Federal Circuit Affirms Earlier Decision Dismissing Amgen's Suit Against Coherus

July 30, 2019
Kelly Davio

In yesterday’s decision, the panel agreed with the district court that, during prosecution of the patent, Amgen “clearly and unmistakably surrendered salt combinations other than the particular combinations recited in the claims,” and that prosecution history estoppel bars Amgen from succeeding on its infringement claims under the doctrine of equivalents.

Yesterday, Amgen lost its fight to block Coherus BioSciences from selling its biosimilar pegfilgrastim, Udenyca, referencing Amgen’s innovator drug, Neulasta. A 3-judge panel of the US Court of Appeals for the Federal Circuit affirmed a decision that, in 2018, dismissed Amgen’s case.

Amgen holds a patent, US patent 8,273,707, on methods of purifying proteins in which specific salts are used in a loading solution. When Coherus filed an abbreviated Biologics License Application (aBLA) for its biosimilar pegfilgrastim, the aBLA revealed that Coherus’ manufacturing process contained steps to purify pegfilgrastim.

One such step involved use of a salt combination in a chromatography buffer, though this combination was not among the specific combinations described in Amgen’s patent. However, Amgen sued Coherus for infringing on its patent under the doctrine of equivalents, a means by which a patent holder can claim infringement even if not all of the elements of the patented invention are identical in the allegedly infringing process.

Coherus moved to dismiss Amgen’s complaint, and a magistrate judge recommended that Coherus’ motion be granted. The district court adopted the magistrate judge’s report and granted Coherus’ motion to dismiss.

In yesterday’s decision, the panel agreed with the district court that, during prosecution of the patent, Amgen “clearly and unmistakably surrendered salt combinations other than the particular combinations recited in the claims,” and that prosecution history estoppel bars Amgen from succeeding on its infringement claims under the doctrine of equivalents.

Thus, according to the decision, “the district court did not err” in its ruling, and the panel affirmed the district court’s decision.

Thomas Fitzpatrick, JD, Coherus’ chief legal officer, said in a statement that “We are pleased by the Federal Circuit’s precedential decision and have always been confident that the District Court’s decision would be affirmed on appeal.” He added, “We are particularly pleased to continue our mission to successfully lower healthcare costs and expand patients’ access to life-saving drugs.”

Coherus launched its pegfilgrastim biosimilar in the United States in January 2019 and recently marked the 6-month anniversary of the product’s launch by revealing that the company has produced more than 400,000 prefilled syringes of the product to date, and by saying that its preliminary unaudited net sales for the product in the last quarter are estimated to be between $79 million and $84 million.