Butamax Adv. Biofuels v. Gevo: No Showing of Clear Intent that Patentee acted as Lexicographer

Category: Claim Construction 
By: Jesus Hernandez, Blog Editor/Contributor 
TitleButamax Adv. Biofuels LLC v. Gevo, Inc., No. 2013-1342 (Fed. Cir. Feb. 18, 2014).
IssueThe primary dispute between the parties concerns whether the claimed KARI must be “NADPH-dependent.” […] [The district court] concluded that in the “state of the art,” the “KARI enzyme known by the EC number was generally understood to be NADPH- dependent.” […] This decision is premised in large part on the district court’s conclusion that the patentees acted as their own lexicographers in defining KARI by reference to EC number and the enzyme’s “use” of NADPH rather than use of NADH or both NADPH and NADH. […]
Butamax Adv. Biofuels LLC at *10 (internal citations omitted, text added).
Holding[The "KARI enzyme" is not “NADPH-dependent,” because (i) the specification’s definition does not exclude the possibility of using additional cofactors, and (ii) the specification’s incorporation of an enzyme classification standard (EC number is not a clear intent to define KARI. Therefore], the term “acetohydroxy acid reductoisomerase” is construed as “an enzyme, whether naturally occurring or otherwise, known by the EC number that catalyzes the conversion of acetolactate to 2,3-dihydroxyisovalerate.”
Id. at *20-21 (text added).

