The US Supreme Court says that it will not hear an appeal by Amgen relating to two patents covering Epogen (epoetin alfa), which relate to the composition and method of manufacture of erythropoietin. Amgen was seeking to have the Supreme Court overturn rulings by a lower court that were issued in favour of Shire's and Sanofi-Aventis' competing anaemia drug, Dynepo (epoetin delta).

Amgen launched its bid after the Court of Appeals for the Federal Circuit reversed a trial judge's decision in August to uphold the two patents. The ruling marked the second time that Amgen, which launched a lawsuit against Sanofi and Shire in 1997 for allegedly violating several patents, has had a favourable decision by the lower court overturned by the appeals court in the case.

In its appeal to the Supreme Court, Amgen argued that the Federal Circuit court should defer to the trial judges on the scope of disputed patents, instead of questioning key patent interpretations made by the lower court. The firm had wanted the Supreme Court to review the Federal Circuit's practice of drawing its own conclusions about patent claims rather than relying solely on findings made by the trial court. "It produces incorrect results and causes litigants and district courts to waste tremendous resources," Amgen said.