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August 5, 2022by Matthew Barnet

In Ex parte Whiteman (Appeal No. 2021-003736), the examiner rejected the claims as obvious based on a hypothetical particle distribution consistent with the prior art. The PTAB reversed.

Independent claim 1 recited:

An inorganic particulate material comprising:

equal to or more than about 3 ppm of particles having a particle size equal to or greater than about 25 μm,

equal to or less than about 40 wt% of particles smaller than about 0.75 μm,

having a d98 less than about 11 μm, and

wherein the % of particles smaller than 0.5 μm is equal to or less than about 25 wt%.

Relevant to the appeal, the italicized limitations required that (i) particles smaller than about 0.75 μm made up no more than about 40 wt% of the particle distribution, and (ii) particles smaller than 0.5 μm made up no more than about 25 wt% of the particle distribution. In other words, there could not be a large fraction of very small particles. For example, a distribution in which 50 wt% of particles were smaller than 0.75 μm would be outside the scope of the claims, as would a distribution in which 30 wt% of particles were smaller than 0.5 μm.

The examiner rejected claim 1 as obvious over a single reference (Calhoun). The examiner relied on a d50 value (rather than wt%) in the range of 0.8 to 3 μm in Calhoun. A d50 value of 0.8 μm, for example, would mean that 50% of the particles were smaller than 0.8 μm. The examiner took the position that the d50 value in Calhoun “impl[ied] or at least suggest[ed] that the claimed wt% of <~0.75μm particles is met.” The examiner found that it would have been obvious “to adjust the particles’ size (either by removing undesirably-sized particles and/or agglomerates, grinding too large particles/agglomerates, and/or agglomerating too small particles)…to meet the claimed wt% of <~0.75μm particles.”

The applicant argued that although Calhoun described a d50 value in the range of 0.8 to 3 μm, the reference said nothing about the fraction of particles smaller than 0.75 μm, or smaller than 0.5 μm, as recited in claim 1. The applicant argued that the examiner had created “a convoluted hypothetical” particle distribution from Calhoun, in which a d50 value of 0.8 μm could be satisfied by 40 wt% of the particles being smaller than 0.75 μm (according to claim 1), and 10 wt% of the particles being between 0.75 and 0.80 μm. Although such a hypothetical particle distribution might have been consistent with the d50 value in Calhoun, the applicant argued that this hypothetical particle distribution was in no way disclosed or suggested by Calhoun.

The PTAB sided with the applicant. The PTAB found that Calhoun’s d50 value of 0.8 to 3 μm “neither discloses nor suggests anything about the particular percentage of particles smaller than about 0.75 μm or smaller than 0.5 μm.” The PTAB found that the “[e]xaminer assumes without providing sufficient evidence that Calhoun’s preferred particulate product having a d50 of 0.8-3 μm contains ‘smaller portion[s] within’ the product, which meet the claimed particular product size distributions.” Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Obviousness cannot be based on speculation. If a U.S. examiner finds a claimed feature to be obvious over prior art describing a somewhat related, but different feature, the examiner must provide supporting evidence instead of mere speculation. If, as in Ex parte Whiteman, the examiner speculates about a “convoluted hypothetical” feature that is consistent with the prior art – but is not disclosed or suggested by the prior art – it is worth challenging the examiner’s position.

Judges: Colaianni, Dennett, McGee


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July 28, 2022by Richard Treanor

Last December, in Modernatx, Inc. v. Arbutus Biopharma Corp., 18 F.4th 1364 (Fed. Cir. 2021), Moderna, in appealing their challenge to an Arbutus patent in an inter partes review, contended that the Board had erred in dismissing their case because it failed to apply a presumption of obviousness based on overlapping ranges in the prior art. While Moderna admitted that not all of the claimed ranges of the Arbutus components were explicitly disclosed in their cited art, they contended that the single missing range could be calculated based on the other ranges and on the “axiomatic” concept that the total of all components must be 100%. The Federal Circuit disagreed.

While the court acknowledged that it had, in the past, found that a presumption of obviousness exists “when the ranges of a claimed composition overlap the ranges disclosed in the prior art,” it found that, in this case, it was undisputed that a range for one of the components was not expressly “disclosed.” Recognizing that it was also true that the court had never affirmatively decided whether the presumption could apply in a case such as this, the court nevertheless declined to make that decision here “because this case turns on a narrower issue, specifically, Moderna’s failure to show that the overlapping range is actually taught by the prior art.”

