Efficacy and Safety of Azilsartan Medoxomil Combined With Chlorthalidone in Participants With Moderate to Severe Hypertension

The purpose of this study is to determine the efficacy and safety of azilsartan medoxomil combined with chlorthalidone, once daily (QD), in participants with moderate to severe hypertension.

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. As the population ages, the prevalence of hypertension will continue to increase if broad and effective preventive measures are not implemented. Despite the availability of antihypertensive agents, hypertension remains inadequately controlled; only about one third of patients continue to maintain control successfully.

Although most antihypertensive agents are effective at the appropriate dose, the majority have side effects that limit their use. As a class, angiotensin II receptor blockers generally are considered more tolerable than other classes of antihypertensive agents. TAK-491 (azilsartan medoxomil) is an angiotensin II receptor blocker that is being evaluated by Takeda to treat essential hypertension.

Treatments for essential hypertension commonly include use of a thiazide-like diuretic, either alone or as part of combination treatment.

This study is designed to compare the antihypertensive effect and the safety and tolerability of the azilsartan medoxomil plus chlorthalidone fixed-dose combination product (TAK 491CLD FDC) with azilsartan monotherapy and chlorthalidone monotherapy during 8 weeks of treatment.

Participants in this study will be randomized to receive one of 11 possible dosing combinations of azilsartan medoxomil , chlorthalidone and placebo over an 8 week period. The total duration of the study will be approximately 13 weeks. Participants will make 12 visits to the clinic. Each participant will also be contacted by telephone 14 days after last dose of study drug for a follow-up assessment.

Eligibility Criteria:
Inclusion Criteria:

1. Is treated with antihypertensive therapy and has a post-washout mean sitting clinic systolic blood pressure greater than or equal to 160 and less than or equal to 190 mm Hg on the day prior to randomization, or the participant has not received antihypertensive treatment within 28 days prior to Screening and has a mean sitting clinic systolic blood pressure greater than or equal to 160 and less than or equal to 190 mm Hg at the Screening Visit and on the day prior to randomization.
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. Has clinical laboratory test results within the reference range for the testing laboratory or the investigator does not consider the results to be clinically significant.
4. Is willing to discontinue current antihypertensive medications on Day -21 or on Day -28 if on amlodipine or chlorthalidone.

Exclusion Criteria:

1. Has a mean sitting clinic diastolic blood pressure greater than 119 mm Hg on the day prior to randomization.
2. Has a baseline 24-hour ambulatory blood pressure measurement reading of insufficient quality.
3. Has works a night (third) shift (defined as 11 PM \[2300\] to 7 AM \[0700\]).
4. Has an upper arm circumference less than 24 cm or greater than 42 cm.
5. Has is noncompliant with study medication during the placebo run-in period.
6. Has secondary hypertension of any etiology.
7. Has recent history of myocardial infarction, heart failure, unstable angina, coronary artery bypass graft, percutaneous coronary intervention, hypertensive encephalopathy, cerebrovascular accident, or transient ischemic attack.
8. Has clinically significant cardiac conduction defects.
9. Has hemodynamically significant left ventricular outflow obstruction due to aortic valvular disease.
10. Has severe renal dysfunction or disease.
11. Has known or suspected unilateral or bilateral renal artery stenosis.
12. Has a history of cancer that has not been in remission for at least 5 years prior to the first dose of study drug.
13. Has poorly controlled type 1 or type 2 diabetes mellitus at Screening.
14. Has hypokalemia or hyperkalemia.
15. Has an alanine aminotransferase or aspartate aminotransferase level of greater than 2.5 times the upper limit of normal, active liver disease, or jaundice.
16. Has any other known serious disease or condition that would compromise safety, might affect life expectancy, or make it difficult to successfully manage and follow Has according to the protocol.
17. Has known hypersensitivity to angiotensin II receptor blockers, thiazide-type diuretics or other sulfonamide-derived compounds.
18. Has been randomized in a previous azilsartan medoxomil study.
19. Is currently participating in another investigational study or is receiving or has received any investigational compound within 30 days prior to Screening.
20. Has a history of drug abuse or a history of alcohol abuse within the past 2 years.