To examine antihypertensive effect and safety of administration of CS-3150 in patients with severe hypertension (Grade III).

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.

De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.