Extension Study of Protocol ENB-002-08 - Study of Asfotase Alfa in Infants and Young Children With Hypophosphatasia (HPP)

Asfotase Alfa was formerly referred to as ENB-0040

Hypophosphatasia (HPP) is a life-threatening, genetic, and ultra-rare metabolic disease
characterized by defective bone mineralization and impaired phosphate and calcium regulation
that can lead to progressive damage to multiple vital organs, including destruction and
deformity of bones, profound muscle weakness, seizures, impaired renal function, and
respiratory failure. There are limited data available on the natural course of this disease
over time, particularly in patients with the juvenile-onset form.

Inclusion Criteria

- Patient completed participation in ENB-002-08 (NCT00744042)

- Written informed consent by parent or other legal guardian prior to any study
procedures being performed

- Parent or other legal guardian willing to comply with study requirements

Exclusion Criteria

- History of sensitivity to any of the constituents of the study drug

- Clinically significant disease that precludes study participation

- Enrollment in any study (other than ENB-002-08) involving an investigational drug,
device, or treatment for HPP (e.g., bone marrow transplantation)