Hunter Syndrome 302

Inclusion Criteria:

1. Patients must have completed Visit Week 52 assessments in Study HGT-HIT-094
2. The patient's parent(s) or legally authorized guardian(s) must have voluntarily signed an Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved informed consent form after all relevant aspects of the study have been explained and discussed. Consent of the patient's parent(s) or legally authorized guardian(s) and the patient's assent, as relevant, must be obtained
3. The patient has continued to receive Elaprase on a regular basis in Study HGT-HIT-094

Exclusion Criteria:

1. The patient has experienced, in the opinion of the Investigator, a safety or medical issue that contraindicates treatment with idursulfase-IT, including, but not limited to,uncontrolled seizure disorder, bleeding disorder, and clinically relevant hypertension
2. The patient has a known hypersensitivity to any of the components of idursulfase-IT
3. The patient has clinically relevant intracranial hypertension
4. The patient is enrolled in another clinical study, other than HGT-HIT-094, that involves clinical investigations or use of any investigational product (drug or [intrathecal/spinal] device) within 30 days prior to study enrollment or at any time during the study
5. The patient has any known or suspected hypersensitivity to anesthesia or is thought to be at an unacceptably high risk for anesthesia due to compromised airways or other conditions.

6. The patient has a condition that is contraindicated as described in the SOPH-A-PORT Mini S IDDD Instructions for Use, including:

   1. The patient has had, or may have, an allergic reaction to the materials of construction of the SOPH-A-PORT Mini S device
   2. The patient's body size is too small to support the size of the SOPH-A-PORT Mini S Access Port, as judged by the Investigator
   3. The patient's drug therapy requires substances known to be incompatible with the materials of construction
   4. The patient has a known or suspected local or general infection
   5. The patient is at risk of abnormal bleeding due to a medical condition or therapy
   6. The patient has one or more spinal abnormalities that could complicate safe implantation or fixation
   7. The patient has a functioning CSF shunt device
   8. The patient has shown an intolerance to an implanted device