Best Mode Patent-Raptor Devours Another Victim in Ajinomoto

There are certain “patent-eating” monsters that lurk nowhere else but in America.  One created by the “duty of disclosure” obligation is “inequitable conduct” which devours patents like a Tyrannosaurus Rex.  There’s also a stealthier but ravenous patentivour that is as deadly as a velociraptor in Jurassic Park.  It’s called the “best mode” requirement of 35 U.S.C. § 112, first paragraph.

The latest victim of the “best mode” patentraptor was a foreign patent applicant in Ajinomoto Co., Inc. v. International Trade Commission.  In the end, Ajinomoto was unable to outrun the “best mode” patentraptor.  And like the sequels to Jurassic Park, there are likely to be future instances where this patentivour devours other U.S. patents, including those of foreign applicants who may even be ignorant of this patent monster.  But ignorance of the “best mode” patentraptor is equivalent to not being aware that the bioengineered dinosaurs were multiplying in dangerous numbers in Jurassic Park.

In Ajinomoto, not one but two patents were consumed by failure to satisfy the “best mode” requirement.  What was even more startling was that Judge Newman, considered by many to be very “pro-patent,” was unwilling to slay this patentivour in this instance.

Similar to part of the story line in Jurassic Park, the two patents in Ajinomoto, U.S. Pat. No. 5,827,698 (the ‘698 patent) and U.S. Pat. No. 6,040,160 (the ‘160 patent), were about producing the essential amino acid, lysine.  As an essential amino acid, animals, like the dinosaurs in Jurassic Park, cannot synthesize lysine, but must instead obtain it by consuming foods which contain it.  The microorganism Esherichia coli (better known as E. coli) can produce lysine but only in limited quantities because of two inhibitory mechanisms:  (1) “feedback inhibition” triggered by lysine production itself; and (2) lysine decarboxylases which breakdown extra lysine produced into a non-nutritive byproduct.

Also like the bioengineered Tyrannosaurus Rex and velociraptors of Jurassic Park, the ‘698 and ‘160 patents involved bioengineered E. coli strains to combat these two inhibitory mechanisms.  The ‘160 patent addressed the first mechanism (“feedback inhibition”) by creating in the E. coli strain at least one of two mutations in the gene (dapA) encoding a biosynthetic enzyme (dihydrodipicolinate synthase or DDPS) to remove the “feedback inhibition” imposed by excess lysine and thus produce greater amounts of lysine.  The ‘698 patent addressed the second mechanism (lysine decarboxylases) by creating mutations in the lysine decarboxylase gene (Idc) to provide an E. coli strain that reduced or eliminated lysine decarboxylase activity.

So far so good.  What eventually caused the ‘698 and ‘160 patents to be consumed by the “best mode” patentraptor were the following disclosures and omissions:

a.         The ‘698 patent described a two-step process for producing the mutant Idc host strain.  The first step subjected the native (“wild”) E. coli strain to selection to identify a strain (called WC196) having lysine productivity.  In the second step, the mutant Idc gene was inserted in the identified WC196 strain to create the Idc mutant strain.  But what the ‘698 patent neglected to describe was the actual strain used by the inventors which had two other gene alterations:  (i) prior to the first step, insertion of a variant lysC (a gene encoding an enzyme in the lysine biosynthesis pathway) in the wild-type (W3110) strain, the resulting modification being identified as the WC80 strain; and (ii) after the first selection step which resulted in the strain WC80-196, insertion of sucrose utilization genes in the E. coli to permit the resulting strain to use sucrose as a carbon source.  This host strain (identified as WC80-196S) was the one into which the Idc mutation was inserted in the second step.

b.         The ‘160 patent identified two host strains (B-399 and W3100(tyrA) into which the mutant dapA was introduced.  But what the ‘160 patent neglected to do, even though known before the filing of the Japanese application from which the ‘160 patent claimed priority, was that the inventors characterized a different strain (AE-70) as their best lysine producer.

In April 2006, Ajinomoto (the owner of the ‘698 and ‘160 patents) filed a complaint under section 337 of the 1930 Tariff Act (19 U.S.C. § 1337) with the International Trade Commission (ITC) to prevent alleged improper importation and sale of lysine feed products made using the methods of the ‘698 and ‘160 patents.  In fact, the collective respondents (GBT) admitted infringement.  But the “best mode” patentraptor reared its ugly head as the Administrative Law Judge (ALJ) found no violation of section 337 because the ‘698 and ‘160 patents were invalid for failing to satisfy this requirement based on the disclosures/omissions noted above.

When the ITC didn’t disturb the ALJ’s finding of no violation of section 337, Ajinomoto appealed.  But the “best mode” patentraptor became an insurmountable obstacle to getting the Federal Circuit panel to reverse.  In fact, Ajinomoto didn’t contest that the disclosures/omissions noted above had occurred.  Instead, Ajinomoto argued that these disclosures, and especially omissions, didn’t relate to the “innovative aspects” of the claimed invention, thus there was no “best mode” violation.

