Eye Therapies, LLC v. Slayback Pharma LLC

141 F.4th 1264

• Court: Court of Appeals for the Federal Circuit
• Decided: June 30, 2025
• Docket: 23-2173
• Status: Published

Opinion

Case: 23-2173 Document: 58 Page: 1 Filed: 06/30/2025

United States Court of Appeals for the Federal Circuit ______________________

EYE THERAPIES, LLC, Appellant

v.

SLAYBACK PHARMA, LLC, Appellee ______________________

2023-2173 ______________________

Appeal from the United States Patent and Trademark Office, Patent Trial and Appeal Board in No. IPR2022- 00142. ______________________

Decided: June 30, 2025 ______________________

JAMES R. BARNEY, Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, Washington, DC, argued for ap- pellant. Also represented by BRYAN DINER, JUSTIN JAMES HASFORD, CHRISTINA JI-HYE YANG; CHARLES E. LIPSEY, Reston, VA.

KEVIN P. MARTIN, Goodwin Procter LLP, Boston, MA, argued for appellee. Also represented by ELAINE BLAIS, WILLIAM EVANS, ROBERT FREDERICKSON, III; LINNEA P. CIPRIANO, New York, NY. ______________________ Case: 23-2173 Document: 58 Page: 2 Filed: 06/30/2025

Before TARANTO and STOLL, Circuit Judges, and SCARSI, District Judge.1 SCARSI, District Judge. Appellant Eye Therapies, LLC (“Eye Therapies”) ap- peals from a final written decision of the Patent Trial and Appeal Board (the “Board”) holding all claims of U.S. Pa- tent No. 8,293,742 (“the ’742 patent”) unpatentable. Eye Therapies challenges (1) the Board’s construction of the phrase “consisting essentially of” and (2) the Board’s con- clusion that all claims of the ’742 patent would have been obvious over the prior art. For reasons explained below, we reverse the Board’s claim construction of the “consisting es- sentially of” limitation, vacate its obviousness finding, and remand for further proceedings. BACKGROUND Eye Therapies owns and licenses the ’742 patent, which teaches a method to reduce eye redness using a low-concen- tration dose of brimonidine.2 ’742 patent col. 22 ll. 17–21, 25–32. As relevant to the appeal, independent claims 1 and 3 recite: 1. A method for reducing eye redness consisting es- sentially of administering brimonidine to a patient

1 Honorable Mark C. Scarsi, District Judge, United States District Court for the Central District of California, sitting by designation. 2 Brimonidine is an alpha-adrenergic receptor ago- nist, a category of compounds known to cause vasocon- striction. ’742 patent col. 1 ll. 60–63. Vasoconstriction counteracts vasodilation, or “[d]ilation of small blood ves- sels,” a condition that “causes many clinically undesirable events” including “surface hemorrhage and hyperemia fol- lowing Lasik surgery” and “eye redness (conjunctival hy- peremia).” Id. col. 1 ll. 6–9. Case: 23-2173 Document: 58 Page: 3 Filed: 06/30/2025

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having an ocular condition, wherein brimonidine is present at a concentration between about 0.001% weight by volume and about 0.05% weight by vol- ume. 3. A method for reducing eye redness consisting es- sentially 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 con- centration is between about 0.001% and about 0.025% weight by volume and wherein said compo- sition is formulated as an ocular drop. ’742 patent col. 22 ll. 17–21, 25–32 (emphases added). During patent prosecution, the examiner rejected prior versions of these claims that used “comprising” instead of “consisting essentially of.” The examiner found that the claims that used “comprising” were anticipated by U.S. Pa- tent No. 6,242,442 (“Dean”), which discloses the admin- istration of brimonidine and brinzolamide to treat ocular diseases. J.A. 1033–35. In response, the applicant re- placed “comprising” with the phrase “consisting essentially of,” among other amendments. J.A. 1049. The applicant then argued that Dean only disclosed the use of brimoni- dine in combination with brinzolamide. J.A. 1053. Whereas Dean required brinzolamide as “an active ingre- dient” in addition to brimonidine, the applicant explained that the revised claims “do not require the use of any other active ingredients (emphasis added) in addition to brimoni- dine.” Id. The examiner allowed the amended claims, cit- ing the applicant’s representation “that the presently claimed methods do not require the use of any other active ingredients (emphasis added) in addition to brimonidine.” J.A. 1082. On petition by Appellee Slayback Pharma, LLC (“Slay- back”), the Board instituted an inter partes review of Case: 23-2173 Document: 58 Page: 4 Filed: 06/30/2025

