An Open-Label, Multicenter, Multinational Study of the Safety, Efficacy and Pharmacokinetics of Asfotase Alfa (human recombinant tissue non-specific alkaline phosphatase fusion protein) in Infants and Children ≤ 5 Years of Age with Hypophosphatasia (HPP). Read more about An Open-Label, Multicenter, Multinational Study of the Safety, Efficacy and Pharmacokinetics of Asfotase Alfa (human recombinant tissue non-specific alkaline phosphatase fusion protein) in Infants and Children ≤ 5 Years of Age with Hypophosphatasia (HPP).