One of the critical differences between a finding of prima facie obviousness versus a finding of anticipation is that a prima facie finding of obviousness may be rebutted by a sufficient showing of secondary indicia of non obviousness (Graham step 4).Keep in mind, that unlike a finding of a lack of novelty, which cannot be rebutted once established, obviousness is a more flexible standard that must take into account all of the prior art as a whole as well as how one of ordinary skill in the art would interpret this art in view of the claimed invention as a whole. Given the difficult and somewhat subjective nature of this inquiry, obviousness determinations are open to more information as to how to reach the ultimate conclusion. Thus, as we will see in this section, there is a large variety of information and evidence that can be entered into the obviousness determination. As we discuss each one of the secondary considerations on its own, you will better be able to see how these criteria are useful in assisting the fact-finder in making the ultimate conclusion regarding non obviousness.
In the course of prosecution of a patent application before the USPTO, the examiner will accept or reject each claim in the application, and for claims rejected on the basis of alleged obviousness, the applicant has a few options regarding how to proceed.The applicants and/or their representative may decide that the examiner is correcting the allegation of obviousness and either cancel the claim or amend the claiming such a way that they think that the allegation of obviousness will no longer be valid. Alternatively, the applicant may choose to argue that the examiner’s argument is not valid and may highlight flaws in the examiner’s argument, preferably citing legal precedent that supports the applicant’s position. However, in some cases, the applicant may choose not to argue against the examiner’s position, either believing that it is correct or that perhaps reliance solely on legal arguments is unlikely to prevail. Assuming he wishes to further pursue the claim, the applicant may decide to submit evidence of unexpected or superior results to rebut the prima facie case of obviousness. Such submissions are typically provided to the USPTO by way of a signed declaration, wherein the declarant provides a statement containing factual information regarding the claimed invention. The evidence so submitted must be sufficient, together with whatever other arguments and evidence of record that exists,to demonstrate that the invention would not have been obvious to one of ordinary skill in the art.
One could reasonably ask why a demonstration of results matters if the invention is obvious on its face. If it would have been obvious to make the invention that the applicant is attempting to claim, why does it matter if that invention turns out to have some unexpected or superior results regarding its performance? To better understand this, it is helpful to analyze this inquiry as directed to the patenting of molecules or chemical compositions. Whether it would have been obvious to claim a particular compound or genus of compounds is typically made by an examination of other molecules or genera of molecules that have been taught in the art. As a general matter,the closer the prior art structures are to the claimed structures, the more likely it is that a prima facie case of obviousness will be successfully asserted against the claimed structures. However, the obviousness of a compound or composition cannot be considered independent of its properties, for as the CCPA (CAFC predecessor court)explained:
A compound and all of its properties are inseparable; they are one and the samething . . . . But a formula is not a compound and while it may serve in a claim to identity what is being patented, as the metes and bounds of a deed identify a plot of land, the thing that is patented is not the formula but the compound identified by it. And the patentability of the thing does not depend on the similarity of its formula to that of another compound but of the similarity of the former compound to the latter. There is no basis in law for ignoring any property in making such a comparison.
Since the obviousness or non obviousness of a compound should be determined on the basis of whether one of ordinary skill in the art would have appreciated the “invention as a whole,” the obviousness determination of a claimed molecule or composition cannot exclude its properties in view of the prior art. Thus if an allegation is made that a prior art disclosure or combination of disclosures renders a later claimed compound obvious, then that allegation of obviousness must hold true for the compound as a whole, including its properties. A showing that the claimed compound or composition provides unexpected results or superior benefits(which necessarily relate to the properties of the claimed compound in question)when compared to the prior art compound or composition rebuts the basis of the obviousness allegation. For example, a chemist may wish to patent a compound or genus of compounds where the compounds are structurally similar to a compound or genus of compounds with some utility that have been disclosed in the prior art. The USPTO examiner may assert that the structures are obvious in view of the prior art due to the structural similarity and disclosed activity and may issue a rejection on that basis. If the applicants believe that they can demonstrate superior or unexpected results for their claimed compound or genus, they may wish to provide that additional evidence to the examiner; often in the form of an affidavit or declaration. This discussion raises two key questions. First,what type of unexpected or superior results are necessary to overcome an obviousness rejection in chemical cases? Second,what part of the claimed invention must demonstrate unexpected results and what part of the art are the unexpected results determined in comparison to? To answer these two questions, we’ll break the inquiry down into the following four aspects:

