Study of CS-3150 in Patients With Severe Hypertension

Inclusion Criteria: * Male and female subjects aged 20 to 80 years at informed consent * Subjects with severe hypertension, who do not receive any antihypertensive drugs or receive antihypertensive drug (except for potassium-sparing diuretics) during run-in period (Sitting SBP ≥ 180 mmHg or Sitting DBP ≥ 110 mmHg) Exclusion Criteria: * Patients who are suspected hypertensive emergency * Secondary hypertension or malignant hypertension * Diabetes mellitus with albuminuria * Serum potassium level \< 3.5 or ≥ 5.1 mEq/L (≥ 4.8 mEq/L if receive RA inhibitor) * eGFR \< 60 mL/min/1.73 m\^2.