In the making: a vaccine against hypertension

You’ve heard of vaccines against polio, measles, small pox. What about a vaccine against hypertension? Last year, a paper presented at the American Heart Association Scientific Sessions reported about an investigational vaccine against angiotensin II. Angiotensin II is a vasoconstrictor agent – it causes constriction of blood vessels leading to increase in blood pressure. When a vaccine is investigational, it is still being tested and not yet ready for use.

However, this vaccine being tested by Cytos Biotechnology seems to be promising.

The name of the vaccine is CYT006-AngQb and is a virus-like particle-based conjugate vaccine. The vaccine is now tested in Phase II clinical trials. This means that the vaccine has passed through tests with animals and healthy humans without major safety problems. In Phase II trials, medications are tested in people showing the symptoms for which the drugs are indicated. In this case, CYT006-AngQb is intended for patients with mild to moderate hypertension.

Is the vaccine effective?

Preliminary results of the 2007 tests show that

“treatment with the high dose produced a significant reduction of daytime ambulatory blood pressure [BP] and a marked reduction in the early morning hours, when most adverse cardiovascular events occur.”

If approved, what would be the advantage of the vaccine over currently available antihypertensive drugs?

Well, antihypertensive drugs have to be taken on a daily basis because of their short half-life. CYT006-AngQb, on the other hand, produces extended antibody response because it has a half-life of about 4 months. That means, a hypertensive patient only needs to take medication 3 to 4 times a year.  In addition, currently available hypertensive drugs are not so effective in controlling early morning increases in blood pressure, the time of the day when major cardiac events such as heart attacks and stroke usually occur.

Even if the vaccine proves to be effective, will it be safe?

The study tested the vaccine in 72 patients with mild to moderate hypertension and followed-for 12 moths. During this period, the vaccine was observed to be well-tolerated by the study participants. There were side effects but they were mostly mild and the most common of these were headaches and irritation on the injection site.

The author, Prof. Juerg Nussberger

“Despite the fact that effective drugs are available to treat hypertension, only about one out of four hypertensive patients has the blood pressure successfully controlled. Once people are aware of the often symptomless hypertension, they have to take their medications daily, and many are apparently unable or unwilling to take pills every day for the rest of their lives. The major remaining medical need in this important therapeutic area is thus improved patient compliance. If we could support or substitute the oral therapy with a vaccine that would need to be given just every few months, I think we could achieve a better control of high blood pressure.”

The results of the study were later published in the journal Lancet.

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