September 23, 2022by Richard Treanor

On June 21, 2022, the Federal Circuit decided Novartis Pharm. Corp. v. Accord Healthcare, Inc., No. 2021-1070 (Fed. Cir. June 21, 2022) finding that a negative limitation added during the course of prosecution was not supported by the original specification.

The claims in this case were originally directed to a method for treating multiple sclerosis by administering a certain “daily dosage” of the drug fingolimod to a patient. Importantly, a “daily dosage” was well known in the art to be different from a “loading dose,” which is a more concentrated dose typically given only once – at the initiation of treatment, and prior to the administration of daily dosages. During prosecution, a preliminary amendment was submitted in which the claims were amended to exclude the use of a loading dose. No support was cited for this amendment.

On rehearing, the Federal Circuit found that this negative limitation lacked written description support in the original specification, noting that the specification was completely silent regarding loading doses. The fact that the (prophetic) example did not use a loading dose was not helpful, according to the court, because it had not been shown that “a skilled artisan would understand the specification as inherently disclosing the negative limitation” for example by establishing “that in a particular field, the absence of mention of a limitation necessarily excluded that limitation.” Otherwise, the court noted, “[i]f silence were generally sufficient, all negative limitations would be supported by a silent specification.”

In Novartis, although the Federal Circuit reversed its prior decision and found the disputed limitation unsupported, the court mentioned all the usual forms of support for negative limitations (stated disadvantages; listed alternatives; etc.) and acknowledged the possibility that silence could also form the basis of support. This is an important reminder for the practitioner trying to distinguish a claim from the prior art – not everything at your disposal is before your eyes: “[w]hile a written description’s silence about a negative claim limitation is a useful and important clue and may often be dispositive, it is possible that the written description requirement may be satisfied when a skilled artisan would understand the specification as inherently disclosing the negative limitation.” Discussion of how the PTAB recently handled a similar can be found on our blog.


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


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


July 23, 2021by Matthew Barnet

In a recent IPR, the PTAB found a chemical formula in the claims not to be fully supported by a provisional application, opening the claims to anticipatory prior art. IPR2020-00349, Paper 53 (PTAB July 15, 2021).

The patented claims related to a battery comprising an additive represented by Chemical Formula 1:

where each of k, l and m is independently an integer of 0 to 20; each of k, l and m are different from each other such that the compound has an asymmetric structure; and n is an integer of 1 to 7.

Chemical Formula 1 itself was identical between the provisional and nonprovisional applications. However, the nonprovisional application added the following statement: “For example, the compound represented by Chemical Formula 1 may be 1,3,6-hexane tricarbonitrile, 1,3,5-hexane tricarbonitrile, or 2,3,6-hexane tricarbonitrile.”

The petitioner argued that a skilled artisan would not have understood the originally disclosed Chemical Formula 1 to encompass the second and third of these exemplary compounds. In particular, 1,3,5-hexane tricarbonitrile does not have a cyano group at position 6 of the hexane backbone. Thus, to map this compound onto Chemical Formula 1 would require a methyl substituent on the main carbon backbone of Chemical Formula 1. Similarly, 2,3,6-hexane tricarbonitrile does not have a cyano group at position 1 of the hexane backbone. To map this compound onto Chemical Formula 1 also would require a methyl substituent on the main carbon backbone of Chemical Formula 1.

The petitioner argued that Chemical Formula 1 is a “bond-line formula” which would be understood in the provisional application to exclude substituents from the backbone -CH2– moieties. The petitioner argued that the inclusion of 1,3,5-hexane tricarbonitrile and 2,3,6-hexane tricarbonitrile as examples of compounds of Chemical Formula 1 in the nonprovisional application broadened the meaning of Chemical Formula 1 to include substituents on the backbone. Because of this, the petitioner argued that the scope of the patented claims was not fully supported by the provisional application.

The PTAB agreed with the petitioner. The PTAB was not persuaded by the patent owner’s argument that the possibility of substituents was implied in Chemical Formula 1 in the provisional application. The PTAB noted other instances within the provisional application where R groups were used to identify optional substituents, and found that “[w]hen the inventors…intended to disclose a chemical formula that permitted substituents to be optionally added, they knew how to do so.”

Since the priority chain from the patent to the provisional application was broken, the PTAB found the claims to be anticipated by prior art that could not be antedated.

Takeaway: Innovation is dynamic, and often continues between the filing of a priority (e.g. provisional) application and a nonprovisional application. New material that is developed within this time generally can be included in the nonprovisional application. Caution is required, however, since the new material can raise an issue of written description support, breaking the priority chain and opening the application or patent to additional prior art.

Judges: Crumbley, Kokoski, McGee


March 26, 2021by Yanhong Hu

In Ex parte Hassler (Appeal 2020-001367), the Patent Trial and Appeal Board (“Board”) considered Appellant’s two arguments rebutting the Examiner’s obviousness rejection based on the combination of the primary reference (Fischmann) with the secondary reference (McNew).

