BioWorld International Correspondent

LONDON - Amgen Inc. received a double blow against the patent covering its blockbuster drug erythropoietin (EPO) when the UK House of Lords reversed an earlier legal decision and ruled the claims of the patent are too broad, while at the same time upholding an earlier judgment that Transkaryotic Therapies Inc.'s method of producing EPO does not infringe Amgen's EPO patent.

In his ruling, Lord Hoffman said: "It is clear Amgen have got themselves into difficulties because, having invented a perfectly good and groundbreaking process for making EPO and its analogues, they were determined to try and patent the protein itself, notwithstanding that even when isolated, it was not new."

The judgment by the highest court in the UK has wide-ranging implications for the UK biopharmaceutical industry, said Penny Gilbert, a partner in Bristows, a specialist intellectual property law firm in London. She told BioWorld International that users of innovative technologies that are loosely based on earlier patented inventions but work differently (as is the case with TKT) will not be prevented from operating.

"There are broad implications for anyone trying to get a patent on a protein," she said. "Overly broad claims that try to cover all possible forms of a molecule, however made, will weaken the patent."

The ruling concerns the UK portion of Amgen's European EPO patent. Gilbert said, "In terms of reading across to [mainland] Europe there won't be a direct consequence."

TKT, of Cambridge, Mass., welcomed the ruling, saying it intends to launch Dynepo, its version of EPO, in Europe in 2005. However, Amgen's patent expires at the end of 2004 in the UK and Europe, so the Thousand Oaks, Calif.-based company would have found itself facing competition in the EPO market in Europe regardless.

In 2003, worldwide sales of Epogen, Amgen's version of EPO, reached $2.4 billion.

The UK ruling was in contrast to the U.S., where a week earlier the District Court of Massachusetts ruled in Amgen's favor on its EPO patents. TKT, with partner Aventis Pharma AG, of Frankfurt, Germany, have said they will appeal. The U.S. and UK cases cannot be compared directly, as the claims in the patents are different.

TKT now plans to license its gene-activation technology more widely for the production of other biogenerics. In gene activation, a DNA sequence is added to a cell to turn on an endogenous gene and stimulate production of EPO, or another desired protein. That is in contrast to Amgen's EPO production process in which the human gene for EPO is inserted into Chinese hamster ovary cell lines.

Although the House of Lords ruling clears the way for biogenerics of known proteins to be produced by an alternative process, Gilbert does not believe it will have any implications for the process of getting biogeneric regulatory approval.

"Because it has removed the risk of litigation it might encourage people to try and get into the market earlier," she said. "But in terms of the regulatory process for biogenerics - you have still got to prove bioequivalence, which is very difficult, or conduct full clinical trials, which is expensive. These are the current sticking points with the regulators. The patent doesn't come into it."

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