A Open-label Study Investigating the Safety and Tolerability of NPSP558, a Recombinant Human Parathyroid Hormone (rhPTH [1-84]), for the Treatment of Adults With Hypoparathyroidism - A Clinical Extension Study (RACE)

A Long-term Open-label Study Investigating the Safety and Tolerability of NPSP558, a Recombinant Human Parathyroid Hormone (rhPTH[1-84]), for the Treatment of Adults With Hypoparathyroidism - A Clinical Extension Study (RACE)

This study is a long-term, open-label study using NPSP558 for the treatment of adult patients with Hypoparathyroidism.

Patients with a history of Hypoparathyroidism will be enrolled to receive study drug for up to 80 months, which will be injected daily in either thigh. During that time they will be monitored for safety (specifically calcium levels in blood or urine). In addition, the patients' intake of Vitamin D and Calcium will be measured.

Inclusion Criteria:

• Previously completed the rhPTH[1-84] RELAY study (8 weeks of active therapy) and/or previously completed the rhPTH[1-84] REPLACE study (Visit 18).
• Able to perform daily SC self-injections of study medication (or have a designee perform injection).
• Women who are (1) postmenopausal; (2) surgically sterilized; or, (3) of childbearing potential with a negative pregnancy test and who consent to use two acceptable methods of contraception for the duration of the study.
• Males who have female partners of childbearing potential must use two acceptable forms of contraception for the duration of the study.
• Serum creatinine <1.5 mg/dL at enrollment.
• Total serum calcium less than or equal to upper limit of normal (ULN) based on local laboratory result prior to enrollment.
• Serum 25 hydroxy (OH) vitamin D less than or equal to 1.5 times the ULN within approximately 16 weeks prior to enrollment.

Exclusion Criteria:

• Any condition that, in the investigator's opinion after consultation with the sponsor, would preclude the safe use of parathyroid hormone (PTH).
• Pregnant or lactating women.
• Any disease or condition which has a high probability of precluding the subject from completing the study or where the subject cannot or will not appropriately comply with study requirements.