This study is for adults who have a condition called hypoparathyroidism. This condition means the body doesn't make enough of a hormone called parathyroid hormone, which helps control calcium levels in the blood. The study will look at how safe and easy it is to take a medicine called MBX 2109 over a long time. This medicine is given once a week. The study also checks if MBX 2109 can keep calcium levels normal without needing extra vitamin D and with less calcium supplements. To join, you must have finished a previous 12-week study with MBX 2109 and be at least 18 years old. You should also have had hypoparathyroidism for at least 26 weeks.

• The study is long-term, following an earlier study.
• You will take the medicine once a week.
• You need to be comfortable giving yourself the medicine.