May 28, 2021by Matthew Barnet1

U.S. patent examiners often use an optimization rationale when rejecting claims as obvious. Such situations typically arise when a claim recites a range of possible values for a certain variable, and the prior art discloses a value of the variable that is outside the claimed range. In these situations, examiners usually take the position that the claimed range would have been obvious to obtain by routine optimization of a “result-effective variable,” i.e., a variable that achieves a recognized result in the prior art.

In other situations, however, examiners apply a result-effective variable rationale to a claimed property that is not disclosed in the applied prior art. This is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Horiuchi (Appeal No. 2020-000126).

In Horiuchi, independent claim 1 recited:

A covering material for an electric wire, the covering material having a composition containing a polyvinyl chloride,

wherein the composition of the covering material comprises a characteristic such that a change curve of a loss modulus with respect to temperature for the composition of the covering material containing the polyvinyl chloride has no peak within a temperature range of -30°C to 60°C, which is a temperature range in a usage environment for the electric wire, and

wherein the composition of the covering material comprises more than or equal to 35 parts by weight and less than or equal to 50 parts by weight of a plasticizer and 2 to 20 parts by weight of a flexible resin with a melt flow rate of 1.0 g/10 min or less, the plasticizer and the flexible resin combined with respect to 100 parts by weight of the polyvinyl chloride such that the composition comprises the characteristic.

The examiner rejected claim 1 as obvious. The examiner acknowledged that the applied prior art did not disclose the claimed property of a change curve of loss modulus having no peak within a temperature range of -30°C to 60°C. However, the examiner took the position that the

change curve of loss modulus with respect to temperature is a result effective variable. As the change curve of loss modulus with respect to temperature peaks the material undergoes a decrease in flexibility. Thus, it would have been obvious to…have a covering material that has a change curve of loss modulus with respect to temperature which shows no peak within a temperature range in a usage environment for the electric wire motivated by the expectation of maintaining flexibility over the usage environment for the electric wire, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art.

In response, the applicant argued that the claimed property of having no peak within a certain temperature range of the change curve of loss modulus was not itself a result-effective variable known in the prior art. Instead, the applicant explained that this claimed property depended on at least five other variables: the amount of plasticizer, the amount of flexible resin, the melt flow rate of the flexible resin, the relative proportions of components, and temperature. The applicant argued that a skilled artisan would understand that “such a complex combination of material concentrations along with melt flow rates could not be summarily characterized as one ‘variable’ in the form of a simple graph of loss modulus v. temperature, that could be routinely manipulated.” Thus, the applicant argued that it would not have been obvious to achieve the claimed property from the applied prior art.

The Board agreed with the applicant, and reversed the obviousness rejection. The Board did not explain its reasoning regarding the examiner’s result-effective variable rationale, other than mentioning that it adopted the reasoning provided by the applicant. However, the Board emphasized that the amount of plasticizer in the claims (35 to 50 parts by weight with respect to 100 parts PVC) was higher than the upper limit in the applied prior art (30 parts by weight with respect to 100 parts PVC). The Board noted that the applied prior art taught away from using an amount of plasticizer higher than 30 parts by weight, since doing so could cause the covering material to have an insufficient damage-resistance property. The Board concluded that “the Examiner does not explain adequately how one skilled in the art would arrive at the claimed covering material from the [applied prior art].”

Takeaway: Whenever an examiner takes the position that a claimed property is a result-effective variable that would have been obvious to optimize, it is important to carefully evaluate the teachings of the prior art relating to the claimed property. If, as in Ex parte Horiuchi, the claimed property is distinguishable from variables in the prior art, then this distinction can help overcome an examiner’s obviousness rejection. If the claimed property is related to certain claimed variables (such as concentration of a component), but the claimed values of these variables do not overlap the corresponding values in the prior art, this approach can be particularly useful.

Judges: Smith, Cashion Jr., Inglese


May 21, 2021by Jacob Doughty

Ex parte Ha, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing the sufficiency of an examiner’s rationale for combining references and the sufficiency of an applicant’s evidence of unexpected results.