claims 1–6 of the ’742 patent and entered a final written decision determining all challenged claims were unpatent- able. J.A. 2–3, 166. On claim construction, “the parties dis- pute[d] whether the scope of the claims includes the use of additional drugs along with low-dose brimonidine.” J.A. 12. The Board noted that “the use of ‘consisting essentially of’ ‘signals that the invention necessarily includes the listed ingredients [but] is open to unlisted ingredients that do not materially affect the basic and novel properties of the invention,’” in accordance with the phrase’s typical meaning. Id. (alteration in original) (quoting PPG Indus. v. Guardian Indus. Corp., 156 F.3d 1351, 1354 (Fed. Cir. 1998)). The Board rejected Eye Therapies’ arguments that the prosecution history demonstrated that “consisting es- sentially of” in this context should be read to claim a method for administering brimonidine as the sole active in- gredient, reasoning: During prosecution, the patentee asserted that “[o]ne of the basic and novel characteristics of the presently claimed methods is that they do not re- quire the use of any other active ingredients (em- phasis added) in addition to brimonidine.” But, unlike Patent Owner, we do not read the prosecu- tion history as prohibiting the use of any other ac- tive ingredients besides brimonidine. To do so would construe the semi-open-ended transition phrase “consisting essentially of” to have the same scope as the closed transition phrase “consisting of.” J.A. 14 (alteration in original) (citations omitted). Instead, the Board concluded that “under the proper scope of the claims and consistent with the prosecution history, the claimed methods cannot include additional active ingredi- ents that are required to perform the method.” Id. (empha- sis added). Case: 23-2173 Document: 58 Page: 5 Filed: 06/30/2025

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Applying our decision in Ecolab, Inc. v. FMC Corp., 569 F.3d 1335 (Fed. Cir. 2009), the Board reasoned that “be- cause the Specification states that low-dose brimonidine alone can significantly reduce hyperemia, if there are addi- tional agents beyond low-dose brimonidine administered to a patient that may also reduce eye redness . . . those addi- tional agents would not materially affect the basic and novel characteristics of the invention.” J.A. 15. Accord- ingly, the Board held that “the transitional phrase ‘consist- ing essentially of’ does not preclude the use of additional active agents that may also cause vasoconstriction and re- duction of hyperemia along with low-dose brimonidine.” J.A. 15–16. Applying this construction, the Board concluded “that the combination of [the prior art] teach[es] or suggest[s] each limitation of the challenged claims and a [person of ordinary skill in the art] would have had a reason to com- bine the references with a reasonable expectation of suc- cess.” J.A. 52–53.3 Eye Therapies timely filed this appeal. We have juris- diction pursuant to 28 U.S.C. § 1295(a)(4)(A). STANDARD OF REVIEW “We review de novo the Board’s ultimate claim con- structions and any supporting determinations based on in- trinsic evidence,” and “[w]e review any subsidiary factual findings involving extrinsic evidence for substantial evi- dence.” Personalized Media Commc’ns, LLC v. Apple Inc., 952 F.3d 1336, 1339 (Fed. Cir. 2020). Obviousness is a “mixed question of law and fact.” Ho- logic, Inc. v. Smith & Nephew, Inc., 884 F.3d 1357, 1361 (Fed. Cir. 2018). We review the Board’s ultimate

3 The Board also resolved other issues not relevant to this appeal. J.A. 16–40. Case: 23-2173 Document: 58 Page: 6 Filed: 06/30/2025