In dismissing Moderna’s seemingly reasonable theory of overlapping ranges using a calculated missing range the court found that “[o]ne of the key flawed assumptions that Moderna makes is that the amount of each individual … component in the prior art … can be freely manipulated and adjusted across the full scope of the disclosed ranges” and that, as a corollary, Moderna “assumes that any … component … can be increased as long as any … component … is decreased by a corresponding amount to maintain a total of 100%.” The court came to this position because Arbutus had put forth a “plethora of evidence, including evidence from the prior art references as well as expert testimony” demonstrating that “this case is not that simple because the … components … are interdependent, … they interact with each other unpredictably” and “as a whole, rather than on any one component.” The court then reminded Moderna that even in prior cases with fully, explicitly disclosed overlapping ranges involving multiple components “we have held that evidence that the components interacted in an unpredictable or unexpected way could render the combination nonobvious,” emphasizing in the opinion that such earlier holdings apply even more strongly here, where Moderna’s assumptions necessary to derive the unstated/implicit overlapping range are themselves undermined by the unpredictable interactivity between the components.

Takeaway: Because a rejection involving overlapping ranges can give rise to a presumption of unpatentability which puts the burden of going forward on applicant/patentee, it must be vigorously contested. The several ways in which Arbutus “fought off” the presumption in the Moderna case provide an instructive framework for traversing such rejections.

Judges: LOURIE, O’MALLEY, and STOLL


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July 21, 2022by Beau Burton

A specification must enable one of ordinary skill in the art to practice the full scope of the claimed invention. But as noted by the Federal Circuit, “[t]hat is not to say that the specification itself must necessarily describe how to make and use every possible variant of the claimed invention, for the artisan’s knowledge of the prior art and routine experimentation can often fill gaps, interpolate between embodiments, and perhaps even extrapolate beyond the disclosed embodiments, depending upon the predictability of the art.”

A recent decision from the Patent Trial and Appeal Board, Ex parte Seppo, shows the interplay between enablement and a skilled artisan’s ability to extrapolate beyond potentially inoperative embodiments.

In Seppo, the claims covered a method of generating a composite image of a region of a human tissue sample by generating a first image by binding a human target protein-specific monoclonal antibody labeled with a fluorophore and detecting the bound fluorophore; generating a second image by hybridizing a nucleic acid probe labeled with a fluorophore and detecting the hybridized probe fluorophore; and generating a composite image by registering fluorescent signals from the first image with fluorescent signals from the second image.

The Examiner took issue with a theoretical embodiment involving the use of the same fluorescent label/marker/signal for both steps, stating:

If the label used for the monoclonal antibodies and the label used on the nucleic acid probes is the same … one would not be able to accurately and reproducibly >>register<<, in a composite image, the fluorescent signals from each of the different binding reactions, as they would all be the same.

The Examiner further noted that the examples in the specification used multiple labels on different antibodies and nucleic acid probes, but failed to show how to obtain a composite image with the same fluorescent label – an embodiment covered by the independent claim. Accordingly, the Examiner found “the specification, while being enabling for the method of claim 1 wherein different fluorophores are used … does not reasonably provide enablement for use of the same fluorescent label/marker/signal for all steps.” The Board disagreed.

First, the Board found that although the Examiner “has posited one variant of the claimed method … that in his view would not yield useful information … the Examiner’s reasoning itself suggests that a skilled artisan would expect that embodiment to be of limited or perhaps no utility, and thus those in the art would have known to avoid it.”

Second, the Board noted that the Examiner’s reasoning at best identified a single inoperative embodiment encompassed by the claim, while Federal Circuit precedent suggest that number must be significant and force one of skill in the art to experiment unduly in order to practice the claimed invention. Absent a persuasive showing that undue experimentation would be required to practice the claimed method, the Board reversed the rejection.

Takeaway: When an Examiner alleges that a claim does not satisfy the enablement requirement because it encompasses one or more inoperative embodiments, the Examiner must show that the inclusion of inoperative embodiments is so significant that a skilled artisan would be forced to experiment unduly. In Seppo, the Examiner’s rationale folded on itself because the Examiner admitted that a skilled artisan would have expected his single, hypothetical inoperative embodiment to provide limited information such that a skilled artisan would know to avoid it.

