Safety, Pharmacokinetics, and Pharmacodynamics/Efficacy of SBC-103 in Mucopolysaccharidosis III, Type B (MPS IIIB)

A Phase I/II Open Label Study in MPS IIIB Subjects to Investigate the Safety, Pharmacokinetics, and Pharmacodynamics/Efficacy of SBC-103 Administered Intravenously

Study to evaluate the safety and tolerability of intravenous (IV) administration of SBC-103 in participants with mucopolysaccharidosis III, type B (MPS IIIB, Sanfilippo B) with evaluable signs or symptoms of developmental delay.

This study was designed as a 3-part study to evaluate the safety and tolerability of IV administration of SBC-103. Participants enrolled in Part A (0.3, 1.0, or 3.0 milligrams [mg] per kilogram [kg] of SBC-103 administered every other week [QOW] for 24 consecutive weeks). Participants who completed Part A were eligible for Part B (an increase to 1.0 or 3.0 mg/kg QOW). Participants who completed Part B were eligible for Part C (5.0 and/or 10.0 mg/kg to continue through Week156; no participants received both 5.0 and 10.0 mg/kg). Due to the early termination of the SBC-103 development program, including this study, all participants withdrew from Part C at the sponsor's decision. As a result of the early termination of this program, this report provides only safety data.

Key Inclusion Criteria:

• A participant was greater than or equal to 2 years of age but less than 12 years of age at the time of informed consent.
• Definitive diagnosis of MPS IIIB.
• Documented developmental delay.

Key Exclusion Criteria:

• Received treatment with gene therapy at any time.
• Previous hematopoietic stem cell or bone marrow transplant.
• Had any internal or non-removable external metal items that presented a safety risk for study assessments that utilized magnetic fields, or any other medical condition or circumstance in which magnetic resonance imaging was contraindicated according to local institutional policy.
• Known hypersensitivity to eggs.