Navigating the Best Mode Requirement

Written by Michael Davitz M.D. J.D. (Partner at Axinn, Veltrop, & Harkrider, L.L.P. and one of our newest Practice Center Contributors)and Elizabeth Retersdorf J.D. (Associate at Axinn, Veltrop, & Harkrider,LLP) 

            The Patent Act provides that the patent specification “shall set forth the best mode contemplated by the inventor of carrying out his invention.”[1]  This requirement, also known as the best mode requirement, is in essence a quid pro quo with the inventor.  In return for granting the right to exclude others from making or using a patented invention, the inventor must disclose or conversely not conceal from the public the preferred embodiment.  But, what constitutes the preferred embodiment, how much information actually needs to be disclosed, what can be withheld and what happens when the inventor is not aware of the best mode?  The recent case law provides some answers to these questions, but also raises other concerns, especially as we enter the brave new era of biosimilars and the inevitable wave of litigation that will likely ensue.

            In order to satisfy the best mode requirement, the inventor must disclose the preferred embodiment of his invention as well as any preferences that could materially affect the invention.[2]  The first step in a best mode inquiry begins, as is always the case with patent law, with the claims.[3]  This past March the Federal Circuit handed down a decision in Ajinomoto Co. v. ITC where the scope of the claims created a problem for the inventors.[4]

            In Ajinomoto the claims dealt with production of L-Lysine, an essential amino acid that cannot be synthesized by most animals.[5]  Farmers and feed producers supplement feed with L-lysine which can be produced from microganisms such as Escherichia coli (E. coli).[6]  Because only small amounts of L-lysine are produced constitutively by E. coli, the inventors developed two recombinant strains of E. coli; one where the feedback inhibition loop was knocked-out and the other where the degradation pathway was greatly reduced or eliminated.[7]  Two patents were filed covering these new mutated strains, U.S. Patent Nos. 5,827,698 (the “ ‘698 patent”) and 6,040,160 (the “ ‘160 patent”).[8]  In April of 2006, Ajinomoto filed a complaint with the International Trade Commission (“ITC”) alleging that the importation of various lysine feed products was a violation of section 337 of the Tariff Act of 1930 as amended, 19 U.S.C. § 1337 (2010).[9]  The Administrative Law Judge (“ALJ”) found no violation of section 337, but found that both patents were unenforceable for inequitable conduct and invalid because of best mode violations.[10] The Federal Circuit affirmed the ALJ’s decision.[11]

            The relevant claims from the ‘698 and ‘160 patents covered a method of producing lysine from an E. coli strain by cultivating an isolated microorganism belonging to the genus Escherichia, where the isolated microorganism contains an altered lysine decarboxylase (ldc) or a desensitized feedback inhibition loop (dapA) mutation.[12]  Lysine is then harvested from the culture medium.[13]  At issue was the preferred host strain for each mutated gene.[14]  Although both the ‘698 and ‘160 patents disclosed a mode for generating the mutant strains, the inventors failed to disclose several critical features of the invention.[15]  First, in the ‘698 patent, it was clear that the actual strain used by the inventors had two additional genetic modifications that were made before the inventors inserted the mutant lysine decarboxylase gene.[16]  In the ‘160 patent, the inventors characterized a different strain from the one deposited as their best lysine producer.[17]

            Ajinomoto sought to claim that the best mode requirement was satisfied by the disclosure of the “innovative aspects” of the invention alone.[18]  Anijimoto argued that because it could not “exclude others from cultivating lysine-producing strains without the claimed ldc or dapA mutations, its best mode obligations extended only to those mutations,” i.e., the unique aspects of that invention.[19]  The Federal Circuit rejected Ajinomoto’s reasoning outright, stating that the best mode requirement applied to the entire invention, not just the “vague ‘innovative aspects’ or ‘inventive features’ of the invention.”[20]  The court explained that just as infringement “requires all claim limitations to be present, not just those that distinguish the claim from the prior art…[s]o too with the best mode requirement, which applies to the invention claimed, with all its limitations, not just the novel ones.”[21]

            The take-home message of Ajinomoto is clear: best mode disclosures are guided by claim scope and encompass all elements of the claims, not just selected features.  Moreover, the decision made it clear that the best mode requirement does not simply require disclosure of only those aspects of the invention that distinguish it over the prior art. 