Judges: D. Adams, E. Grimes, J. Fredman


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July 8, 2022by Yanhong Hu

Ex parte Deporter (Appeal 2021-003598) is a recent decision of the Patent Trial and Appeal Board (“Board”) where the Board considered whether a prior art reference taught away from Appellant’s claimed invention.

The claim at issue was directed to a composite structure of at least one spunbonded, nonwoven, polymeric layer and at least one meltblown, nonwoven, polymeric layer. The Examiner found that the primary reference, Moore, disclosed each element of the claim except that Moore did not teach “at least one of the spunbonded layers comprises inorganic particulate filler in an amount from about 12% by weight to about 16% by weight of the spunbonded layer.” The Examiner found that the secondary reference, McAmish, taught nonwoven fabrics of spunbonded polymeric fibers which contained fillers such as calcium carbonate particles in an amount of about 10-15 wt% and the associated advantages. The Examiner thus determined it would have been obvious to use from 10-15 wt% of filler in one of Moore’s spunbonded layers as motivated by the advantages described in McAmish.

Appellant argued that there would be no motivation to modify Moore’s structure using McAmish’s amount of filler because Moore taught away from using so much filler. In particular, as noted by Appellant, Moore disclosed that “[f]illers, plasticizers, and other additives, when used at levels above 3% by weight, and more certainly above 5% by weight of the aliphatic polyester, can have a significant negative effect on physical properties such as tensile strength of the nonwoven web. Above 10% by weight of the aliphatic polyester resin, these optional additives can have a dramatic negative effect on physical properties.”

However, Moore also disclosed that “total optional additives including any particulate phase other than antishrinkage additive, preferably are present at no more than 10% by weight, preferably no more than 5% by weight and, most preferably no more than 3% by weight.” Based on such disclosure, the Examiner contended that Moore “does not … expressly teach away from the combination [of Moore and McAmish]” because “Moore acknowledges fillers as high as 10%.”

The Board acknowledged that “[in] some circumstances, the use of the word ‘preferably’ in this context might militate against a finding of teaching away.” However, the Board found that Moore’s specific statement that using above 10% by weight “can have a dramatic negative effect on physical properties” was “direct and specific enough” to outweigh the possibility that “a person of skill in the art might see the word ‘preferably’ and consider using more than 10% of filler.”

Therefore, the Board agreed with Appellant that Moore taught away from using 12-16% by weight of an inorganic particulate filler in at least one of the spunbonded layers and reversed the Examiner’s obviousness rejection.

Takeaway:  Teaching away from an applicant’s claimed invention is a strong indication that it would not have been obvious. Teaching away can be found in a situation where a reference criticizes, discredits, or otherwise discourages the route the applicant takes. However, it is also well-settled that the indication that a certain embodiment is a preferred embodiment is not a teaching away. Deporter is a case where the two situations coexist. It illustrates that “teaching away” is still an effective rebuttal argument for patentees, especially when a reference specifically and directly discourages the alleged modification.

Judges:  B. A. Franklin, G. C. Best, and N. W. Wilson


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June 27, 2022by Matthew Barnet

In Ex parte Jung (Appeal No. 2021-003163), the examiner rejected the claims as obvious based on an inherency rationale. The PTAB reversed.

Independent claim 16 recited an inkjet set consisting of:

a black inkjet ink, a cyan inkjet ink, and two inkjet inks A and B… wherein

the inkjet ink A has a hue angle H* between 70 and 85 and a chroma C* between 30 and 80;

the inkjet ink B has a hue angle H* between 20 and 40 and a chroma C* between 30 and 80 …

The dispositive issue on appeal was whether the hue angle H* and chroma C* were inherent in the applied art.

The examiner cited a reference broadly disclosing mixtures of pigments, and including the specific pigments C.I. Pigment Orange 71, C.I. Pigment Yellow 139, C.I. Pigment Red 254, and C.I. Pigment Red 122 among a long list of suitable pigments. The examiner noted that these specific pigments were recited in the applicant’s dependent claims 19 and 21. Based on this, the examiner took the position that if these specific pigments were selected in the reference, the resulting inks “would intrinsically [i.e., inherently] have” the claimed H* and C* values.

