The Food and Drug Administration (FDA) announced today the approval of ARIXTRA™ (fondaparinux sodium) Injection for reducing the risk of blood clots after orthopedic surgery for hip fracture, hip replacement, and knee replacement. ARIXTRA™ is the first synthetic anticoagulant indicated for use in these types of surgeries.

The formation of clots in the deep veins of the legs is common after these surgeries and can lead to serious and potentially fatal consequences, such as when the clots break off and travel to the lungs. The drug works by inhibiting Factor Xa, a key component involved in blood clotting.

FDA based its approval on randomized double-blind clinical trials conducted in 8,000 patients, of whom over 4,000 received ARIXTRA™ for hip fracture, hip replacement, or knee replacement surgeries. The population ranged in age from 17 to 97 years and in body weight between 66 and 373 pounds and included both men and women.

The major side effect of ARIXTRA™ is serious bleeding. ARIXTRA™ is not to be used in patients with severly impaired kidney function or in patients who weigh less than 110 pounds, because they may have an increased risk for serious bleeding. Elderly patients also may be more likely to experience serious bleeding complications.

In addition, the labeling for this product includes a black box warning that states ARIXTRA™ is not to be used when spinal anesthesia or spinal puncture is employed. There is a risk of developing a blood clot in the spine, which can result in long-term or permanent paralysis.

ARIXTRA™ was developed by Sanofi-Synthelabo LLC, and Organon.