  1. Unexpected results must be taught by, or flow from, the patent application.

  2. Unexpected results in one area may be sufficient.

  3. Unexpected results may be a difference in degree or kind.

  4. The claimed invention must be tested against the closest prior art and not all of the prior art.

8.8.a Unexpected Results Must Be Taught by, or Flow from the Patent Application

At the outset, it is important that we appreciate that any unexpected results that the applicant hopes to rely on in rebutting a prima facie case of obviousness need to be explicitly disclosed or at least inherently flow from a described feature of the invention. This means that one cannot expect to overcome a rejection based on alleged obviousness by demonstrating unexpected properties that were not disclosed in the patent application as filed or do not flow naturally (inherently) from the disclosure in the application.
As an example, the case of In re Davies dealt with claimed subject matter related to “toughened styrene polymers” that had been prepared using a butadiene/styrene toughening agent. In appealing claims that were rejected by the USPTO, the applicant did not argue the allegation of prima facie obviousness in view of the several references cited, but rather argued that the USPTO should have considered certain indices of unexpected or superior results. In particular, the applicants wished to enter affidavits containing evidence of not only improved mechanical strength but also improved gloss, transparency, and processability. The CCPA upheld the USPTO’s rejection of the proffered evidence, stating that the “the basic property or utility must


FIGURE :Claimed compound 1 and prior art compound 2.

be disclosed in order for affidavit evidence of un expected properties to be offered.” The properties in question, the allegedly unexpected combination of improvement of strength to gether with the improved gloss, transparency, and processability, were not disclosed in the application, and the CCPA did not believe that such properties would inherently flow from the disclosure either. The CCPA noted that it was difficult to understand how un expected properties of improved gloss, transparency, and process ability find a basis in or inherently flow from the disclosure that appeared to be limited to the discussion of the use of toughening agents as well as the fact that the application appeared to be limited in discussion of improved mechanical properties, such as impact resistance.

8.8.b Unexpected or Superior Results Can Be Demonstrated
Through a Single Property

Before considering the type of unexpected or superior results that are sufficient for overcoming a legal conclusion of obviousness, it is important to appreciate that unexpected or superior properties do not have to be demonstrated for every tested aspect of the invention. In other words, the claimed invention may prove superior in only one property but still be found to demonstrate unexpected or superior results enough to merit patenting. In the case of In re Chupp, the applicant for patent was attempting to claim compound 1 shown in Figure above, where the prior art disclosed compound 2.
The specification of the application disclosed that compound 1 and related compounds were useful as herbicides, and the examiner rejected the claimed compound alleging obviousness over a prior art reference (a Swiss patent) that included a specific example with the structure 2. As rebuttal, the applicant submitted a declaration that discussed results obtained when compound 1 was compared to compound 2.

In particular, the compounds were tested for their ability to control two weeds— quack grass and yellow nutsedge—in fields of two crops—corn and soybean. The tests demonstrated that the claimed compound gave superior results compared to the prior art compound, exhibiting selectivity factors (crop safety combined with weed killing activity) at least five times better than the prior art compound. The examiner persisted in rejecting the claimed compound on the grounds that the applicant’s own specification indicated that the claimed compound would not show superior activity in crops other than corn and soybean. The applicant appealed first to the USPTO Board of Appeals, where the examiner’s rejection was upheld, and subsequently to the CAFC, where the obviousness rejection was overturned and the claim was ultimately allowed to issue (U.S. 4,731,109). In its written opinion, the CAFC held that it was not essential that a claimed compound demonstrate superior activity over a prior art compound in all common activities but rather that it might be sufficient if the compound is unexpectedly superior in one of the spectrums of a common property, as was the case here.