In their defense, Ajinomoto relied on a number of cases.  Because they provide insight into the legal boundaries of the best mode requirement, these cases are instructive.  First, in Christianson v. Colt Industries Operating Corp. the court found no best mode violation when the inventor of interchangeable rifle parts did not disclose his preferred (and unclaimed) weapon for their use.[22]  In other words, the best mode requirement did not extend to the production details used for the rifle parts in particular weapons since the production details did not form part of the claims.[23]  Thus, Anjinomoto argued that just like the rifle parts, the mutations, ldc and dapA, could be used in any E. coli strain and therefore, Anjinomoto was not obligated to disclose the preferred strain.[24]  But unlike Christianson where the claims encompassed the rifle parts alone, the claims in Anjinomoto covered not only the mutations themselves, but also the methods for cultivating such bacteria.[25]  Therefore, Ajinomoto had to disclose these methods.

But not everything has to be disclosed in order to satisfy the best mode requirement.  In Bayer AG v. Schein Pharms., Inc. the claimed invention was an antibiotic, ciprofloxacin.[26]  The failure to disclose the process for making an unclaimed starting material did not represent a best mode violation since the process did not materially affect the claimed antibiotic.[27]  The court in Ajinomoto contrasted this fact pattern with Ajinomoto’s situation where the strains were claimed and, therefore, the host strain, methods of preparation or other alterations that formed part of the claimed strains had to be disclosed in order to satisfy the best mode requirement.[28]

Thus, if the methods of making or using the claimed invention are material to the invention itself or could materially affect its properties, the court has required disclosure.  For example, the court has required disclosure of preferences for a fluoride surface treatment in construction of a valve stem seal,[29] for specific parameters for cutting to obtain the micropitting needed for the claimed invention,[30] for production of the invention with diamond indentations that rendered it strong enough to support stacks of rolls of material,[31] and for a method of brazing used to create a claimed laser.[32]  In each of these cases the preferences materially affected either the invention’s intrinsic properties, or how the invention performs its function.

            Combined with Ajinomoto, these cases suggest that there exists a comparatively high barrier to patenting an invention while maintaining trade secrets that are material to the invention.  Inventors must disclose preferences for their inventions, especially if these preferences are material, even if these features are not called out explicitly in the claim language or not different from the prior art.  However, the disclosure requirements are not open-ended. 

            The first limitation on the best mode requirement is that it is a subjective requirement, namely, what did the inventor actually believe at the time the application was filed?  The Federal Circuit put the matter succinctly stating that  “[t]he existence of a best mode is a purely subjective matter depending upon what the inventor actually believed at the time the application was filed.”[33]  Thus, the best mode requirement does not require disclosure of a “best mode” if the inventor himself does not actually have a preference.[34]  Furthermore, the subjective test only looks at the inventor— if an inventor’s colleagues and employers may prefer another best mode and no disclosure is required.  For example, in Glaxo Inc. v. Novopharm Ltd. the Federal Circuit explicitly found that such concealment is not a violation of the best mode, and the preference held by an inventor’s company or assignee cannot be imputed to the inventor himself in order to find a best mode violation.[35]  Although the court recognized that this holding creates a strong incentive for companies to screen their inventors off from any actually marketable and useful form of the invention, it declined to depart from the traditional test.[36] 

Moreover the duty to disclose the best mode is not on-going, like the duty of disclosure with patent prosecution, but only occurs at the time the application is filed.  For disclosure to be required, the inventor must recognize any preference at the time of filing.[37]  The best mode requirement is not a continuing requirement.  In Hay & Forage Indus., the inventor knew of the mode in question but did not recognize it as best.[38]  By the time the inventor signed the application—less than two months later—he was aware that the mode was in fact best.[39]  The court still found no best mode violation.[40]  However, courts have found that while the preference for a particular mode is subjective, the lack of an inventor’s active intent to conceal the mode is not dispositive.[41]   