The applicant argued that even if the specific pigments were selected in the reference, the claimed H* and C* values would not necessarily result. The applicant stated that these limitations “are not only achieved by selecting specific pigments, but also by the amounts of the pigments used and the weight ratio of the different pigments in the mixture.” Additionally, the applicant provided calculations of H* and C* values resulting from the examples of the reference, showing them to fall outside the claimed ranges. However, the examiner dismissed these calculations as “attorney argument and not evidence.”

The PTAB sided with the applicant. The PTAB found that “the use of the recited pigments alone is not adequate to guarantee that the H* and C* limitations are met” and that the ratio of different pigments mattered. Regarding the calculations provided by the applicant, the PTAB found that the examiner dismissed them in error (“There is no dispute that the calculations are based on examples disclosed by [the reference], and there is no dispute as to the accuracy of the calculations. Because [the reference] itself is evidence, the calculations made using the data from [its] examples should not have been disregarded as mere ‘attorney arguments.’”).

The PTAB acknowledged that the claims still might have been obvious if the reference “teaches or suggests combining pigments in a way (e.g., optimizing the weight ratios of different pigments) that would have resulted in H* and C* values within the scope of claim 16.” However, the PTAB found no such teaching or suggestion. While the reference taught that the pigments or mixture of pigments be present “in an amount of 0.1 to 20% by weight based on the total weight of the non-aqueous inkjet ink,” the reference provided no teaching or suggestion for weight ratios among different pigments. Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Whenever an examiner takes the position that a claimed property is inherent in the applied art, it is important to carefully evaluate embodiments of the applied art that might result in the claimed property. Inherency requires necessity, not merely possibility. That is, just because it might be possible for the applied art to satisfy a claimed property, that does not mean that the applied art necessarily satisfies the property. If the prior art does not necessarily satisfy the claimed property, then inherency has not been established.

Judges: Abraham, Kennedy, Gupta


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June 1, 2022by Richard Treanor

On February 28, 2022, the Patent Trial and Appeal Board (PTAB) issued a decision in Ex parte Chen (Appeal 2021-001752) affirming an Examiner’s rejection of claims directed to a polyisocyanurate foam composition comprising a certain two-component blowing agent.

In making the rejection, the Examiner used the same technique used in Almirall, LLC v. Amneal Pharm., No. 2020-2331 (Fed. Cir. Mar. 14, 2022) (discussed here) – she applied a primary reference disclosing one of the claimed blowing agent components and combined it with a secondary reference disclosing an expansive laundry list of blowing agent components that partially overlapped with species described in the primary reference and which, importantly, included the claimed blowing agent component missing from the primary reference. In justifying the combination, the Examiner took the position that because all the blowing agent components in the laundry list were “interchangeable and equivalent” it would have been obvious to substitute one of the overlapping components in the primary reference with the missing component.

Applicant traversed the rejection in three different ways in their Brief. First, they argued that neither reference, on its own, rendered the claims obvious (never a good idea in an obviousness rejection based on two references). Next, they asserted that because the primary and secondary references focused on different types of blowing agents one of ordinary skill in the art would not have combined the references. And finally, they argued that the data submitted during prosecution showed unexpected synergy for their blowing agent composition at their claimed ratios.

The Board, in its decision affirming the Examiner, ignored the first argument, rejected the second argument as lacking evidence and support, and found the data submitted during prosecution to be insufficient because it did not show the beneficial trend asserted and was not commensurate in scope with the claims.

Takeaway: Unfortunately, and as we learned in our prior blog on Almirall, where Applicant went wrong in this case was in not fleshing out its non-combinability argument. The primary and secondary references did indeed focus on different types of blowing agents – saturated v. unsaturated. A declaration explaining why the co-blowing agents listed in each reference were specially tailored for use with only one of these types of agents, and an explanation why only the few overlapping agents could be used with both types, might well have overcome the rejection.

Judges: J. Robertson, M. Cashion, Jr., S. McGee


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May 26, 2022by Beau Burton

Conclusions of obviousness require a reasonable expectation of successfully making and using an applicant’s claimed invention. Ex parte Micka (Appeal 2021-003755) is a recent decision from the Patent Trial and Appeal Board (“Board”) that shows whether there is a reasonable expectation of success can depend on the number of selections required to arrive at a claimed invention and how those selections would have been expected to affect the resulting combination of elements/ingredients.

