Board IPR obviousness decision reversed due to erroneous claim construction

Amgen Inc. et al. v. USPTO (Intervenor)

Docket No. 2019-2171 (IPR2016-01542) (https://cafc.uscourts.gov/opinions-orders/19-2171.OPINION.4-14-2022_1936036.pdf) (Non-Precedential)

CHEN, SCHALL, STOLL

April 14, 2022

Brief Summary:   Board IPR obviousness decision reversed due to erroneous claim construction (“[a] straightforward reading of the claim language”, “the only conclusion supported by substantial evidence”).

Summary:  Amgen appealed USPTO Board Final Written Decision (FWD) finding claims 1-124 of US 8,952,138 relating to methods for producing recombinant proteins unpatentable for obviousness that turned on the Board’s claim construction of the term “final thiol-pair ratio”.  The FC panel opinion explains that the ‘138 patent provides methods for avoiding recombinant protein misfolding into “inclusion bodies…using a controlled reduction-oxidation (redox) reaction”.  Claim 1 recites the use of a ““contacting the protein with a refold buffer comprising a redox component comprising a final thiol-pair ratio. . . . to form a refold mixture,” and the Board construed “final thiol-pair ratio” “to mean ‘the relationship of the reduced and oxidized redox species used in the redox component of the refold buffer as defined by the [following] equation [reductant]² / [oxidant]”.  Based on this construction, the Board found the claims to be unpatentable as obvious in view of two prior art references (Schleg and Hevehan).  The FC panel explained that it applied the broadest reasonable construction standard as Apotex filed the petition for IPR before November 23, 2018 (Valve Corp., FC 2021) and that there since there was “no dispute here about findings or evidence of facts extrinsic to the patent, we conduct a de novo review of the Board’s determination of the broadest reasonable interpretation of the claim language” (In re Cuozzo, FC 2015; Microsoft, FC 2015).  The FC panel reviewed the Board’s legal conclusions on obviousness de novo and its factual findings for substantial evidence (ACCO, FC 2016).  Amgen argued the Board’s construction was erroneous because it construed the “‘final thiol-pair ratio’ in the context of the ultimate solution—i.e., the refold mixture—rather than specific ingredients therein—e.g., the redox component”.  The FC panel agreed with Amgen that “claim 1’s ‘language makes clear that the redox component is a distinct volume from the refold buffer, and it is that redox component [rather than the refold buffer] that comprises the claimed ‘final thiol-pair ratio’” (e.g., “[a] straightforward reading of the claim language”) which finds additional support in the specification.  The FC panel wrote that the Board’s construction is “inconsistent with the plain language of claim 1 and the specification and is therefore unreasonably broad” (In re Smith, FC 2017 (“the Board cannot construe the claims so broadly that its constructions are unreasonable under general claim construction principles”, “giving claim terms ‘a strained breadth in the face of the otherwise different description in the specification [is] unreasonable’”).  Based on this error, the FC panel found that Apotex failed to show the claims to be unpatentable (“the only conclusion supported by substantial evidence” (Owens Corning, FC 2017)).  The Board decision was therefore reversed.