Background of Patent as Motivation to Modify Prior Art
Implicit in a rejection for obviousness based on similarity of structure to prior art structures is the supposition that close chemic structures should have similar chemic backdrop such that a modify in a chemical structure should yield a some what predictable result, the smaller the alter, the more like the expected molecular properties. In an admittedly anticipated art, one might be able to calculate the result that a given change will accept on the function or performance of the object or material being modified, for example, an increase in series resistance in an electrical circuit yields a proportionate decrease in current. Therefore, a prior fine art disclosure of an electrical circuit might render a later claimed circuit obvious where the only thing that was changed in the claimed excursion was the resistance, where that change would be expected to yield a highly predictable result. In contrast, an art that is highly unpredictable would make the predicted effect of any given change less obvious. We accept already been introduced to the notion in chemic patent law that compounds that are similar in structure are predicted to have similar properties; this is the cadre basis for aprima facie obviousness challenge on similar structures. Assuming the prior fine art disclosed a meaningful utility for the disclosed structures, one of ordinary skill in the art ismotivated to make close structural analogs to make additional active compounds. However, chemistry-related arts are often unpredictable due to the fact that pocket-size modifications in a molecule's structure or components of a composition can very frequently lead to large and unpredictable changes in the molecule or limerick's role .Notice a contradiction here? If not a contradiction, conspicuously these two principles are in tension to each other.
How can this tension be reconciled? Start, information technology'southward clear that a more nuanced approach is necessary. In this regard, it is e'er preferable to refer more specifically to the predictability (or lack there of) where enough is known about the particular chemical subject affair being discussed. For example, it is frequently the instance that a class of drugs are known to relate to their target receptor or enzyme in a detail way.Information technology may exist understood in the art that certain areas of the compound can exist varied considerably without greatly affecting compound activity, whereas other areas of the compound may be highly sensitive to pocket-size structural changes. A PHOSITA would expect the variation in the less critical region to yield compounds possessing the priorart disclosed activity whereas the changes in the critical or sensitive surface area would exist less anticipated since the art taught that even small-scale variations could lead to inactive compounds. In existent-world patent prosecution, the more than nuanced analysis will oft
FIGURE : Claimed azatetracycle.
exist offered and explained past the patent applicants themselves since they will exist near familiar with the prior art and too because they will be advocating their position. For instance, a patent part examiner might allege that a claimed structure is prima facie obvious and will betoken to the structural similarities between the claimed compound or genus and the construction(s) disclosed in the prior art. The applicants may and then argue that the specific art the examiner is relying on is really highly unpredictable and may signal to boosted teaching in that or other references that support their assertion.
To see how the specific un predictability of the fine art can argue in favor of not obviousness,consider a case heard before the USPTO Board of Appeals that dealt with this issue. Ex parte Blattnerconcerns a set of claims that were rejected past an examiner at the USPTO. The rejected claims were later appealed to the Board. The claimed subject matter in dispute concerned compound claims and methods directed to a gear up of azatetracyclic compounds for which the abbreviated claim 17, shown in Figure higher up , was considered representative. Additional claims were directed to diverse structural sub embodiments and pharmaceutical compositions containing the compounds of the invention as well as particular methods of use of the compounds including the treatment of agitation in a mammal.
The examiner rejected applicant's claimed invention for obviousness, citing United states of america4,002,632 (the '632 patent), which was prior art to applicant's claimed invention and disclosed the genus in Figure above equally having antide pressant activity.
Figure : Prior art genus from '632 patent reference having described antide pressant activity.
The prior art genus differs primarily from applicant's claimed genus by virtue of the fused six-membered piperidine ring instead of the fused 7-membered homopiperidinering claimed by the bidder. The '632 reference farther discussed the surprising finding that their piperidine-fused compounds demonstrated antidepressant activeness in pharmacological assays whereas five-membered pyrrolidine-fused compounds had depressive effects in those same assays. Thus the prior art taught that going from the five-member pyrrolidine-fused ring to the six-member piperidine-fused ring caused the activity to switch from depressive to anti depressive action. The examiner, past asserting that the claimed genus disclosed in U.S. 4,002,632 rendered the applicant's later on claimed genus prima facie obvious was relying on the axiom that similar structures should result in like activities. While this might be persuasive in the absence of additional data, the prior fine art cited by the examiner actually indicated that a small structural modify in the exact same surface area of the compound that was the source of the difference between the applicant's claimed invention and the genus cited against information technology resulted in a complete reversal in the compound's functional activity. If a five-membered ring and a six-membered ring resulted in compounds with very different activities, what would ane predict for a seven-membered band? While the examiner wished to rely on a generality regarding the structural similarity of vi- and vii-membered, nitrogen-containing ring structures, the Board was more persuaded by the specific unpredictability demonstrated by the very art that the examiner used to back up his argument. Every bit a result, the Board overruled the examiner, and the claims were allowed.
What is worth appreciating here is that the Lath of Appeals was not looking at the action of bidder's claimed compounds. This was non a case in which the properties of the claimed compounds were being used to demonstrate a surprising or unexpected result. Rather, this decision by the Board was specifically focused on the motivation to modify prior art compounds. The bodily activity of the claimed compounds was not relevant to the Board's determination, as they believed that the motivation to make the applicant's claimed genus was absent from the prior art given the cited unpredictability in the art, specifically with respect to a change in the modified region of the compound's structure. As the Board put it when rejecting the examiner'due south finding: "What motivation would a person of ordinary skill in the art have expected for the azepine or vii-membered ring compound? A tranquilizer?An anti-depressant?
A chemical compound which is neither because the depressant and anti-depressant furnishings counteract each other?" The Board's pointed questions on this point are very important as they aid acuminate our ain agreement of what motivation means. When we utilize the term motivation in the obviousness/patentability sense, we are referring to a specific motivation to make that compound or that genus with the reasonable expectation that such a change will exist successful. In the instant case, one could see a general motivation to make additional homologues to explore what consequence the modify might have on the chemical compound's activity. However, since the art already teaches that as mall change could pb to a very different activeness, one would not have the specific motivation necessary to pursue any of the utilities alleged in the literature as whatsoever number of activities (or none at all) could be the result.
Finally we should non confuse the motivation issue in this case with the previous discussion of In re Dillon. Recall that for In re Dillon, the bidder filed a claim for a composition comprising a hydrocarbon fuel with a tetra-orthoester, with the motivation beingness to reduce particulate emissions. Prior art taught compositions of hydrocarbon fuel with tri-orthoesters for de watering fuels, and as well taught the equivalence of tri-orthoesters and tetra-orthoesters for de watering hydraulic fluids. In Dillon, the Board held that there was a reasonable expectation that the tri-orthoesters and tetra-orthoesters would carry similarly in hydrocarbon fuels too. So the priorart "provided the motivation to make the claimed compositions in the expectation that they would take similar properties." In Ex parte Blattner, no such equivalence was taught, in fact, the prior art taught that a minor change in ring size could greatly alter the activeness of the chemical compound, thus making the results of additional modifications to the band size unpredictable.
Source: https://www.wisdomjobs.com/e-university/patent-law-tutorial-505/obviousness-and-unpredictability-in-the-art-14613.html
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