Efficacy and Safety Comparison of Azilsartan Medoxomil to Valsartan in Participants With Essential Hypertension

The purpose of this study is to compare the efficacy and safety of TAK-491 (azilsartan medoxomil), once daily (QD), to valsartan in participants with essential hypertension.

Hypertension affects approximately 50 million individuals in the United States. As the population ages, the prevalence of hypertension will continue to increase if broad and effective preventive measures are not implemented. According to the World Health Organization (WHO), hypertension is the most common attributable cause of preventable death in developed nations, as uncontrolled hypertension greatly increases the risk of cardiovascular disease, cerebrovascular disease, and renal failure. Despite the availability of antihypertensive treatments, hypertension remains inadequately controlled; only about one-third of patients continue to maintain control successfully.

This study is being conducted to determine whether administration of azilsartan medoxomil in subjects with essential hypertension is more efficacious in reducing systolic blood pressure than valsartan.

Study participation is anticipated to be approximately 7 months. Outside of the study center, participants will be required to wear an ambulatory blood pressure monitoring device at 24 hour intervals.

Following completion of the 6-month double-blind treatment period, all available subjects will be offered the option to continue in a 28-week extension study with open-label azilsartan medoxomil 40 mg.

For the extension study, participants will take azilsartan medoxomil 40 mg, tablets, orally, once daily for up to 28 weeks. Hydrochlorothiazide 12.5 mg or 25 mg or any other antihypertensive (except angiotensin II receptor blockers) may be added in a step-wise fashion to maintain blood pressure within target \<140/90 mmHg for non-diabetic subjects and \<130/80 mmHg for diabetic subjects

Eligibility Criteria:
Inclusion Criteria

1. Essential hypertension (defined as sitting trough clinic systolic blood pressure between 150 and 180 mm Hg inclusive at Day minus 1 and 24-hour mean systolic blood pressure between 130 and 170 mm Hg inclusive at Day 1).
2. Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study.
3. Clinical laboratory evaluations (including clinical chemistry, hematology, and complete urinalysis) within the reference range for the testing laboratory or the results are deemed not clinically significant for inclusion into this study by the investigator.
4. Willing to discontinue current antihypertensive medications at the Screening Day minus 21 visit. If the subject is on amlodipine prior to Screening, the subject is willing to discontinue this medication at Screening Day minus 28.

Exclusion Criteria

1. Sitting trough clinic diastolic blood pressure greater than 114 mm Hg at Day minus 1.
2. The subject has a baseline 24-hour ambulatory blood pressure monitor reading of insufficient quality.
3. Is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication that may interfere with evaluation of the study medication.
4. Hypersensitive to angiotensin II receptor blockers.
5. Recent history (within the last 6 months) of myocardial infarction, heart failure, unstable angina, coronary artery bypass graft, percutaneous coronary intervention, hypertensive encephalopathy, cerebrovascular accident, or transient ischemic attack.
6. Clinically significant cardiac conduction defects (eg, 3rd degree atrioventricular block, left bundle branch block, sick sinus syndrome, atrial fibrillation or flutter).
7. Hemodynamically significant left ventricular outflow obstruction due to aortic valvular disease.
8. Secondary hypertension of any etiology.
9. Non-compliant (less than 70% or greater than 130%) with study medication during placebo run-in period.
10. Severe renal dysfunction or disease (based on calculated creatinine clearance less than 30 mL per min/1.73m2) at Screening.
11. Known or suspected unilateral or bilateral renal artery stenosis.
12. History of drug or alcohol abuse within the past 2 years.
13. Previous history of cancer that has not been in remission for at least 5 years prior to the first dose of study drug. (This criterion does not apply to those subjects with basal cell or Stage 1 squamous cell carcinoma of the skin).
14. Type 1 or poorly controlled type 2 diabetes mellitus (glycosylated hemoglobin greater than 8.0%) at Screening.
15. Hyperkalemia as defined by the central laboratory normal reference range at Screening.
16. Upper arm circumference less than 24 cm or greater than 42 cm.
17. Works night (3rd) shift (defined as 11PM to 7AM).
18. Alanine aminotransferase level of greater than 2.5 times the upper limit of normal, active liver disease, or jaundice at Screening.
19. Currently is participating in another investigational study or has participated in an investigational study within 30 days prior to randomization.
20. Any other serious disease or condition at Screening (or Randomization) that would compromise subject safety, might affect life expectancy, or make it difficult to successfully manage and follow the subject according to the protocol.
21. Randomized in a previous azilsartan medoxomil study.