8.8.c Unexpected Results: Different in Degree or Different in Kind?

As we have seen for so much of our obviousness analyses so far, the obviousness determination is made on a weighing of the evidence as a whole. Thus when a primafacie case of obviousness is made and a rebuttal attempted with a demonstration of unexpected results, it is incumbent on the examiner (or fact-finder) to make the determination in view of all of the evidence. Having said this, it is possible to make some qualitative assessments regarding the types of showing that have or have not been found capable of overcoming a prima facie case of obviousness by examining several cases, bearing in mind that the rebuttal evidence of unexpected results cannot be isolated out as the dispositive variable since all of the evidence and arguments must ultimately be considered together.
Before we get started in our analysis of actual court cases dealing with this issue, let’s first consider some general propositions. In the cases in which unexpected results have been submitted to attempt to rebut a prima facie case of obviousness, the courts have generally characterized the evidence as either a “difference in kind” or a“difference in degree.” To differentiate between a difference of kind and a difference of degree, first imagine the situation in which a compound is compared to a prior art compound for which a prima facie case of obviousness has been alleged. In supporting the prima facie case of obviousness, the USPTO examiner references a prior art compound that is structurally very similar to the claimed compound and has disclosed utility as an agonist at a particular receptor. The examiner further notes additional priorart where similar structural changes have retained compound activity and thus concludes that one of ordinary skill in the art would have been motivated to make the small structural change with the reasonable expectation that such a change will result in additional compounds with similar activity. However, the applicant submits a declaration with evidence comparing the two compounds, demonstrating that the prior art compound was an agonist while the claimed compound was an antagonist at the same receptor. In this instance, the unexpected results are not simply one of degree but rather are one of kind. Such a complete change in the molecule’s function should carry considerable weight as it strongly rebuts the presumption that molecules with similar structures are presumed to have similar activity.
Next, assume the claimed compound is also an agonist at the same receptor but that the applicant’s compound has 30% greater potency for the receptor than the prior art compound. Again the examiner makes the same case for obviousness as before, and the applicant prepares a rebuttal declaration documenting the 30% greater affinity of the claimed compound for the receptor. Here, it is much less likely that the applicant will prevail with such a showing of results. Rather, the applicant is likely to be met with yet another rejection, this one stating that the results are only a difference of degree and not a difference of kind. The examiner will likely point out that such differences in activity are expected as one of ordinary skill in the art would expect that small changes in structure are likely to result in small changes in potency.
So you may well ask, at what point does a difference of degree become a difference of kind? While a 30% increase in receptor affinity might not be a difference in kind,what about a 100%, 200%, 400%, or 800% increase?What if those numbers are or are not statistically significant? How about a 50% difference, but with differences across multiple receptors? How about other properties of the compound such as solubility,lipophilicity, or toxicity? As you may have guessed, there is no easy answer to any of these questions. Further complicating our analysis is that we are considering these questions in the abstract. In the actual situations for which we are concerned, the examiner or the court will be considering the weight of all the evidence. In so doing,the determination of obviousness is not based solely on the basis of the un expected results submitted but on the strength of the prima facie case as well. To the extent that the characterization of unexpected results as a matter of degree or a matter of kind is a conclusion, then that conclusion must be consistent with the ultimate conclusion in regard to obviousness. Accordingly, it is often difficult to parse the actual weight afforded the unexpected results relative to the entirety of the evidence. In other words,evidence that might be deemed a matter of degree for one case in which the overall conclusion is going to be that the claimed invention is obvious could very well be deemed as a matter of kind for a different case in which the overall conclusion is going to be that the claimed invention is not obvious. Please keep these thoughts in mind as we analyze two different cases where evidence of unexpected results were submitted.
In the first case, In re Soni, the CAFC heard an appeal from the applicants for a patent where several claims to a high molecular weight conducting polymer were rejected by the USPTO as being obvious over a number of selected references, citing lower molecular weight polymer compositions. Claim 1 of the patent application was considered to be illustrative of the invention by the court and is shown below.