Independent claim 1 illustrated the subject matter of the appealed claims and was directed to a method that included a step (a) of receiving an oxyanion-containing water comprising at least one non-metal-containing oxyanion and a subsequent step (b) of contacting the oxyanion-containing water with a separate rare-earth-element-containing component to remove more than 50% of the oxyanions from the oxyanion-containing water.  The claim further limited the non-metal-containing oxyanion to an anion that contained one or more particular species recited in a Markush group.

The Examiner admitted Fischmann, which disclosed step (a), failed to teach a separate component containing a rare-earth element as claimed in step (b) and thus resorted to McNew for the admitted deficiency.  Appellant first argued Fischmann did not constitute prior art because the claimed subject matter enjoyed priority to applications that predated Fischmann.  Secondly, Appellant argued even if Fischmann constituted prior art, the Examiner’s substitution of McNew’s composition into the process of Fischmann was improper.

The Board reversed the obviousness rejection because the Board agreed with Appellant’s second argument.  However, the Board sided with the Examiner regarding Appellant’s first argument.  The Board’s analysis of Appellant’s first argument involving the written description and enablement requirements of 35 U.S.C. § 112(a) (or pre-AIA § 112, ¶ 1) is the focus of this blog.

Appellant argued the application at issue had an earlier effective filing date because it claimed priority to two provisional applications (“the Hassler provisionals”), which incorporated by reference three earlier filed non-provisional applications (“the incorporated applications”).  Appellant argued all the incorporated applications and the Hassler provisionals defined the terms “oxyanion” and “target material-containing oxyanion” in the same way.

The Examiner contended the claim could not be afforded priority of the Hassler provisionals because the Hassler provisionals did not support the claimed subject matter in a manner that complied with the written description requirement of § 112(a).  The Examiner explained the Hassler provisionals merely described the oxyanions generally as AxOy with A being a metal, metalloid, or non-metal but did not disclose any species of non-metal oxyanions other than selenium.  The Examiner similarly found the incorporated applications failed to disclose the Markush species recited in claim 1.

Appellant did not dispute the Examiner’s contention that the Hassler provisionals failed to expressly disclose the particular Markush species.  However, Appellant argued “the fact that the Hassler provisionals do not define non-metal oxyanions other than selenium oxyanions as ‘target-material containing’ oxyanions does not limit the scope of the genus of ‘oxyanions’ generally [described therein].”  Appellant continued, “it [is] well known to those of ordinary skill in the art that the term ‘oxyanion’ referred to any anion ‘containing one or more oxygen atoms bonded to another element.’”  Citing Regents of the University of California v. Eli Lilly, 119 F.3d 1559, 1568 (Fed. Cir. 1997) and relevant MPEP sections, Appellant further argued that “in assessing a disclosure for compliance with 35 U.S.C. § 112(a), … ‘[w]hat is conventional or well known to one of ordinary skill in the art need not be disclosed in detail’” and that the general chemical formula AxOyz- disclosed in the Hassler provisionals eliminated any ambiguity in that “such a formula, even standing alone, provides adequate disclosure for the genus of oxyanions because, ‘[i]n claims involving chemical materials, generic formulae usually indicate with specificity what the generic claims encompass [and] [a]ccordingly, such a formula is normally an adequate description of the claimed genus.”

The Board disagreed and found Appellant confused the written description requirement of § 112(a) with the enablement requirement of § 112(a).  The Board noted that the enablement requirement was more indulgent than the written description requirement.  The Board acknowledged a specification did not necessarily need to disclose what was well-known and conventional in order to satisfy the enablement prong of § 112(a).  However, the Board emphasized written description and enablement were separate requirements.  In particular, “[a]dequate written description means that the applicant, in the specification, must ‘convey with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the [claimed] invention.’”  The Board further noted a specification must provide some guides or “blaze marks” that disclosed the claimed invention “specifically, as something appellants actually invented.”  The Board did not find Appellant’s argument about whether oxyanions, as a class, were well known to those skilled in the art addressed the separate inquiry of whether the Hassler provisionals provided adequate written description to establish the claim to priority.

Because “one cannot disclose a forest in the original application, and then later pick a tree out of the forest and say here is my invention,” Purdue Pharma L.P. v. Faulding Inc., 230 F.3d 1320, 1326 (Fed. Cir. 2000), the Board did not find Appellant sufficiently demonstrated that any of the earlier filed applications conveyed with reasonable clarity to those skilled in the art that, as of the filing date sought, Appellant was in possession of the claimed Markush species.  Accordingly, the Board held Fischmann constituted prior art.

