• Age 18 to 65 years (inclusive), male or female.

• Documented history of post-surgical chronic HP or autoimmune, genetic, or idiopathic HP for at least 26 weeks. Diagnosis of HP is confirmed based on a history of hypocalcemia accompanied by an inappropriately low serum PTH level (below the upper limit of the normal range of the local laboratory). \* Note: If a subject lacks documented diagnosis of chronic HP but has exhibited hypocalcemia accompanied by an inappropriately low serum PTH level for at least 26 weeks prior to screening, and is judged by the investigator to meet the diagnostic criteria for chronic HP, they will be considered eligible for this criterion.

• Poorly controlled or intolerant to conventional therapy (calcium and active vitamin D).

• Conventional therapy (including vitamin D or magnesium supplements, if applicable) can be optimized during the screening period to achieve the following target serum levels: 25(OH) Vitamin D level: 10 - 100 ng/mL (25 - 250 nmol/L, inclusive). Blood magnesium level: Within the normal range or slightly below, i.e., ≥ 1.3 mg/dL (≥ 0.53 mmol/L). Albumin-corrected serum calcium (sCa) level: Within the normal range or slightly below

• Body Mass Index (BMI) of 17 to 40 kg/m² (inclusive) at screening.

• If aged ≤ 25 years, radiological evidence of closed epiphyses based on X-ray of the non-dominant hand (wrist and palm).