October 17, 2022by Jacob Doughty

Mylan Pharm. v. Merck Sharp & Dohme Corp., No. 2021-2121 (Fed. Cir. Sep. 29, 2022), is a recent decision of the Federal Circuit considering, inter alia, whether a prior art disclosure of a genus of salts was sufficient to anticipate or render obvious a single salt species.

In an Inter Partes Review proceeding before the PTAB, Mylan asserted that claims of a Merck patent were anticipated by or obvious over a prior Merck patent publication, Edmondson. The PTAB concluded that Mylan failed to prove unpatentability, and Mylan appealed. The claims of the Merck patent at issue were directed to sitagliptin dihydrogenphosphate (DHP). Exemplary claims include claims 1, 2, and 4:

1. A dihydrogenphosphate salt of a 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4]tria-zolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-tri-fluorophenyl)butan-2-amine… or a hydrate thereof.

2. The salt of claim 1 of structural formula II having the (R)-configuration at the chiral center marked with an *


4. The salt of claim 2 characterized in being a crystalline monohydrate.

Edmondson disclosed sitagliptin in a list of 33 compounds. Edmondson further disclosed acids forming pharmaceutically acceptable salts including phosphoric acid in a list of eight preferred acids. Mylan argued that this was sufficient to anticipate claim 1, relying on the reasoning of In re Petering, 301 F.2d 676, 681 (C.C.P.A. 1962) (prior art may be deemed to disclose each member of prior art genus when skilled artisan can “at once envisage each member of this limited class”).

Merck countered that the combined list of 33 compounds and eight preferred salts, taking into account various stoichiometric possibilities, encompassed  957 salts, which was not sufficient for a skilled artisan to “at once envisage” the salt of claim 1.

The Federal Circuit agreed with Merck that Edmondson did not “expressly disclose a 1:1 sitagliptin DHP salt.” The Federal Circuit credited expert testimony (including testimony of Mylan’s own expert) that Edmondson did not direct a skilled artisan to sitagliptin among the list of 33 compounds and did not single out phosphoric acid or any phosphate salt among the enumerated salts. The Federal Circuit noted particularly that the 957 salts of Edmondson was “a far cry from the 20 compounds ‘envisaged’ by the narrow genus in Petering.”

As to obviousness, interestingly, Merck was able to eliminate Edmondson as a reference as to claims 1 and 2 by proving prior invention and relying on the obviousness exception for commonly owned prior art of pre-AIA 35 USC 103(c). However, this approach was not effective as to claim 4, which was limited to a crystalline monohydrate of the (R)-configuration of 1:1 sitagliptin DHP.

As to claim 4, Mylan relied on Edmondson’s indication that the described salts may exist in more than one crystal structure and in the form of hydrates. Mylan further relied on the disclosure in a secondary reference of the pharmaceutical importance and prevalence of crystalline hydrates of pharmaceutical compounds.

The CAFC agreed with the PTAB and Merck that the general teachings of the secondary reference would not have led a skilled artisan to prepare a crystalline monohydrate of the (R)-configuration of 1:1 sitagliptin DHP based on the teachings of Edmondson with a reasonable expectation of success, noting the unpredictability of hydrate formation and function for specific compounds.

The Federal Circuit briefly noted the PTAB’s consideration of Merck’s evidence of unexpected results, but also noted that “there is no need to reach objective indicia of nonobviousness where the petitioner has not made a showing necessary to prevail on threshold obviousness issues.”

Takeaway: During examination, claims directed to chemical compounds and compositions are often rejected over prior art disclosing generic chemical formulae or separate lists of components. The numbers of specific compounds or compositions encompassed by such prior art can be astronomical. The Mylan case provides some tips for arguing over such rejections (preferably without the need to rely on additional experimental results). Possible arguments include identifying the large number of species encompassed by a prior art genus, emphasizing the lack of direction in the prior art toward the specific selections necessary to obtain a claimed compound or composition, and pointing out the difficulty of applying general teachings regarding selection (e.g., of substituents, subcomponents, etc.) to specific compounds or compositions.