obviousness determination de novo and its underlying find- ings of fact for substantial evidence. Id. DISCUSSION We conclude the Board erred in its construction of the phrase “consisting essentially of” as allowing the coadmin- istration of active ingredients other than brimonidine. Given the prosecution history, we interpret the phrase as used in the ’742 patent to preclude the use of active ingre- dients other than brimonidine. Because the Board’s obvi- ousness analysis materially relied on its erroneous claim construction, we cannot affirm the Board’s unpatentability determination. We reverse the Board’s claim construction, vacate the Board’s decision, and remand the matter to the Board. A. Claim Construction The central dispute on appeal is the meaning of limit- ing claim language “consisting essentially of.” Eye Thera- pies contends that this transition phrase “should be construed to exclude active ingredients other than brimoni- dine in the claimed method.” Appellant’s Br. 29. Slayback argues that the Board properly construed “consisting es- sentially of” in line with our caselaw interpreting the phrase and the patent prosecution history. Appellee’s Br. 25. Claim terms “are generally given their ordinary and customary meaning” as understood by “a person of ordi- nary skill in the art in question at the time of the inven- tion.” Phillips v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005) (en banc) (internal quotation marks and citation omitted). “Claim construction requires a determination as to how a person of ordinary skill in the art would under- stand a claim term ‘in the context of the entire patent, in- cluding the specification.’” Trs. of Columbia Univ. v. Symantec Corp., 811 F.3d 1359, 1362 (Fed. Cir. 2016) (quoting Phillips, 415 F.3d at 1313). Case: 23-2173 Document: 58 Page: 7 Filed: 06/30/2025

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Generally, the term “comprising” is an open-ended transitional term that allows for additional steps. Invitro- gen Corp. v. Biocrest Mfg., L.P., 327 F.3d 1364, 1368 (Fed. Cir. 2003). On the other hand, the transitional phrase “consisting essentially of” generally “has long been under- stood 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.’” AK Steel Corp. v. Sollac, 344 F.3d 1234, 1239 (Fed. Cir. 2003) (quoting PPG Indus., 156 F.3d at 1354). However, “a patentee can alter that typical meaning”; for example, the patentee can make the intended meaning clear in the specification or disclaim an alternative meaning in the prosecution history. Ecolab, 569 F.3d at 1343–44. Limiting statements in the patent prosecution history can “inform the meaning of the claim language by demonstrating how the inventor understood the invention and whether the inventor limited the inven- tion in the course of prosecution, making the claim scope narrower than it would otherwise be.” Phillips, 415 F.3d at 1317. Eye Therapies contends the prosecution history sup- ports an atypical meaning of “consisting essentially of,” as the applicant “expressly argued that the amended claims preclude the use of other active ingredients and that a basic and novel property of the invention is the administration of brimonidine without other therapeutic drugs.” Appel- lant’s Br. 30. We agree with Eye Therapies that the pros- ecution history informs an atypical meaning of “consisting essentially of” in the ’742 patent. Following the examiner’s rejection of the ’742 patent over Dean, the applicant amended the claims, replacing “comprising” with “consisting essentially of.” J.A. 1049. The applicant explained that the amendment distin- guished the claims from Dean, which “does not disclose a method . . . which consists essentially of administering to a patient with an ocular condition brimonidine . . . or a phar- maceutical composition consisting essentially of Case: 23-2173 Document: 58 Page: 8 Filed: 06/30/2025

brimonidine.” J.A. 1053. The applicant explained that the innovation in the “claimed methods is that they do not re- quire the use of any other active ingredients (emphasis added) in addition to brimonidine.” Id. In allowing the claims, the patent examiner echoed the applicant’s repre- sentation “that the presently claimed methods do not re- quire the use of any other active ingredients (emphasis added) in addition to brimonidine, thereby instating the ‘consisting essentially of’ language.” J.A. 1082 (citation omitted). Even if these representations to the examiner “do not rise to the level of unmistakable disavowal, they do inform the claim construction.” Shire Dev., LLC v. Watson Pharms., Inc., 787 F.3d 1359, 1366 (Fed. Cir. 2015). “[A]n applicant’s amendment accompanied by explanatory re- marks can define a claim term by demonstrating what the applicant meant by the amendment.” Personalized Media Commc’ns, 952 F.3d at 1340. For example, arguments ad- vanced in prosecution “to convince the examiner that the claimed invention meets the statutory requirements of nov- elty, utility, and nonobviousness” can limit claim interpre- tation. Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 452 (Fed. Cir. 1985). The only material difference in the language circum- scribing the scope of the rejected claims and the allowed amended claims is the replacement of the open-ended term “comprising” with the less-open phrase “consisting essen- tially of.” As confirmed by the examiner’s repetition of and maintained emphasis on the applicant’s representations, the applicant secured allowance of the amended claims by arguing that the claimed methods were novel because they “do not require the use of any other active ingredients.” This promotes a more restrictive interpretation of “consisting essentially of” than our precedents interpreting the typical use of the phrase would prescribe. Whereas an interpreta- tion applying the standard meaning might permit addi- tional unlisted active ingredients, the applicant persuaded Case: 23-2173 Document: 58 Page: 9 Filed: 06/30/2025

