Patent law in many respects has its own language and idiosyncratic expressions, and one such respect involves so-called "transitional" words or phrases (discussed in greater depth in the Manual of Patent Examination Procedure § 2111.03). They are termed "transitional" because they mediate the transition between a claim preamble and the elements of the invention recited therein. The most common such word is "comprises" or "comprising," which indicates that the claim drafter intends the element to encompass what is expressly recited and anything else (within the limits of what the skilled artisan would understand would be operable; this is not an "everything but the kitchen sink" situation). On the other hand, the words "consisting of" indicate the exact opposite: the elements recited following this phrase are limited to just what is recited and nothing more. In what was considered in simpler days to be especially arcane arts such as chemistry there arose a somewhat looser version of this more restricted terminology, the phrase "consisting essentially of." This transitional phrase was much more limited than "comprising" but permitted a slightly broader scope than "consisting of"; examples included additional unrecited elements in complicated chemical combinations like shampoos. Any "loosening" of the strictures of "consisting of" is limited to such elements that do not materially affect the "basic and novel" characteristics of the claimed invention. See, as examples, In re Herz, 537 F.2d 549, 551-52 (CCPA 1976), and Atlas Powder v. E.I. duPont de Nemours & Co., 750 F.2d 1569 (Fed. Cir. 1984).
The proper construction of this phrase was at issue in Eye Therapies LLC v. Slayback Pharma, LLC, which arose as an inter partes review of all claims of Patent Owner Eye Therapies' U.S. Patent No. 8,293,742. This patent claims a method to reduce eye redness using a low-concentration dose of brimonidine, which active ingredient is described in a footnote as being "an alpha-adrenergic receptor agonist, a category of compounds known to cause vasoconstriction." The footnote goes on to explain that this vasoconstrictive effect counteracts vasodilation, which is the cause of many "clinically undesirable events" such as "surface hemorrhage and hyperemia following Lasik surgery" and "eye redness (conjunctival hyperemia)."
Claims 1 and 3 are set forth in the opinion as representative:
1. A method for reducing eye redness consisting essentially of administering brimonidine to a patient having an ocular condition, wherein brimonidine is present at a concentration between about 0.001% weight by volume and about 0.05% weight by volume.
3. A method for reducing eye redness consisting essentially of topically administering to a patient having an ocular condition a composition consisting essentially of brimonidine into ocular tissue, wherein pH of said composition is between about 5.5 and about 6.5, wherein said brimonidine concentration is between about 0.001% and about 0.025% weight by volume and wherein said composition is formulated as an ocular drop.
(wherein the italicized transitional language was at issue in this appeal). The opinion sets forth the ex parte prosecution context of the importance of this transitional phrase, wherein the patentee had amended the word "comprising" to "consisting essentially of" in the face of a novelty rejection asserted using prior art disclosing a combination of brimonidine and brinzolamide, and applicant argument that "the revised claims 'do not require the use of any other active ingredients (emphasis added) in addition to brimonidine'" (and wherein the examiner expressly recited this argument in their Notice of Allowance).
In its Petition, Slayback challenged claims 1-6 of the '742 patent; in the Final Written Decision (FWD), the Patent Trial and Appeal Board found all claims of the patent to be invalid for obviousness. In its claim construction, the Board expressly rejected Patent Owner's arguments that "consisting essentially of" limited the claim to exclude any other active ingredients (despite both the patent applicant and examiner expressly having relied on this distinction in prosecution of the '742 patent claims to allowance). The Board's reasoning in the FWD was that to do so would construe the phrase to have the same scope as "consisting of." Under the Board's construction, "the claimed methods cannot include additional active ingredients that are 'required' to perform the method" (emphasis in FWD). Nevertheless, the Board considered the addition of other active ingredients that "would not materially affect the basic and novel characteristics of the invention" could be included within the scope of the claim. Under this construction, the prior art disclosure of the combination of combination of brimonidine and brinzolamide would render the '742 claims obvious. This appeal followed.
The Federal Circuit reversed in part and vacated in part the PTAB's decision and remanded, in an opinion by Honorable Mark C. Scarsi, District Judge from U.S. District Court for the Central District of California, sitting by designation, joined by Judges Taranto and Stoll. The panel opinion came straight to the point: in view of the prosecution history the Board erred in construing the phrase "consisting essentially of" to encompass methods using active ingredients other than brimonidine. Because this error permitted the Board to consider the combination prior art formulations as falling within the scope of the claim and thus being obvious, the Court vacated the Board's obviousness determination and remanded.
