An Extension Study to Determine Safety and Efficacy for Pediatric Patients With MPS Type IIIA Disease Who Participated in Study HGT-SAN-093.

Exclusion Criteria

• •Patients will be excluded from the study if any of the following criteria are met:
• •1. The patient, if randomized to treatment in Study HGT-SAN-093, has experienced a decline of more than 20 points in the BSID-III cognitive DQ score between Baseline and the Week 48 visit in Study HGT-SAN-093, AND, upon individual evaluation by the Investigator, has been deemed a treatment failure\*
• •2. The patient has experienced, in the opinion of the Investigator, a safety or medical issue that contraindicates treatment with HGT-1410, including but not limited to clinically relevant intracranial hypertension, severe infusion-related reactions after treatment with HGT-1410, uncontrollable seizure disorder
• •3. The patient has a known hypersensitivity to any of the components of HGT-1410
• •4. The patient is enrolled in another clinical study, other than HGT-SAN-093, 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 airway compromise 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
• •7. The patient is unable to comply with the protocol (eg, is unable to return for safety evaluations, or is otherwise unlikely to complete the study) as determined by the Investigator
• •* All treated patients in Study HGT-SAN-093 will have their cognitive development assessed at the Week 48 Visit in Study HGT-SAN-093. If a decline from Baseline of 20 points or less in the BSID-III DQ score is observed, then the patient may proceed into the Study SHP-610-201 without further evaluation. If a decline from Baseline of more than 20 points in DQ score is observed, then an individual evaluation by the Investigator will occur to determine if the patient is a treatment failure. This individual evaluation will take into account the DQ scores, VABS-II score, physical status, and any other information available for that patient at that time. If the Investigator deems the patient to be a treatment failure, then the patient may not enter the Study SHP-610-201