The claims in Micka were directed to a process of preparing a solid dosage form by blending an active pharmaceutical ingredient (API) with a natural gum and a particular combination of  hydrophilic gelling polymers, “wherein the solid dosage form deters abuse and provides immediate release of the at least one API.”

The Examiner relied on a prior art reference for the specific ingredients and alleged that it would have been obvious to combine them in the manner claimed because the reference describes blending the ingredients and the dosage form as providing immediate release and being abuse resistant. This, however, was not the complete picture.

First, the appellant pointed out that the prior art described hundreds of polymers, diluents, binders, lubricants, disintegrants, gelling agents, plasticizers, and release modifiers at any concentration from 0-95% w/w in the abuse deterrent compositions. According to the appellant’s estimate, which the Examiner did not contest, the prior art disclosed ~17 trillion possible combinations of polymers, diluents, binders, lubricants, disintegrants, gelling agents, plasticizers, and release modifiers before even considering the concentrations.

Second, the appellant pointed out that the prior art’s focus was on controlled release compositions. The appellant’s argument here was not as strong because the prior art reference did use the phrase “immediate release,” but only once in the abstract. The Examiner grabbed onto this single mention of “immediate release” to argue there would have been a motivation and a reasonable expectation of success. The Board did not agree.

The Examiner’s error here resided in the fact that the prior art reference did not differentiate between excipients that would result in controlled release and immediate release. In the Examiner’s view, this was irrelevant because the same ingredients were suitable for making both. Not only did the Board disagree with this finding, but the Board also found that the prior art taught the choice of ingredients affects the release such that “it cannot be the case that any and all of these possible combinations will provide immediate release dosage forms.” Having no guide for what ingredient(s) could provide an immediate release composition, the Board found there was no reasonable expectation of success and reversed the rejection.

Takeaway: The factual scenarios under which the lack of a reasonable expectation of success can be successfully argued are less common than motivation to combine. A key in Micka was the claimed composition providing the immediate release of the API. And the facts in Micka were particularly strong because of the litany of selections required to arrive at the claimed composition and the complete lack of guidance as to which selections would have resulted in the immediate release property. Without claiming the immediate release property, the obviousness determination would have devolved into whether it would have been obvious to select the combination of ingredients – a more difficult position to rebut.

Judges: J. Morgan, J. Schneider, M. Valek


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May 20, 2022by Yanhong Hu

In Ex parte Stone (Appeal 2021-004177), the Patent Trial and Appeal Board (“Board”) reversed the Examiner’s obviousness rejection citing Lucas, Kaersgaard, and Wu because the Examiner did not meet his initial burden of presenting a prima facie case of obviousness.

Appellant’s claimed invention in Stone was directed to a method of “selectively removing a proteinaceous impurity from a sample comprising at least an immunoglobulin and the proteinaceous impurity.” It included steps of “adjusting the solution pH of the sample, such that the pH is within 2.0 pH units of the isoelectric point of the proteinaceous impurity to be selectively removed,” then “contacting the sample with activated carbon, [which] selectively binds the proteinaceous impurity,” and “removing the activated carbon from the sample.”

Lucas described the presence of contaminants in monoclonal antibodies and also taught that the contaminants should be removed to produce monoclonal antibodies of the highest purity. However, Lucas did not disclose how to remove the contaminants. The Examiner acknowledged this deficiency. The Examiner found that Kaersgaard described removing PEG from immunoglobulins using activated carbon and Wu described removing proteinaceous material from corn syrup using activated carbon. The Examiner also found that Wu disclosed that the maximum adsorption of the proteinaceous material by the activated carbon occurred at the protein’s isoelectric point. The Examiner thus determined that it would have been obvious to a skilled artisan “to remove the impurities of Lucas” by Wu’s method “motivated by the desire for highest purity, described by Lucas;” and reasoned that because Kaersgaard “teach[es] using very similar methods for purifying immunoglobulins, and explicitly discuss[es] using the methods to remove other impurities, an artisan in this field would attempt this process with a reasonable expectation of success.”

Appellant argued that the combination of cited references did not suggest the claimed method or provide the motivation to combine Wu with Lucas and Kaersgaard. Specifically, Appellant argued that none of the cited references described the selective removal of a protein impurity from other proteins, noting that Kaersgaard disclosed removing PEG rather than a protein impurity from immunoglobulins and Wu disclosed removing proteins from corn syrup, but did not teach selectively removing a proteinaceous impurity from other proteins based on the isoelectric point of the impurity as required by Appellant’s claimed method.

