BOSTON, USA – A federal judge on Thursday tentatively barred Roche Holding AG from beginning US sales of an anemia medication that a jury found violates patents held by Amgen.

But US District Judge William Young said Thursday he was open to allowing US sales of the drug Mircera if Roche agrees to certain conditions, including paying a higher royalty to Amgen of 22.5% of the drug’s US sales, compared with the 20% royalty Roche had proposed earlier this month.

Basel, Switzerland-based Roche also would have to guarantee that it wouldn’t charge higher prices than those for Amgen’s two top-selling anemia treatments, Aranesp, introduced in 2001, and Epogen, introduced in 1989.

The Boston-based judge gave Roche the option of resubmitting a proposal under which it could begin US marketing of Mircera under the judge’s terms.

Roche said it was disappointed by the order barring US sales and will evaluate Young’s request for another proposal as it also considers filing an appeal.

Spokeswoman Linda Dyson said Roche “earnestly believes its original proposal submitted to the court is fair and aggressive.”

Young’s ruling was tentative, and allows the sides to suggest modifications within 30 days. The judge also said he was still considering whether to expand his temporary order barring US sales of Mircera by imposing a permanent injunction that would remain after the Amgen patents begin expiring in 2013.

“The parties are free to argue for different terms,” Young said. “But this is my first cut.”

Dan Whelan, a spokesman for Thousand Oaks, Calif.-based Amgen, said, “We are pleased the court is providing preliminary relief against a prover infringer. We do believe a permanent injunction is the appropriate remedy in this case, and look forward to the court’s decision on that matter.”

Shares of Amgen fell $1.07, or 2.3%, to $45.53. Roche’s shares traded in Zurich fell 0.4% to CHF228.60 Thursday.

In November, Roche won US Food and Drug Administration approval to sell Mircera for patients with anemia caused by kidney failure. But sales have been held up by the patent dispute. In October, a jury in Young’s court ruled that Roche’s treatment infringed on several Amgen patent claims.

On Thursday, Young denied Roche’s motion to overturn the jury verdict.

The drug has been sold since last summer in Europe, where sales are not affected by Young’s rulings.

U.S. sales of Mircera would present the latest challenge for Amgen’s two anemia drugs, which had combined sales of more than $6 billion last year. Amgen has had a virtual lock on the anemia treatment market for nearly two decades.

While Amgen argues that Mircera would not offer patients significant benefits compared with its own medications, Roche says its treatment would give patients an important new option. Roche says Mircera is the only FDA-approved medicine capable of stabilizing patients’ hemoglobin levels with either a single dose every two weeks, or a dose every four weeks.

Sales of Amgen’s anemia drugs have fallen off after the FDA last year required stronger warnings for Aranesp and asked for additional studies. Using too much of the drug can increase the risk of blood clots, heart attack and death, according to the FDA.

In August, Amgen announced plans to cut up to 14 percent of its work force, or 2,200 to 2,600 positions, and it lowered its profit expectations because of declining Aranesp sales.

[Copyright ap 2008]