BEST MODE - Patent law

The last required gear in the written description machinery is the best mode. The best mode requirement exists to ensure that the applicants do not reap the benefits of a patent while hiding from the public the best way to practice the invention. How could they do that? Wouldn’t the patentee want to make sure not only to disclose the best method of practicing the invention but also specifically to claim the best mode to the extent possible? The answer is often but not always, and here is why. Applicants are primarily interested in obtaining a right to exclude others from practicing the invention they wish to claim. At the same time, the applicants may be reluctant to give away all of their secrets. Absent the best mode requirement, applicants might try to have the best of both worlds by providing enough written description (enablement, written description) to get the claim issued but withhold from disclosing their best way of practicing the invention that they have claimed. In this way, they can retain at least some of their trade secrets and at the same time have a valid enforceable right of exclusion against the public for the entire claim scope, including their best mode of practicing the claimed invention. Does this seem fair? I don’t think so either. The best mode requirement serves to prevent the just-described scenario from happening.

The best mode requirement is a two-prong inquiry that first asks if the inventor (s)contemplated a best mode of practicing the claimed invention and second, whether the written description in the patent application disclosed the best mode such that one reasonably skilled in the art could practice it. The first prong of the inquiry addresses whose best mode we are talking about. The use of the word best implies subjectivity—ask any group of people what the best of anything is, and you are likely to get more than just one answer. Since the inventors of the claimed invention are the most knowledgeable about the invention, it is reasonable to require the inventors to provide what they think is the best mode of practicing the claimed invention. It is possible that another way of practicing the invention is arguably a “better best mode,” but if the inventors did not reasonably contemplate it as such, they have not violated the requirement. The first prong of the inquiry is a subjective standard, meaning the judicial body evaluating the evidence must make the determination whether the inventor(s) did not provide what he believed to be the best mode of practicing the claimed invention. Figuring out somebody’s actual belief can be very difficult because the ultimate keeper of that information may not be the most reliable of tour guides.Who is going to admit hiding the best mode of practicing their claimed invention when they know that admission might invalidate the claim or even the entire patent?This is not meant to imply that inventors are fundamentally dishonest, but there can be many versions of the same story and time and personal interests have a way of re coloring details long since faded. However, proving somebody’s state of mind or knowledge does not require a signed confession or direct admission but rather can be gleaned from all of the circumstances including the witness’s personal connection with the case. The inventor has the advantage of being the person familiar with the relevant facts but also may have a strong personal interest in seeing the patent validity upheld. The fact-finder will take into account not only what a witness says but also that witness’s credibility; statements are measured in their overall context. This overall context can include an inventor’s publications, notebook entries, and grant applications. Where joint inventors are listed on a patent, each inventor’s perceived best mode must be included in the patent. In such a circumstance, there may be more than one best mode, and accordingly, each of the best modes will need to be included in the patent application.

While we have properly focused on the inventor’s perception of what the best mode is, the best mode does not have to be part of the applicant’s invention per se but can be part of what is known in the art or even provided to the inventor by, for example, a particular commercial supplier. For example, if a claimed process requires a catalyst and the inventors have found that a particular commercial supplier’s catalyst is best for practicing the claimed process, then that detail will need to be disclosed in the patent application. However, the potential inconvenience of this latter requirement is significantly tempered by the more fundamental requirement that the best mode applies to the claimed invention only.

The focus on the claimed invention is sensible from both policy and practical enforcement standpoints. It is not fair to grant a right to exclude that is greater than the scope of disclosure, but it’s also not fair to require disclosure beyond the granted right of exclusion. If the patent claims only a composition then it is usually not necessary to describe the best way to make the compound; the process to make the compound might even be the subject of a separate patent application or kept as the applicant’s trade secret. In such a circumstance, the patent would need only to disclose those details that materially affected the invention as claimed. This issue will be specifically covered in our next case.The case of Bayer v. Schein Pharm. arose when Bayer sued Schein for patent infringement.40 Bayer Corporation is the assignee of the U.S. 4,670,444 patent (the ’444 patent) that includes the potent, broad-spectrum antibiotic ciprofloxacin (Cipro_R ).