  1. A melt-processed composition which comprises

    1. an organic polymer which is not cross-linked and has a molecular weight which is greater than 150,000 when measured by high temperature gel permeation chromatography, and

    2. a particulate conductive filler which is dispersed in the polymer and which is present in an amount sufficient to render the composition electrically conductive.

In the specification, the applicants for patent had included a number of tests comparing the properties of a polyethylene polymer having a molecular weight of 203,000 with a polyethylene polymer having a molecular weight of 148,000. The data provided in the specification for the two polymers indicated that the higher molecular weight polymer had at least a 50-fold increase in tensile strength as well as at leasta 5-fold increase in peel strength in addition to improved resistivity and recovery behavior. The applicant conceded that the prior art cited by the USPTO was sufficient to support a prima facie case of obviousness but argued that the data they provided in the specification were sufficient to demonstrate superior results beyond what one of ordinary skill in the art would have predicted. In overruling a final rejection from the USPTO and finding for the applicants, the CAFC stated: “Mere improvement in properties does not always suffice to show unexpected results. In our view, however,when an applicant demonstrates substantially improved results, as Soni did here, and states that the results were unexpected, this should suffice to establish unexpected results in the absence of evidence to the contrary.”
In contrast, in In re Merck & Co. the court found that the applicants for a reissue patent did not demonstrate unexpected results sufficient to overcome the prima facie case of obviousness established by the USPTO. In this example, claim 1 of the patent in question (U.S. 3,428,735) will be considered illustrative of the matters at issue:

  1. A method of treating human mental disorders involving depression which comprises orally administering to a human affected by depression 5-(3-dimethylaminopropylidene) dibenzo[a,d][1,4]cycloheptadiene (amitriptyline) or its non-toxic salts in daily dosages of 25 to 250 mg of said compound.

The chemical formula referred to in claim 1 is also known as amitriptyline, and its chemical structure is given in Figure 8.13, along with the chemical structure of imipramine used as an antidepressant and additional prior art compounds having central nervous system activity from which the method of claim 1 was deemed obvious.
The CAFC upheld the USPTO’s finding of a prima facie case of obviousness.In so doing, the court first noted the structural similarity between amitriptyline and


FIGURE :Structure of claimed compound (amitriptyline) and prior art compounds.