Procedural HistoryButamaxTM Advanced Biofuels LLC (“Butamax”) owns U.S. Pat. No. 7,851,188 (“’188 patent”) and No. 7,993,889 (“’889 patent”) (collectively, the “patents-in-suit”) and appeals a final judgment entered against it following the district court’s […] claim construction and denial of Butamax’s motion for summary judgment of literal infringement of the asserted claims of the ’188 and ’889 patents by Gevo, Inc. (“Gevo”) […].
Butamax Adv. Biofuels LLC at *2 (internal citations omitted).
Legal Reasoning (Rader, CJ, Linn, Wallach)
Claim term at issueThis appeal primarily concerns step (ii): the conversion of acetolactate (“AL”) to 2,3-dihydroxyisovalerate (“DHIV”), catalyzed by the polypeptide enzyme acetohydroxy acid isomeroreductase (also known as keto-acid reductoisomerase, or “KARI”) “having the EC number” KARI assists reactions by rearranging (i.e., isomerizing) a reagent and also by “reducing” (the process of adding electrons) this rearranged molecule. To accomplish the reduction, KARI needs a source for the added electrons. This electron source is known as the “cofactor” or “coenzyme.” Two such cofactors are NADH (nicotinamide adenine dinucleotide + hydrogen) and NADPH (nicotinamide adenine dinucleotide phosphate + hydro- gen).
Butamax Adv. Biofuels LLC at *4.
Definition in the Spec.The ’188 patent’s specification provides “definitions . . . to be used for the interpretation of the claims,” including a definition of KARI: an enzyme that catalyzes the conversion of aceto- lactate to 2,3-dihydroxyisovalerate using NADPH (reduced nicotinamide adenine dinucleotide phos- phate) as an electron donor. Preferred acetohydroxy acid isomeroreductases are known by the EC number and sequences are available from a vast array of microorganisms, including but not limited to . . . Methanococcus maripaludis . . . .
Id. at *4-5.
EC number number, referenced in both this definition and claim 1, is an Enzyme Commission number for an enzyme known by the names KARI, “acetohydroxy acid isomeroreductase,” and several other names. The EC enzyme classification system was developed in the 1950s to standardize enzyme nomenclature. […] Notably, Rule 18 of the EC system states that “[f]or oxidoreductases using NAD+ or NADP+ [the oxidized states of NADH and NADPH, respectively], the coenzyme should always be named as the acceptor” […] However, it also appears common to assign different EC numbers to the same enzyme, where the difference between the numbers is the identity of the cofactor named. […] EC number names only NADP+ as an acceptor, and neither party calls attention to another EC number for KARI naming any other cofactor as an acceptor.
Id. at *4-5.
Legal Standard: LexicographerGenerally, claim terms are: given their ordinary and customary meaning as understood by a person of ordinary skill in the art when read in the context of the specification and prosecution history. There are only two exceptions to this general rule: 1) when a patentee sets out a definition and acts as his own lexicographer, or 2) when the patentee disavows the full scope of a claim term either in the specification or during prosecution. […] “To act as its own lexicographer, a patentee must ‘clearly set forth a definition of the disputed claim term’ other than its plain and ordinary meaning.” […] “It is not enough for a patentee to simply disclose a single embodiment or use a word in the same manner in all embodiments, the patentee must ‘clearly express an intent’ to redefine the term.” […]
Id. at *11-12 (internal citations omitted).
There is No Clear Intent that Patentee Intended to be a Lexicographer
The Patentees’ Definition of KARI (keto-acid reductoisomerase)Butamax […] asserts that the fact that an enzyme can catalyze the conversion of AL to DHIV “using NADPH” does not, on its own, indicate that the enzyme cannot also use other cofactors, such as NADH, to catalyze that conversion.[…] We agree with Butamax and find no reason to constrict the phrase “using NADPH” to mean “only use NADPH” or “NADPH-dependent.” We also disagree with Gevo’s argument that such an interpretation reads out an important part of the patentees’ definition. The patents’ definition at least excludes as-yet-undiscovered KARI enzymes that could catalyze the conversion of AL to DHIV without using NADPH at all. Moreover, the description of specific types of KARI as NADPH-dependent does not clearly express an intent to redefine all KARI “using NADPH” as KARI that must be NADPH-dependent.
Butamax Adv. Biofuels LLC at *13-14 (internal citations omitted).
Reference to EC Number in Claim 1 not a clear intent of adopting a Specific Definition[T]he Court cannot conclude that the reference to EC number is an expression of a clear intent to redefine KARI to be NADPH- dependent [because (i) EC nomenclature was drafted to categorize naturally-occurring enzymes and new EC numbers generally are not created for modified forms of enzymes and (ii) and the industry practice, including Gevo itself, was to use EC number if it was the best way to describe a mutant enzyme].
Id. at *17 (text added).
Preferred Embodiments and Dependent ClaimsButamax note[d] that “NADH supported 60% of the methanococcal activity obtained with NADPH.” See R. Xing & W. Whitman, Characterization of Enzymes of the Branched-Chain Amino Acid Biosynthetic Pathway in Methanococcus spp, 173(6) J. Bacteriol- ogy 2086–92 (1991) (“Xing”). The district court discounted Xing because it provided no references or data to support these findings. […] The district court’s claim construction, without justification, excludes a preferred embodiment, which in this case also is the subject of dependent claim 15, and this court “normally do[es] not interpret claim terms in a way that excludes embodiments disclosed in the specification.” Oatey Co. v. IPS Corp., 514 F.3d 1271, 1276 (Fed. Cir. 2008).
Id. at *17-18.
Prosecution HistoryThe Patent Office concluded that “[o]ne skilled in the art would require additional guidance, such as information regarding the specific identity and structure of the polypeptides that catalyze[]” the conversions in the claim. J.A. 6927. The patentees responded, amending the claim to refer to the EC numbers of the various enzymes, submitting a copy of the EC nomenclature rules, and pointing to the specific examples of the enzymes in the specification (including SEQ ID No: 183— Methanococcus maripaludis—as an example of KARI).[…] these references do not clearly express an intent by the patentees to redefine KARI to be NADPH-dependent. Indeed, the patentees specifically named Methanococcus maripaludis KARI as an example during the prosecution history, a KARI that appears to “use” NADH.
Id. at *19-20.
Extrinsic Evidence: Butamax’s internal documents and subsequent patent applications.Butamax filed a patent application in 2008 which stated that “discovery of a KARI enzyme that can use NADH as a cofactor as opposed to NADPH would be an advance in the art.” […] However, as discussed above, the ordinary meaning of KARI is not cofactor dependent, and this subsequent extrinsic evidence does not clearly express an intent at the time of the invention to redefine KARI to use one cofactor over another
Id. at *20.
For the forgoing reasons, this court vacates the dis- trict court’s denial of Butamax’s motion for summary judgment of literal infringement of the asserted claims of the ’188 and ’889 patents and remands the question of infringement to the district court for reconsideration under the claim construction set forth herein.
Butamax Adv. Biofuels LLC at *26.
Editor Comment
This case also briefly discusses written description. For further reading, click here.

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