The U.S. Supreme Court said it would not hear an appeal by drug maker Amgen that centers on how much leeway appeals courts should have in overruling the findings of lower courts in patent cases.
In the latest in a series of major patent cases, the high court declined to review whether a specialized patent appeals court in Washington, D.C., can scrap key patent interpretations made by district court judges during an appeal.
The case is part of Amgen's long-standing patent battle to prevent two other drugmakers from selling a product that would compete with its widely used Epogen anemia treatment.
Amgen in 1997 sued the drugmakers, Hoechst Marion Roussel and Transkaryotic Therapies, in U.S. District Court for the District of Massachusetts, alleging their planned product infringed five Amgen patents. Hoechst, after a merger, is now part of Paris-based Sanofi-Aventis. Transkaryotic has since been acquired by Shire Pharmaceuticals Group of Britain.