Inclusion Criteria:  Confirmed clinical diagnosis of HPP Not anticipated to require further treatment with enzyme replacement therapy to treat participant's HPP after study completion Willing and able to follow protocol-specified contraception requirements Willing and able to give informed consent  Exclusion Criteria:  Primary or secondary hyperparathyroidism or hypoparathyroidism Fracture within 12 weeks of screening Current or relevant history of unstable physical or psychiatric illness Significant allergies Asfotase alfa use within 6 months and/or positive for asfotase alfa antidrug antibody/neutralizing antibodies