Judges: Lourie, Reyna, Stoll



September 9, 2022by Jacob Doughty

Ex parte Ihn is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing obviousness and enablement of a claim directed to an organic light-emitting device – particularly to a compound present in the emission layer of the device. Interestingly, the primary reference in the appealed obviousness rejection, Endo, originated from an anonymous third-party submission.

The claim at issue was directed to an organic light-emitting device comprising, inter alia, an emission layer comprising a thermally activated delayed fluorescence (TADF) emitter and a host (two different compounds). The TADF emitter was required to provide particular emission characteristics in use and to have a structure defined by a generic chemical formula.

Endo disclosed specific compounds that were also disclosed in applicant’s specification as TADF emitters. The claim as filed did not require a specific structure for the TADF emitter – merely that the TADF emitter provide the particular emission characteristics. Based on the commonly disclosed compounds, the third-party submitter – and subsequently the examiner – asserted that the claim was unpatentable (identical compounds have identical properties). During prosecution, applicant added the generic chemical formula which excluded the specific compounds disclosed in the primary reference.

The examiner then took the position that a generic formula in Endo encompassed structures falling within the scope of that amended claim, notwithstanding that no specific compound within the scope of the claim was disclosed in Endo. Applicant countered by arguing that the claim required that a linking group be present between, e.g., an indolocarbazole group and a heteroaromatic group:

“… L1 is selected from: a cyclopentane group, a cyclohexane group… a1 is an integer from 1 to 5…”

while the structural formula from Endo relied on by the examiner required a single bond:


While the structural formula from Endo showed connection via a single bond, and most of the exemplary compounds in Endo were connected via a single bond, some exemplary compounds in Endo included an aromatic heterocyclic group indirectly attached to an indolocarbazole skeleton by way of a hydrocarbon group. (This was not inconsistent with the description of Endo’s structural formula, in which polycyclic groups having both aromatic and heteroaromatic rings could be “Ar”).

In view Endo’s disclosure of some compounds in which an aromatic heterocyclic group was indirectly attached, the PTAB found that this “… would have indicated to one of ordinary skill in the art that those structures provide the possibly improved delayed fluorescence emission efficiency and appropriate positional relationship for intermolecular conformation Endo desires from the compounds within…” the structural formula. Thus, the obviousness rejection was affirmed.

With respect to enablement, the examiner argued that the claim covered innumerable combinations of TADF emitters and hosts and that it would have required an undue amount of experimentation to identify combinations of TADF emitters and hosts that provided the claimed emission characteristics. The PTAB declined to adopt the examiner’s reasoning with respect to enablement. The PTAB noted that a large amount of experimentation is not necessarily undue, and the examiner had provided no evidence to support her assertion: “[t]he Examiner’s mere assertions to that effect are insufficient to establish a prima facie case of nonenablement.”

Takeaway: Third-party submissions provide mixed results – sometimes an examiner will rely heavily on the submitted information, and other times it seems that the submitted information has not been carefully considered by the examiner. However, in this case, the third-party submission led to a PTAB finding of unpatentability. This case shows that third-party submissions should not be ignored (particularly in view of their relative low cost) as part of a strategy for influencing the scope of a competitor’s patents.

Compounds are often defined in claims with generic formulae encompassing large numbers of specific compounds. This creates a tension between arguing about what the prior art fairly suggests and arguing about what your own specification fairly enables. It is important to take some care when arguing that prior art does not provide sufficient guidance to lead a skilled artisan to a claimed genus of compounds – particularly if the prior art’s disclosure is not significantly less robust than the disclosure of your own specification.

Judges: Owens, Hastings, Range


July 15, 2022by Jacob Doughty

LG Elecs. v. Immervision, Inc., No. 2021-2037 (Fed. Cir. July 11, 2022), is a recent decision of the Federal Circuit, considering whether errant information in a prior art reference can be relied upon to demonstrate unpatentability.

LGE challenged an Immervision patent directed to capturing digital panoramic images in an IPR. The Immervision patent claimed, inter alia, a method in which, “… the objective lens compresses the center of the image and the edges of the image and expands an intermediate zone of the image located between the center and the edges of the image.”

