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)

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.