If Prior Art Discloses Ingredients and How to Mix Them, the “Cake” Is Anticipated

By on April 20, 2023
Posted In Patents

The US Court of Appeals for the Federal Circuit affirmed that challenged claims were invalid as anticipated based on principles of inherency where the disclosed prior art formulations and processes necessarily met a disputed claim limitation. Arbutus Biopharma Corp. v. ModernaTx, Inc., Case No. 20-1183 (Fed. Cir. April 11, 2023) (Reyna, Schall, Chen, JJ.)

Arbutus Biopharma owns a patent that matured from an application filed on March 9, 2015, that claims priority to a provisional application filed on June 30, 2010. The claimed invention provides stable nucleic acid-lipid particle (SNALP) formulations with a non-lamellar structure that function to increase the efficiency of nucleic acid entry into cells to promote the downregulation of gene expression. The non-lamellar morphology of a SNALP formulation was known to depend on two factors: the lipids incorporated into the SNALP formulation, and the process used to form the SNALPs. The patent disclosed five SNALP formulations of various compositions that can be used and incorporated by reference two US patent publications, which describe two methods that can be used to make SNALP formulations: the Direct Dilution Method (DDM) and the Stepwise Dilution Method (SDM). The representative independent claim recites a composition of SNALPs, wherein each particle in the plurality of SNALP particles comprises a nucleic acid and various lipid types. The claim also requires that at least 95% of the particles in the plurality of particles have a non-lamellar morphology (the Morphology Limitation).

Moderna filed a petition for inter partes review (IPR) asserting that all the claims of the Arbutus patent were anticipated by a prior art patent. The Patent Trial & Appeal Board found that although the Morphology Limitation was not expressly found in the prior art, the claims were anticipated. The Board determined that the Morphology Limitation was an inherent property (or natural result) of the prior art disclosures. On appeal, Arbutus challenged the Board’s inherent and express anticipation findings for many of the challenged claims, including for the Morphology Limitation.

A limitation is inherent if it is the natural result flowing from the prior art’s explicit disclosure. In other words, a limitation is inherent when the limitation is a property necessarily present in the invention and not actually an additional requirement imposed by the claims. In the IPR proceeding, Moderna argued that the Morphology Limitation was inherent because one skilled in the art would necessarily obtain formulations meeting this limitation by making formulations using the five formulations disclosed by the patent and using the DDM method (from the incorporated-by-reference disclosures) to prepare the formulations.

Both the challenged patent and the prior art disclosed five formulations that can be used to obtain the SNALP formulations. Evidence showed that any differences between the formulations disclosed in these patents would not impact the Morphology Limitation. The Federal Circuit found that substantial evidence supported a finding that the formulations disclosed in both the challenged patent and the prior art were the same or essentially the same.

The Federal Circuit further explained that both the challenged patent and the prior art referred to the DDM method and incorporated by reference a publication that detailed how to carry out the DDM process. The Court recognized that the disclosures of the incorporated publications were relevant because an incorporated reference is effectively part of the host document as if it was explicitly contained therein. The Court therefore found that substantial evidence showed that by using this limited number of tools—i.e., the five formulations and the DDM method—a SNALP formulation meeting the Morphology Limitation would necessarily be the result. Therefore, the Court concluded that the Morphology Limitation would inherently be met by a person skilled in the art following these disclosures.

Kyle Sorenson, PhD
Kyle Sorenson, PhD, focuses his practice on patent litigation, patent prosecution, due diligence and licensing. Read Kyle Sorenson's full bio.