Compare Efficacy and Safety of Telmisartan/Hydrochlorothiazide With Telmisartan/Hydrochlorothiazide Plus Amlodipine

An Eight-week Randomised Double-blind Study to Compare the Efficacy and Safety of Telmisartan 80 mg and Amlodipine 5 mg and Hydrochlorothiazide 12.5 mg vs. Telmisartan 80 mg and Hydrochlorothiazide 12.5 mg in Patients With Hypertension Who Fail to Respond Adequately to Treatment With Telmisartan 80 mg and Hydrochlorothiazide 12.5 mg, Followed by a 52 Weeks Extension Study to Assess Long Term Safety of Telmisartan 80 mg and Amlodipine 5 mg and Hydrochlorothiazide 12.5 mg

This is a multi-centre, randomised, double-blind, active-controlled, parallel-group comparative trial to compare the fixed dose combination (FDC) of telmisartan 80 mg + hydrochlorothiazide 12.5 mg and amlodipine 5 mg (T80/A5/H12.5 mg) to telmisartan 80 mg+ hydrochlorothiazide 12.5 mg (T80/H12.5 mg) in blood pressure lowering effect at week 8, the end of the double-blind period in essential hypertensive patients who fail to respond adequately to telmisartan 80 mg+ hydrochlorothiazide 12.5 mg.

Patients are assigned to one of the two groups after a 6-week open-label run-in period taking T80/H12.5 mg.

In addition the long-term safety of telmisartan 80 mg+ amlodipine 5 mg+ hydrochlorothiazide 12.5 mg will be evaluated in a 52-week extension period.

In the 52-week open label extension period patients who are assigned to the T80/A5/H12.5 mg group continue the T80/A5/H12.5 mg therapy, and patients who are assigned to the T80/ /H12.5 mg group change to the T80/A5/H12.5 mg therapy.

Inclusion criteria:

1. Essential hypertensive patients who have already taking 2 or 3 antihypertensive drugs and mean seated diastolic blood pressure (DBP) must be >=90 and <=114 mmHg and mean seated systolic blood pressure (SBP) must be =<200 mmHg
2. Able to stop all current antihypertensive drugs (other than study medication) from Visit 1b through the end of the trial without risk to the patient based on the investigator's opinion
3. Age 20 years or older

Exclusion criteria:

1. Patients with known or suspected secondary hypertension
2. Patients with clinically relevant cardiac arrhythmia
3. Congestive heart failure with New York Heart Association (NYHA) functional class III-IV
4. Patients with recent cardiovascular events
5. Patients with recent stroke events
6. Patients with a history of sudden deterioration of renal function with angiotensin II receptor blockers or angiotensin converting enzyme inhibitors; or patients with post-renal transplant or post-nephrectomy
7. Patients with hepatic and/or renal dysfunction
8. Pre-menopausal women who are nursing or pregnant