In Ex parte Ha, the claim at issue was directed to a thermoplastic resin composition for electronic device housing. The claims required, inter alia, five known components in specific amounts and a specific weight ratio between two of the components – a very typical composition claim. Independent claim 1 is reproduced in part below:

1. A thermoplastic resin composition comprising:

about 100 parts by weight of a polycarbonate resin;

about 1 to about 30 parts by weight of a rubber-modified aromatic vinyl graft copolymer;

about 1 to about 30 parts by weight of a polyester resin;

about 1 to about 20 parts by weight of a glycol-modified polyester resin having about 10 mol% to about 60 mol% of a cyclohexanedimethanol (CHDM) content based on a total amount of a diol component; and

about 0.5 to about 15 parts by weight of a vinyl copolymer comprising an epoxy group,

wherein a weight ratio of the polyester resin to the glycol-modified polyester resin

ranges from about 1:0.1 to about 1:1.

The examiner rejected the claim as obvious, citing a primary reference that disclosed a resin composition having each of the above recited features except for the glycol-modified polyester resin and the claimed weight ratio. For this, the examiner relied on the resin composition in a secondary reference.

Applicant noted that the resin composition of the primary reference was developed to solve the problem of achieving flame retardancy in a rubber-modified aromatic vinyl copolymer resin without using harmful compounds and without deteriorating impact strength. Applicant asserted that the secondary reference did not recognize or address issues relating to the use of flame retardants and, thus, a skilled artisan would not look to the secondary reference to improve the resin compositions of the primary reference.

The PTAB found applicant’s reasoning unpersuasive, noting that the secondary reference employed the claimed glycol-modified polyester resin in a resin composition that solved the different problem of achieving improved dimensional stability, heat resistance, and weld line strength. The PTAB stated that a skilled artisan would have found the improved dimensional stability, heat resistance, and weld line strength achieved in the secondary reference to be desirable attributes in the resin compositions of the primary reference and, thus, would have been led to incorporate the glycol-modified polyester resin.

Perhaps recognizing the challenges of arguing over the examiner’s prima facie case of obviousness, applicant relied heavily on rebuttal evidence of unexpected results. Applicant presented supplemental experimental evidence during prosecution showing that excluding the glycol-modified polyester resin of secondary reference from the claimed resin composition and/or including the glycol-modified polyester resin in amounts outside of claimed weight ratio resulted in inferior impact resistance and processibility.

The examiner did not appear to contest that applicant’s results demonstrated that the claimed composition exhibited an improvement over the primary reference or that such improvement would have been unexpected. Instead, the examiner argued that applicant simply did not provide a sufficient number of inventive examples to demonstrate that the improvement would occur over the entire scope of the claims (noting the generic components and wide ranges of amounts recited in the claims).

Applicant affirmatively argued during the appeal that a “skilled artisan… can clearly and reasonably extrapolate or extend the probative value of the data to other compositions within the scope of the claims.” However, the PTAB found applicant’s argument to be merely conclusory, noting applicant’s burden to provide “an adequate basis to support the conclusion that other embodiments falling within the claim will behave in the same manner… as the exemplary embodiment.”

Takeaways: Demonstrating obviousness in the US can be a bit different than in other jurisdictions. Applicant, in this case, presented arguments akin to the “problem-solution approach” used to argue inventive step in EP practice. However, US examiners and the PTAB often find motivation to combine references far afield from the specific problem addressed by the closest prior art. It is important to bring US obviousness arguments to bear against US obviousness rejections.

Because of the ease with which an examiner can make a prima facie case of obviousness as to composition claims, the patentability of such claims often turns on evidence of unexpected results. The sufficiency of such results often turns on whether the results are “commensurate in scope” with the claims. Arguments of unexpected results should be accompanied with at least a technical explanation – preferably from a skilled artisan – of why results for inventive examples would be expected for all compositions within the scope of a claim.

Judges: Gaudette, Cashion, McGee


May 12, 2021by Richard Treanor

The Patent Trial and Appeal Board issued a decision in Ex Parte Shaw in which an Examiner’s choice of lead compounds (i.e., prior art compounds identified by the Examiner which are then modified to produce the claimed compounds) was reviewed.

