Therapeutic vaccination is an exciting new development in hypertension, but proof-of-concept in the clinic is not yet clearly established. Effective renin-angiotensin system (RAS) inhibition by a twice-yearly treatment would be attractive in pre-hypertension, maybe even preventing hypertension itself from developing. However, it is hoped that proof-of-concept with a vaccine, the efficacy of which is easy to measure, will encourage development of more adventurous vaccines directed against targets such as aldosterone or completely novel pathways where alternative treatments are scarce or absent.
Two current angiotensin vaccines are in development. PMD3117 is a modified angiotensin I coupled to keyhole limpet haemocyanin. CYT006-AngQb is a conjugate of angiotensin II linked to virus particles. Studies in patients with hypertension demonstrate some efficacy for both vaccines, but far short of what is seen with existing RAS inhibitors. Modification of the immunogen or adjuvant is required to boost the antibody titre.