Zeneca Fights Off Tamoxifen Challenge

Zeneca has successfully defended its US patent for Nolvadex (tamoxifencitrate) against a challenge by generics firm Novopharm. Zeneca said that Novopharm's case "has now been effectively disposed of." As a result of the new decision, Zeneca's patent for tamoxifen has been safeguarded until 2002.

Theoretically, Novopharm could take the case still further to the US Supreme Court, but this is thought to be unlikely. Zeneca's shares were buoyed by the decision, as Nolvadex remains one of the company's biggest-selling drugs, producing sales of L332 million ($538 million) in 1996 (down from L359 million in 1995). The reason for the downturn is that tamoxifen's patents have already expired in most European countries, where strong generic competition now exists.

The US Court of Appeals for the Federal Circuit upheld an earlier District Court ruling in favor of Zeneca, which first began patent infringement proceedings against Novopharm in January 1995. This was sparked by Novopharm filing an Abbreviated New Drug Application for a generic version of tamoxifen, which under US law is an act of patent infringement. After the District Court upheld Zeneca's patent in April 1996, Novopharm was prohibited from making any sale of generic tamoxifen.