A Study to Assess the Safety, Tolerability and Efficacy of IONIS-AGT-LRx

Inclusion criteria

• Males or females aged 18-75 inclusive and weighing ≥ 50 kilograms (kg) at the time of informed consent
• Females must be non-pregnant and non-lactating, and either surgically sterile or post-menopausal
• Males must be surgically sterile or, abstinent or, if engaged in sexual relations with a woman of child-bearing potential (WOCBP), the participant or participant's non-pregnant female partner must be using a highly effective contraceptive method
• Body mass index (BMI) ≤ 35.0 kg/square meter (m^2)
• Participant must have been diagnosed with essential hypertension for a minimum of 3 months prior to screening
• At screening, the participant must have been on a stable regimen of 2 to 3 antihypertensive medications for at least 1 month prior to screening and will be required to maintain this regimen throughout the study, using either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB), as well as 1 or 2 additional antihypertensive medications in the following categories: beta blocker, acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, nebivolol, propranolol, pindolol, calcium channel blocker or, non-potassium sparing diuretic

Exclusion Criteria

• Clinically significant abnormalities in medical history, screening laboratory results, or physical examination that would render the participant unsuitable for inclusion
• History of secondary hypertension (HTN)

The use of the following at time of screening and during the course of the study:

• Other medications for the treatment of HTN (e.g., clonidine, guanfacine, guanabenz, alpha-methyldopa, hydralazine, minoxidil, diazoxide, renin inhibitors)
• Medications that may cause hyperkalemia (e.g., cyclosporine or tacrolimus, pentamidine, trimethoprim-sulfamethoxazole, all heparins)
• Oral or SC anticoagulants (e.g., warfarin, rivaroxaban, apixaban, heparin, lovenox)
• Organic nitrate preparations (e.g., nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, or pentaerythritol)
• Phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil)
• Potassium-sparing diuretics (e.g., eplerenone, spironolactone, amiloride, triamterene)

Unstable/underlying cardiovascular disease defined as:

• Any history of congestive heart failure (New York Heart Association [NYHA] class II-IV)
• Any history of previous stroke, transient ischemic attack, unstable or stable angina pectoris, or myocardial infarction prior to screening
• 12-lead electrocardiogram (ECG) corrected using Fridericia's formula (QTcF) > 450 milliseconds (msec) in males and > 470 msec in females at screening, or a history or evidence of long QT syndrome
• Any clinically significant active atrial or ventricular arrhythmias
• Any history of coronary bypass or percutaneous coronary intervention