A Study to Evaluate Efficacy and Safety of GW906 Used as Add-on Therapy in Patients With Hypertension Not Adequately Controlled by One or Two Antihypertensive Medications

Inclusion Criteria: * Age ≥ 18 years, of either sex. * Treated hypertension on stable therapy with up to 1 or 2 antihypertensive medications. Stable therapy is defined as having no change in antihypertensive medication or dose within 4 weeks prior to randomization. * Mean sitting systolic blood pressure (msSBP) ≥ 140 mmHg and \< 180 mmHg at the randomization visit. * Willing to participate in the study and provide written informed consent. Exclusion Criteria: * Secondary hypertension. * orthostatic hypotension. * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>2.5× upper limit of normal (ULN); Total bilirubin \> 1.5 × ULN; International normalized ratio (INR) \> 2.0; Serum potassium \> 5.0 mmol/L or \< 3.5 mmol/L; eGFR≤30 mL/min/1.73m\^2. * Received an investigational agent within the last 3 months. * Type 1 diabetes mellitus, poorly controlled Type 2 diabetes mellitus. * History of any cardiovascular event within 12 months. * History of intolerance to SC injection(s).