Efficacy and Safety of Combination Therapy of Aliskiren/Amlodipine or Aliskiren/Amlodipine/Hydrochlorothiazide in Patients With Stage II Hypertension

Inclusion Criteria: * Outpatients 18 years of age or older * Male or female patients are eligible. Female patients must be either post-menopausal for one year, surgically sterile, or using effective contraceptive methods such as oral contraceptives, barrier method with spermicidal or an intrauterine device. * Patients with a diagnosis of hypertension as following msDBP \& msSBP Requirements: * For newly diagnosed/untreated patients: * Mean Sitting Diastolic Blood Pressure (msDBP) ≥ 100 and \< 120 mmHg, and/or mean sitting Systolic Blood Pressure (msSBP) ≥ 160 and \< 200 mmHg at Visit1. * For previously treated patients with 1 or 2 antihypertensive medications: * msDBP ≥ 90 and \< 100 mmHg, and/or msSBP ≥ 140 and \< 160 mmHg at Visit 1 AND * msDBP ≥ 100 and \< 120 mmHg, and/or msSBP ≥ 160 and \< 200 mmHg at Visit 2. * For previously treated patients with Atenolol 50 mg once daily alone more than 2 weeks consecutively at visit 1: * msDBP ≥ 100 and \< 120 mmHg, and/or msSBP ≥ 160 and \< 200 mmHg. * Patients who are eligible and able to participate in the study, and who consent to do so after the purpose and nature of the investigation has been clearly explained to them (written informed consent). Exclusion Criteria: * Patients that previously participated in any Aliskiren study. * Inability to receive or completely replace all previous antihypertensive medications with Atenolol 50 mg once daily for a period of 2 weeks as required by the protocol. * Patients on 1 (other than Atenolol 50 mg once daily) or 2 antihypertensive drugs with msDBP ≥ 100 mmHg and/or msSBP ≥ 160 mmHg at Visit 1. * Patients on 3 or more antihypertensive drugs at Visit 1. * Pregnant or nursing (lactating) women, when pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive hCG laboratory test (≥ 5 mIU/mL). * Sexually active female patients who are not using effective contraceptive methods. * Serum potassium \<3.5 mEq/L (mmol/L) or \> 5.5 mEq/L at Visit 1. * Second or third degree heart block with or without a pacemaker, or other potentially life-threatening or symptomatic arrhythmia current or by history. * History of noncompliance to medical regimens or unwillingness to comply with the study protocol. Other protocol-defined inclusion/exclusion criteria may apply