In challenging the patent, LGE relied on a prior art U.S. patent, Tada, which did not expressly disclose compressing the center and edges of an image and expanding an intermediate zone, but which included tables setting forth various measurements of specific embodiments of the disclosed lens system. LGE retained an expert who performed calculations based on the measurements and concluded that one of the lens systems of Tada (Embodiment 3) compressed the center and edges of an image and expanded an intermediate zone.

Immervision also retained an expert, who, in the course of performing his own calculations, discovered discrepancies in the measurements for Embodiment 3 of Tada. After some detailed examination of other embodiments of Tada and the Japanese patent application from which priority was claimed, Immervision’s expert determined that the measurements for Embodiment 3 shown in Tada erroneously included measurements for a different embodiment.

That is, due to an apparent cutting-and-pasting error in translating the Japanese application on which Tada was based, LGE’s expert’s calculations indicated that the lens system of Embodiment 3 of Tada compressed the center and edges of an image and expanded an intermediate zone. However, if LGE’s expert had used the correct measurements, this would not have been the case.

Based on the testimony of Immervision’s expert, the PTAB concluded that LGE failed to carry its burden in demonstrating unpatentability. LGE appealed.

The Federal Circuit noted that “… the standard for evaluating these types of apparent or ‘obvious typographical error[s],’” is set forth in a decision of its predecessor court, more than 50 years ago, in In re Yale, 434 F.2d 666 (C.C.P.A. 1970). Particularly:

The court in Yale held that where a prior art reference includes an obvious error of a typographical or similar nature that would be apparent to one of ordinary skill in the art who would mentally disregard the errant information as a misprint or mentally substitute it for the correct information, the errant information cannot be said to disclose subject matter.

In Yale, the CCPA concluded that a reference could not be relied on for disclosing a compound that appeared in a single instance due to an error (CF3CHClBr was shown as CF3CF2CHClBr in a graph).

LGE argued that the error in Tada could not possibly be an obvious error because it took Immervision’s expert hours of detailed investigation to find. LGE further argued that the error in Tada was not “of a typographical or similar nature.” The Federal Circuit was not persuaded. In affirming the PTAB, the Federal Circuit noted that the length of time and manner in which an error was discovered did not diminish its obviousness. Further, the Federal Circuit further stated that “[t]he distinction between the typographical error in Yale and the copy-and-paste error here is a distinction without a difference.”

In dissent, Judge Newman was more sympathetic to LGE’s position:

I agree with the panel majority that Yale establishes the correct standard to determine if an error would be obvious to a person of ordinary skill in the field. However, I do not agree with the majority’s application of this standard to the facts herein. An “obvious error” should be apparent on its face and should not require the conduct of experiments or a search for possibly conflicting information to determine whether error exists. When a reference contains an erroneous teaching, its value as prior art must be determined.

Takeaway: It is not uncommon for technical documents relied on as prior art (e.g., patent publications, journal articles) to include errors – particularly in descriptions of experimental results. Such errors may undermine an assertion that a property or parameter is inherent – and thus possibly provide an avenue for attacking a prior art rejection or assertion of invalidity.

Judges: Newman (dissenting in part), Stoll, Cunningham


June 10, 2022by Jacob Doughty

Pavo Sols. v. Kingston Tech. Co., No. 2021-1834 (Fed. Cir. June 3, 2022), is a recent decision of the Federal Circuit considering, inter alia, whether a district court acted appropriately in “judicially correcting” an error in claim language. Kingston was found by the district court to have willfully infringed the judicially corrected claim.

The claim at issue recited:

A flash memory apparatus comprising:

a flash memory main body including a rectangular shaped case within which a memory element is mounted, a[] USB (Universal Serial Bus) terminal piece electrically connected with the memory element and installed at a front end of the case in a projecting manner, and a hinge protuberance formed on at least one side of the case; and

a cover including [a] pair of parallel plate members facing each other and spaced by an interval corresponding to the thickness of the case, the cover having an open front end and a closed rear end with a pair of lateral side openings; the parallel plate members having at least one hinge hole receiving the hinge protuberance on the case for pivoting the case with respect to the flash memory main body, whereby the USB terminal piece is received in an inner space of the cover or exposed outside the cover.

