New antithrombotic Arixtra cleared in USA

Akzo Nobel subsidiary Organon and Sanofi-Synthelabo have been granted USapproval for their novel antithrombotic drug Arixtra (fondaparinux sodium) for the prophylaxis of deep vein thrombosis in patients undergoing surgery for hip fracture as well as hip and knee replacement procedures. The companies said that the registration, which was widely anticipated, will be followed by a launch in the first quarter of 2002 in the USA, possibly by the end of January. Arixtra is also under regulatory review in the European Union.

However, some of the shine for the drug's sponsors was rubbed off by what some analysts considered as a restricted approval for Arixtra, which could limit the number of patients eligible to receive it. Reported in the Financial Times, the analysts said that the FDA approval included a clause that the drug should not be used in patients weighing less than 110 pounds or in those with reduced kidney function, because of a higher risk of serious bleeding. Also, unlike Arixtra's closest rival, Aventis' low-molecular weight heparin Lovenox/Clexane (enoxaparin), there is no antidote to reverse its effects.

The labeling for the product also includes a black box warning stating that Arixtra is not to be used when spinal anesthesia or spinal puncture is employed, as there is a risk of developing a blood clot in the spine which can result in long-term or permanent paralysis.