TRENTON, N.J. (AP) — Biotech company Amgen Inc said Tuesday that a federal court has sided with it in a patent dispute related to its anemia medication. Thousand Oaks, Calif.-based Amgen said the Boston-based 1st U.S. Circuit Court of Appeals ruled that the Roche Group's rival product, Mircera, infringes on four Amgen patents. The patents relate to genetically engineered erythropoietin, a hormone that stimulates red blood cell production, and to the processes used for making it. Amgen sells erythropoietin products under the brand names Epogen and Aranesp. They are generally prescribed to kidney dialysis patients and people undergoing chemotherapy. The ruling upheld a prior ruling by the Massachusetts District Court, Amgen said. The federal court remanded for a new trial the issue of whether Switzerland-based Roche infringes on a fifth patent with its product, reversing a finding of non-infringement by the District Court. The appeals court left in place a permanent injunction that bars Roche from selling Mircera in the United States. Amgen shares closed down 73 cents, or 1.2 percent, at $58.48 Tuesday.