This study is an exploratory Phase 1 randomized, double-blind (Investigator and study subject and 2-D echo endpoint assessor), placebo-controlled single IV infusion dose escalation study that will enroll up to approximately 32 subjects with stage 1 or 2 essential hypertension.

The study will be conducted in two parts.

Part 1: For the initial evaluation of safety, pharmacokinetic exposure and pharmacodynamic response, subjects will be tapered off antihypertensive background therapy.The initial starting dose will be a sub-therapeutic dose. Dose escalation will continue with a maximum of a doubling of the previous dose until either 1) a maximum tolerated dose (MTD) is identified or 2) modeling of the pharmacokinetic (PK) data indicate that maximum exposure (Cmax) at the next planned dose level would exceed a maximum drug concentration (Cmax) which was the maximum observed drug concentration following a single subcutaneous administration in Study PB1046-PT-CL-0001.

Part 2: The dose group which is capable of providing a Cmax exposure which is capable of eliciting a clinically relevant hemodynamic response, will be expanded to enroll an additional 12 subjects (6 active and 6 placebo).

Inclusion Criteria:

• Willing and able to sign a written informed consent and follow all study related procedures.
• Males or females age 18 - 80 years of age inclusive.
• Male and female subjects of childbearing potential must be willing and able to practice effective contraception during the study, and be willing and able to continue contraception for 1 month (30 days) after their last dose of study drug.
• BMI ≥ 20 but ≤ 40 kg/m2
• Diagnosed with essential hypertension and are currently taking one or more antihypertensive medications to control their blood pressure and, who in the opinion of the investigator, could be safely withdrawn from antihypertensive therapy.

Exclusion Criteria:

• Known allergy to the study drug or any of its components, or who have previously received Vasomera (PB1046).
• Inadequate "imaging window" by echocardiography as determined by screening echocardiography (core assessment), or cardiac abnormalities that may confound echocardiography readings (i.e., mitral regurgitation, "floppy-valve" syndrome) for evaluation of secondary study endpoints.
• Seated systolic blood pressure <120 mmHg or diastolic blood pressure < 80 mmHg (confirmed in triplicate) at randomization (Day -1) or prior to the first dose of study drug (V3 Day 0) will exclude the subject from participation.
• Evidence of sustained elevation in systolic blood pressure >169 mmHg or diastolic blood pressure >109 mmHg prior to dosing (Day 0) during the washout period which in the opinion of the investigator would place the subject at risk for continued study participation (i.e., can not be safely withdrawn from antihypertensive therapy).
• Clinically significant changes in health status or concomitant prescription medications within 2 weeks prior to dosing (V3 Day 0) that could place the subject at risk for dosing with study drug or confound the primary or secondary outcome measures as assessed by the Investigator.
• Unstable/underlying cardiovascular disease defined as: a. Congestive heart failure (NYHA class III-IV), stroke, transient ischemic attack, unstable angina pectoris, or myocardial infarction within the 6 months prior to screening (V1) b. Mean triplicate 12-lead ECG demonstrating a QT interval (corrected using Fridericia's formula (QTcF)) >450 msec in males and >470 msec in females at Screening, (V1) or a history or evidence of long QT syndrome. c. Sustained heart rate >100 beats per minute (BPM) (at rest) at screening (V1), prior to randomization (V3 Day -1), or prior to dosing (V3 Day 0). d. Any episode of atrial fibrillation, ventricular tachycardia (defined as ten (10) or more beats with heart rate greater than 130 beats per minute), ventricular fibrillation, firing of an implantable cardiac defibrillator (ICD) for documented ventricular ectopy, or other clinically significant documented arrhythmias within 3 months prior to administration of study drug (V3 Day 0).
• Uncontrolled diabetes defined as a Hemoglobin A1c > 10.0%. Note: only applicable for subjects with a known or suspected history of diabetes.
• Clinically significant renal and/or hepatic dysfunction at Screening (V1) or at baseline (V3 Day -1).
• Pregnant or lactating females.
• Known history of or active drug or alcohol abuse within the 12 months prior to screening (V1) and/or positive drug screen (for illicit drugs) or detection of alcohol at baseline.
• Positive for Human Immunodeficiency Virus (HIV) antibodies, hepatitis B surface antigen (HBsAg) or hepatitis C virus (HCV) antibodies.
• Participation in any other study and have received any other investigational drug or device within 30 days prior to the Screening visit or are taking part in a non-drug study which in the opinion of the Investigator would interfere with the outcome of the study.
• Major surgery, donated or lost > or = 1 unit of blood (approximately 500 mL) within 30 days prior to Screening (V1) or display evidence of volume depletion (i.e., postural hypotension) prior to randomization (V3 Day -1) or dosing (V3 Day 0).
• Other medical or psychiatric condition which in the opinion of the Investigator would place the subject at increased risk, would preclude obtaining voluntary consent, or would confound the results of the study.