Study of Intrathecal Idursulfase-IT Administered in Conjunction With Elaprase® in Pediatric Patients With Hunter Syndrome and Early Cognitive Impairment

Study HGT-HIT-094 is a multicenter study designed to determine the effect on clinical parameters of neurodevelopmental status of monthly IT administration of idursulfase-IT 10 mg for 12 months in pediatric patients with Hunter syndrome and cognitive impairment who have previously received and tolerated a minimum of 4 months of therapy with Elaprase.

Elaprase, a large molecular protein, is not expected to cross the blood brain barrier when administered intravenously. A revised formulation of idursulfase, idursulfase-IT, that differs from that of the intravenous (IV) formulation, Elaprase, has been developed to be suitable for delivery into the cerebrospinal fluid (CSF) via intrathecal administration. Mucopolysaccharidosis II (MPS II) is a rare, X-linked, inherited disease that affects males nearly exclusively. The disease is caused by the absence of, or deficiency in, the activity of the lysosomal enzyme, iduronate-2-sulfatase (I2S) which acts to cleave O-linked sulfate moieties from the glycosaminoglycan (GAG) molecules dermatan sulfate and heparan sulfate. Study HGT-HIT-094 is a controlled, randomized, two-arm, open-label, assessor-blinded, multicenter study to determine the effect on clinical parameters of neurodevelopmental status of monthly IT administration of idursulfase-IT 10 mg for 12 months in pediatric patients with Hunter syndrome and cognitive impairment who have previously received and tolerated a minimum of 4 months of therapy with Elaprase. Pediatric patients under 3 years of age will be enrolled into a separate substudy to evaluate the safety and efficacy of idursulfase-IT. The separate substudy is open label and single arm. Patients who are enrolled in the substudy will receive idursulfase-IT treatment and follow the same schedule of study visits.