SUMMARY:  A recent decision from the Federal Circuit examined the application of the doctrine of equivalents in an infringement suit relating to biological products.  In particular, the Federal Circuit stated that the doctrine only applies in exceptional cases, thereby suggesting a limitation of the application of the doctrine.

In Amgen Inc. v. Sandoz Inc., No. 2018-1551 (Fed. Cir. May 8, 2019), the Court of Appeals for the Federal Circuit affirmed the decision of the United States District Court for the Northern District of California, which granted summary judgment of non-infringement to Sandoz Inc. (“Sandoz”). Id., slip op. at 2.  Particularly, the district court determined Sandoz did not infringe claim 7 of U.S. Patent No. 8,940,878 (“the ’878 patent”). Id.  After confirming the district court’s determination of no literal infringement of claim 7 of the ’878 patent, the Federal Circuit also found that Sandoz did not infringe the claim under the doctrine of equivalents, emphasizing that the doctrine only applies in “exceptional cases.” Id., slip op. at 10-11.

Amgen Inc. (“Amgen”) produced biological products, such as Neupogen® and Neulasta®, for treating neutropenia, a deficiency of white blood cells often associated with exposure to chemotherapeutic regimens or radiation therapy in cancer treatments. Id., slip op. at 3.  Neulasta® is materially identical to, but structurally larger than, Neupogen®, enabling long-acting administration. Id.  In 2014, Sandoz submitted to the Food and Drug Administration (“FDA”) an abbreviated Biologics License Application (“aBLA”) to market a biosimilar product to Neupogen®. Id.  In response, Amgen filed a complaint seeking a declaratory judgment that Sandoz’s proposed product would infringe U.S. Patent No. 6,162,427. Id.  In 2015, Sandoz received FDA approval and launched Zarxio® which resulted in Amgen amending its complaint to plead infringement of the ’878 patent. Id., slip op. at 4.  Also in 2015, Sandoz submitted an aBLA to market a biosimilar product to Neulasta®, which led Amgen to file another complaint for infringement of the ’878 patent. Id.

Focusing on the Federal Circuit’s treatment of the infringement action related to the ’878 patent, the patent-at-issue discloses methods of protein purification via absorbent chromatography. Id.  In particular, claim 7 of the ’878 patent is directed to the use of a non-affinity separation matrix. Id., slip op. at 5.  The district court construed the claim to require separate washing and eluting steps, with the eluting step necessarily performed after the washing step. Id., slip op. at 7.  Thus, the district court granted summary judgment for Sandoz for non-infringement of claim 7 of the ’878 patent because Sandoz’s process only involved one step (applying a refold solution to a matrix without separate washing or eluting steps). Id.

On appeal, Amgen argued that claim 7 “cover[ed] any number of solutions or steps as long as the functions of washing and eluting happen[ed] in sequence.” Id., slip op. at 8.  Particularly, Amgen argued that Sandoz’s process required washing preceding elution at any given point in the separation matrix. Id.  However, the Federal Circuit found the washing and eluting steps of claim 7 to require “discrete solutions.” Id., slip op. at 9.  In addition, the Federal Circuit determined that the washing and eluting steps must be performed in sequence. Id.  As such, the Federal Circuit found that Sandoz’s process could not literally infringe claim 7 of the ’878 patent—as it was undisputed that Sandoz’s process used only one step and one solution. Id.

Amgen further argued that the district court erred by rejecting the argument that Sandoz’s process infringed claim 7 through the doctrine of equivalents. Id., slip op. at 10.  Amgen presented that Sandoz’s one-step, one-solution process was insubstantially different because it “achieves the same functions (washing and eluting), in substantially the same way (binding protein preferentially compared to contaminants, and then rising salt concentrations to reverse protein binding) to achieve the same result (protein purification).” Id. (citation omitted).

Under the doctrine of equivalents, a product or process that does not literally infringe a patent claim may nonetheless infringe if there is “equivalence” between the elements of the accused product or process and the claimed elements. Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 21 (1997).  Rather than applying the doctrine of equivalents to a patent claim as a whole, the doctrine must be applied to each element of the claim that is not literally present in the allegedly infringing product or process. Id. at 29.  Moreover, the doctrine of equivalents is not so broad as to effectively eliminate an element in its entirety. Id.  As such, in order for an accused product or process to infringe, the accused product or process must contain elements identical or equivalent to each claimed element of the patented invention. Id. at 40.  Equivalency may be found by examining a substitute element for a matching function, way, and result of the claimed element or a finding of insubstantial differences between the substitute element and the claimed element. Id.

Applying the doctrine of equivalents to this case, the Federal Circuit affirmed the district court’s finding that Sandoz’s one-step, one-solution process does not function in the same way as the claimed process. Amgen Inc., slip op. at 11.  The Federal Circuit concluded that Amgen was seeking to cover any method of using a salt concentration gradient in an absorbent matrix to separate a protein of interest. Id.  However, claim 7 of the ’878 patent included narrower limitations. Id.  For instance, the Federal Circuit affirmed that claim 7 required separate steps including “refolding,” “washing,” and “eluting” solutions and thus stated that the language of claim 7 could not extend these “limitations to cover nearly any type of absorbent chromatographic separation.” Id.  The Federal Circuit further explained that the doctrine of equivalents is not simply an additional prong of every infringement charge to “extend protection beyond the scope of the claims.” Id. (quoting London v. Carson Pirie Scott & Co., 946 F.2d 1534, 1538 (Fed. Cir. 1991)).  Specifically, the doctrine of equivalents cannot be applied to “effectively read out a claim limitation.” Id. (quoting Primos, Inc. v. Hunter’s Specialties, Inc., 451 F.3d 841, 850 (Fed. Cir. 2006)).  Considering the aforementioned principles, the Federal Circuit determined that the doctrine of equivalents applies only in “exceptional cases.” Id.

TAKEAWAY:  In Amgen Inc., the Federal Circuit suggests that the doctrine of equivalents may only be used to find infringement of an accused product or process that does not literally infringe the claimed elements in “exceptional cases.”  Such an interpretation may represent a restriction or narrowing of the doctrine.  Thus, when drafting patent claims, additional consideration might be given to literal infringement of foreseeable third party processes or products as infringement under the doctrine of equivalents may now be even more difficult to establish.