But researchers had to add an anticoagulant to keep it from clotting after it's out of the body.

FORBES: The Plot Thickens

The FDA has approved only one product, ATryn, an anticoagulant derived from the milk of transgenic goats.

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Boehringer Ingelheim is starting to inform physicians about a new contraindication for its oral anticoagulant drug Pradaxa (dabigatran).

FORBES: Pradaxa To Be Contraindicated In Patients With Mechanical Heart Valves

Apixaban (tradename: Eliquis) is a novel anticoagulant for the prevention of stroke and other thromboembolic events that is awaiting FDA approval.

FORBES: Why Is Pharma Out-Licensing Its Compounds?

Another possibility that has many doctors excited is Exanta, a new oral anticoagulant being developed by AstraZeneca (nyse: AZN - news - people ).

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We are not making any changes to our anticoagulant market model because we reduced our Xarelto and Pradaxa share assumptions when the top-line data from ARISTOTLE were released this past June.

FORBES: Analyst Says Xarelto Niche "Still Secure"

Eliquis now has the unique distinction of being the only new anticoagulant to reduce stroke, major bleeding, and death versus the gold standard warfarin in atrial fibrillation patients (the largest commercial opportunity, in our view).

FORBES: Analyst Says Xarelto Niche "Still Secure"

Charles Francis , a professor of medicine at the University of Rochester who headed up this clinical trial, says that these results are especially promising because orthopedic surgery is a difficult test of an anticoagulant.

FORBES: Magazine Article