Takeaway:  To satisfy the written description requirement, a specification must describe the claimed invention in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention at the filing date sought.  For a claim to comply with the written description requirement or to be entitled to a priority date, each claim limitation must be expressly or inherently supported in the originally or previously filed disclosure.  When an explicit limitation in a claim is not present, it must be shown that those skilled in the art would have understood that the description requires that limitation.  As illustrated by Hassler, in the chemical art, a structural chemical formula that is not sufficiently detailed fails to show applicant was in possession of the claimed invention as of the filing date sought.

Judges:  T. J. Owens, B. W. Baumeister, and B. D. Range


October 5, 2020by Jacob Doughty

Ex parte Porro is a 2008 decision of the Board of Patent Appeals and Interferences (BPAI) that is listed among the Patent Trial and Appeal Board’s (PTAB) informative decisions. Ex parte Porro is indicated by the PTAB to be informative as to “Specification and claim requirements – 35 U.S.C. § 112… Written description… species-genus.”

According to the PTAB’s Standard Operating Procedure, “[i]nformative decisions set forth Board norms that should be followed in most cases, absent justification, although an informative decision is not binding authority on the Board.”

In Ex parte Porro, the BPAI considered whether a claim defining a recombinant yeast as having a coding region encoding an enzyme having “at least about 90% identity with SEQ ID NO: 11” was properly rejected for failing to comply with the written description requirement of 35 USC 112.

Independent claim 13 was at issue:

A method of generating ascorbic acid, comprising:

a) obtaining a recombinant yeast capable of converting an ascorbic acid precursor into ascorbic acid, wherein the yeast is functionally transformed with a coding region encoding L-galactose dehydrogenase (LGDH) enzyme having at least about 90% identity with SEQ ID NO: 11,

b) culturing the recombinant yeast in a medium comprising an ascorbic acid precursor, thereby forming ascorbic acid, and

c) isolating the ascorbic acid.

In rejecting the claim, the examiner asserted that the claim encompassed a set of coding regions/amino acids (90% identity with SEQ ID NO: 11) defined by the function of the encoded protein (LGDH). Applicant acknowledged that “90% identity with SEQ ID NO: 11” included approximately 3.4 x 1041 variants. The examiner found that the specification disclosed only a single LGDH sequence, derived from Arabidopsis thaliana. The examiner further noted a teaching in the prior art that an LGDH discovered in A. thaliana was, “as far as we know, the only plant dehydrogenase acting on a non-phosphorylated sugar.” The examiner concluded that, in view of the size of the genus and the lack of guidance in the specification and the prior art, a skilled artisan “would not have been able to envision a sufficient number of specific embodiments that meet the functional limitations of the claims.”

The BPAI agreed with the examiner. The BPAI noted particularly that the specification did not provide guidance regarding what structural features were responsible for the enzymatic activity of LGDH or describe what amino acid changes could be made in the wild-type sequence without affecting the enzymatic activity of the protein. The BPAI conceded that a skilled artisan could make libraries of SEQ ID NO: 11 variants and screen them to identify specific proteins that are at least 90% identical to SEQ ID NO: 11 and that have LGDH enzymatic activity – however, this was not sufficient to demonstrate possession of the claimed invention.

The BPAI indicated that the applicant could have described a representative number of functional variants, or it could have described structural features that are common to functional variants that distinguish them from the rest of the genus. But neither was done in this case. The BPAI noted that different inventions can be described in different ways, but a chemical genus must be described in some way that demonstrates to those of skill in the art that the applicant was in possession of the claimed genus at the time the application was filed.

The result in Ex parte Porro is reflected in Example 11 of the USPTO’s Written Description Training Materials. It should be noted, however, that the USPTO has indicated in its Clarification of Written Description Guidance For Claims Drawn to Antibodies and Status of 2008 Training Materials that such materials are being revised at the time of this post.

Takeaway: When claiming a genus of structures defined by a nucleic acid or amino acid sequence, it is not necessary to describe any particular number of specific sequences. However, it must be apparent (e.g., to the examiner) that the inventor(s) grasped the necessary common attributes or features possessed by the members of the genus in view of the species disclosed. This can be achieved through disclosure of sufficient number of species that are representative of the full scope of the genus or disclosure/demonstration of a structure-function correlation common to members of the genus. Of course, this is easier to do when drafting an application than when responding to a rejection.

Judges: Scheiner, Mills, Grimes


August 31, 2020by Beau Burton

On July 31, 2020, the Patent Trial and Appeal Board (“Board”) issued a decision in Ex parte Marco (Appeal No. 2020-000873) reversing an Examiner’s rejection for failure to comply with the written description requirement.

The written description controversy in Marco centered on a requirement in claim 2 for a hat having an opposing pair of under-chin straps that were “at least about one inch in width.” According to the Applicant, the width of “at least about one inch” was supported by the original specification, particularly the embodiments illustrated Figures 5 and 7 (shown below):