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the examiner of the novelty of the claims by underscoring the absence of other active ingredients in the claimed meth- ods. The strongest indicators of a more-restrictive-than-typ- ical interpretation of the phrase “consisting essentially of” are the applicant’s arguments on amendment contrasting the claimed methods and Dean’s: Dean is directed to the combinational use of brimonidine and brinzolamide, and there is noth- ing in the reference that would lead a person hav- ing ordinary skill in the art to omit one of the two essential components of the Dean’s compositions to arrive at the claimed methods. Moreover, Dean teaches away from methods consisting essentially of administering brimonidine (i.e., methods which do not include administering other active agents). J.A. 1061–62 (second emphasis added); see also J.A. 1055 (“Thus, Dean . . . does not teach any methods of treating any conditions by administering a pharmaceutical compo- sition consisting essentially of brimonidine (i.e., a pharma- ceutical composition which does not include any other active agents).” (emphasis added)). “[U]se of ‘i.e.’ signals an intent to define the word to which it refers.” Edwards Lifesciences LLC v. Cook Inc., 582 F.3d 1322, 1334 (Fed. Cir. 2009); see also Rembrandt Wireless Techs., LP v. Sam- sung Elecs. Co., Ltd., 853 F.3d 1370, 1376 (Fed. Cir. 2017) (“A patentee’s use of ‘i.e.,’ in the intrinsic record . . . is often definitional.”). The applicant’s use of “i.e.” here indicates an intent to define the claimed “methods consisting essen- tially of brimonidine” as “methods which do not include ad- ministering other active agents.” In this way, the standard meaning of “consisting essentially of” is incompatible with the more restrictive meaning the applicant ascribed to the phrase. Ecolab, which the Board analogized to reach a different result, is consistent with our conclusion. In Ecolab, we Case: 23-2173 Document: 58 Page: 10 Filed: 06/30/2025

interpreted a method for sanitizing fowl using a solution “which consists essentially of . . . peracetic acid” not to be limited to compositions containing peracetic acid as the sole antimicrobial agent. 569 F.3d at 1342–44. We rejected a party’s argument for departing from the typical interpre- tation of “consisting essentially of,” reasoning that the pa- tent specification provided examples describing compositions that contain antimicrobial agents other than peracetic acid. Id. at 1343–44. In other words, we found that the intrinsic evidence was irreconcilable with the al- ternative meaning the party advanced.4 In contrast, the prosecution history here strongly evinces a restrictive meaning of “consisting essentially of.” Admittedly, other aspects of the intrinsic record are less conducive to the con- struction. Our construction would not embrace some em- bodiments in the ’742 patent specification that describe compositions containing active ingredients other than brimonidine. E.g., ’742 patent col. 9 ll. 35–42. But an atyp- ically restrictive construction of “consisting essentially of” remains compatible with other embodiments that describe compositions in which brimonidine is the only active ingre- dient. E.g., id. col. 10 ll. 3–8. And it is hardly surprising or unusual that a specification written with broader claim language (“comprising”) would contain embodiments no longer compatible with narrowed claim language adopted

4 The Board rested its Ecolab analogy on the specifi- cation’s statement “that low-dose brimonidine alone can significantly reduce hyperemia,” reasoning that “if there are additional agents . . . those additional agents would not materially affect the basic and novel characteristics of the invention.” J.A. 15 (emphasis added). The contingency the Board identifies extends well beyond the text of the speci- fication. And while the Board’s logic is consistent with the typical meaning of “consisting essentially of,” it does not foreclose the more restrictive meaning the prosecution his- tory supports. Case: 23-2173 Document: 58 Page: 11 Filed: 06/30/2025