In Shaw, Appellant’s principal argument was that the Examiner lacked any basis for choosing Examples 33 and 53 of the primary reference as lead compounds because there was nothing in the reference that distinguished them from the other 363 disclosed compounds. Arguing that the reference failed to provide specific, favorable biological activity for Examples 33 and 53, and citing the activity requirements for lead compounds set out in Daiichi Sankyo Co., Ltd. v. Matrix Labs. Ltd., 619 F.3d 1346 (Fed. Cir. 2010) (“proving a reason to select a compound as a lead compound depends on more than just structural similarity, but also knowledge in the art of the functional properties and limitations of the prior art compounds. Potent and promising activity in the prior art trumps mere structural relationships.”) Appellant urged that the Examiner’s selection of Examples 33 and 53 was improperly based on hindsight structural similarity to the claimed compounds, as there was simply no other good reason to choose Examples 33 and 53 as lead compounds.

The Board disagreed, affirmed the Examiner, and cited a passage in the primary reference seemingly generic to all compounds disclosed therein:

The compounds of Examples 1-365 were tested in the … in vitro AMPK activation assay . . . and found to have EC50 values of less than 10 micromolar and greater than 80% maximum AMP activation.

In explaining its opinion, the Board took the position that this indication of activity was sufficient to justify the Examiner’s choice of lead compounds, even in view of the Daiichi court’s instruction, cited with approval by the Board, that:

[T]he analysis still requires the challenger to demonstrate by clear and convincing evidence that one of ordinary skill in the art would have had a reason to select a proposed lead compound or compounds over other compounds in the prior art.

While the primary reference in Shaw did not do this, likely underlying the Board’s decision were several factors hinted at in the decision – the fact that the lead compound analysis was Appellant’s only real argument, and the fact that Appellant’s claimed compounds were only as efficacious as those of the primary reference.

Takeaway: In Shaw we see the Board willing to bend somewhat on the requirements of the lead compound analysis in a case where Appellant was not able to (or at least, did not) argue the existence of better lead compound candidates in the prior art, and in which no unexpected results were provided. With nothing to tip the scales in Appellant’s favor, the Board seemed willing to set a lower limit on the evidence needed to sustain a lead compound designation.

Judges: F. Prats, R. Guest, D. Katz


April 30, 2021by Beau Burton

Ratios can be useful when claiming a subset of two well-known components or variables, particularly when the subset (defined by a ratio) provides a new and useful result. However, when the prior art teaches broad ranges for the individual components or variables, it is common for examiners and petitioners to argue obviousness based on overlapping theoretical ranges of the ratio derived from selecting the maximum and/or minimum values for each of the components or variables. The issue with this is approach is that the prior art may not direct a person of ordinary skill in the art  (POSA) to the particular selections required to arrive at the claimed ratio. SNF S.A. v. Solenis Technologies is illustrative. IPR2020-01730, Paper 10 at 4 (PTAB April 22, 2021).

In SNF S.A., the challenged claims required a glyoxalated copolymer (G-PAM) obtained by reacting:

[A] 5–40 parts of glyoxal; and

[B] 60–95 parts of a cationic copolymer including:

[b1] ~15–85 wt% of diallyldimethylammonium halide monomer (DADMAC); and

[b2] ~85–15 wt% of acrylamide monomer,

the cationic copolymer having a weight average molecular weight (WAMW) of 120,000 to 1,000,000 Daltons, and

a ratio of the WAMW to the weight % of the DADMAC being greater than 4000 Daltons/weight%.

According to the background of the patent, the patentee found that the ranges of the WAMW and % DADMAC in combination with the claimed ratio thereof improved water drainage during processing and increased the strength of paper or boards treated with the G-PAM.

The petitioner, SNF S.A., argued obviousness based on three different primary references: Wright, Lu, and Dauplaise. The petitioner admitted that none of the cited references disclosed a ratio between WAMW and % DADMAC. To remedy this deficiency, the petitioner presented two arguments.

The petitioner’s first argument was that a POSA would have selected values of the WAMW and % DADMAC disclosed by each of the references to arrive at the ratio required by the claims. Specifically, with respect to the Wright reference, the petitioner argued “the ratio of 150,000 WAMW to 25 wt.% DADMAC, as both taught by Wright ’343, is 6,000 [and] … the ratio of 1,000,000 WAMW to 30 wt.% DADMAC is 33,333.” The petitioner supported this assertion with an expert declaration that similarly stated it would have been “obvious” and “routine” to select molecular weights of 150,000 (an upper endpoint of the preferred range) and to select DADMAC concentrations of 25% and 30% (preferred concentrations).

For ease of discussion, the scope covered by the claims (shaded blue box) relative to the scope disclosed by the Wright reference (shaded red box) and the two particular data points of the Wright reference relied on by the petitioner (red dots) are shown graphically below and here:

As shown above, Wright’s broad WAMW range of 30,000 to 5,000,000 and broad % DADMAC range of 0.1–90 wt% cover a WAMW/%DADMAC ratio of 4,000, as they theoretically cover ratios from 333 to 5×107. And although one of the ratios derived by the petitioner (lower red dot) was derived from a preferred amount of DADMAC (25 wt%) and an upper endpoint of a preferred WAMW range (150,000), the Board found:

Petitioner, however, never explains how or why a person of ordinary skill in the art would have been led to select the value ‘150,000 WAMW,’ or ‘25 wt.% DADMAC,’ or any of the specific values it uses to calculate the claimed ratio. Nor does Petitioner direct us to any disclosure in the prior art showing an embodiment having the specific values used in Petitioner’s calculations.

Absent explanation from Petitioner, it appears that Petitioner picked the specific values it used to calculate a ratio from broad, unrelated ranges of WAMW and % DADMAC disclosed in the prior art simply because they combine to produce a ratio that meets the ratio recited in the claims of the ’320 patent. This suggests Petitioner relied on hindsight in forming its challenges. Metalcraft of Mayville, Inc. v. The Toro Co., 848 F.3d 1358, 1367 (Fed. Cir. 2017) (‘[W]e cannot allow hindsight bias to be the thread that stitches together prior art patches into something that is the claimed invention.’).

This use of hindsight is not excused by the mere fact that the specific values combined to produce the claimed ratio fall within the ranges disclosed in the prior art.

The other two primary references relied on by the petitioner, Lu, and Dauplaise, suffered similar defects.

The petitioner’s second argument was that “a POSA would have arrived at the ratio using routine experimentation to optimize result-effective variables, as guided by the art.” The Board also rejected this argument.

First, the Board found that a POSA would not have optimized the ratio itself because “there is no evidence that skilled artisans knew that the claimed ratio of WAMW to % DADMAC was a parameter of any importance or one worth optimizing.” That is, the ratio was not a result-effective variable.

Second, the Board found that there was no persuasive evidence to support a conclusion that independently optimizing WAMW and % DADMAC would result in a polymer having the claimed ratio rather than one of the many ratios falling outside the scope of the claims. Again, the Board emphasized the innumerable combinations of values. But it seemed that the Board was more persuaded by the fact that there was evidence of polymers outside the scope of the claim exhibiting the same properties as those having the claimed ratio such that optimization could equally result in a copolymer having a ratio outside the claim. Ultimately, the Board concluded that the evidence did not support the petitioner’s assertion that independent optimization would lead to the claimed ratio.

For the foregoing reasons, the Board concluded that the petitioner failed to carry its burden and declined to institute the IPR.

Takeaway: When facing an office action or post-grant petition in which a claimed ratio is alleged to be obvious based on the selection or optimization of the components making up the numerator and denominator, you should first determine whether the ratio itself is a result-effective variable. If not, the next step is to determine whether there is an embodiment that discloses values for the numerator and denominator that would result in the claimed ratio. As shown in SNF S.A., the fact that specific values can be combined to produce the claimed ratio is insufficient by itself when there are innumerable combinations of values. If neither of these applies, the final step is to determine whether the prior art teaches a reason to optimize the numerator and denominator in a manner that would result in the claimed ratio.

Judges: C. Crumbley, J. Abraham, D. Cotta


April 23, 2021by Matthew Barnet

In an anticipation rejection, every element and limitation of the claimed invention must be found in a single prior art reference, arranged as in the claim. However, “it is not enough that the prior art reference . . . includes multiple, distinct teachings that [an ordinary] artisan might somehow combine to achieve the claimed invention.” Net MoneyIN, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1371 (Fed. Cir. 2008). Instead, the reference must “clearly and unequivocally disclose the claimed [invention] or direct those skilled in the art to the [invention] without any need for picking, choosing, and combining various disclosures not directly related to each other by the teachings of the cited reference.” Id. (quoting In re Arkley, 455 F.2d 586, 587 (C.C.P.A. 1972)). Although “[s]uch picking and choosing may be entirely proper in the making of a 103, obviousness rejection . . . it has no place in the making of a 102, anticipation rejection.” Arkley, 455 F.2d at 587-88.

This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Eckhardt.

Independent claim 16 recited a multilayer pressure-sensitive adhesive assembly comprising a propylheptyl acrylate adhesive copolymer layer and a second acrylate pressure-sensitive adhesive foam layer. The propylheptyl acrylate adhesive copolymer layer comprised (a) 50 to 99.5 weight percent of 2-propylheptyl acrylate as a first monomer, (b) 1.0 to 50 weight percent of a second non-polar monomer, (c) 0.1 to 15 weight percent of a third polar acrylate monomer, and (d) a tackifying resin in an amount of 3 to 100 parts per 100 parts of the copolymer. Independent claims 37 and 38 recited similar multilayer pressure-sensitive assemblies, but with somewhat different components (d), and different scope of components (a), (b) and (c).

The examiner rejected independent claims 16, 37 and 38 as anticipated by a single reference, Bartholomew. In response, the applicant argued that “[t]he cited reference provides a great multiplicity of possible combinations and no direction that would lead one of skill in the art to the claimed invention.” For component (a), the applicant explained that Bartholomew listed “2-propylheptyl acrylate as one of 10 options.” For the specific components (b) and (c) recited in claims 37 and 38, the applicant explained that component (b) was one of eight options listed in Bartholomew, and component (c) was one of ten listed options. For component (d), Bartholomew described a tackifying resin as optional. Based on this, the applicant argued that “the number of possible combinations presented by these passages in Bartholomew is 10 x 8 x 10 x 2 = 1600.” The applicant argued against anticipation because “one of ordinary skill in the art would be required to pick items from at least 1600 types of polymer to arrive at the claimed invention.”

The Board agreed with the applicant, finding that the anticipation rejections “rely upon picking and choosing from various lists in Bartholomew,” and that “[a] preponderance of the evidence supports Appellant’s position that Bartholomew’s disclosure is insufficient to establish anticipation of the compositional components of independent claims 16, 37, and 38.”

Additionally, the Board noted that although the ranges of amounts of components (a), (b) and (c) in Bartholomew overlapped the claimed ranges, “the Examiner has not adequately explained how Bartholomew anticipates the claims” in view of Titanium Metals Corp. v. Banner, 778 F.2d 775 (Fed. Cir. 1985).

Accordingly, the Board reversed the anticipation rejections. However, the Board entered a new ground of rejection, finding the claims obvious over Bartholomew. Specifically, the Board found that the selection of the claimed components, in the claimed amounts, would have been obvious from Bartholomew. The Board was not persuaded by the applicant’s argument of unexpected results, particularly with respect to a showing of criticality and whether the unexpected results were commensurate in scope with the claims.

Takeaway: When an examiner rejects a claim as anticipated based on several selections from lists disclosed in a prior art reference, a strong case can be made against anticipation. After overcoming the anticipation rejection, however, the question of obviousness usually remains. To rebut the case of obviousness, strong evidence of unexpected results often is necessary.

Judges: Gaudette, Hastings, Ren


April 16, 2021by Jacob Doughty1

Ex parte Yim, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether claimed properties were inherent in prior art compositions.

In Ex parte Yim, the claim at issue was directed to a resin. However, the resin was not defined by structure or composition. Instead, only properties of the resin were recited in the claim: (a) content of water-soluble fraction, (b) absorbency against pressure property, and (c) water-soluble fraction shear index property. Independent claim 16 is reproduced in part below:

16. A water-absorbing resin, in which

[a] a content of a water-soluble fraction is 15 wt% or less based on the total weight of the resin,

[b] an absorbency against pressure at 0.3 psi with respect to a saline solution including sodium chloride at 0.9 wt% is 25 g/g or more, and

[c] a water-soluble fraction shear index A/B represented by the following Expression 1 is in a range of 0.1 x 10-5 (s) to 10 x 10-5 (s)….

In rejecting the claim, the examiner relied on a single prior art reference that disclosed a water-absorbing resin but did not disclose the properties recited in the claim. Both the prior art reference and the application on appeal disclosed forming water-absorbing polymers by polymerizing and crosslinking an acrylic acid monomer. The examiner asserted that, in view of the similarities in starting materials and processing steps used in the prior art reference and the application on appeal, the properties in the claim were inherent in the water-soluble resins of the prior art reference.

The examiner further asserted that, even if applicant could demonstrate that none of the water-soluble resins exemplified in the prior art reference had the claimed properties, it would have been obvious to tune the reactions in the prior art references to optimize absorbance/solubility characteristics.

The examiner’s inherency arguments turned, particularly, on the examiner’s determination that the prior art reference used two internal crosslinkers to crosslink an acrylic acid, which was the same or similar to the method disclosed in the application on appeal. Applicant countered by arguing, inter alia, that the steps of the prior art method were different such that the two internal crosslinkers were reacted together before being added to acrylic acid, which could not be said to necessarily result in the claimed properties.

The PTAB found that the examiner had made a good argument that the processes of the prior art reference would result in the claimed properties, such that it became applicant’s burden to show that the exemplified resins did not possess the claimed properties. The PTAB also noted that applicant failed to present arguments rebutting the examiner’s fallback assertion that optimizing the properties of the prior art resin would have been a mere matter of routine experimentation to a skilled artisan. Thus, the examiner’s rejection was affirmed.

Takeaway: Parameter or property claims can be valuable in a patent directed to a material or chemical composition. By keeping strict compositional or structural limitations out of a claim, materials or compositions not contemplated at the time of filing may be encompassed by the claim. Further, if claimed parameters/properties are not explicitly disclosed in the prior art, it can be difficult for a third party to confidently analyze the validity of the claim. However, these advantages in a patent claim can be challenges during examination. While some parameter/property claims “sail through” examination, Ex parte Yim shows that an applicant should be prepared to reproduce prior art examples and provide evidence to rebut assertions of routine optimization to obtain allowance.

Judges: Timm, Smith, Range


April 6, 2021by Richard Treanor

In February, the Federal Circuit issued a decision in Takeda Pharmaceutical Co. v. Torrent Pharmaceuticals Ltd. concerning the obviousness of a chemical compound. Perhaps the most interesting aspect of the court’s decision was the framework that they used in making their decision.

The case arose in ANDA litigation, with Takeda alleging that Torrent would infringe Takeda’s Orange Book-listed patent claiming certain alogliptin benzoates. Torrent defended by alleging obviousness – both statutory obviousness (35 U.S.C. 103) and non-statutory obviousness-type double patenting – and in all cases relied on the obvious modification of a “lead compound” to produce Takeda’s claimed compounds.

In Takeda, central to the court’s ultimate decision-making process was determining whether there was a “reasonable expectation of success” in making Torrent’s suggested modifications. But in essentially answering this question before it was asked, the court prefaced its discussion with the following statement:

Relevant to ‘the assessment of [reasonable] expectation of success’ in all three of [Torrent’s] invalidity theories … is the undisputed factual finding that ‘in the relevant art of pharmaceutical development, very small changes in molecular structure can have dramatic effects on the properties of the molecule,’ …. Indeed, ‘the more distantly related two chemical structures are, the less probable it will be that they have the same biological effect.’ … Against this backdrop, we turn to the details of Appellants’ invalidity theories.

As one might guess just from reading this opening decisional framework, the court found in favor of Takeda, holding that a skilled artisan would not have been motivated to modify Torrent’s lead compound with a reasonable expectation of success.

Takeaway: Does the Takeda case provide us with a roadmap to nonobviousness? Perhaps. In Takeda patentee used expert testimony, buttressed by a publication, to establish the unpredictability of chemical structural changes vis-à-vis functionality in the relevant pharmaceutical art. In the absence of evidence to the contrary, the Federal Circuit found it very easy to affirm the validity of Takeda’s claims and deny Torrent’s allegations of obviousness. Using this strategy during prosecution should yield the same results, with the advantage of an “adversary” (i.e., the Examiner) who lacks the resources of a pharmaceutical litigant.

Judges: Dyk, Mayer, Chen


March 31, 2021by Beau Burton

A conclusion of obviousness requires that a skilled artisan would have had a reason to combine the teachings of the prior art references to achieve the claimed invention, and that the skilled artisan would have had a reasonable expectation of success from doing so.

The reasonable expectation of success requirement can be difficult to challenge during prosecution because the reply is consistently that “only a reasonable expectation of success, not absolute predictability, is necessary for a conclusion of obviousness.” In re Longi, 759 F.2d 887, 897 (Fed. Cir. 1985). This seemingly insurmountable conclusion is compounded by a lack of bright-line rules defining when a reasonable expectation of success exists. However, Ex parte Saerens provides a nice example of facts resulting in a conclusion that a skilled artisan would not have had a reasonable expectation of success. Appeal No. 2020-005386 (PTAB Feb. 25, 2021) (non-precedential).

The claims in Saerens were drawn to a method for fermenting cocoa beans with at least one Pichia kluyveri yeast strain, where the fermented cocoa beans exhibited particular ratios of isobutyl acetate/isobutanol and isoamyl acetate/isoamyl alcohol.

The Examiner relied on a primary reference for its disclosure of adding pectinolytic yeast during cocoa bean fermentation and cited a secondary reference for evidence that certain strains of Pichia kluyveri are pectinolytic. According to the Examiner, a skilled artisan would have had a reason to select Pichia kluyveri from the secondary reference for use as the pectinolytic yeast in the primary reference.

The Appellant disagreed because the secondary reference “focused on examination of pectinolytic activity on a coffee substrate, not cocoa” and there was no evidence the Pichia kluyveri would have exhibited similar activity on all pectin-containing substrates, or would otherwise have been useful for cocoa bean fermentation. In response, the Examiner argued that “pectinolytic activity is universal,” and predictably stated that “Appellants are reminded that only a ‘reasonable expectation of success’, not an ‘absolute success’ would have been required in an obviousness rejection.” Examiner’s Answer at 15.

Reversing the Examiner’s rejection, the Board held that “the prior art must give some indication of which parameters were critical or which of many possible choices is likely to be successful.” Here, however, the secondary reference relied on by the Examiner showed significantly different Pichia kluyveri activity when cultured on yeast polygalacturonic acid medium vs. coffee broth. Consequently, the evidence of record showed that Pichia kluyveri activity would have been considered substrate-specific in complete contradiction to the Examiner’s unsubstantiated finding that “pectinolytic activity is universal,” irrespective of whether the substrate is coffee or cocoa.

Accordingly, the Board found that a skilled artisan would not have been guided by the secondary reference to substitute Pichia kluyveri for any of the yeasts in the primary reference, and reversed the Examiner’s rejection.

Takeaway: It can be difficult to persuade an Examiner who has already concluded there would have been a reasonable expectation of success even when the subject matter claimed is unpredictable, as with the chemical and biological arts. This is illustrated in Saerens, where the Examiner maintained the obviousness rejection despite the experimental data in the secondary reference itself contradicting his conclusion of “universal activity.” Nevertheless, it is important to present any experimental data, technical publications, and/or expert testimony that shows unpredictability as these will be more persuasive than mere attorney argument. In the event that an Examiner is not persuaded by such evidence, the evidence can serve as a basis for reversal in a formal appeal.

