A Study to Evaluate the Effect of ASP7991 in Secondary Hyperparathyroidism Patients Undergoing Hemodialysis

Inclusion Criteria: * Patients who are on stable chronic maintenance dialysis who are receiving hemodialysis therapy 3 times/week since before 12-week (84 days) administration and are also scheduled to undergo the regimen of 3 times/week hemodialysis during the study period * Patients with secondary hyperparathyroidism * Patients whose serum iPTH concentration is \>240 pg/mL and corrected serum Ca is ≥ 9.0 mg/dL * Patients who have had no changes in the following items ≥4-week (28 days). * Dosage and regimen, including new administration, of active vitamin D, calcitonin preparation, phosphate binder, and medication with phosphate absorption (including foods) * Ca concentration of the dialysate, membrane area of the dialyzer, and dialysis time of each week Exclusion Criteria: * Patients who underwent parathyroid intervention, such as parathyroidectomy (PTx) or percutaneous ethanol injection therapy (PEIT), within 24 weeks (168 days) prior to the administration * Patients who have primary hyperparathyroidism * Patients who received bisphosphonate, estrogen preparation, parathyroid hormone within 4 weeks (28 days) * Patients with uncontrolled hypertension (systolic blood pressure ≥ 180 mmHg and diastolic blood pressure ≥ 120 mmHg are observed at \>2/3 of all confirmable measurements * Patients who are complicated by severe heart disorder \[congestive cardiac failure (NYHA classification III or higher), or wide range of old myocardial infarction\], or having a history of …