Placebo controlled study of an angiotensin immunotherapeutic vaccine (PMD3117) in hypertensive subjects

Objective: Immunisation against the renin system might obviate the need for daily drug administration. No previous study has determined whether a sustained antibody titre can be achieved, and whether this might have pharmacological activity. Our primary objective was to determine the antibody response to two PMD3117 vaccine dosing regimes. Secondary objectives were to assess tolerability, and to determine if immunisation changes renin and aldosterone secretion, or attenuates the BP rise after withdrawal from an ACE inhibitor. Methods: PMD3117 is a 12 amino acid analogue of angiotensin-I linked to Keyhole Limpet Haemocyanin, and adsorbed onto aluminium hydroxide (Alhydrogel). 24 patients responsive to an ACE inhibitor or angiotensin blocker were randomly assigned to 3 or 4 subcutaneous injections over 6 weeks with 100 mg peptide equivalent of PMD3117 or Alhydrogel. Blood was drawn at each visit for estimation of renin, aldosterone, and the IgG antibodies to angiotensin. Existing treatment was withdrawn for 2 weeks before and after the 6 weeks of vaccination. 24-ABPM was performed at the start and finish of the withdrawals.