Ajinomoto’s argument fell on deaf Federal Circuit ears.  In fact, Judge Lourie (writing for the Federal Circuit panel) said that Ajinomoto “misstate[d] the law” as relating the “best mode” requirement only to vague “innovative aspects,” and not the claimed invention as a whole.  That included disclosing in the ‘698 and ‘160 patents the inventors’ preferred host strains (i.e., WC80-196S and AE-70) which the inventors admitted they had neglected to do.  In fact, the undisclosed the WC80-196S was the “only bacterial strain that the inventors used to practice the claimed invention” of the ‘698 patent.

Ajinomoto relied upon (unsuccessfully) four other Federal Circuit cases to argue that the “best mode” requirement hadn’t been violated by the omissions in the ‘698 and ‘160 patents.  The first was the 1987 case of Christianson v. Colt Industries Operating Corp. which held that the “best mode” requirement didn’t extend to the production details for use of the claimed parts in a particular weapon, namely an M-16.  In fact, Judge Lourie distinguished Christianson as claiming only the specific rifle parts, not the rifles themselves.  Contrary to what Ajinomoto asserted, the ‘698 and ‘160 patents covered more than just the isolated mutations (Idc or dapA) but instead cultivating E. coli strains containing those mutations.  That made the preference for cultivating those particular strains relevant to the “best mode” for carrying out the claimed invention “regardless of whether the mutations could be used in other bacteria, and thus that the preferred bacterium had to be disclosed.”

Judge Lourie similarly rejected Ajinomoto’s reliance upon the 2007 case of AllVoice Computing PLC v. Nuance Communications, Inc., the 1996 case of Zygo Corp. v. Wyko Corp., and the 2002 case of Bayer AG v. Schein Pharmaceuticals, Inc. because “the claims as construed did not cover the embodiment alleged to have been concealed.”  In AllVoice, the claimed invention was construed as excluding the undisclosed updating and maintaining functionalities present in the patentee’s commercial embodiment.  Similarly in Zygo, the patent on an interferometer system was held not to violate the “best mode” requirement because of an undisclosed commercial embodiment with packaging.  In Bayer, the patent on the antibiotic ciprofloxacin was held not to violate the “best mode” requirement based on an undisclosed process for making an unclaimed starting material because the undisclosed and “unclaimed process did not materially affect the claimed antibiotic.”  By contrast, Judge Lourie characterized the cultivating host strain in Ajinomoto as “claimed rather than unclaimed subject matter, and thus the inventors’ preferred host strain had to be disclosed to comply with the best mode requirement,” citing the 1996 case of United States Gypsum Co. v. National Gypsum Co. (best mode violation for concealing preferred expanded perlite for making claimed joint compound) and the 1990 case of Chemcast Corp. v. Arco Industries Corp. (best mode violation for concealing the preferred material for making the claimed locking portion of a grommet).

Judge Lourie’s opinion also disagreed with Ajinomoto’s contention that the ITC found that the inventors concealed the method for creating the host strain into which the Idc mutation was introduced.  Instead, the ITC had found that the inventors had concealed the identity of the preferred host strain, and “specifically that the other genetic alterations, including the lysC variant and the sucrose utilization genes, had been introduced (by whatever method) into the only host strain used to practice the claimed invention.”  In addition, and contrary to what Ajinomoto asserted, the “best mode” requirement “cannot be satisfied by the deposit of a non-preferred strain.”  Instead, as observed by Judge Lourie, the “inventors could not, consistent with the best mode requirement, claim the cultivation of a bacterium containing an Idc mutation while simultaneously keeping from the public the identity of the one and only bacterium that they used to practice that cultivation,” again citing the Chemcast case.

Ajinomoto’s final “hail Mary” argument (and only for the ‘160 patent which claimed priority to a PCT application) was that even if the best strain was “concealed” as of the original Japanese filing date, that only meant Ajinomoto couldn’t rely upon that Japanese filing date, but could instead rely upon the PCT application filing date.  But Judge Lourie agreed with GBT and the ITC that Ajinomoto waived its right to rely on this PCT application filing date by not raising this issue in pre-trial briefs.

In the end, Ajinomoto, and especially the ‘698 and ‘160 patents, did not prevail.  The message is now clear:  be aware or be eaten by the “best mode” patentraptor.

© 2010 Eric W. Guttag


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Join the Discussion

8 comments so far.

  • [Avatar for EG]
    March 11, 2010 08:47 am


    Thanks for the comment. I hadn’t actually looked at the 2 patents, but used the Federal Circuit description of them. What you mention about each having a “BEST MODE FOR CARRYING OUT THE INVENTION” says these were written using an international/PCT format which, in my opinion, is very dangerous to use in the U.S. because it may imply something that wasn’t intended, but will nonetheless be treated as an “admission” in the U.S. courts (including the Federal Circuit).

