Clinical Data
Researchers presented preliminary results for volumetric brain MRI and neurocognitive assessments performed after 24 weeks of IV SBC-103 at 0.3, 1, or 3 mg/kg every other week (QOW). MRI scans for those dosed at 3 mg/kg showed that 3 out of 4 patients had an increase or no change (-1% to +1%) in CGM volume compared to baseline suggesting a potential for disease stabilization at this dose. In the 1 mg/kg group and 0.3 mg/kg group, MRI scans showed that 2 out of 3 and 0 out of 3 patients respectively had an increase or no change in CGM volume compared to baseline. In the neurocognitive assessments for the 3 mg/kg group, 3 out of 4 patients had an increase in both mental age equivalent (AEq) and developmental quotient (DQ) compared to baseline. For the 1 mg/kg group, 2 out of 4 patients had an increase in both AEq and DQ compared to baseline, and for 0.3 mg/kg group, 1 out of 3 patients had an increase in both AEq and DQ compared to baseline. Overall, response profiles among the 3 mg/kg treatment groups suggest a potential dose effect as compared to the 0.3 mg/kg and 1 mg/kg groups.1

Eleven children with MPS IIIB (ages 2 years to 10 years at study entry) were enrolled in this first-in-human study, which included three parallel dosing groups of intravenous SBC-103 (0.3, 1.0 and 3.0 mg/kg QOW). The primary endpoint of the ongoing trial is safety and tolerability, and key secondary endpoints presented at MPS 2016 include effect of SBC-103 on total HS levels in cerebrospinal fluid (CSF) and serum, brain structures (MRI) and neurocognitive status, and pharmacokinetic (PK) profile of SBC-103.


During 24 weeks of treatment with SBC-103 at the highest dose of 3 mg/kg, most adverse events (AEs) were mild in severity and no patient discontinued the study. Two patients experienced a total of four serious AEs (bacteremia, pyrexia, staphylococcal bacteremia, and cyanosis [pre-treatment]) that were deemed not related to SBC-103. Seven infusion-associated reactions occurred in three patients (pyrexia, chills, hypertension, and tachycardia).1As previously presented at the 12th Annual WORLDSymposiumTM, patients treated with SBC-103 had a 26.2 percent mean reduction from baseline in total HS levels in CSF at 24 weeks in the highest dose studied (3 mg/kg QOW). Additionally, at week 24, patients in the 0.3 mg/kg and 1.0 mg/kg groups had a 10.9 percent mean increase and a 0.4 percent mean decrease in HS CSF, respectively. HS reduction in CSF was linearly correlated with SBC-103 serum PK exposures. Total change from baseline in serum HS was -39.6 percent, -53.9 percent and -40.5 percent for 0.3 mg/kg, 1 mg/kg, and 3 mg/kg groups, respectively.8