Main criteria are listed hereafter:

Inclusion Criteria:

• at Screening

  • Outpatients

  • With newly diagnosed and untreated OR previously diagnosed, treated and uncontrolled Isolated Systolic Hypertension defined as:

    • seated Systolic Blood Pressure (SBP) ≥ 160mmHg and < 220 mmHg [160-220[
    • AND seated Diastolic Blood Pressure (DBP)< 90 mmHg

• at Randomization

  • Having completed the 2 to 4-week wash-out/placebo run-in phase
  • Still eligible for Blood Pressure
  • seated SBP ≥ 160mmHg and < 220 mmHg [160-220[
  • AND seated DBP < 90 mmHg.

Exclusion Criteria (at Screening):

• Participation in a clinical trial within the previous 3 months
• Patients with a history of irbesartan, amlodipine, or hydrochlorothiazide sensitivity defined as irbesartan, amlodipine, or hydrochlorothiazide discontinuation due to medically significant adverse effects
• Patients currently or previously treated with Angiotensin II Receptor Blocker (irbesartan, losartan, candesartan, valsartan, telmisartan, etc.) or dihydropiridine Calcium Channel Blocker (amlodipine, nicardipine, felodipine, nifedipine, etc.) AND not responding despite maximum tolerated dose
• Known or suspected secondary hypertension (e.g., coarctation of aorta, renovascular stenosis, etc.)
• Known single functional kidney
• History of recent myocardial infarction, coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty, or cerebrovascular accident (Transient Ischaemic Attack, stroke) within the last 6 months of study entry
• Patients with known gastrointestinal, renal, hepatic, endocrine, cardiovascular, pulmonary, immunological or hematological disease which in the opinion of the investigator is active or uncontrolled
• Patients with significant renal (clearance of creatinine < 30 mL/mn), hepatic or cardiac insufficiency, or known valvular heart disease
• Serum potassium < 3.5 mmol/L (mEq/L) or > 5.5 mmol/L (mEq/L)
• Presence of clinically significant ventricular or supraventricular arrhythmias, or second or third degree atrioventricular block, or QTc prolongation (Bazett > 450 msec.) on the ECG
• Pregnancy or lactation. Women of child bearing potential (not post-menopausal) should be using a reliable contraceptive method

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.