A Study of TAK-536 in Children From 2 to Less Than 6 Years Old With High Blood Pressure

Inclusion Criteria

• In the opinion of the investigator or subinvestigator, the participant's parent or legal guardian is capable of understanding and complying with protocol requirements.
• The participant's parent or the participant's legal guardian is capable of signing and dating a written informed consent form on behalf of the participant prior to the initiation of any study procedures.
• A Japanese participant who has a diagnosis of hypertension. A participant is eligible if he/she is deemed hypertensive according to the reference blood pressure values of children by gender and age; office sitting diastolic or systolic blood pressure >=95th percentile for essential hypertension without concomitant hypertensive organ damage, and >=90th percentile for secondary hypertension with concomitant CKD, diabetes mellitus, heart failure or hypertensive organ damage.

In addition, participants need to meet the following criteria:

If currently treated with any antihypertensive drugs at the start of the Run-in Period: Participant has a documented diagnosis of hypertension and an office sitting diastolic or systolic blood pressure meeting the above criteria at the end of the Run-in Period (Week 0).

If currently untreated with any antihypertensive drugs at the start of the Run-in Period: Participant meets the above criteria for hypertension on 3 separate time points including screening and the end of the Run-in Period (Week 0). In addition, for a participant with essential hypertension without hypertensive organ damage, the participant does not respond to non-pharmacological therapy such as diet modification or exercises for at least 3 months within 1 year prior to the start of screening.

• The participant is male or female and aged 2 to less than 6 years at the time of informed consent.
• At screening, the participant has not less than minus 2 standard deviations from mean weight for age of reference population shown in the table of pediatric body weight by the Japanese Society for Pediatric Endocrinology.
• The participant is able to swallow the study drug.
• A participant who has undergone kidney transplantation is eligible if he/she underwent the transplantation, and the graft has been functionally stable (estimated glomerular filtration rate [eGFR] >= 30 mL/min/1.73 m^2) for at least 6 months with evidence (eg, Doppler echography, CT [computed tomography] scan or MRI [magnetic resonance imaging]) excluding dose at least 30 days prior to screening is eligible.
• The participant, judged by the investigator or subinvestigator, who can safely discontinue the therapy with RAS inhibitors for 2 weeks prior to the Treatment Period. This period may change to between 1 and 4 weeks depending on the participant's duration of Run-in Period.

Exclusion Criteria

• The participant has received any investigational compound within 30 days prior to screening or is participating in another clinical study or a post-marketing clinical study.

Note: This does not apply to participants participating in observational studies without interventional or surgical therapy.

• The participant previously received therapy with azilsartan.
• The participant has poorly controlled hypertension indicated by an office sitting systolic blood pressure higher by at least 22 mmHg and/or an office sitting diastolic blood pressure higher by at least 17 mmHg than the 95th percentiles of the reference blood pressure values of children by gender and age.
• The participant has a diagnosis of malignant or accelerated hypertension.
• The participant was noncompliant (compliance: 130%) with the study drug during the Run-in Period. The proportion of the number of the received the study drug to the number of the study drug which the participants should receive.
• The participant has severe renal dysfunction (eGFR 9.0% at screening.
• The participant has an alanine aminotransferase (ALT) or aspartate aminotransferase (AST) level >=2.5 × the upper limit of normal (