Safety and Efficacy Study of Angiotensin Therapeutic Vaccine in Subjects With Mild to Moderate Hypertension

Inclusion Criteria (at randomisation): 1. Competent to provide written informed consent 2. 35-70 years old 3. Body Mass Index (BMI) 19 to 33 kg/m2 4. Mild to moderate hypertension per British Hypertension Society (BHS) Guidelines BHS-IV based on the following criteria of sitting blood pressure for subjects without diabetes or renal dysfunction. 5. Average sitting morning DBP 90 to 109 mmHg and SBP 140 to 179 mmHg and have responded positively to a quinapril challenge. Principal exclusion criteria: 1. Women of childbearing potential: defined to be not surgically sterile and \<2 y post-menopausal 2. Average sitting SBP of \>180 mmHg or DBP of \>110 mmHg. 3. A BP difference between left and right arm greater than 20 mmHg for SBP and 10 mmHg for DBP which is present on 3 consecutive readings. 4. Left ventricular (LV) systolic dysfunction as evidenced by a known LV ejection fraction \<40% or symptomatic congestive heart failure requiring treatment. 5. HbA1c \>7.0% or a history of Type 1 or Type 2 diabetes. 6. Haemoglobin \<12 g/dL at Screening. 7. Hypo- or hyperthyroidism 8. Serum alanine aminotransferase or aspartate aminotransferase \>2X ULN. 9. Other identifiable secondary causes of hypertension 10. Myocardial infarction, unstable angina pectoris, or a cerebrovascular accident within 6 months of Screening. 11. Bradycardia \<50 beats per minute at rest in the supine position prior to randomisation. 12. Have sick sinus syndrome or second or third degree atrioventricular block, chronic atrial fibrillation or recurrent atrial tachyarrhythmia (including paroxysmal atrial tachycardia), history of recurrent ventricular tachycardia, or symptomatic bradycardia. 13. Implanted pacemakers or cardioverter defibrillator. 14. Haemodynamically significant valvular heart disease. 15. History of renal dysfunction and/or estimated glomerular filtration rate \<60 mL/min/1.73 m2. 16. Diagnosis or recurrence of malignancy within the past 3 years, with the exception of basal cell carcinoma of the skin or in situ carcinoma of the cervix. 17. Sleep apnea unless a recent (within 30 days of Screening) sleep study demonstrates no recordings of arterial oxygen saturation (SaO2) \<90%, treated or untreated, at any time during the Screening Period. 18. Perform alternating shift or night work. 19. Not on stable doses of all concomitant medications for a minimum of 4 weeks prior to Screening, and subjects treated with any of the following prohibited medications: * Oral corticosteroids within 3 months of Screening. * Acetylsalicylic acid in excess of 325 mg per day. * Chronic stable or unstable use of non-steroidal anti-inflammatory drugs (NSAIDs) other than acetylsalicylic acid is prohibited. * Selective serotonin reuptake inhibitors or selective serotonin norepinephrine reuptake inhibitors, if a subject is not compliant with the medication and/or has not been receiving a stable dose for at least 3 months prior to Screening. * Tricyclic antidepressants, if a subject is not compliant with the medication and/or has not been receiving a stable dose for at least 3 months prior to Screening. * Any angiotensin vaccine, including prior exposure to ATV. 20. Have participated in a clinical study involving another investigational drug or device within 4 weeks of Screening. 21. Any concomitant condition that, in the opinion of the investigator, may adversely affect the safety and/or efficacy of the study drug or severely limit the subject's ability to complete the study (eg, disabling or terminal illness, mental disorders). 22. Any major contraindication to stopping antihypertension medications for a period of up to 14 weeks. 23. Previous exposure to CoVaccine HT adjuvant, or other keyhole limpet haemocyanin-containing vaccines. 24. Previous serious reaction to a vaccine, such as angioedema or anaphylaxis. 25. Known history of drug and/or alcohol abuse and those known to be hepatitis positive.