The Board agreed with the Appellant. The Board noted that Lucas identified the need to remove protein contaminants but did not teach how to do so. The Board also noted that neither Kaersgaard nor Wu described selective removal of a protein. In particular, Wu described removal of all protein contaminants, despite teaching that the maximum adsorption of a protein could be achieved using the pH of the protein’s isoelectric point. The Board noted that the Examiner did not provide adequate reasoning to modify Wu to selectively remove impurities. Specifically, regarding the Examiner’s contention that Appellant’s arguments “assume that a person of skill in the art cannot make the leap from the explicit experiments and motivations of the reference to other, closely related applications and goals,” the Board pointed out that the Examiner did not provide a reason for making the “leap” from adsorbing all proteins from a solution to adsorbing only certain proteins based on their isoelectric point.

The Board emphasized that it was the Examiner who had the initial burden of presenting a prima facie case of obviousness and that ordinary creativity and/or common sense “cannot be used as a wholesale substitute for reasoned analysis and evidentiary support, especially when dealing with a limitation missing from the prior art references specified.” The Board cautioned that although the Supreme Court emphasized “an expansive and flexible approach” to the obviousness approach, it also reaffirmed the importance of determining “whether there was an apparent reason to combine the known elements in the fashion claimed by the patent at issue.”

Because the Examiner failed to provide sufficient reason to selectively remove proteinaceous impurity as claimed, the Board reversed the Examiner’s obviousness rejection.

Takeaway:  Obviousness can be established by combining or modifying the teachings of prior art references to produce a claimed invention where there is some teaching, suggestion, or motivation to do so and there is a reasonable expectation of success. The Examiner in Stone did not establish obviousness because, although Wu disclosed adsorption of a protein was related to the pH of the protein’s isoelectric point, the Examiner failed to present sufficient reasoning to modify Wu’s teachings to achieve the claimed selective removal of a proteinaceous impurity. As the Board pointed out, an examiner’s assertion of ordinary creativity and/or common sense cannot substitute for reasoned analysis and evidentiary support.

Judges:  E. B. Grimes, R. M. Lebovitz, and G. C. Best


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May 13, 2022by Matthew Barnet

Composition claims sometimes recite a ratio of amounts of two different components in the composition. Similarly, claims relating to a polymeric compound sometimes recite a ratio between two different structural units of the compound. In evaluating obviousness, U.S. examiners search the prior art for ratios that overlap the claimed ratio. Ex parte Kraus (Appeal No. 2021-002347) is a recent decision of the Patent Trial and Appeal Board (“Board”) in which the examiner went a little too far in trying to find such a ratio in the prior art.

Independent claim 1 related to a polycondensate comprising at least four different structural units: (I), (IIa), (IIb) and (III). Among other limitations, the claim recited a molar ratio of structural unit (IIa) to (IIb) within the range of 0.2 to 1.5.

The examiner rejected claim 1 as obvious over one reference (Wieland), and separately over a different reference (Kraus). In the rejection based on Wieland, the examiner relied on a ratio that included structural units corresponding to (IIa) and (IIb). However, the examiner acknowledged that this was not exactly a ratio of (IIa) to (IIb) since the structural units of Wieland corresponding to (IIa) and (IIb) both were encompassed by the denominator of Wieland’s disclosed ratio. The examiner also relied on values derived from two specific examples in Wieland to construct a ratio of (IIa) to (IIb) overlapping the claimed range.

The Board reversed the rejection over Wieland. The Board found that “[t]he Examiner has not explained sufficiently why one of ordinary skill in the art would mix and match molar concentration values from two different examples to determine a ratio of (IIa) to (IIb) as claimed, particularly given that Wieland’s ratio is different.” The examiner’s calculation “involves picking and choosing convenient values from two unrelated examples to calculate a ratio not used by Wieland.”

In the rejection based on Kraus, the examiner combined a disclosed ratio of structural unit (I) to (IIa) with a disclosed ratio of the sum of structural units (I) and (IIa) to structural unit (IIb). The examiner found that this combination supported a range of molar ratios (IIa) to (IIb) that overlapped the claimed range of 0.2 to 1.5.

