BioMarin reports Phase I/II data for BMN 250 in mucopolysaccharidosis IIIB

In September, BioMarin Pharmaceutical Inc. (NASDAQ:BMRN) reported interim data from 3 patients with mucopolysaccharidosis IIIB (MPS IIIB, Sanfilippo type B syndrome) in the dose-escalation portion of the Phase I/II BMN 250-201 trial showing that intracerebroventricular (ICV) BMN 250 led to stabilization or improvement in cognitive Development Quotient (DQ), a co-primary endpoint, in 2 patients compared to baseline. In all 3 patients, BMN 250 decreased liver size and reduced cerebrospinal fluid (CSF) heparan sulfate levels. BMN 250 was well tolerated, with ICV infection, site erythema, CSF pleocytosis and blood clot in CSF reported as the most common device-related adverse events. The most common treatment-related adverse events were pyrexia/fever and bradycardia.

The open-label, international trial is evaluating safety and change in DQ as its primary endpoints. Secondary endpoints include pharmacokinetics and impact on brain structure assessed by MRI. In the dose-escalation portion, patients received 30, 100 and 300 mg BMN 250 over 9-12 months. The trial's second portion enrolled patients from the BMN 250-901 observational study as well as patients from the dose-escalation portion of BMN 250-201 to receive once-weekly 300 mg BMN 250. Data were presented at the Inborn Errors of Metabolism meeting in Rio de Janeiro...