Study of Efficacy and Safety of Tonlamarsen in Participants With a Recent Hospitalization and a Concurrent Episode of Acute Severe Hypertension

Key Inclusion Criteria:

* Age 18 or older, body weight ≥ 50 kg with BMI ≤45.0 kg/m2
* Ready for discharge or recently discharged from the hospital to home (within the past 7 days) during which evaluation and/or treatment of acute severe hypertension (documented SBP ≥ 180 mmHg and/or DBP ≥ 110 mmHg) occurred, as measured by a healthcare provider (HCP) within the 24 hours preceding hospitalization or during the initial 24 hours of hospitalization
* At Screening and Randomization visit, average resting office systolic blood pressure ≥ 145 mmHg
* Presence of established cardiovascular or renal disease

Key Exclusion Criteria:

* Has known history of secondary hypertension
* Any malignancy requiring treatment within 5 years (except for basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix that has been successfully treated)
* Has abnormal thyroid function with clinical significance
* Recent hospitalization for stroke, myocardial infarction or coronary revascularization within 30 days prior to screening
* History of and/or obvious clinical signs or symptoms of cirrhosis or other significant liver disease
* Alanine aminotransferase or aspartate aminotransferase \>2 x upper limit of normal
* Most recent hospitalization was for non-cardiovascular or non-renal conditions