As emphasized above, the claim requires cover features that permit the case to pivot with respect to the flash memory main body.  However, the case is part of the flash memory main body and not part of the cover, so it is unclear how the features of the cover could cause a part of the flash memory main body to pivot with respect to itself (or another part thereof). The district court found that it was apparent from the claim language that “pivoting the case” should be “pivoting the cover” and judicially corrected the language in its claim construction order.

The Federal Circuit noted that it is permissible for a court to correct “an obvious minor typographical or clerical error” in a patent claim “only if (1) the correction is not subject to reasonable debate based on consideration of the claim language and the specification and (2) the prosecution history does not suggest a different interpretation of the claims.”

Kingston argued that the error could not possibly be minor because the correction replaced one structural element with another and broadened the claims. Kingston further argued that alternative corrections were plausible in view of the claim language, specification, and prosecution history.

The Federal Circuit found that its precedent did not prohibit corrections that resulted in changes to recited structure. Further, the Federal Circuit found Kingston’s arguments with respect to broadening and plausible alternative corrections (and the supporting expert testimony) to be insufficient to raise a reasonable debate about claim scope.

Having affirmed the district court’s correction of the claim, the Federal Circuit concluded that the district court’s finding of willful infringement was also appropriate. Specifically, “[w]e hold, however, that reliance on an obvious minor clerical error in the claim language is not a defense to willful infringement.”

Takeaway: When performing a clearance or freedom-to-operate analysis, patent counsel often search for “errors” made in drafting or prosecution of a patent application that could result in a narrow construction or estoppel that will give a client comfort that a finding of infringement is unlikely. However, it is important not to be too strict or literal in this analysis. If the intended meaning of claim term is clear using common sense, it may be risky to base a conclusion of non-infringement on errors in a claim even if they seem significant.

Judges: Lourie, Prost, Chen


May 6, 2022by Jacob Doughty

Niazi Licensing Corp. v. St. Jude Med. S.C., No. 2021-1864 (Fed. Cir. Apr. 11, 2022), is a recent decision of the Federal Circuit considering, inter alia, the definiteness of descriptive words (or terms of degree) in a claim.

The claim at issue recited:

A double catheter, comprising:

an outer, resilient catheter having shape memory and a hook shaped distal end configured for cannulation of the coronary sinus with at least one curved bend;

an inner, pliable catheter slidably disposed in the outer catheter and of greater length than the outer catheter…

The district court found that the terms “resilient” and “pliable” rendered the claim invalid as indefinite. The Federal Circuit disagreed and reversed.

The Federal Circuit began by noting that, while terms of degree in a claim may inherently result in broader claim scope, a claim is not indefinite just because it is broad. However, terms of degree will render a claim indefinite when the intrinsic evidence (or extrinsic evidence, when relevant and available) provides insufficient guidance as to any objective boundaries for the claim – i.e., when claim scope is “purely subjective.”

With respect to the term “resilient,” the Federal Circuit found that the claim itself provided guidance with respect to the meaning of the term by requiring that the outer catheter have “shape memory.” Dependent claims further indicated exemplary materials that could be used to make the outer catheter. Likewise, the specification indicated that the outer catheter should have “sufficient shape memory to return to its original shape when un-distorted.” Although the Federal Circuit indicated that reliance on extrinsic evidence was not necessary, dictionary definitions were consistent with the claims and specification. Thus, the Federal Circuit concluded that a skilled artisan reading the claims and specification would know of exemplary materials that can be used to make a resilient outer catheter, i.e., one that has shape memory and stiffness such that it can return to its original shape.

As to “pliable,” the claim language was not as illuminating, but the specification indicated that, relative to the outer catheter, the inner catheter “is constructed of a more pliable, soft material such as silicone.” Dictionary definitions, again, were consistent with the specification. The Federal Circuit found that a skilled artisan would have understood that the inner catheter is made of a more flexible material than the outer catheter.

