This Phase 3 study will evaluate the efficacy and safety of 2.0 mg/kg/week BMN 110 and 2.0 mg/kg/every other week BMN 110 in patients with mucopolysaccharidosis IVA (Morquio A Syndrome).

There is currently no standard accepted treatment for MPS IVA other than supportive care. Enzyme replacement therapy (ERT) may be a potential new treatment option for MPS IVA patients. BMN 110 is administered to MPS IVA patients by IV infusion, allowing cellular uptake by the mannose-6-phosphate receptor and transportation to the lysosomes.

This enzyme uptake into the lysosomes is hypothesized to promote increased catabolism of keratan sulfate (KS) in tissue macrophages, hyaline cartilage, other connective tissues, and heart valve, and reduce the progressive accumulation of KS which is responsible for the clinical manifestations of the disorders.

Inclusion Criteria:

• At least 5 years of age.
• Documented clinical diagnosis of MPS IVA based on clinical signs and symptoms of MPS IVA and documented reduced fibroblast or leukocyte GALNS enzyme activity or genetic testing confirming diagnosis of MPS IVA.
• Willing and able to provide written, signed informed consent, or in the case of patients under the age of 18 (or 16 years, depending on the region), provide written assent (if required) and written informed consent by a legally authorized representative after the nature of the study has been explained, and prior to any research-related procedures.
• Must meet the study entrance requirements for the 6-minute walk test.
• Sexually active patients must be willing to use an acceptable method of contraception while participating in the study.
• Females of childbearing potential must have a negative pregnancy test at Screening and be willing to have additional pregnancy tests during the study.

Exclusion Criteria:

• Previous hematopoietic stem cell transplant (HSCT).
• Previous treatment with BMN 110.
• Has known hypersensitivity to any of the components of BMN 110.
• Major surgery within 3 months prior to study entry or planned major surgery during the 24-week treatment period.
• Pregnant or breastfeeding at Screening or planning to become pregnant (self or partner) at any time during the study.
• Use of any investigational product or investigational medical device within 30 days prior to Screening, or requirement for any investigational agent prior to completion of all scheduled study assessments.
• Concurrent disease or condition, including but not limited to symptomatic cervical spine instability, clinically significant spinal cord compression, or severe cardiac disease that would interfere with study participation or safety as determined by the Investigator.
• Any condition that, in the view of the Investigator, places the patient at high risk of poor treatment compliance or of not completing the study.