The basis for the panel's decision that the Board erred in construing "consisting essentially of" was that this phrase had been "long understood" to "permit inclusion of components not listed in the claim, provided that they do not 'materially affect the basic and novel properties of the invention,'" citing AK Steel Corp. v. Sollac, 344 F.3d 1234, 1239 (Fed. Cir. 2003). And under Phillips v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc), a patent applicant "can alter the typical meaning . . . by mak[ing] the intended meaning clear in the specification or disclaim an alternative meaning in the prosecution history," citing Ecolab, Inc. v. FMC Corp., 569 F.3d 1335 (Fed. Cir. 2009). The panel agreed with Eye Therapies' argument that the prosecution here was an example of the patentee so altering the typical scope of a claim reciting "consisting essentially of" as a transitional phrase. The opinion sets forth ample quotations from the prosecution history of the '742 patent in support of their decision, from both the applicant and patent examiner. The opinion relies on Shire Dev., LLC v. Watson Pharms., Inc., 787 F.3d 1359, 1366 (Fed. Cir. 2015), Personalized Media Commc'ns, LLC v. Apple Inc., 952 F.3d 1336, 1339 (Fed. Cir. 2020), and Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 452 (Fed. Cir. 1985), for the principle that "explanatory remarks" made during prosecution can demonstrate what an applicant "meant" by the amendment. (Of course the converse is also true, to the extent that improvident or unclear "remarks" can produce a construction not intended or anticipated by an applicant.)
The panel also considered the "strongest indicators" of patent owner's intention to have a "more-restrictive-than-typical interpretation of the phrase 'consisting essentially of'" to be a comparison with the asserted combination prior art, wherein the Court considered patent owner's representations during prosecution that "Dean teaches away from methods consisting essentially of administering brimonidine (i.e., methods which do not include administering other active agents)" (emphasis in opinion). Also factoring into the panel's decision here is the use of "i.e.," where use of this abbreviation "indicates an intent to define the claimed 'methods'" to exclude other active ingredients. The panel also found the intrinsic evidence (the prosecution history) to be incompatible with the Board's claim construction. Nor was the panel persuaded that the existence of alternative embodiments in the '742 specification, reciting "comprising" were incompatible with the restrictive scope of the altered/amended claim language, citing TIP Sys., LLC v. Phillips & Brooks/Gladwin, Inc., 529 F.3d 1364, 1373 (Fed. Cir. 2008), and Pacing Techs., LLC v. Garmin Int'l, Inc., 778 F.3d 1021, 1026 (Fed. Cir. 2015).
Petitioner Slayback's argument was that although Patent Owner Eye Therapies had represented to the patent examiner that their claims did not require other active ingredients this was not the same as precluding the use of such ingredients. The panel rejected Slayback's argument that the circumstances here were analogous to the Court's decision in Aylus Networks, Inc. v. Apple Inc., 856 F.3d 1353 (Fed. Cir. 2017), based inter alia on different factual predicates. According to the opinion:
Given the applicant's arguments distinguishing Dean and definitional use of "i.e." to equate its claimed "methods consisting essentially of administering brimonidine" with "methods which do not include administering other active agents," (emphasis added), the appropriate interpretation of the applicant's representation that the claimed methods "do not require" agents other than brimonidine is that its claimed methods preclude the use of such agents.
On this basis the Court reversed the Board's claim construction.
The Court's assessment of the Board's obviousness determination was that the Board's claim construction was erroneous and "infected its obviousness analysis." Evidence for this conclusion was the Board's reliance on other prior art directed to methods using combinations with other active ingredients in support for finding the challenged claims obvious.
Finally, in explaining the decision to vacate and remand, the opinion states:
We do not prejudge whether the correct claim construction permits the same factual findings or obviousness conclusion. We do note, however, that because the Board applied an erroneous claim construction, it had no occasion to consider whether, under the prior art, a person of ordinary skill in the art would have been motivated to employ a method with the properly understood limitation signified by the '742 patent's use of "consisting essentially of." We conclude that the appropriate course in this case, as in so many others involving a reversal of a Board claim construction, is to vacate the Board's decision and remand the matter, citing Kaken Pharma. Co., Ltd. v. Iancu, 952 F.3d 1346, 1355 (Fed. Cir. 2020).
Eye Therapies, LLC v. Slayback Pharma, LLC (Fed. Cir. 2025)
Panel: Circuit Judges Taranto and Stoll and District Judge Scarsi
Opinion by District Judge Scarsi
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