Efficacy and Safety of LCZ696 Compared to Olmesartan in Essential Hypertensive Patients Not Responsive to Olmesartan

Inclusion Criteria: * patients with mild to moderate hypertension, untreated or currently taking antihypertensive therapy * treated patients (using antihypertensive drugs within 4 weeks prior to first visit) must have an office msSBP ≥ 145 mmHg and \< 180 mmHg after washout epoch and after 4 weeks run-in epoch * untreated patients (either newly diagnosed or those patients with a history of hypertension but have not been taking any antihypertensive drugs for at least 4 weeks prior to first visit) must have an offcie msSBP ≥ 150 mmHg and \< 180 mmHg at screening and 1 week after screening and must have an office msSBP ≥ 145 mmHg and \< 180 mmHg after 4 weeks run-in epoch * patients must successfully complete ABPM and pass technical requirements to be qualified for randomization Exclusion Criteria: * Malignant or severe hypertension (grade 3 of WHO classification; msDBP ≥110 mmHg and/or msSBP ≥ 180 mmHg) * History of angioedema, drug-related or otherwise * History or evidence of a secondary form of hypertension, including but not limited to any of the following: renal parenchymal hypertension, renovascular hypertension (unilateral or bilateral renal artery stenosis), coarctation of the aorta, primary hyperaldosteronism, Cushing's disease, pheochromocytoma, polycystic kidney disease (PKD), drug-induced hypertension * Patients who previously entered a LCZ696 study and had been randomized or enrolled to receive active drug treatment