    Step back is also correct that “best mode” is directly related to what is claimed, and the claimed method was for producing lysine using genetically altered E. coli strain. That put the omitted but preferred host strains squarely within the “best mode” target zone. I’m also not so sure that Lourie’s basis for distinguishing the Bayer case is completely correct as “best mode” also relates to the preferred embodiment for “making and using” the claimed invention (this comes out of the 1st paragraph of 35 USC 112).

    The problem I see with the ruling in Ajinomoto is why were these “preferred” host strains omitted. If Ajinomoto omitted these host strains because they didn’t want to disclose them but wanted to keep them as a trade secret, I’ve got very little sympathy for them (even though Ajinomoto is a Japanese company, they’re still pretty savvy about U.S. patent law or should be); that offends the fundamental concept of quid pro quo in U.S. patent law. But if these host strains were omitted innocently and out of ignorance, that would be a different story to me (as long as there is at least one enabling embodiment), and is why the “best mode” requirement, as currently interpreted, has problems. (Others have also commented about the confusing and inconsistent recent application of the “best mode” requirement by the Federal Circuit.) I could also make a similar observation about “inequitable conduct” which should only apply to deliberate efforts to mislead during patent prosecution (not benign neglect which is all too often the basis for an IC allegation). What is ironic is the so-called “patent law reform” keeps the “best mode” requirement, but makes a violation of this requirement unavailable as an invalidity defense. (Some have argued that an allegation of IC would be still available, and unfortunately, the sloppy language in the so-called “patent law reform” on this doesn’t make clear that IC is out.)

    Again, thanks for the thought provoking comments.

  • [Avatar for step back]
    step back
    March 10, 2010 10:20 pm


    No. Things would have turned out different if the claims had not included the cultivating step. Best mode is determined based on what is claimed. This is the point this particular CAFC opinion tries to make.

  • [Avatar for Jod]
    March 10, 2010 04:56 pm

    I looked at the 2 patents, both contain a “BEST MODE FOR CARRYING OUT THE INVENTION ” – so it seems that omitting the step (insertion of the variant) is what got them?

  • [Avatar for Jod]
    March 10, 2010 04:00 pm

    It is unclear whether this was a result of omitting a necessary enablement step (insertion of a variant) vs omitting a preferred embodiment?

  • [Avatar for Jod]
    March 10, 2010 02:33 pm

    Would things possibly have turned out differently for Ajinomoto if each patent described multiple embodiments instead of a “Preferred Embodiment”? In other words, is this more of omitting a necessary step or omitting a “Preferred Embodiment”?

  • [Avatar for EG]
    March 10, 2010 12:31 pm


    A very interesting angle you present on “best mode.” I’m sort in Gene’s camp: I think the “best mode” requirement should exist, but that the inventor shouldn’t be punished for simple innocent omission, as opposed to deliberate failure to include to keep the “best mode” a trade secret. I’ve got a similar view for the “intent” standard for “inequitable conduct” (which given the current litigation climate and absurdity with how IC is applied, I would be prefectly happy to join the ROW and ditch).

  • [Avatar for Gene Quinn]
    Gene Quinn
    March 10, 2010 12:06 pm


    I have to admit I had never thought of best mode in these terms, but I definitely see where you are coming from and at least initially (on first consideration) I agree. I find myself torn. I like the idea of requiring best information to be disclosed, but don’t like the inequities you point out. I also think the best mode penalty is draconian. It ignores the contribution of the inventor and focuses on deficiencies that kill the right granted. It almost seems like the law is set up with a piracy mentality. Find a problem and then take the invention and all the hard work away. I think best mode should have a less draconian penalty if we are going to keep it, although if patent reform does go through it will be a thing of the past anyway.


  • [Avatar for step back]
    step back
    March 10, 2010 11:45 am

    Best mode is something not well understood in detail by many a patent practitioner.

    If one had to explain “best mode” very briefly, part of the communist manifesto may come into mind: ‘From each according to his ability [and according to what he claims]’.

    While it sounds anti-patriotic to accuse the US Congress of engaging in communist like activities, when it comes to inventors (and the best mode requirement) that is exactly what they do. They try to squeeze from each inventor the full value of what he (or she) as an individual has to contribute to the common welfare. That’s part of the quid quo pro bargain.

    Therefore you can have two inventors of a same basic thing and yet the smarter of the two inventors is punished into having to disclose more than his dumber cousin. That’s because the smarter cousin has conceived of a better mode of “carrying out” the invention and Congress is going to make sure to squeeze out those extra two ounces of flesh from the smarter inventor by way of the best mode requirement.

    Best mode violations are generally found out during litigation rather than during prosecution. The accuser has to come up with clear, convincing and objective evidence showing that the inventor(s) had possession of something they subjectively considered to be a better mode and they did not adequately disclose it (on purpose or otherwise) in the application,