A federal appeals court ruled that Roche’s Mircera anemia med could be imported - so long as it wasn’t for sale, but reversed a decision from the International Trade Commission that it couldn’t rule on whether the importation infringed on patents held by Amgen.

The decision (look here) is the latest twist in a searing battle between Roche and Amgen, which is trying to prevent the drugmaker from selling Mircera in the US, after winning a trial last year in which Roche was found to have violated patents on Amgen’s best-selling Aranesp anemia drug. The October decision came just one month before the FDA approved Mircera for the US market for patients with anemia caused by kidney damage.

“Roche has set a course to export Amgen’s hard-earned jobs and income through the sale of peg-EPO in the United States in violation of our patents,” Amgen spokesman Dan Whelan tells Reuters. “Today Amgen’s position that the ITC has the authority to protect domestic industry from threatened patent infringement has been vindicated.” A Roche spokeswoman writes us to say that “we are studying the Federal Circuit Court opinion and are reviewing it in light of our ongoing litigation.”

Meanwhile, a federal court in Massachusetts is deciding whether to approve Amgen’s request to grant a permanent injunction banning Roche from selling Mircera in the US. A federal judge William Young this week indicated he would allow Mircera on the market if Roche agreed to several conditions, including a 22.5 percent royalty payable to Amgen and not to charge a higher price than rivals.

If final approval is granted to the tentative agreement with Roche, Amgen would face a new rival to its top-selling anemia treatments, Aranesp and Epogen, whose sales already are sagging amid recent safety concerns.

Amgen’s anemia meds were both among the 10 biggest-selling drugs in the US last year, with Aranesp at $3.2 billion and Epogen at $3.1 billion, according to IMS Health. Amgen’s patents on the drugs, which accounted for more than 40 percent of its revenue last year, begin expiring in 2013.

Roche Chief Executive Franz Humer has said the company could wait until Amgen’s patents expire before launching its drug.

Source: The Wall Street Journal