A Rare Event for Biotechnology: Two Anjimoto Patents Struck for Violation of the Best Mode Requirement

In Ajinomoto v. ITC, decided March 8, 2010, the Federal Circuit affirmed the International Trade Commission's determination that two patents claiming methods for producing the amino acid L-Lysine in E. coli are invalid for failure to adequately disclose the best mode of practicing the invention. One of the patents was also found to be unenforceable due to inequitable conduct, based on the Commission’s finding that omission of the best mode was material and made with deceptive intent.

The claimed methods are used to prepare lysine to be sold as a dietary supplement, primarily for animals such as livestock, in what is described in the opinion as a billion-dollar, worldwide market. Both claimed methods recite the use of E. coli strains that have been genetically engineered to produce very high concentrations of lysine, by mutating genes involved in lysine metabolism in order to impair feedback inhibition and lysine degradation, respectively.

The best mode requirement is an anomaly of US patent law, and is not found in other major patent jurisdictions such as Europe and Japan. It essentially requires a patent applicant to adequately disclose what the inventor considers to be the best mode of practicing the claimed invention. In this case, the court found that at the time the original patent applications were filed, the inventors considered certain strains of E. coli to be the best for practicing the invention. These preferred strains included additional genetic alterations besides those recited in the patent claims, including another modified gene involved in lysine metabolism, and genes that allowed the bacterium to utilize sucrose as a carbon source. The patent specifications accompanying the invalidated claims do not disclose these additional genetic alterations, nor the inventor’s preference for use of sucrose as the carbon source, but do include data associated with "fictitious host strains."

This was not the first challenge to an Ajinomoto patent based on an alleged violation of the best mode requirement. In Ajinomoto v. Archer-Daniels-Midland, 228 F.3d 1338 (Fed. Cir. 2000), the Federal Circuit affirmed a district court's determination that a patent owned by Ajinomoto claiming methods of modifying bacteria to increase the production of amino acids was not invalid for failure to disclose the best mode. In that case, the alleged violation was based on the failure of the patent specification to disclose a particular bacterial gene that the inventor considered necessary to practice the best mode of the invention. The court rejected the allegation, and held that even though the patent did not explicitly identify the preferred gene, it disclosed the use of a strain of bacteria that includes the preferred gene, and one of skill in the art would have been aware that the disclosed bacterium included the preferred gene.

Although violation of the best mode requirement is often invoked as a defense in patent litigation, courts rarely invalidate claims for failure to disclose the best mode. In a 2002 Federal Circuit decision, the majority noted that the Federal Circuit and its predecessor courts had only held claims invalid for failure to satisfy the best mode requirement on seven occasions. Bayer AG v. Schein Pharms, 301 F.3d 1306 (Fed. Cir. 2002). To my knowledge, Ajinomoto is the first reported decision wherein a biotechnology patent has been invalidated under the best mode requirement - I have not done an exhaustive search, but I'm sure it has rarely if ever happened before.

The last best mode challenge to a biotechnology patent to make it to the Federal Circuit that I am aware of was in the case of Invitrogen Corp. v. BioCrestMfg., in which the appeal was filed in 2007. The District Court had refused to even submit the issue to the jury. The parties settled prior to the Federal Circuit deciding the issue. In that case, the alleged violation of the best mode requirement also involved the failure to disclose a preferred strain of E. coli for use with the invention. Clearly, patent practitioners should be vigilant to ensure that preferred E. coli strains are disclosed in the specification in order to ward off this common basis for attacking biotechnology patents.

Notably, the best mode violation was the only basis for invalidating either Ajinomoto patent, since the inequitable conduct finding was based solely on the failure to disclose the best mode. The inventors might very well have fully enabled a useful and nonobvious invention, which outside the US would be sufficient to secure a valid patent.

It is perhaps relevant that the best mode violation was based on the failure of the original Japanese patent applications, which were the priority documents for the US patents, to disclose the preferred bacterial hosts and carbon source. Similarly, the Ajinomoto patent which survived the earlier best mode challenge by Archer-Daniels-Midland was based on an application for an Inventor’s Certificate filed in the former Soviet Union. The Inventor’s Certificate was essentially the Soviet analog to a patent under the communist regime. The best mode requirement can be a trap for non-US inventors and patent practitioners unfamiliar with US law, and maybe this played a role in these cases.

There is currently relatively strong support for eliminating the best mode requirement in the US, at least as a basis for invalidating patent claims or rendering patents unenforceable, and some of the recent legislative proposals for patent reform have included provisions to that effect, including the most recent Senate draft that was made publicly available last week (available here).

I am personally of the opinion that the best mode requirement should be eliminated from US law; it seems to me that the rest of the world is doing fine without it, and whatever benefits flow from the doctrine in the form of enhanced disclosure are outweighed by the cost of litigating the issue, the potential for invalidating an objectively valid patent based on the outcome of a litigation-driven inquiry into the inventor’s subjective state of mind many years prior to the litigation, and the potential unfairness to foreign inventors unfamiliar with the best mode requirement.