The Board also reversed this rejection. The Board found that the examiner had not adequately explained how the two disclosed ratios could be combined to obtain the claimed ratio. The Board noted that “[t]he calculation posited by the Examiner apparently requires substitution of a range within another range,” which it found not to be obvious.

Takeaway: A ratio between two components in a composition, or two structural units in a polymeric compound, can be a useful way to distinguish a claimed invention from prior art. If an examiner appears to be stretching the prior art to construct an overlapping ratio, it is worth challenging the examiner’s rationale.

Judges: Hastings, Kennedy, Cashion Jr.


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April 21, 2022by Beau Burton

Nine times out of ten a negative limitation satisfies the written description requirement when the specification positively describes the limitation to be excluded or better yet provides a reason to exclude the limitation. The rationale for the former being that a description of the whole, necessarily describes the part remaining. For instance, when the specification discloses a composition that includes an additive selected from A, B, and C, there is support for a composition that does not include A, B, or C.

Satisfying the written description requirement without a positive recitation of the limitation to be excluded is rare; however, Ex parte Kroepke provides an example in which the Patent Trial and Appeal Board found support for a negative limitation based on silence.

The following claim on appeal is illustrative:

A cosmetic or dermatological preparation, wherein the preparation comprises from 0.01 % to 5 % by weight of at least one red light-filtering dye, at least one white pigment, and from 0.0001 % to 10 % by weight of at least one anti-inflammatory active ingredient which comprises at least one aqueous extract of Glycyrrhiza inflata, and wherein the preparation does not contain strontium cations.

Of note here is that the specification did not positively mention strontium cations, group II cations, or even alkaline earth metals. The closest disclosure of cations appears to be from ingredients in the examples such as magnesium sulphate, sodium citrate, and potassium sorbate. However, Appellant did not rely on these cation containing ingredients. Appellant simply argued that the written description requirement was satisfied because the specification included “sixty exemplified (most diverse) preparations, none of which contains strontium cations.”

The Examiner disagreed, finding Appellant’s disclosure “as a whole does not conceptualize that the preparation should or should not contain strontium cation. Further, as to the sixty examples disclosed in the application, no explicit[] disclosure of strontium cation does not mean that exemplified preparations do not contain strontium cation.”

The Board found Appellant’s position more persuasive in view of the Federal Circuit’s recent Almirall, LLC v. Amneal Pharms. LLC decision, which held:

[A] reference need not state a feature’s absence in order to disclose a negative limitation. Instead, it was reasonable for the Board to find that, in the context of Garrett, a skilled artisan would recognize that the reference discloses a complete formulation—excluding the possibility of an additional active ingredient… It is undisputed that Garrett discloses dapsone formulations that lack adapalene. The Board thus did not err in concluding that Garrett discloses the negative adapalene claim limitation.

28 F.4th 265, 273–274 (Fed. Cir. 2022) (citations omitted).

At first glance, Kroepke appears to extend the rationale from Almirall permitting the exclusion of an additional unrecited active ingredient to the exclusion of any unrecited ingredients. However, upon closer inspection, Kroepke fits the same pattern as Almirall. First, the invention in Kroepke related to “preparations that include a combination of a dye and an anti-inflammatory active ingredient, and particularly to preparations for the prophylaxis and treatment of sun-irritated skin that aid the body’s own repair mechanisms.” Second, the prior art relied upon by the Examiner in Kroepke for an obviousness rejection (which was also reversed by the Board), required the mandatory presence of strontium for its anti-irritation function when used in combinations with ingredients such as moisturizers and anti-inflammatory agents. Consequently, both Kroepke and Almirall support the exclusion of an additional active ingredient where there are exemplary and complete formulations that do not include an additional active ingredient.

Takeaway: Kroepke and Almirall illustrate a continued expansion of negative limitations satisfying the written description requirement to an extent that might not be possible in other jurisdictions. Nevertheless, it is important to keep in mind that Kroepke and Almirall fit a specific pattern in which exemplary compositions include an active ingredient, and the negative limitation relates to another active ingredient. It is unlikely that these holdings can be extended to the exclusion of any ingredient that is not recited in an example.

Notably, Appellant never had the chance to raise or argue the facts of the Almirall decision because it was decided only one month prior to the decision in Kroepke. Thus, the Board’s reliance on Almirall shows it is applying the most recent Federal Circuit precedents.

Judges: D.E. Adams, J. N. Fredman, T. Chang