Thus, the Federal Circuit concluded that the intrinsic and extrinsic record provided objective boundaries by which a skilled artisan could determine the scope of the claims. The terms “resilient” and “pliable” were determined not to be “purely subjective terms,” resulting in a variable claim scope depending on the particular eye of any one observer.

Takeaway: Terms of degree in a claim can be troublesome during prosecution – an examiner can easily make a rejection, and a response proving “objective boundaries” can be difficult. However, if a term of degree cannot be deleted, the Niazi decision provides some suggestions for responding to an assertion of indefiniteness. Any indications of the scope of the term from the claims and specification can be supplemented with evidence (literature, opinion declaration, etc.) of how a skilled artisan would view the term. Although not explicitly stated in the Niazi decision, the court’s reasoning suggests that an explanation of why terms do not overlap in scope can be particularly persuasive.

Judges: Taranto, Bryson, Stoll


April 1, 2022by Jacob Doughty

Ex parte Nakanishi, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing obviousness of a claim directed to a steel composition.

The claim at issue recited, in part:

A non-oriented electrical steel sheet having a chemical composition consisting of, in mass%…

Si: 1.0% or more and 4.0% or less;

Mn: 0.10% or more and 3.0% or less…

Al: less than 0.0005%;

Cu: 0.02% or more and less than 0.04%; and

Ca: 0.003% or more and 0.0100% or less…

In asserting obviousness, the examiner cited a single prior art reference disclosing a steel sheet including components and amounts that could overlap with those recited in the claim. Applicant’s arguments focused first on differences between the claimed composition and the prior art composition and then on evidence of unexpected results.

Applicant’s arguments as to composition focused particularly on the amounts of Al, Cu, and Ca in the claims and the prior art reference. Notably, applicant’s ranges of amounts of Al, Cu, and Ca were much narrower than those in the prior art reference.

Component Claim Prior Art Reference
Al Al < 0.0005% Al ≤ 3%
Cu 0.02% ≤ Cu < 0.04% Cu ≤ 5%
Ca 0.003% ≤ Ca  ≤ 0.0100% (total content of Mo, W, Sn, Sb, Mg, Ca, Ce, and Co trace elements) ≤ 0.5%

Applicant first argued that the prior art reference did not disclose a single example composition having the claimed amounts of Al, Cu, and Ca. The PTAB quickly dismissed this argument, noting that the prior art reference was “not limited to its examples.”

Next applicant argued that the prior art reference did not recognize that the amounts of Al, Cu, and Ca were result effective and undue experimentation would have been required to arrive at the claimed narrow ranges. The PTAB replied that the prior art reference would have suggested to a skilled artisan that “all Al, Cu, and total trace element amounts within the disclosed ranges are effective for achieving” the goal of the prior art reference, “a non-oriented magnetic steel sheet whose core loss in a high frequency range can be fully reduced… including amounts within the… [claimed] ranges.”

Applicant then turned to its experimental results. Applicant argued that its experimental results showed that adding Ca in the claimed amounts to a steel sheet containing ultra-low amounts of Al unexpectedly reduces iron loss.

The PTAB noted that applicant’s experimental results were limited to compositions having a Si content of 1.3% and 1.6 % and an Mn content of 0.5%, while the claim encompassed Si contents as high as 4.0% and Mn contents as high as 3.0%. The PTAB then noted a statement in applicant’s specification that Si and Mn have the effect of reducing iron loss (the same effect applicant attributed to addition of Ca in describing its experimental results). In view of this statement, the PTAB concluded that applicant would have to provide evidence that its experimental results were representative of compositions including the minimum claimed amount of Ca and the maximum claimed amounts of Si and Mn, to effectively rebut the examiner’s assertion of obviousness.

Takeaway: Once an examiner has established that a prior art range overlaps with a claimed range, it will be difficult to persuade the examiner (or PTAB) that selection of a subrange would not have been obvious in the absence of evidence of unexpected results – in this case, the PTAB seemed annoyed that applicant even tried. It may be preferable to leave out arguments that will never succeed (e.g., the claimed composition is not exemplified in the prior art reference) and emphasize the results that might succeed (unexpected results).

