In a significant decision, a Delaware federal court judge recently ruled on several motions and cross-motions for summary judgment with respect to two Butamax patents – U.S. Patent Nos. 7,993,889 (’889 Patent) and 7,851,188 (’188 Patent).
The ’889 and ’188 Patents are both entitled “Fermentive production of four carbon alcohols” and directed to a more cost efficient method of producing isobutanol directly from pyruvate via a particular production pathway using recombinant microbial host cells.
Butamax had moved for summary judgment of infringement of the ’889 and’ 188 Patents and no invalidity while Gevo had moved for summary judgment of non-infringement and invalidity of the two patents.
On infringement Gevo achieved a partial victory. The court granted summary judgment of no infringement under the doctrine of equivalents, but denied both parties’ motions as to literal infringement.
The doctrine of equivalents provides that there can be infringement of a patent where the accused device or process does not literally meet all the elements of a patent claim but has an equivalent or only insubstantially different element.
The patented processes use an enzyme called KARI, which needs a cofactor that donates electrons to enable it to catalyze a reaction. Based on statements in the patents, the court interpreted the claims to require a KARI defined with respect to the NADPH cofactor only.
Gevo’s process uses an NADH-dependent enzyme, so the issue was whether an NADH-dependent KARI enzyme is equivalent to an NADPH-dependent enzyme. The court noted that their chemical structures are different and not interchangeable:
NADH and NADPH have distinct chemical structures, with NADPH containing an additional phosphate group. This extra phosphate group allows NADPH “to be recognized selectively by the enzymes involved in biosynthesis;” thus, “despite their close chemical resemblance,’ NADH and NADPH are ’not metabolically interchangeable.’”
Accordingly, the court held that the two cofactors could not be deemed equivalents:
For the reasons discussed above in claim constructions, the court does not agree that NADH and NADPH are insubstantially different.
However, the court denied both parties’ motions for summary judgment with respect to literal infringement because there was a question of fact about interpreting certain data about Gevo’s KARI enzymes’ NADH or NADPH dependency:
While Butamax’s evidence of infringement is less than compelling, nonetheless, the court finds it sufficient to withstand Gevo’s motion for summary judgment, as it raises genuine issues of material fact as to how a person of ordinary skill in the art at the time the invention was made would determine NADH-dependency.
The court also reached split decisions on validity, holding claims 12 and 13 of the ’889 Patent invalid for lack of written description but denying Gevo’s summary judgment motion with respect to claim 8. Finally, the court denied Gevo’s motions for summary judgment that some of the asserted claims of the ’188 and ’889 Patents are anticipated and obvious.
Although this is a significant decision, it appears to only slightly narrow the issues and only with respect to two of the patents. There are at least 15 other patents in the dispute so there will undoubtedly be much more to come.
Eric Lane is a patent attorney at McKenna Long & Aldridge LLP in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at firstname.lastname@example.org