            The best mode requirement does not require disclosure of preferences preferred for commercial, manufacturing, or cost reasons nor does it require disclosure of details that can be come to by one of ordinary skill in the art.  For example, if an inventor prefers a specific mode not because of its effectiveness but instead because of its cost, he need not disclose it.[42]  Similarly, features or general best modes preferred for the ease of mass production are exempt from the best mode requirement.[43]  Commercial embodiments do not automatically require disclosure.  The Federal Circuit has found that the existence of an undisclosed commercial embodiment does not show a violation without evidence that it was chosen for quality or performance reasons.[44]  Companies should be aware, however, that the best mode requirement is still triggered when a mode is preferred both for its commercial advantages and its effect on the nature or quality of the invention.[45]  

            Finally, even if a specific preference is covered by the patent claims or materially affects its performance or quality, and is preferred for those reasons, an inventor need not disclose it if such a preference is the result of routine decisions made by one of ordinary skill in the art.[46]  This test, however, is measured by what decisions one can come to from the specification.[47]  In Eli Lilly & Co. v. Barr Labs., Inc. the Federal Circuit found no best mode violation when the inventors did not disclose their preferred solvent for recrystallizing the claimed compound because solvents were known in the art and could be found with routine experimentation.[48]  So long as someone can, even with some experimentation, come to the preferred mode from the specification, the inventor does not himself need to disclose it. 

            The case law points the way to how trade secrets could be separated from the patented invention.  First, carefully limiting the scope of the claims to certain aspects of the invention will likely minimize the risk of violating the best mode requirement.  Second, scale-up or manufacturing techniques that are often the subject of trade secrets do not have to be disclosed, especially if they are developed after filing of the patent application or by a separate group within the organization.  Third, decisions that are made for reasons relating to the marketing of the product, the cost, or efficiency of manufacture will likely not fall under the best mode requirement.           

Given the critical importance of manufacturing processes for biologicals coupled with the arguments by the biologics industry that the FDA should not rely on the innovator’s trade secrets when determining whether a sponsored biosimilar is interchangeable and safe, trade secrets are likely to play an even bigger role in the follow-on biologicals arena.[49]  Since biologics are so inextricably tied to their manufacturing process,[50] there is strong incentive to keep as much secret as possible.  Only time will tell how this incentive plays out with the best mode requirement.

[1]  35 U.S.C. §112, first paragraph.

[2]  Bayer AG v. Schein Pharms, Inc., 301 F.3d 1306, 1319-20 (Fed. Cir. 2002).

[3]  Id. at 1320.

[4]  597 F.3d 1267 (Fed. Cir. 2010).

[5]  Id. at 1269.

[6]  Id.

[7]  Id. at 1269-70.

[8]  Id. at 1270.

[9]  Id. at 1269. 

[10]  Id.

[11]  Id

[12]  Id. at 1270.

[13]  Id.

[14]  Id. at 1270-71.

[15]  Id. at 1271.

[16]  Id.

[17]  Id.

[18]  Id. at 1273. 

[19]  Id. at 1274. 

[20]  Id.

[21]  Id. at 1274-75  (emphasis added).

[22]  822 F.2d 1544, 1563 (Fed. Cir. 1987) rev’d on other grounds.

[23]  Id. at 1562-63. 

[24]  Ajinomoto, 597 F.3d at 1275.

[25]  Id. 

[26]  301 F.3d 1306,1309 (Fed. Cir. 2002). 

[27]  Id. at 1323.

[28]  597 F.3d at 1275.

[29]  Dana Corp. v. IPC Ltd. P’ship, 860 F.2d 415, 418-420 (Fed. Cir. 1998).

[30]  Nobelpharma AB v. Implant Innovations, Inc., 141 F.3d 1059, 1064-66 (Fed. Cir. 1998).