A composition claim with many components, each with its own range of amounts, can make it difficult to prove that evidence of unexpected results is “commensurate in scope” with the claim. In this case, applicant showed a desirable effect over the entire range of amounts of the component it believed was important (Ca amount), provided a limited number of data points for the other components. It is often not practical to prepare a large number of compositions encompassed by a claim, but this can be addressed with a technical explanation for why additional experiments would not be expected to yield significantly different results (even more helpful if such explanation is provided in a declaration by a skilled artisan).

Judges: Owens, McGee, Inglese


January 20, 2022by Jacob Doughty

Ex parte Myers is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing enablement and written description of a claim amended to recite a range during prosecution.

The claim at issue recited:

A composition comprising oolitic aragonite particles, wherein the oolitic aragonite particles have an average particle size of between 100 nm to 1 mm, and a median (D50) particle size distribution (PSD) of between 2.0 to 3.5 μm, and a Hunter brightness level greater than 90.

The Hunter brightness feature was added during prosecution to distinguish over prior art. Applicant asserted that the following disclosure in the specification enabled and supported the newly added feature:

[T]he size of (milled) aragonite will also have a substantial effect on brightness of the material. For example, when milled to a fine particle size of 2 to 8 micron, the Hunter brightness level is approximately 94, which is very bright white. Thus, by selecting a suitable particle size, brightness of the milled aragonite can be adjusted.

The foregoing was the only disclosure of any Hunter brightness level – only a single value and no disclosure of any range.

The examiner acknowledged the disclosure of a single value of 94 for Hunter brightness level but asserted that such disclosure did not reasonably provide enablement for, or demonstrate possession of, the entire range of “greater than 90.”

As to enablement, the PTAB disagreed with the examiner, finding that the examiner had failed to establish that undue experimentation would be required for a skilled artisan to make and use the claimed composition. The PTAB appeared to find plausible applicant’s contention that disclosure of a single Hunter brightness level paired with disclosure that milling or otherwise adjusting particle size affects Hunter brightness would be enabling.

However, as to written description, the PTAB affirmed the examiner’s rejection. Applicant asserted that the particles described in the specification inherently have Hunter brightness values between 90 and 100. The PTAB noted that, while the specification indicated that particle size related to Hunter brightness, there was nothing in the record to indicate that the particles sizes in the specification necessarily resulted in Hunter brightness values greater than 90. The PTAB further noted that the specification indicated that parameters other than particle size influence Hunter brightness, concluding that the specification did not reasonably convey that applicant was in possession of the recited range of Hunter brightness levels.

Takeaway: US practice is much more flexible than other jurisdictions with respect to the degree of specification disclosure required to support claim amendments made during prosecution. This is especially true when amending ranges to include new endpoints from subranges and/or individual examples in the specification (but keep an eye on the Federal Circuit link, link). However, even under US practice, it will be difficult to create a claimed range from a single data point. If a parameter is important enough to identify in a patent application, it is worth the small additional effort to identify ranges of values that encompass the described invention.

Judges: Hanlon, Gupta, Inglese


December 13, 2021by Jacob Doughty

AstraZeneca AB v. Mylan Pharm., 2021-1729 (Fed. Cir. Dec. 8, 2021), is a recent decision of the Federal Circuit interpreting the scope of a numerical limitation in a claim.

The claims on appeal in AstraZeneca were directed to pharmaceutical formulations for administration via pressurized metered dose inhalers. The formulations required a formulation stabilizer, PVP K25, and recited “the PVP K25 is present at a concentration of 0.001% w/w.”

The district court interpreted 0.001% w/w as encompassing 0.001% w/w “within one significant figure” – i.e., any value that could be rounded up or down to 0.001% w/w, or 0.0005% to 0.0014% w/w. The Federal Circuit disagreed and interpreted 0.001% w/w as “that precise number, with only minor variations” – i.e., 0.00095% to 0.00104% w/w. A further alternative was offered in Judge Taranto’s dissent.

