By Tony Dutra
Feb. 18 --ButamaxTM Advanced Biofuels LLC will have another chance to assert patents against isobutanol manufacturer Gevo Inc. after a Feb. 18 reversal of a district court's summary judgments by the U.S. Court of Appeals for the Federal Circuit (Butamax(TM) Advanced Biofuels LLC v. Gevo, Inc., Fed. Cir., No. 2013-1342, 2/18/14).
The court's decision followed from a revised claim construction, where it held that the patentee's definition of a key term was not as narrow as the lower court found because evidence about the knowledge of the person of ordinary skill at the time showed that a broader interpretation was more reasonable.
In a twist, each party filed patent applications, subsequent to the ones at issue here, with disclosures likely to hurt their own arguments at trial.
Butamax is a joint venture between BP Plc--British Petroleum--and E. I. du Pont de Nemours and Co. and is assignee of patents (U.S. Patent Nos. 7,851,188 and 7,993,889) related to isobutanol, which is useful as a solvent and a gasoline blendstock. Both patents emanate from an application filed in 2005.
The patents describe a biosynthetic pathway for the production of isobutanol, including use of “acetohydroxy acid isomeroreductase [also known as KARI] having the EC number 18.104.22.168.” KARI is further defined in the specification with reference to the same “Enzyme Commission” (EC) classification system number. By convention, that system requires specific identification of cofactors, and EC number 22.214.171.124 only specifies a cofactor known as NADPH.
Butamax sued Gevo for patent infringement in the U.S. District Court for the District of Delaware. Judge Sue L. Robinson construed the asserted claims limiting KARI in terms of the cofactor used. Since Gevo makes isobutanol using other cofactors, she made additional infringement and invalidity rulings on summary judgment motions favoring Gevo, and Butamax appealed.
The appeals court, in an opinion written by Judge Richard Linn, first reversed the claim construction judgment.
The court agreed that Butamax had “offered a definition of KARI” in the specification, but that this definition did not “ 'clearly express[ ] an intent” to redefine KARI in a way that differs from the plain and ordinary meaning” of a skilled artisan--that KARI was not limited to NADPH as a cofactor--quoting CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1366, 62 U.S.P.Q.2d 1658 (Fed. Cir. 2002).
Gevo presented arguments, to no avail, based on the EC convention for describing cofactors, preferred embodiments listed in the specification and Butamax's prosecution history. In part, the alleged infringer was defeated by its own statements and patent applications. In 2008, it described its own mutant enzymes with reference to the same EC number and at the same time contended that its enzymes were not NADPH-dependent. And while the district court discounted Butamax's reliance on a 1991 reference, Gevo's 2007 patent application cited the same reference for the proposition that an alternative cofactor could be used.
Butamax cited references to “other cofactors where appropriate” in the specification and relied on another enzyme database that noted the alternative as a substitute for NADPH. Thus, the court said, the circumstances did not represent a case where Butamax had acted as its own lexicographer to change the meaning a skilled artisan would understand.
With the reversal of the claim construction judgment, most of Gevo's noninfringement arguments were of no consequence either. However, the court acknowledged that Gevo established at least one genuine issue of material fact for the district court to reconsider on remand.
The lower court found two claims invalid for inadequate written description in that they claimed “inactivated genes” to reduce the effect of competing pathways, with no description of how to inactive genes. And the appeals court was skeptical of Butamax's arguments that “it was 'conventional' in 2005 to deactivate the pathway,” seeing in the specification and other references only a desire to do so.
Ultimately, the court agreed with Butamax, however, that it had established a genuine dispute of material fact. On the other hand, the reference Butamax relied on also said that the deactivation “virtually abolished” isobutanol production. On remand, then, Butamax will have to address that seeming contradiction.
More problematic for Butamax may be its subsequently filed continuation-in-part application, which provided additional detail on the deactivation of certain genes. That at least raised an additional question of what was known in the art in 2005, the court said.
Nevertheless, the court reversed summary judgment of invalidity for lack of adequate written description and remanded that aspect of the case for further development as well.
Chief Judge Randall R. Rader and Judge Evan J. Wallach joined the opinion.
Leora Ben-Ami of Kirkland & Ellis LLP, New York, represented Butamax. Michelle S. Rhyu of Cooley LLP, Palo Alto, Calif., represented Gevo.
To contact the reporter on this story: Tony Dutra in Washington at firstname.lastname@example.org
To contact the editor responsible for this story: Naresh Sritharan at email@example.com
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