[31]  Great N. Corp. v. Henry Molded Prods., Inc., 94 F.3d 1569, 1571-3 (Fed. Cir. 1996).

[32]  Spectra Physics, Inc. v. Coherent, Inc., 827 F.2d 1524, 1535-37 (Fed. Cir. 1987).

[33]  Bayer AG v. Schein Pharms., Inc., 301 F.3d 1306, 1314 (Fed. Cir. 2002). 

[34]  See, e.g., Minco, Inc. v. Combustion Eng’g, Inc., 95 F.3d 1109, 1116 (Fed. Cir. 1996) (“Before an inventor can conceal a best mode, the record must first show his appreciation of the superiority of one mode over those modes disclosed in the specification.”).

[35]  52 F.3d 1043, 1050-51 (Fed. Cir. 1995).

[36]  Id. at 1051-52.

[37]  Hay & Forage Indus. v. New Holland N. Am., Inc., 25 F. Supp. 2d 1180, 1192-93 (D. Kan. 1998).

[38]  Id.  

[39]  Id. at 1192.

[40]  Id. at 1193

[41]  U.S. Gypsum Co. v. Nat’l Gypsum Co., 74 F.3d 1209, 1215 (Fed. Cir. 1996) (“A best mode violation may occur if the disclosure of the best mode is so objectively inadequate as to effectively conceal the best mode from the public.); Spectra-Physics, Inc. v. Coherent, Inc., 827 F.2d 1524, 1535 (Fed. Cir. 1987) (“Only evidence of ‘concealment,’ whether accidental or intentional, is considered.”). But see High Concrete Structures, Inc. v. New Enter. Stone & Lime Co., 377 F.3d 1379, 1383 (Fed. Cir. 2004) (“Known ways of performing a known operation cannot be deemed intentionally concealed absent evidence of intent to deliberately withhold that information.”)

[42]  Ricoh Co. v. Nashua Corp., No. 97-1344, 1999 U.S. App. LEXIS 2672, at *14-*16 (Fed. Cir. Feb. 18, 1999) (rejecting argument that best mode was not disclosed when preferred mode was only way to make invention cost-effective). 

[43]  Wahl Instruments, Inc. v. Acvious, Inc., 950 F.2d 1575, 1581 (Fed. Cir. 1991). 

[44]  See, e.g., Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1332 (Fed. Cir. 2002). 

[45]  U.S. Gypsum Co. v. Nat’l Gypsum Co., 74 F.3d 1209, 1213 (Fed. Cir. 1996); see also Great N. Corp. v. Henry Molded Prods., 94 F.3d 1569, 1572 (Fed. Cir. 1996) (stating that “we cannot decide whether the diamonds constitute a best mode merely by examining whether the diamonds relate to the production process” and that since the preferred mode was “critical to practicing the claimed invention rather than simply a commercial consideration” it was a best mode).

[46]  Young Dental Mfg. Co. v. Q3 Special Prods., Inc., 112 F.3d 1137, 1144-45 (Fed. Cir. 1997) (one skilled in the art could select a proper gear ratio from the figures and design of the gears and therefore the gear ratio need not be disclosed). 

[47]  Herr-Voss Corp. v. Delta Brands, Inc., No. 96-1022, 1996 U.S. App. LEXIS 29585, at *15 (Fed. Cir. Nov. 8, 1996); see also Dana Corp. v. IPC Ltd. P’shp., 860 F.2d 415, 419 (Fed. Cir. 1988) (“The best mode requirement is not satisfied by reference to the level of skill in the art, but entails a comparison of the facts known to the inventor regarding the invention at the time the application was filed and the disclosure in the specification.”).

[48]  251 F.3d 955, 966-67 (Fed. Cir. 2001).

[49]  See, e.g., Biotechnology Industry Organization, What Legal Issues are Presented by Biosimilars?, (last visited Oct. 25, 2010); Genentech, Views on Public Policy: Biosimilars or Follow On Biologics, (last visited Oct. 25, 2010).

[50]  See id.

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