imipramine (a compound with known antidepressant activity) but also that the literature taught bioisosterism between the bridgehead nitrogen in imipramine and the alkene carbon of amitriptyline. The court further highlighted the inter changeability of the alkene and the aminomethyl moiety through the prior art structures of chlorpromazine and chlorprothixene (structures also shown in Figure above), both of which were reported to possess similar pharmacological properties to each other, including a strong central nervous system (CNS) effect. The CAFC also discussed a set of priorart documents that revealed data from several tests of amitriptyline and imipramine indicating the two compounds were very similar in a variety of properties, including their use as tranquilizers having narcosis-potentiating effects. The prior art document went on to further suggest that amitripty line should be tested for depression alleviation,a property that imipramine was known for, and that side effects were likely to be similar to those seen with imipramine.
In response to the USPTO prima facie case for obviousness, Merck attempted a number of approaches. First, they argued that the USPTO had relied on an “obvious to try” standard and that there was not motivation in the prior art to create their invention. However, the court noted that obviousness does not require absolute predictability but rather only a reasonable expectation that the desired result will be achieved.Merck further argued evidence of unexpected results, including data that amitripty line has an “unexpectedly more potent sedative and a stronger anti-cholinergic effect.”
As part of this approach, Merck introduced an affidavit by an expert witness that some patients responded better to amitripty line than imipramine. The CAFC was not convinced. They highlighted the fact that the prior art of record “clearly” taught that amitripty line was a known sedative and, further, that all tricyclic antidepressants, in general, possess the secondary properties of sedative and anticyclone effects. The fact that some patients were helped more by one drug than another was not held to be significant. In citing a reference indicating that amitriptyline was “highly sedative” while imipramine was “somewhat less sedative than amitriptyline,” the court stated that the difference was a “matter of degree rather than kind,” and affirmed the finding of obviousness.
To better understand the different holdings in In re Soni and In re Merck & Co.,it is helpful to examine a few points that are not explicitly of the record but merit discussion. It appears from its holding that the Merck court’s overall decision was at least in part due to a very strong prima facie case. Besides the structural similarity,the court was able to point to a number of references that appeared to provide a direct suggestion that amitriptyline be tested as an antidepressant. Such a strong and direct suggestion was due to the fact that this was a special circumstance where the applicant was attempting to patent a method for a compound that was already well known in the art as a CNS-active agent. Many of the primary activities of the compound were already understood, and some discussion had already occurred in the prior art regarding the possibility (or even desirability) of using it as an antidepressant.Obviousness as a whole means that the elements of structural similarities, prior artteaching of equivalence, and unexpected results must be considered together. Where a prima facie case of obviousness is very strong, a greater degree of unexpectedness of the demonstrated results will be required in rebuttal.

8.8.d The Claimed Invention Must Be Tested Against the Closest Prior Art

When the applicant for patent is attempting to make a showing of unexpected results or benefits to rebut a prima facie case of obviousness, the question often comes up as to what prior art does the claimed invention need to be compared against. The short answer is “the closest prior art.” However, the closest prior art does not need to bethel same prior art that the patent examiner relied on but rather can be different priorart if that different prior art is in fact closer to the claimed invention. For example, in the appeal of Ex parte Humber, claimed 13-chloro substituted compounds were found prima facie obvious in view of prior art non chlorinated compounds. Instead of making a showing over the prior art non chlorinated compounds, the applicant showed unexpected results over more closely related 9-, 12- and 14- chloro substituted compounds; this was deemed sufficient to rebut the prima facie case of obviousness.
In situations in which there is more than one prior art reference and both are equally close to the claimed invention, the applicant will be required to make a showing in regard to both of the prior art disclosures, unless the teachings of the priorart references are each sufficiently similar to each other that making a showing again stone will suffice for the other. For example, let’s assume an applicant is attempting to claim the structure in Figure below and the two prior art structures have each been cited against the claimed structure.

claim the structure

FIGURE :Comparison of claimed compound to more than one prior art compound.

Assuming the both prior art compounds have a disclosed utility, the examiner alleges that one of ordinary skill in the art would have been motivated to make close structural analogs of the disclosed prior art compounds in order to find additional compounds having the disclosed activity. Further, the examiner has cited additional references from the literature in which saturated propionic esters have been replaced with unsaturated propionic esters and where chlorides have been successfully replaced with trifluoromethyl groups, and the molecules so derived have had similar if not better activity. Thus the examiner argues that it would have been obvious to make those modifications to the prior art compounds. Sounds like a strong prima facie case of obviousness unless the applicant can show her claimed compounds demonstrate unexpected properties or superior results, but compared to which structure? The answer in this example would most likely be both. The reason is that if the applicant compares the claimed compound to prior art compound 1, she will be demonstrating an unexpected result for the trifluoromethyl group relative to the chloro group .However, this still does not answer the question of whether the unsaturated ester can demonstrate unexpected results compared to the saturated ester of the prior art. Both prior art compounds will need to be prepared or otherwise acquired and compared to the claimed compound.

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