatment with an antigen-specific immunosuppressive can decrease or stop an antibody response to laronidase (Aldurazyme®) during enzyme replacement therapy with laronidase in severe Mucopolysaccharidosis I (MPS I) participants.

Detailed description:

Arms:
arm 1: Tolerance Induction Period (TIP): Cyclosporine A (CsA) starting at 5 milligram per kilogram (mg/kg) orally three times daily until the target trough concentration of at least 350 nanogram per milliliter (ng/mL) (preferably 400 ng/mL) achieved along with azathioprine (Aza) 2.5 mg/kg/day orally. Once target CsA trough level achieved and maintained for at least 1 week, participants received laronidase 0.058 mg/kg (low-dose) once weekly intravenous (IV) infusion (starting from Day 1) up to Week 12. CsA and Aza were gradually discontinued. Immune Challenge Period (ICP): following TIP, laronidase dose increased to 0.12 mg/kg once weekly IV infusion for 1 week followed by 0.25 mg/kg once weekly IV infusion for 1 week and then 0.58 mg/kg (full-dose) once weekly IV infusion up to Week 39. arm 2: TIP: CsA starting at 6.7 mg/kg orally three times daily until the target trough concentration of at least 350 ng/mL (preferably 400 ng/mL) achieved along with Aza 5 mg/kg orally every other day. Once target CsA trough level achieved and maintained for at least 1 week, participants received laronidase 0.058 mg/kg (low-dose) once weekly IV infusion (starting from Day 1) up to Week 18. CsA and Aza were gradually discontinued. ICP: following TIP, laronidase dose increased to 0.12 mg/kg once weekly IV infusion for 1 week followed by 0.25 mg/kg once weekly IV infusion for 1 week and then 0.58 mg/kg (full-dose) once weekly IV infusion up to Week 45.

Interventions: intervention 1: Laronidase intervention 2: Cyclosporine A (CsA) intervention 3: Azathioprine (Aza)
Intervention descriptions: intervention 1: 0.058 mg/kg - 0.58 mg/kg IV infusion weekly. intervention 2: Orally three times daily. intervention 3: Orally either every day for Cohort 1 or every other day for Cohort 2.

Protocol document: