obviousness Archives - Page 5 of 9

Ex parte Slark, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether the changes to a prior art composition that would result from an examiner’s proposed modification were sufficiently dramatic to negate obviousness.

In Ex parte Slark, the claim at issue was directed to a hot melt adhesive composition. The relevant claim recited:

A non-reactive hot melt adhesive composition comprising two thermoplastic polyurethane copolymers (A) and (B), wherein

the thermoplastic polyurethane copolymer (A) comprises a reaction product of at least one polyester polyol, and at least one polyisocyanate, and has a number average molecular weight (M_n) of at least 25,000 g/mol;

the thermoplastic polyurethane copolymer (B) comprises a reaction product of at least one polyester polyol, and at least one polyisocyanate, and has a number average molecular weight (M_n) of less than 25,000 g/mol; and

wherein the hot melt adhesive composition has a melt viscosity of 1,000 to 100,000 mPas at 160 °C and

wherein both thermoplastic polyurethane copolymers (A) and (B) are essentially free of NCO groups.

The examiner cited a primary reference that disclosed a solvent-free hot melt adhesive composition including two thermoplastic polyurethane copolymers, each copolymer being a reaction product of at least one polyester polyol and at least one polyisocyanate. The examiner acknowledged that the primary reference failed to disclose that the hot melt adhesive was non-reactive or that the polyurethane copolymers were essentially free of NCO groups. The examiner noted particularly that the preferred ratio of NCO groups to OH groups in the copolymers of the primary reference (>1) would not result in a “non-reactive” composition in which the copolymers were “essentially free of NCO groups.”

To address this deficiency, the examiner turned to a secondary reference. The secondary reference disclosed a solvent-free hot melt adhesive composition including a polyurethane obtained from a polyester polyol and an isocyanate, in which the ratio of NCO groups to OH groups in the polyurethane (~1) resulted in a “non-reactive” composition in which the polyurethane was “essentially free of NCO groups.” The examiner asserted that it would have been obvious to modify the polyurethanes of the primary reference to have the NCO:OH ratio of the polyurethane of the secondary reference, because the secondary reference disclosed that the ratio was suitable for reacting a polyester polyol with a polyisocyanate such that the resulting hot melt adhesive would be essentially free of NCO groups and nonreactive.

Applicant argued over the rejection by relying on two non-obviousness arguments that are explicitly identified in the MPEP: (1) modifying the composition of the primary reference as proposed by the examiner would render the composition “unsatisfactory for its intended purpose” (MPEP 2143.01.V); and (2) modifying the composition of the primary reference as proposed by the examiner would “change the principle of operation” of the composition (MPEP 2143.01.VI).

With respect to (1), applicant argued that the primary reference was directed to a reactive thermoset hot melt adhesive composition – not a non-reactive thermoplastic composition as required by the claims. Applicant noted that the purpose of the primary reference was to provide a moisture reactive polyurethane hot melt adhesive having a particular cured strength and excellent adhesion to metals. Applicant argued that the examiner’s proposed modification would eliminate essentially all of the isocyanate moieties in the prepolymers, rendering them non-reactive and unsatisfactory for the intended purpose of the primary reference. With respect to (2), applicant similarly argued that, because the examiner’s proposed modification involved eliminating the isocyanate groups from the prepolymers, the principle of operation of the composition of the primary reference would be different – the composition would no longer be a reactive, moisture-curable thermosetting polyurethane adhesive composition.

The PTAB agreed with applicant. The PTAB indicated that the “intended purpose” and “principle of operation” of the adhesive composition of the primary reference were intertwined. The examiner attempted to broadly characterize the composition of the primary reference as involving adhesion – an intended purpose and principle of operation that would be preserved even if the examiner’s proposed modification was made. However, the PTAB indicated that the examiner should have considered the contribution of the primary reference to the art when identifying the intended purpose and principle of operation. The PTAB noted that the primary reference expressly stated that mixtures of isocyanate-terminated polyurethanes provide good adhesion to metal substrates by achieving an initial bond strength upon cooling on a substrate and eventually achieving an ultimate bond strength when cured with ambient moisture. The PTAB agreed with applicant that the examiner’s proposed modification would render the composition of the primary reference unsatisfactory for its intended purpose and would change the principle of operation.

Takeaway: When facing obviousness rejections of chemical compositions, it can be difficult to persuade an examiner that he or she has failed to make a prima facie case. Absent a plain oversight by the examiner regarding the scope of the claims or prior art, it is often necessary to significantly narrow the scope of the claims and/or rely on experimental evidence of unexpected results. However, there are legal arguments that can be effective in overcoming obviousness arguments without amendments or experimental results – and the MPEP remains a great source for identifying compelling reasoning for arguing over obviousness rejections.

Judges: Hanlon, Housel, Inglese

In Ex parte Sharma (Appeal 2020-004468), the Patent Trial and Appeal Board (“Board”) considered the Examiner’s obviousness rejection of Appellant’s claimed method of treating once-through steam generator (OTSG) blowdown water for reuse based on “equivalents” allegedly described in a secondary reference.

Claim 1 was representative and the claimed method included, among other steps, a step of “settling precipitants out of said OTSG blowdown water for at least 12 hours to produce an acid clarified blowdown water having more than 50% of the acid insoluble organics removed.”

The Examiner found that Bansal, the primary reference, described a method of treating OTSG blowdown water by separating the solids from the liquid via a centrifuge and admitted that Bansal did not teach that solids and precipitants were settled out for at least 12 hours as claimed. However, the Examiner alleged that Cote, the secondary reference, described various equivalent separation devices, including settling ponds and centrifuges. The Examiner thus alleged claim 1 would have been obvious over Bansal in view of Cote.

Appellant countered that Cote did not teach that pond settling was “equivalent” to Bansal’s high speed centrifuging and particularly pointed out that the high pressure centrifuges described in Bansal exerted 3000-3500 times the force exerted in a settling pond.

The Board noted Cote disclosed that solids generated during wastewater processing of a phosphogypsum pond processes “may be removed by one or more suitable solids separation devices such as a clarifier, settling pond, lamella clarifier, upflow sludge blanket clarifier, disk filter, centrifuge, vacuum filter, dissolved air floatation device or the like.” According to the Board, Cote’s statement that “one or more” of these separation devices could be used only indicated that settling and centrifuges were both solids separation devices, but “not that they are equivalent.” Instead, as the Board continued, “the suggestion is that settling and centrifugation are complementary approaches that may be used in combination.”

Further, as the Board noted, Bansal disclosed that the smaller size and relative softness of the solids described therein limited the ability to separate liquid and solid phases by conventional centrifuging or hydrocycles and that the oily organics further limited ability to utilize filtering since the particles tended to stick together agglomerating and clogging filter media. Therefore, the Board found Bansal indicated that settling would not work in its process.

Citing In re Ruff, the Board emphasized “[t]hat two things are actually equivalents, in the sense that they will both perform the same function, is not enough to bring into play the rule that when one of them is in the prior art the use of the other is obvious and cannot give rise to patentable invention” and “[t]o rely on equivalence as a rationale supporting an obviousness rejection, the equivalency must be recognized in the prior art, and cannot be based on an applicant’s disclosure or the mere fact that the components at issue are functional or mechanical equivalents.”

Because the Examiner erred by finding that the prior art recognized settling and centrifugation as equivalents, the Board concluded one of ordinary skill in the art would not be expected to substitute settling for Bansal’s high pressure centrifugation and reversed the Examiner’s obviousness rejection.

Takeaway: As noted in Mat Barnet’s prior blog on interchangeable equivalents, for a component missing from a primary reference, U.S. patent examiners usually cite a secondary reference disclosing the missing component and resort to the rationale of simple substitution by alleging that the substituting component disclosed in the secondary reference is equivalent to one of the components in the primary reference (i.e., the substituted component). One justification for the substitution the examiners often rely on is that the secondary reference describes various components, including both the substituting and substituted components, by using terms such as “include,” “one or more,” and “at least one.” As illustrated by Sharma, such description alone cannot justify the substitution rationale. Instead, the equivalency must be described in the prior art references so that it is recognized by one of ordinary skill in the art in light of the prior art description.

Judges: G. C. Best, D. M. Praiss, D. L. Dennett

When U.S. patent examiners cannot find all the components of a claim in a single prior art reference, they usually cite a secondary reference for a missing component. In such cases, examiners often take the position that the missing component is equivalent to one of the components in the primary reference, and that it would have been obvious to replace the component in the primary reference with the equivalent component from the secondary reference.

Sometimes, however, the two components are not actually interchangeable equivalents. This issue is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Fei (Appeal No. 2020-006288).

Independent claim 1 recited:

An anyhydrous dentifrice or toothpaste, comprising:

an orally acceptable vehicle, the orally acceptable vehicle comprising propylene glycol;

a thickening system, the thickening system comprising a polymeric thickener, wherein the polymeric thickener is a copolymer of 2-acrylamidomethylpropanesulphonic acid or a salt thereof; and

a peroxide whitening agent.

The examiner rejected claim 1 as obvious over the combination of two references: Golding and Joiner. Golding described a composition for whitening teeth, comprising propylene glycol, a copolymer of 2-acrylamidomethylpropanesulphonic acid, and a phthalocyanine blue pigment as whitening agent. However, Golding did not describe a peroxide whitening agent.

Joiner described whitening agents such as hydrogen peroxide. The examiner took the position that it would have been obvious to replace the pigment whitening agent in Golding with the peroxide whitening agent in Joiner, since both were “used in the prior art as useful for the same purpose…as a tooth whitening agent.”

The applicant argued that such a replacement would not have been obvious. The applicant explained that in Golding, whitening of teeth was performed “without the use of harsh chemicals or components that effect permanent whitening.” Golding used pigments as temporary whitening agents, applied to teeth to directly alter color. In contrast, Joiner used peroxides as permanent whitening agents, applied to teeth to remove existing stain coloring. The applicant argued that these different mechanisms of action meant that pigments and peroxides were not interchangeable equivalents.

The applicant also argued that if the pigment in Golding were replaced with the peroxide in Joiner, there would be no “need for the copolymer, since peroxide whiteners are not dependent upon being maintained on the teeth throughout the day to achieve their effect.”

The Board agreed with the applicant. The Board found that these whitening components were “not simple substitutes but rather operate in different ways. Golding’s pigment needs to remain on the teeth the entire time that a whitening effect is desired…The peroxide of Joiner, meanwhile, may be removed after it chemically reacts with stains in teeth resulting in whiter teeth.” The Board also found that the examiner provided “no persuasive reason why the other components of claim 1 or Golding, added to result in retention of pigment on teeth, would provide any benefit or improvement on the chemical tooth whitening effect of the peroxide compounds used by Joiner.” Accordingly, the Board reversed the obviousness rejection.

Takeaway: When an examiner takes the position that certain components are interchangeable equivalents, it is worth analyzing whether they really are equivalent. If there is a technical reason why it would not be obvious to substitute the components for each other (such as a difference in the mechanism of action of the components), then this reason can help overcome an obviousness rejection.

Judges: Adams, Fredman, Jenks

In Google LLC v. NavBlazer, LLC, the Patent Trial and Appeal Board (“Board”) declined to institute inter partes review of U.S. Patent No 9,075,136 (“the ’136 patent”). IPR2021-00502, Paper 6 (mailed Aug. 5, 2021).

The ’136 patent is directed to an apparatus that provides a vehicle user with information such as road and traffic conditions. Each of the independent claims of the ’136 patent required an apparatus that “automatically detects a departure of the vehicle from the first travel route, and … identifies a second travel route on which the vehicle can travel to the destination in response to the detected departure of the vehicle from the first travel route.”

The petitioner argued that the claimed dynamic rerouting functionality would have been obvious over the combination of: a primary reference (Behr) that disclosed a base unit that calculated route guidance in response to a query using an up-to-date database located in the base unit and then transmitted the response to a display unit; and a secondary reference (Schreder) that disclosed an automobile equipped with an RF GPS navigation system and RF receivers that monitored updated traffic condition information for dynamic rerouting guidance.

According to the Petitioner, it would have been obvious to include Schreder’s dynamic rerouting functionality within the base unit of Behr so that when the base unit detected a deviation from a specified route, it would identify a new route. The Petitioner further argued that an artisan would have been motivated to make this modification because Behr teaches that guidance systems that are self-contained within a vehicle, such as the system disclosed in Schreder, suffered from many drawbacks, including the need for large data storage capabilities onboard the vehicle.

The Board was not persuaded, stating:

We disagree with Petitioner that reducing vehicle-side processing and data storage justifies modifying Behr’s navigation system to include Schreder’s dynamic rerouting feature. Petitioner’s proffered rationale justifies where a skilled artisan would have located Schreder’s rerouting functionality—in Behr’s central system—but does not address why a skilled artisan would have added that functionality to Behr in the first place. Given this deficiency, we find that Petitioner has not produced the required ‘articulated reasoning with some rational underpinning to support the legal conclusion of obviousness.’

Absent an articulated reason for “why” an artisan would have made the modification, the Board found that the Petitioner failed to carry its burden to show a reasonable likelihood of prevailing on any claim, and thus declined to institute inter partes review of the ’136 patent.

Takeaway: In Google v. NavBlazer, the Petitioner arrived at the claimed subject matter but neglected to explain why the modification would have been obvious in the first place. Unlike anticipation, obviousness requires a story, and the most important part of that story is why a skilled artisan would have been motivated to modify the primary reference to arrive at the claimed subject matter. Without “the why” (i.e., a reason), the obviousness rationale collapses into a hindsight-guided combination of elements. Therefore, when challenging the claims of patent for obviousness it is critical to supply the Board with “the why” of the story you are telling.

Judges: K. Turner, G. Baer, A. Moore

Ex parte Hwang, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether a claimed sequence of layers was rendered obvious by a similar sequence of layers in the prior art.

In Ex parte Hwang, the claim at issue was directed to a barrier film used to protect a display device, such as a liquid crystal, electronic ink, or organic light emitting diode (OLED) type device. The relevant claim recited, in part:

A barrier film comprising:

a stacked sheet having a top surface and a bottom surface and comprising:

at least two first layers formed of a semicovalent inorganic material; and

at least one second layer formed of an ionic inorganic material,

wherein:

each second layer is disposed between two first layers with one first layer in contact with a first surface of the second layer and the other first layer in contact with an opposite second surface of the second layer,

each first layer and second layer are alternately disposed, the first layers are disposed to form both the top and bottom surfaces of the stacked sheet…

the difference in binding energy between the semicovalent inorganic material and the ionic inorganic material is in the range of 0.1 eV to 3.9 eV…

Thus, the claim was directed to a film including a stack of alternating layers of a first material and second material, with a layer of the first material at the top of the stack and the bottom of the stack:

1—2—1; or

1—2—1—2—1….

In rejecting the claim, the examiner relied on a prior art reference disclosing a similar sequence of layers in a barrier film. However, in the prior art reference, the alternating layers were joined by “anchor coat” layers for “improving interlayer adhesiveness between two layers.” The prior art reference disclosed, for example:

1—AC—2—AC—1

Applicant argued the first layers could not be “in contact” with the second layers because of the presence of the anchor coat layers.

The PTAB noted that the examiner must give broadest reasonable meaning to “contact” and that such term was not defined in the specification. Interestingly, the PTAB noted that applicant added the requirement of contact to the claim during prosecution, relying for support on the description of sequential deposition of first and second layers in an actual example. Ultimately, the PTAB relied on a dictionary definition as providing the conventional meaning of “contact” as requiring a “union or junction of surfaces.”

The PTAB concluded that the examiner had impermissibly read the requirement of contact out of the claim and relied on impermissible hindsight in making the rejection over the prior art reference.

Takeaway: The number of patents that are directed to new sequences of layers of known materials would probably surprise a non-practitioner. There is always a tension between defining sequences of layers concretely to distinguish over prior art and being permissive of additional, intervening layers to avoid a design-around. Terms that are seemingly clear – “on,” “over,” “in sequence,” “in contact” – can be the source of disputes during examination and thereafter (“indirect contact”? “contact via”?). To avoid uncertainty (if this is desired), terms defining relative location should be defined explicitly in the specification and used consistently in the claims.

Judges: Colaianni, Dennett, McGee

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

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

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

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

2021年4月16日、CAFCは、発明の優先日時点で実施可能でない引用文献だけを基礎にしたのではその発明を自明とすることはできない、という判断をしました (Raytheon Technologies Corp. v. General Electric Co. (Fed. Cir. Apr. 16, 2021))。

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