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during prosecution (“consisting essentially of”) accompa- nied by a clear narrowing explanation, as here. Such ac- tions, post-dating the filing of the specification, naturally can and often do result in claims that do not cover all em- bodiments in the specification. The fact that our construc- tion does not encompass all alternative embodiments does not foreclose its application, especially given its compelling support in the prosecution history. TIP Sys., LLC v. Phil- lips & Brooks/Gladwin, Inc., 529 F.3d 1364, 1373 (Fed. Cir. 2008); see also Pacing Techs., LLC v. Garmin Int’l, Inc., 778 F.3d 1021, 1026 (Fed. Cir. 2015) (“[W]here the patent describes multiple embodiments, every claim does not need to cover every embodiment.”). Slayback argues that the applicant told the examiner only that the amended claims do not require the use of any other active ingredients, not that they preclude the use of such ingredients. Appellee’s Br. 29. We rejected a similar argument in Aylus Networks, Inc. v. Apple Inc., 856 F.3d 1353 (Fed. Cir. 2017). There, a patentee made “repeated statements” in an inter partes review proceeding that its claims “require that . . . only the [CPP logic] be invoked.” 856 F.3d at 1363 (ellipsis in original). We dismissed the patentee’s argument that these statements could “reason- ably be interpreted to mean that ‘only’ the CPP logic is re- quired to be invoked in those claims—not that the [conceptually distinct] CP logic is precluded from being in- voked.” Id. We found the patentee’s interpretation unrea- sonable given the context in which it made its concessions, which did “not change the plain meaning of [the] disavow- ing statements.” Id.5 So too here. Given the applicant’s

5 We applied prosecution history estoppel in Aylus, 856 F.3d at 1362–64. We do not apply that doctrine here, even as we employ the prosecution history to inform the claim construction. See Shire Dev., 787 F.3d at 1366 (dis- tinguishing between prosecution history statements that Case: 23-2173 Document: 58 Page: 12 Filed: 06/30/2025

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,” J.A. 1055, 1061–62 (emphasis added), the appropriate interpretation of the applicant’s representation that the claimed methods “do not require” agents other than brimonidine, J.A. 1053, 1082, is that its claimed methods preclude the use of such agents. Accordingly, we reverse the Board’s claim construction. We read the transition phrase “consisting essentially of” as used in claims 1 and 3 of the ’742 patent to exclude use of active ingredients other than brimonidine. B. Obviousness The Board’s erroneous claim construction infected its consideration of facts in its obviousness analysis. For ex- ample, the Board considered Dean and two other prior art references—Richard A. Norden, Effect of Prophylactic Brimonidine on Bleeding Complications and Flap Adher- ence after Laser in situ Keratomileusis, 18 J. REFRACTIVE SURGERY 468 (July/Aug. 2002) (“Norden”), and U.S. Patent No. 6,294,553 (“Gil”)—all of which involved compositions including active agents other than brimonidine, as teach- ing toward the use of brimonidine alone. J.A. 42, 54. The Board reasoned that “[a]lthough Norden and Gil may also teach the possibility of co-administering pain medication, steroids, and antibiotics, . . . the claims—when properly construed—do not preclude administering other drugs that do not materially affect the basic and novel characteristics of the claims.” J.A. 54. Under the appropriate construction of “consisting essentially of,” the claimed methods exclude

constitute “unmistakable disavowal” and those that “in- form the claim construction”). Notwithstanding, our rea- soning in Aylus is helpful to address Slayback’s argument. Case: 23-2173 Document: 58 Page: 13 Filed: 06/30/2025

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compositions that contain active agents other than brimonidine, undermining the Board’s conclusion. One final point bears discussion. As Slayback points out, the Board was careful to note that “even if the claim term ‘consisting essentially of’ were construed to preclude agents that reduced eye redness, Norden suggests that those additional agents do not affect brimonidine’s redness- reducing action and, would therefore, still satisfy the ‘con- sisting essentially of’ limitation.” J.A. 54 n.24. But this fallback position still relies upon a construction of “consist- ing essentially of” inconsistent with the prosecution his- tory. After all, Dean teaches co-administration of brimonidine with an active ingredient that does not reduce redness, brinzolamide. Dean col. 2 ll. 21–29, col. 3 ll. 26– 43. By amending the claims to include the phrase “consist- ing essentially of” to overcome Dean, the applicant inten- tionally sought to limit the claims to exclude applications with any other active agent, whether or not the agent ad- dresses eye redness. We do not prejudge whether the correct claim construc- tion permits the same factual findings or obviousness con- clusion. 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 ordi- nary 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 construc- tion, is to vacate the Board’s decision and remand the mat- ter.” Kaken Pharma. Co., Ltd. v. Iancu, 952 F.3d 1346, 1355 (Fed. Cir. 2020). CONCLUSION For the foregoing reasons, we reverse the Board’s claim construction, vacate the Board’s final written decision, and Case: 23-2173 Document: 58 Page: 14 Filed: 06/30/2025

remand the matter to the Board for further proceedings consistent with the construction provided above. Costs awarded to appellant. REVERSED IN PART, VACATED, AND REMANDED