August 24, 2011
Law360
By Carla Mouta-Bellum, Ph.D.; Thomas L. Irving; *Stacy D. Lewis, Carlos M. Tellez, David J. Martens
Post-KSR,1 the Federal Circuit has decided various cases addressing the patentability of new chemical compounds. In those cases, the Federal Circuit expressly engaged in a determination of whether prior art compounds proposed by the patent challenger ("lead compounds") would have been compounds that one of ordinary skill in the art would have chosen as starting points for further innovation. Based on the legal framework from the lead compound cases, briefly discussed below, we propose a "Lead Prior Art" methodology for approaching obviousness determinations in all technical disciplines.2
Traditionally, a primary prior art reference is selected by an examiner during prosecution or by a patent challenger during litigation. We observe that the propriety of the selected primary reference is seldom questioned. For example, a typical approach for obviousness analysis of new chemical compounds involves litigants and USPTO examiners identifying a structurally similar compound in the prior art, and then proposing suitable modifications of that compound to arrive at the claimed compound.
The structurally similar compound could be identified through structure-based searches using the claimed compound as a template. That approach, clearly loaded with impermissible hindsight, does not explain why a person of ordinary skill in the art (POSITA, representing a hypothetical person presumed to have been aware of all pertinent prior art at the time of the invention) would have selected the most structurally similar compound as a starting point for further development. In particular, the POSITA would not have had the benefit of knowing the claimed compound in advance to work backward and select a structurally similar compound.
In post-KSR chemical cases, the Federal Circuit has attempted to avoid hindsight by expressly questioning whether the selected primary reference was indeed a proper starting point for the obviousness analysis. The court analyzed whether prior art compounds selected in each case as a basis for obviousness analysis would have been properly considered "lead compounds"; i.e., compounds that a POSITA would have selected as starting points for further development given the knowledge available in the prior art.
To illustrate the concept of the lead compound analysis, consider the facts of Takeda.3 Pioglitazone, a patented compound useful in the treatment of diabetes, had two structural differences with respect to prior art "Compound b": (1) an ethyl group, rather than a methyl group, as a side chain attached to a pyridine ring moiety, and (2) the ethyl group in pioglitazone was attached to a carbon in the pyridine ring different from the carbon having the methyl group in Compound b. Aside from these differences, the compounds were identical.
Alphapharm, the accused infringer, argued that once a POSITA had selected Compound b as a lead compound, the POSITA would have replaced the methyl group with an ethyl group, and would have positioned the ethyl group within the ring to match the methyl group's position in pioglitazone.
The Federal Circuit disagreed, explaining that Compound b was not the proper prior art against which to compare the invention. Despite Compound b undisputedly being the most structurally similar compound to pioglitazone, Compound b displayed undesirable physiological side effects, including "considerable increases in body weight and brown fat weight."4
After weighing the available evidence, the Federal Circuit found that a POSITA would not have selected Compound b as a lead compound because of those undesirable side effects, especially because other known compounds displayed promising activity without side effects. Even if Alphapharm had shown that a POSITA would have selected Compound b as a lead compound, the court found that Alphapharm had also failed to show that a POSITA would have had a reason to modify Compound b in the manner necessary to arrive at pioglitazone.
The analysis in Takeda lays the foundation for the lead compound approach, establishing that mere structural similarity is not sufficient to establish a prima facie case of obviousness if: (1) a POSITA would not have selected the close-structural compound or if (2) a POSITA would not have made the modifications necessary to arrive at the claimed invention.
The proper perspective for an obviousness analysis is, by statute, that of a POSITA at the time the invention was made. Thus, in theory, an obviousness determination should consider the state of the art at the time of the invention without using the invention as a blueprint for combining together the teachings of the prior art. Hindsight, however, remains an inherent and significant undesirable influence in an obviousness analysis. Our proposed Lead Prior Art methodology extends lead compound theory to minimize a temptation to employ hindsight by focusing the analysis on information a POSITA would have considered relevant to solving a problem for which the claimed invention is a solution, regardless of whether the inventor sought to solve that problem.
Case law applying 35 U.S.C. § 103 involves several objective factual determinations, collectively known as the Graham5 factors, which include ascertaining the scope and content of the prior art as well as the differences between the claimed invention and the prior art. In order to carry out those factual determinations, an initial step in our methodology reviews the available universe of analogous prior art, which only includes information that was available at the time of the invention.
If a review of the available prior art reveals the existence of an unsolved problem, our methodology determines whether the available prior art also suggests one or more starting points for further development. In our methodology, we call those starting points the "Lead Prior Art." Consistent with an "obvious to try" approach, if the claimed invention is among a few, easily traversed, identified, and predictable solutions suggested by the Lead Prior Art, that solution may have been obvious to a POSITA at the time of the invention. Alternatively, if the prior art does not suggest a solution to the aforementioned problem, or the suggested solution would involve undue experimentation, a next step in our methodology identifies information that a POSITA would have considered relevant to find a solution to that problem.
As the lead compound cases suggest, relevant information could be obtained by analyzing the available options that a POSITA could have followed, with a reasonable chance for success, to solve the problem. In the new-chemical-compound field, for example, prior art compounds that possess "promising useful properties . . . that motivate[] a chemist to make structurally similar compounds" are considered suitable lead compounds.6 And similarly, those compounds possessing undesirable properties, like Compound b in Takeda , may not be sensible prior art starting points to a POSITA.
