Federal Circuit Favors Amgen, Overturns PTAB in Protein Folding Patent Case

On Thursday, the Federal Circuit issued a nonprecedential opinion in a patent case involving Amgen. The case is regarding the patentability of claims 1-24 of a patent for a method of creating folded proteins. The court reversed the holding of the Patent Trial and Appeal Board.

The patent discusses a method of creating certain proteins that are “folded” or shaped in a certain manner. The proteins are generated in the cells of bacteria, then extracted and solubilized in a buffer to unfold the cells from the configuration they were generated in in the host bacteria cells. Finally the cells are washed in a “refolding buffer” which causes the proteins to be refolded into their final distribution shape. The refolding buffer addressed in this patent is a reduction oxidation reaction. In reviewing the claim, the PTAB construed “final thiol-pair ratio,” recited in claim 1, to mean “the relationship of the reduced and oxidized redox species used in the redox component of the refold buffer as defined by” a certain equation. With this formulation, the PTAB found that the first 24 claims were unpatentable due to obviousness in light of the prior literature.

The plaintiffs disagreed, holding that the PTAB interpretation of the claim unreasonably broadened the claim to the point where it was obvious under the prior literature. The Federal Circuit held that “A straightforward reading of the claim language indicates that the “final thiol-pair ratio” is an attribute of the redox component.  Additionally …the specification clearly and exclusively describes “final thiol-part ratio” as an attribute of the redox component.”

The court held that the prior art made obvious the final ratio, but not the ratio prior to the addition of the buffering solution. With the construction narrowed back to the plaintiff’s wording of the claim construction, the court reversed the decision that the claims were unpatentable.

Amgen is represented by Latham & Watkins and Paul, Weiss, Rifkind, Wharton & Garrison.