In one of the most eagerly-awaited patent trials in recent years, Amgen has successfully defended three out of the five patents protecting its best-selling drug Epogen. In a 245-page ruling, Judge William G Young of the US District Court in Boston ruled that Transkaryotic Therapies (TKT) infringed the patents in its experimental drug Dynepo. But he ruled that two further patents on Epogen were not infringed. Dynepo is at present in phase III clinical trials. TKT´ s shares fell over 50% following the decision, while Amgen´ s share price shot up 10%.