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Hypertension Vaccine- anyone got comments, info?

Posted: Sat Nov 10, 2007 4:18 am
by Didi Ananda Rucira
Please see

http://www.medscape.com/viewarticle/565440

Hypertension Vaccine Safe, Well-Tolerated in Phase 2a Study
Susan Jeffrey

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November 6, 2007 (Orlando) ­ Results of a phase 2 study suggest that an investigational vaccine against angiotensin II was safe and well tolerated in patients with mild to moderate hypertension. The vaccine produced a long-lived antibody response with a half-life of about 4 months.

"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," study author Jürg Nussberger, MD, from Centre Hospitalier Université Vaudois, in Lausanne, Switzerland, told attendees at the American Heart Association 2007 Scientific Sessions here.

"Future studies will apply state-of-the-art formulations and treatment regimens to explore the full potential of this approach," he said.

Early Riser

Good control of hypertension has been undermined by problems of patient compliance with antihypertensive medications. Although many effective drugs are available, only about 25% of patients are optimally controlled, Dr. Nussberger said. "This has probably something to do with the fact that these drugs have to be taken daily and lifelong."

However, many of these drugs have a half-life of less than 24 hours, so if patients take them in the morning, the medications are at a trough in the early-morning hours, he said, just as the normal rise in blood pressure takes place and when most cardiovascular events occur.

"With a vaccine against angiotensin II, where there is a long-lasting effect with antibodies, you may not have this problem of peak-trough, and the patient has to come to the doctor maybe only 2 or 3 times a year," Dr. Nussberger said.

Previous work by Morris J. Brown and colleagues at the University of Cambridge, United Kingdom, had tested a vaccine against angiotensin I and shown some reduction of aldosterone, but no blood pressure–lowering effect.

The current study explored the safety and tolerability of CYT006-AngQb, a viruslike particle-based conjugate vaccine that targets angiotensin II in a placebo-controlled phase 2a sequential 2-dose comparison trial. In the study, 72 patients with mild to moderate hypertension, defined as a systolic pressure of 140 to 179 mm Hg and a diastolic pressure of 90 to 109 mm Hg, were enrolled; 5 patients dropped out for reasons unrelated to the study, he noted.

The study was done over 4 months; patients were given 100 µg or 300 µg of the antigen or placebo at time zero, then at 1 month and 3 months, after which they were followed for 8 months for safety. End points were safety and tolerability, with an "exploratory" look at efficacy with ambulatory blood pressure measurements and plasma renin concentrations.

Adverse events occurred in all patients in both groups, a finding that was not unexpected, since even placebo patients received an injection of aluminum hydroxide emulsion and so reported pain, erythema, or edema at the injection site. Headache was also more frequent in the vaccination group, but all of these effects occurred over the first 1 or 2 days and were reversible.

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