Amgen Wins Round in Dispute Over Epogen Anemia Drug

Amgen Inc. won a preliminary victory Friday in its patent dispute with Transkaryotic Therapies Inc. over the best-selling anemia drug Epogen.

U.S. District Judge William Young limited Transkaryotic’s ability to claim Amgen’s patents are invalid. The judge postponed until at least September a final ruling in the patent fight.

Young reserved judgment on whether Transkaryotic infringed Amgen’s patents and certain other defenses. The judge has been trying the case without a jury since May.

“My gut tells me that if there’s other evidence, I’d like to hear it,” Young said. He has said he will hold additional hearings in the case after Sept. 5.

David Kaye, spokesman for Amgen, said, “From our point of view, [the judge] made some comments about his thinking but issued no rulings. He left the door open to change his mind.”

At stake is an estimated $4 billion in annual U.S. sales for Epogen. Amgen developed a method for copying erythropoietin, which healthy kidneys make to stimulate red blood cell production. The final product, Epogen, is given to kidney dialysis patients, who often become anemic.

Though Young didn’t rule on whether Transkaryotic infringed Amgen’s patents, he knocked out two legal defenses the company had hoped to mount to prove them invalid.

Young did preserve the smaller company’s bid to claim the patent examiner based his decision to grant Amgen the patents on insufficient information. The judge declined to rule on whether the descriptions of the technology in Amgen’s patents were too broad.

Thousand Oaks-based Amgen, the world’s biggest biotechnology company, contends that Transkaryotic and Aventis predecessor Hoechst Marion Roussel Inc. are infringing its patents by developing another version of erythropoietin. Amgen sued Transkaryotic in 1997.

The case, closely watched by patent attorneys, investors and drug makers, could permit up-and-coming gene therapy companies such as Transkaryotic to more easily challenge the dominance of established pharmaceutical makers such as Amgen, patent experts say.

Amgen argued that Transkaryotic should not be allowed to capitalize on its success by misappropriating patented inventions.

Amgen shares gained $3.94 to close at a record $78, while Cambridge, Mass.-based Transkaryotic fell $3.88 to close at $31.13, both on Nasdaq.