German President Horst Koehler awarded the researchers the prize as well as the check for 250,000 euros ($377,675) on Wednesday.

Each year, tens of thousands of Germans fall ill due to blot clots that develop in their vessels - a condition known as thrombosis. The most common type of thrombosis occurs in the legs or pelvis. This can be painful and can also result in dangerous complications.

If the clot is carried by the bloodstream to another part of the body, it can block a blood vessel in a vital organ like the brain, lungs or heart. This, in turn, can result in a stroke, pulmonary embolism or a heart attack.

Over 100,000 cases of pulmonary embolism are recorded in Germany each year, with 25,000 to 30,000 of these resulting in death. In the western world, more people die of the effects of thrombosis than of breast cancer, prostate cancer, AIDS and car accidents put together.

Anyone who has had thrombosis just once faces a higher risk of getting it again.

Making an improvement

Until now, two types of thrombosis medicine have been on the market: Heparin and vitamin K antagonists. However, according to anesthesiologist Dagmar Kubitza, their usage is relatively complicated, including the need for daily injections or regular blood tests. In the case of vitamin K antagonists, under-dosing and overdosing are a regular occurrence.

Since 1995, Dagmar Kubitza has been working as project leader in the area of clinical pharmacology for Bayer in the central-western German city of Wuppertal. Together with a team of researchers, she has developed a new thrombosis medicine, Xarelto, which has an advantage over the usual medication.

"Xarelto can be taken as a tablet once a day," said Kubitza. "The dose doesn't have to be adjusted and it doesn't have to be controlled."

According to the company, Xarelto was tested on more than 65,000 patients during clinical studies. Kubitza said that the drug has proven to be well-tolerated by the human body. Since October 2008 it has been available as a preventative measure for vein thrombosis and to adults with artificial hip and knee joints. Other areas of use, such as stroke prophylaxis accompanying atrial fibrillation, are soon to follow.

"I see a wide spectrum of usage," said Dagmar Kubitza. "“And because the substance has advantages over the currently available medication, I think that Xarelto will definitely contribute to medical progress."

The Xa factor

The idea for new thrombosis medication came from pharmacologist Elisabeth Perzborn. Together with Dagmar Kubitza and Frank Misselwitz, Perzborn led the development of the drug.

"I have always been interested in thrombosis," said Perzborn. "The next step was to see what improvements we could make to anti-clotting medication. I observed the clotting process and noticed: factor Xa is what does it."

Clotting is a natural chain-reaction that occurs in the body whenever a blood vessel is injured, like when we cut a finger. Towards the end of this reaction, factor Xa becomes involved. It triggers the production of thrombin, an enzyme that contributes to the formation of blood-clots. Xarelto inhibits factor Xa and therefore the clot-forming process.

Author: Andreas Ziemons (ew)

Editor: Kate Bowen