The Federal Circuit indicated that, in the abstract, the ordinary meaning of 0.001% w/w was consistent with the district court’s interpretation of 0.0005% to 0.0014% w/w (“This is a standard scientific convention, and numbers falling within that range would typically be rounded up or down to 0.001%.”). However, the Federal Circuit found that

…taken as a whole, the intrinsic record supports a narrower construction of 0.001% to reflect that term’s application to the PVP concentration in particular, and the testing evidence in the written description and prosecution history showing that very minor differences in the concentration of PVP—down to the ten thousandth of a percentage (fourth decimal place)—impact stability.

Of particular importance to the Federal Circuit were experimental results in the specification showing significant changes in stability between a composition including 0.001% w/w PVP and a composition including the more precisely defined 0.0005% w/w PVP. The patentee made arguments about the results during prosecution and cancelled claims reciting, e.g., “0.0001% to 0.001% w/w” PVP and “0.0001%, 0.0005%, or 0.001% w/w” PVP. The Federal Circuit further noted that the patentee could have used the term “about” to modify of 0.001% w/w but chose not to.

Based on the Federal Circuit’s construction, the case was remanded for further consideration of infringement.

In his dissent, Judge Taranto found the majority’s approach too exacting. He argued that the disclosure of more precise values in the specification (e.g., 0.0005% w/w PVP) was not a disclaimer of the ordinary meaning of 0.001% w/w PVP. In Judge Taranto’s view, applicant’s arguments during prosecution with respect to stability at most required an exclusion of 0.0005% w/w PVP from the literal scope of 0.001% w/w.

Takeaway: This decision – particularly when the majority and dissent opinions are compared – does not offer much clarity as to how precisely a numerical value in a claim will be interpreted. There appears to be consensus that the starting point is “within one significant figure.” However, based on the majority’s decision, even the mention of more precise values in the specification or prosecution history can impute an additional significant figure to a claimed value. Practitioners should at least be wary of the risks of using different degrees of precision for different data points/values in the specification and claims and consider explicitly defining the degree of error intended for claimed values in the specification.

Judges: Taranto, Hughes, Stoll (Taranto dissenting)


November 5, 2021by Jacob Doughty

Ex parte Kuhlmann, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing prima facie obviousness of a polymer composition.

The substance of the decision in Ex parte Kuhlmann is not particularly remarkable – the examiner was affirmed by the PTAB. However, applicant argued that the allowance of a corresponding application in Europe was relevant to the issue of obviousness in the US, and the argument was not well-received.

In the Appeal Brief, applicant argued:

For reference, the Applicants respectfully submit that the EPO equivalent application EP 3255103 was granted and found to be novel and non-obvious over the US Dangayach et al. (US 5,284,938, herein Dangayach A) reference.

In the Examiner’s Answer, the examiner stated:

In response to Appellant’s statement, p. 9 of the Brief, that EP 3255103 was found novel and non-obvious over the Dangayach A is not persuasive, because that determination was not under US patent laws and rules.

In the Reply Brief, applicant further argued:

If relevant to the Appeal Board, the Appellants submit that the claims as submitted in the Appeal are identical or substantially identical to the claims granted (without issuance of an Action) in European patent EP3255103B1 and validated in 14 countries, which claims were granted over Dangayach et al. (US 5,284,938, herein Dangayach A), the main reference cited by the Examiner herein, for reasons which will further be obvious below.

And finally, in the Decision, the PTAB stated:

We find no merit in Appellant’s argument that the same or substantially the same claims in EP 3255103 B1 were found novel and nonobvious over Dangayach and thereby granted by the European Patent Office (EPO)… We are not bound by an earlier decision of the EPO. In re Gyurik, 596 F.2d 1012, 1016 (CCPA 1979) (“Each case is determined on its own merits; allowed claims in other applications or patents are not considered in reviewing specific rejections of specific claims.”); In re Giolito, 530 F.2d 397, 400 (CCPA 1976) (“We reject appellants’ argument that the instant claims are allowable because similar claims have been allowed in a patent. It is immaterial whether similar claims have been allowed to others.”).