Judges: C. Timm, G. Best, J. Snay


March 19, 2021by Matthew Barnet

Chemical compounds in patent claims often include variables representing different possible substituent groups. For example, a chemical formula may include a variable R1 representing a hydrogen atom or an alkyl group, a variable R2 representing an alkenyl group, and a variable X representing a halogen atom. This notation allows for a compact representation of many different specific compounds (species) within a generic formula (genus).

When evaluating a genus of chemical compounds for obviousness, U.S. examiners often find a disclosed genus of chemical compounds sharing species with the claimed genus. The question then is whether the disclosed genus of chemical compounds is sufficient to render obvious the claimed genus of compounds. This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Alig.

Independent claim 1 recited a method for controlling animal pests with an N-arylamidine substituted trifluoroethyl sulfoxide derivative of formula (I):


n represents the number 1,

X represents fluorine, chlorine, bromine, or iodine,

Y represents (C1-C4)-alkyl or (C1-C4)-haloalkyl,

R2 represents hydrogen, (C1-C4)-alkyl or (C1-C4)-haloalkyl, and

R1 and R3 together with the atoms to which they are attached represent the group

where the arrow points to the remainder of the molecule.

The examiner rejected claim 1 on the ground of non-statutory obviousness-type double patenting over claims 1-20 of U.S. Patent No. 9,642,363 (“the ‘363 patent”) in view of WO 2007/131680. As articulated by the Board, “[t]he Examiner’s position, essentially, [was] that the pending claims would have been obvious over the reference claims because the reference claims disclose a genus of compounds that encompasses the compounds recited in the pending claims.”

The applicant explained that to arrive at the compounds in the pending claims, a person of ordinary skill in the art would need to make several specific choices to narrow the genus recited in the reference claims. For example, the person would need to choose the specific ring structure formed by R1 and R3 in pending claim 1 from among 14 ring systems recited in claim 1 of the ‘363 patent and 16 groups recited in claim 8 of the ‘363 patent. Additionally, the person would need to choose fluorine, chlorine, bromine, or iodine for the variable X in pending claim 1, from among 41 substituents (many of which could contain further substitutions) in the claims of the ‘363 patent. The person also would need to choose (C1-C4)-alkyl or (C1-C4)-haloalkyl for the variable Y in pending claim 1, from among 41 substituents (many of which could contain further substitutions) in the claims of the ‘363 patent. The applicant argued that pending claim 1 was not obvious because the “claims of the ‘363 patent provide no teaching whatsoever that would suggest the specific choices that would lead to the claimed compounds.”

The Board agreed with the applicant. The Board explained that “[t]he fact that the pending claims recite compounds encompassed within the genus disclosed in the prior art is not, by itself, sufficient to establish a prima facie case of obviousness” (citing In re Baird, 16 F.3d 380 (Fed. Cir. 1994) and In re Jones, 958 F.2d 347 (Fed. Cir. 1992)). The Board noted that “[i]n both Baird and Jones, our reviewing court reversed rejections similar to the present rejection, in which the rejected compounds were encompassed by large genera that included millions of compounds, but the prior art did not suggest selecting from those genera the particular compound, or subgenus of compounds, recited in the claims at issue.”

The Board found that the examiner did not “provid[e] a sufficient evidentiary basis explaining why, out of the enormous number of possibilities encompassed within the genus described in the ‘363 patent, a skilled artisan would have made the particular set of selections and modifications that would be required to arrive at the compounds recited in the pending claims.” The Board concluded that “[t]he mere fact that one might arrive at Appellant’s claimed compounds by a hindsight-guided selection of appropriate substituents from the large genus disclosed in the reference claims does not persuade us that the pending claims would have been obvious to a skilled artisan.” Thus, the Board reversed the double patenting rejection.

Takeaway: When claims recite a sub-genus of chemical compounds, and the examiner rejects the claims as obvious over a broader genus of compounds, it is important to analyze the selections necessary to arrive at the sub-genus. If the applied references do not provide guidance for making such selections, then a strong argument can be made against obviousness.

Judges: Fredman, Cotta, Hardman