Amgen Inc. won a jury verdict that may prevent Roche Holdings AG from selling its version of a competing anemia medicine in the U.S., Amgen said Tuesday.

A federal jury in Boston ruled that Roche’s drug, Mircera, which is still in development, would infringe on three existing Amgen patents related to generating a protein component found in the drug.

Amgen sued the Swiss drug maker in 2005 to prevent Mircera from entering the U.S. market and competing with Amgen’s two biggest sellers, anemia drugs Epogen and Aranesp. The two drugs combined for nearly $7 billion in sales last year for Thousand Oaks-based Amgen nearly half of its total revenue.

Roche said it was anticipating the U.S. Food and Drug Administration to approve Mircera next month.

The judge said that if Roche wishes to contest the ruling it must file briefs within 60 days. Roche added that it was evaluating its legal options and was considering an appeal. A Roche executive said earlier this month that it would not launch the drug in the United States if it lost the trial.

Shares in Amgen added 2.5 percent to $57.53 Tuesday in trading on the Nasdaq.