The ’444 patent claimed priority to U.S. application number 292,560 (the ’560' application), an earlier patent application. The defendants (Schein) argued that earlier,foreign-issued Bayer patents to Cipro were prior art against the ’444 patent under§102(d). If the ’444 patent could properly claim priority to the ’560 patent application,then the earlier, foreign-issued Bayer patents would no longer be prior art under§102(d) and no longer the basis for an anticipation rejection. Sche in further asserted that Bayer had failed to provide the best mode of practicing the claimed invention(Cipro) in the ’560 application because the Bayer inventors had failed to disclose the best mode of preparing the claimed compounds (including Cipro). If the ’560 patent application did not meet the requirements of the written description requirement,including the best mode, then Bayer could not rely on the earlier filed parent patent application for a priority date. The foreign patents would provide a §102(d) basis for invalidation of the claim and Bayer would lose.
The synthesis of the target compounds could be accomplished by more than one method, though the inventor involved in the claimed subject matter had a preference to make the target compounds by a procedure using a particular intermediate that was not disclosed in the ’560 patent application. The particular class of intermediate preferred by the inventor was not claimed in the ’560 application, although that particular class of intermediates was claimed separately in a different patent application by Bayer. It was not contested by Sche in that the procedure supplied in the ’560 patent application enabled one of ordinary skill in the art to make the claimed compounds, only that the ’560 patent did not indicate the preferred intermediate.

The majority panel of the CAFC held that the best mode applies only to preferred embodiments of the claimed invention itself or to practices of making or using the claimed invention that materially affected the properties of the claimed invention. In the instant litigation, the claims of the invention were directed to compounds and not to methods of making those compounds. The preparation of the claimed compounds could be accomplished by different routes, some preferred over others. However,since the inventors were not claiming the synthetic route or the intermediate used in the preferred route, it follows that they need not disclose that route or intermediate.In fact, the preferred route became the subject matter of a separate patent application.
According to the Bayer court, however, we still need to determine whether the failure to provide the inventor’s best mode for making the compound “materially affected” the properties of the claimed compound. As an abstract legal matter, one can at least appreciate the CAFC panel’s position because it is conceivable that inventors might not disclose the best mode for making a composition where that best mode positively affected the properties of the claimed composition itself. For example, one might envision a best mode crystallization process as a final synthetic step where that crystallization process yields a particularly preferred crystalline form that cannot be achieved by any of the other methods disclosed in the patent application.
Nevertheless, if the claim is drawn broadly to the composition in any form, then the inventors will be afforded the right to exclude others for making, using or selling all crystalline (and noncrystalline) forms of the composition, without actually providing direction as to the best form. However, phrases such as affect the properties of the claimed subject matter can be tortuous in trying to pin down. To what extent must it affect the properties? Must the properties be affected in a predictable way? Does the inventor need to investigate how the properties are affected once he realizes the yare affected? What if the properties are affected in both positive and negative ways from the inventor’s perspective? While such a rule sounds good in theory, it actually has the potential to open a legal Pandora’s box, and partly for this reason was heavily criticized in a concurring opinion in the decision.

A violation of the best mode requirement has severe consequences. Any claim that fails to meet the best mode requirement is invalid, and the entire patent can possibly be invalidated as well (if the best mode was intentionally withheld). Despite the severity of consequences for not meeting the best mode requirement, the overall impact on patent litigation outcomes is minimal. In fact, the CAFC in Bayer v.Sche in noted that in the history of the CAFC and its predecessor court (the CCPA),only seven patents had had one or more claims invalidated as a consequence of a best mode violation. Despite the fact that best mode violations are found rarely, a discussion of the requirement is still warranted. First, the legal landscape can changeover time and patents can be litigated long after the application is filed. The closer one tries to walk next to the edge of the best mode cliff, the better the chance of falling over should the legal landscape eventually shift. Second, you as an inventor control the best mode because it is your belief that determines what it is though it is sometimes very difficult to determine what the claimed invention will be while you are still drafting the technical description of the invention. The best course is one of full disclosure to your agent or attorney. Drafting and filing decisions should be then made in view of both the ultimate invention likely to be claimed as well as the strategy for dealing with any related material that will not be part of the claimed invention.

This related but potentially not claimed material may be dealt with by keeping it asa trade secret, filing a separate patent application if feasible, or still including it in the patent specification as a defense to others filing on the subject matter, and thus potentially preventing you from practicing your own best mode.

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