Examples of information that could suggest sensible starting points include information that evidences that a starting point: (1) displays some kind of superior performance over other starting points, (2) possesses desirable characteristics not present in other starting points, (3) highlights the availability of more information about a particular starting point that would make the development of an improved solution easier than the development from other starting points, and (4) lacks undesirable features or characteristics present in other starting points.
These examples are a nonexhaustive list of potential information that could influence selection of a particular starting point while disfavoring selection of other starting points. In general, any information properly available to a POSITA that would suggest the desirability of one or more potential starting points over others is relevant to the identification of Lead Prior Art.
We posit that even the level of unpredictability in the art and the degree of expectation of success associated with some of the starting points available to a POSITA should be considered in determining the Lead Prior Art. Although unpredictability and expectation of success are normally considered in an obviousness analysis at stages subsequent to the selection of the proper prior art, they could be nonetheless relevant to a POSITA in the selection of a suitable starting point against a backdrop of particularized facts. For example, if a POSITA considers that the results from steps required to modify a given starting point are unpredictable or lack a reasonable expectation of success, the POSITA would be more likely to disfavor that option and instead pursue other more predictable or promising starting points.
Also, while objective indicia of nonobviousness (e.g., commercial success, long felt but unsolved needs, failure of others, unexpected results, etc.) are commonly viewed as rebuttal evidence against a prima facie case of obviousness, these indicia nonetheless could indicate whether a prima facie case of obviousness had even been established. For instance, prior art evidence that a particular starting point had been unsuccessful in the past would tend to indicate that such a starting point would not have been chosen by a POSITA, based on the POSITA's knowledge of those failures.
Similarly, if the inventor's evidence shows that results obtained from a starting point are unexpectedly equal to, or superior to, results obtained from other prior art starting points, the inventor's evidence could show that a POSITA, absent knowledge of those later-revealed unexpected results, could well have selected other prior art starting points that apriori suggested a better outcome.
Once all available information has been analyzed and one or more potential starting points have been recognized, the information is assessed to determine which of those potential starting points for further development would have been chosen by a POSITA. The resulting starting points constitute the Lead Prior Art to be compared with the claimed invention in the traditional manner; i.e., according to the Graham factors. Identification of the Lead Prior Art, or a determination that a certain reference is not the proper Lead Prior Art, can be dispositive of whether a prima facie case of obviousness exists.
Our proposed methodology has been validated by at least one recent Federal Circuit decision in a nonlead compound case. In re Klein7 involved an invention directed to preparing sugar-water nectar for birds and butterflies. The invention involved a water compartment separated by a movable divider from a sugar compartment. The position of the divider defined the ratio between sugar and water for nectar appropriate for the different consumers.
The examiner rejected the claims over five primary references. The board affirmed, but the Federal Circuit reversed the rejection. Three of the references were directed to containers having dividers that defined various compartments, similar to containers for organizing small items in drawers. The Federal Circuit explained that those references were "non analogous art," which a POSITA would not have consulted to prepare nectar because those containers were not capable of holding liquids and were designed to keep items apart, rather than mixing them.8 The other two references were directed to containers to facilitate mixing of two liquids. The court found that those two references were also nonanalogous art and that a POSITA "would not have been motivated to consider [them because they do not show] a movable divider or the ability to prepare different ratios."9
Although Klein was decided under a "nonanalogous prior art" rationale, the decision is easily understood under our proposed methodology because the references in the rejection were not the proper Lead Prior Art and, thus, not available to support a finding of obviousness.
In summary, our proposed Lead Prior Art methodology is consistent with the guidelines from KSR and Graham, requiring consideration of the prior art from the perspective of one of ordinary skill in the art. As shown above, our methodology also provides a universal framework to unify individual obviousness rationales, such as "obvious to try" and "nonanalogous art," which can be seen as particularized embodiments of our general approach. Additionally, when properly applied, our methodology should minimize hindsight and provide a more objective basis for determining obviousness under § 103. In and of itself, that would be a great step forward for the U.S. Patent System.
1 KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007).
2 The authors have published an article reviewing the existing law of obviousness, among other topics, and introducing the concept of Lead Prior Art in the Santa Clara Computer & High Technology Law Journal. The article is available at http://www.chtlj.org/volumes/v27#v027.i3.Finnegan.pdf (link no longer active as of 2/4/2013). Therein, the authors explain why the en banc Federal Circuit decision in In re Dillon, 919 F.2d 688, 16 U.S.P.Q.2d 1897 (Fed. Cir. 1990), cert. denied, 500 U.S. 904, 111 S.Ct. 1682 (U.S. Apr 29, 1991), is not inconsistent with the points made in this article.
3 Takeda Chemical Industries Ltd. v. Alphapharm Pty. Ltd., 492 F.3d 1350 (Fed. Cir. 2007).
4 Id. at 1358.
5 Graham v. John Deere Co. of Kansas City, 383 U.S. 1 (1966).
6 Daiichi Sankyo Co. Ltd. v. Matrix Laboratories Ltd., 619 F.3d 1346, 1354 (Fed. Cir. 2010), cert. denied, (U.S. Mar 21, 2011).
7 In re Klein, No. 2010-1411 (Fed. Cir. Jun. 6, 2011).
8 Id., Slip op. at 12.
9 Id. at 15-16.
*Stacy Lewis is a law clerk at Finnegan.
Originally printed in Law360 (www.law360.com). Reprinted with permission. This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws. This article is only the opinion of the authors and is not attributable to Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, or the firm’s clients.
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