In a patent owner’s declaratory judgment action under the Biologics Price Competition and Innovation Act (“BPCIA”) a Federal Circuit panel in Amgen Inc. v. Sandoz Inc., Appeal No. 2018-1551 (Fed. Cir. May 8, 2019) narrowly construed the doctrine of equivalents and unanimously affirmed the district court’s grant of summary judgment that Sandoz’s filgrastim and proposed pegfilgrastim biosimilars do not infringe Amgen’s patents in suit. In reaching this conclusion, the Federal Circuit panel proclaimed that the doctrine of equivalents “applies only in exceptional cases and is not simply the second prong of every infringement charge, regularly available to extend protection beyond the scope of the claims.” Slip Op. at 11.

This litigation is noteworthy for two reasons. First, it is one of the earliest in which a reference biological sponsor brought suit for declaratory judgment of patent infringement against a biosimilar applicant that failed to disclose its aBLA application and manufacturing information as set forth in the BPCIA. Second, the panel’s narrow application of the doctrine of equivalents illustrates the unsettled nature of this doctrine in Federal Circuit precedent.

In 2014, Sandoz submitted an abbreviated Biologics License Application (“aBLA”) for a biosimilar to Amgen’s filgrastim product (marketed as Neupogen). Sandoz declined to provide its application and manufacturing information as specified in the BPCIA. In 2017, the Supreme Court ruled that federal law does not provide any injunctive remedy to compel release of this information, but instead authorizes the biologic reference product sponsor to bring a declaratory judgment action against the biosimilar applicant for the infringing act of submitting the aBLA. Sandoz Inc. v. Amgen Inc., 137 S. Ct. 1664, 1672 (2017).

Amgen filed a complaint in 2014 seeking a declaratory judgment action that Sandoz’s proposed filgrastim biosimilar would infringe U.S. Patent No. 6,162,427 (the “‘427 patent”), directed to methods of treatment. In 2015, when Sandoz launched its filgrastim biosimilar, Amgen amended its complaint to also assert infringement of U.S. Patent No. 8,940,878 (the “‘878 patent”), directed to methods of protein purification.

In 2015, Sandoz submitted an aBLA for a biosimilar to Amgen’s pegfilgrastim product (marketed as Neulasta®). In 2016, Amgen filed a separate suit for infringement of the ‘878 patent based on the filing of this aBLA.

The ‘878 patent discloses methods of protein purification by adsorbant chromatography. Claim 7 of the ‘878 patent, at issue in the appeal, is directed to a purification method that includes, among other things, the steps of “washing” a separation matrix and then “eluting” the desired protein from the separation matrix. The Federal Circuit affirmed the district court’s construction that the washing and eluting limitations were separate process steps performed with discrete washing and elution solutions, reasoning that the claim language logically requires that the enumerated steps be performed in sequence, and because the specification consistently described washing and eluting as separate steps performed by different solutions. Since it was undisputed that Sandoz’s process used only one step and one solution, there was no literal infringement.

Rejecting Amgen’s argument for equivalent infringement, the panel reasoned that the doctrine of equivalents only applies “in exceptional cases” and “cannot be used to effectively read out a claim limitation.” Slip Op. at 11. Accordingly, it affirmed the summary judgment of non-infringement.