Protherics says that the first patient has been enrolled in a mid-stage trial of a vaccine it is developing for the treatment of high blood pressure.

A Phase IIa clinical trial has been intiated in the UK of the firm’s Angiotensin Therapeutic Vaccine which will look at 124 patients with mild to moderate hypertension. Patients will be given a course of injections over six weeks to assess the safety and tolerability of the vaccine, which incorporates Protherics' promising novel vaccine adjuvant, CoVaccine HT. In addition both antibody response and effect on blood pressure will be assessed and the latter results are expected in the first half of 2009.

The London-headquartered firm said it has shown in a previous Phase IIa study that a formulation of ATV, incorporating the adjuvant Alhydrogel, modulated key hormones involved in regulating blood pressure in hypertensive patients. However the new formulation, incorporating CoVaccine HT, has demonstrated “a much stronger immune response in pre-clinical models”.

If things go well, ATV could be a massive product. The global market for anti-hypertensives is worth around $30 billion and the vast majority of existing therapies are tablets which need to be taken on a daily basis, usually for the rest of a patient's life. However, Protherics notes that many people with high blood pressure fail to take their medicines as prescribed, and it is estimated that 70% of patients with hypertension do not have their blood pressure adequately controlled.

Protherics' chief executive Andrew Heath said that ATV is a potential value driver for the company. He added that a vaccine approach to the treatment of high blood pressure, which may require only three injections and a booster after six months, “promises to address the issue of poor patient compliance with daily medication and thus reduce the incidence of stroke and heart attacks”.

Mr Heath concluded that with data expected within a year, “this could be a major outlicensing opportunity."