An Extension Study to Assess the Long-term Safety and Efficacy of Hunterase (Idursulfase Beta)

Inclusion Criteria: 1. Subject diagnosed with Hunter syndrome (MPS II) who completed activities at the EOS visit (Visit 54) in the GC1111\_P3 study 2. (Subject who did not participate in the GC1111\_P3 study) Subject diagnosed with Hunter syndrome (MPS II) who received Hunterase for more than 6 months 3. (Subjects who did not participate in the GC1111\_P3 study) Males aged ≥ 5 4. Informed consent form voluntarily signed by the subject or by a legally acceptable representative 5. Subject who agrees to use contraception Exclusion Criteria: 1. Subject with hypersensitivity to any of the ingredients of the investigational product 2. Subject impossible to perform follow-up observation of the safety 3. Subject who received the treatment with another investigational product within 14 days prior to the start of study drug 4. Subject who plans to be treated with another investigational product during the study period 5. Subject who has history of tracheostomy, bone marrow transplant, or cord blood transplant 6. Any other inappropriate conditions for study participation at the investigator's discretion