Takeaway: Prosecuting corresponding patent applications in different countries can be expensive and time consuming. Common sense would suggest that something that is patentable in one jurisdiction should generally be patentable in all jurisdictions. Of course, the patent laws differ from jurisdiction-to-jurisdiction. The US can be particularly idiosyncratic, as US examiners often rely on different references and/or rationales than examiners in other jurisdictions. As is evident from Ex parte Kuhlmann, directly asserting that US claims should be allowed based on an allowance in another jurisdiction can be counterproductive. A more productive approach would be to rely on the reasons for allowance in another jurisdiction to the extent they are applicable under US law. The fact of allowance in another jurisdiction might be of interest to some US examiners – but this might be better conveyed informally in an interview.

Judges: Timm, Praiss, Gupta


October 29, 2021by Jacob Doughty

Ex parte Lindenblatt, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing evidence of unexpected results.

In Ex parte Lindenblatt, the claim at issue was directed to a pharmaceutical (thyroid hormone) formulation. The relevant claim recited:

1. A solid pharmaceutical preparation comprising

levothyroxine sodium,

2-10% by weight based on the preparation of gelatine,

0.2 to 3% by weight based on the preparation of citric acid, and

a filler that is 50 to 80% by weight, based on the preparation, of mannitol, sucrose or lactose, and 10 to 30% by weight, based on the preparation, of maize starch.

In rejecting the claim, the examiner relied on a primary reference that disclosed all of the features except for the gelatin. For this deficiency, the examiner relied on a secondary reference disclosing levothyroxine sodium tablets including gelatin and fillers and describing that, when gelatin is used as a binder, the tablets have surprising stability.

Applicant argued that the tablet of the primary reference was intended to dissolve rapidly in a patient’s mouth and, thus a skilled artisan would not have been led by the secondary reference’s promises of stability through the use of gelatin.

The PTAB was not persuaded, finding that the examiner made a prima facie case of obviousness. The PTAB noted particularly that “while [the primary reference] is concerned with a composition that can easily dissolve in the mouth, such does not indicate that [the primary reference] is not interested in a product that has a stable shelf life until inserted into the mouth of a patient.”

The PTAB was persuaded, however, by applicant’s evidence of unexpected results.

First, applicant provided evidence (a journal article) showing that it was known that citric acid is a pH modifier that reduces the stability of levothyroxine sodium in tablets relative to tablets including a basic pH modifier or no pH modifier (at 10% – much higher than the claimed range and the primary reference). Then, applicant supplemented with experimental evidence, which showed the following results for stability when varying citric acid and gelatin amounts in levothyroxine sodium tablets:

Citric Acid Gelatin Stability
5% ★★★
1.5% 5% ★★★★

Looking at the evidence, the PTAB found that the stability results for the combination of gelatin and citric acid would have been unexpected, because citric acid alone was reported in the literature and shown in applicant’s experimental results to negatively affect the stabilization of levothyroxine sodium in a tablet. That is, the PTAB concluded that a skilled artisan would not have expected the combination of citric acid and gelatin to provide better stabilization of levothyroxine sodium in a tablet composition than the stabilization provided by gelatin alone.

Takeaway: In this case, the examiner provided a credible reason for expecting that addition of gelatin to the citric acid-containing tablets of the primary reference would increase stability – the secondary reference explicitly stated that stability would be increased. Applicant was able to find literature evidence suggesting that a large amount of citric acid is expected to destabilize. Applicant supplemented this with post-filing results showing that small amounts of citric acid destabilize. Together, this evidence persuaded the PTAB that the improved performance of the citric acid/gelatin combination shown by applicant was unexpected.

Applicant provided a good amount of evidence and a compelling narrative regarding unexpectedness. The PTAB’s explanation, however, gives little weight to the fact that the primary reference tablets already included citric acid. Further, the post-filing evidence regarding the effect of small amounts of citric acid would not have informed a skilled artisan of what would have been expected or unexpected at the time of the application. This case illustrates that sometimes a persuasive story can be useful in overcoming weaknesses in evidence of unexpected results.

Judges: Adams, Jenks, Townsend