Heart Disease :: Anticoagulant-antidote combo safe in humans

A novel anticoagulant and its complementary antidote was proven safe in the first human trial, say researchers from Duke University Medical Center, Durham, N.C. The system could be valuable, holding promise that clinicians could titrate anticoagulation, as it may not require monitoring.

?This has the potential to replace heparin. Heparin has a number of inherent limitations, one being that the antidote to heparin, protamine, in some cases can cause anaphylactic shock,? said Richard C. Becker, M.D., professor of medicine and director of the Cardiovascular Thrombosis Center.

Dr. Becker said the two proteins in REG1, as the system is known, are both naturally occurring. The antidote is inert, he said, and the anticoagulant-antidote combination is also inert.

In an interview with reporters here, Dr. Becker described the dose-escalation study of 85 healthy subjects randomly selected to take REG1 or placebo. He said anticoagulant effects were seen within 15 minutes of administration, and that the antidote took complete effect in one to five minutes.

The half-life of the lowest dose of anticoagulant, 15 milligrams, was three hours, Dr. Becker said. At the highest dose, 90 milligrams, half-life was about 30 hours. ?There was no difference in bleeding between those who received the anticoagulant, the combination or placebo,? Dr. Becker said.

Both of the drugs are administered intravenously.

Dr. Becker said the trial was sponsored by Regado Biosciences.

The Duke scientists developed these two drugs as aptamers, drugs that work only on one specific molecule. The REG1 anticoagulant aptamer targets activated factor IXa, folding into a three-dimensional shape to lock precisely into factor IXa and block biologic activity and participation in a sequence of events leading to the generation of thrombin.

The antidote is a complementary protein that binds rapidly to the aptamer and changes its shape so it no longer inhibits factor IXa.

A second trial is now underway, testing REG1 in patients with stable coronary heart disease taking aspirin and/or clopidogrel, Dr. Becker said.

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Heart Disease :: Anticoagulant-antidote combo safe in humans
by ( Author at Spirit India )
Posted on at 12:42 am.
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