Inclusion Criteria:

- Patients who meet any one of the following. Patients with a diagnosis of parathyroid
carcinoma and corrected serum calcium > 11.3 mg/dL at the latest screening test.
Patients with intractable PHPT (defined as follows: impossible to localize
parathyroid tumor before initial surgery or in relapse after surgery, or impossible
to perform parathyroidectomy (PTx) for complications, and corrected serum calcium is
> 12.5 mg/dL at the screening test).

- Patients who provided their voluntary written informed consent to participate in the
study.

Exclusion Criteria:

- Patients diagnosed with malignant tumor except for parathyroid carcinoma, nonmelanoma
skin cancer, and carcinoma in situ of the cervix within 5 years before enrollment.

- Patients receiving anticancer chemotherapy except for the treatment of parathyroid
carcinoma.

- Patients diagnosed with hypercalcemia associated with malignant tumors other than
parathyroid carcinoma.

- Patients who had hypersensitivities to cinacalcet HCl preparations or vehicles.