Patent Docs

Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc. (Fed. Cir. 2025)

By Kevin E. Noonan --

Early last year, Aurobindo, one of the Defendants* in ANDA litigation against Merck, advanced the proposition that in cases where a patent had been reissued patent term extension ("PTE") under 35 U.S.C. § 156 should be calculated based on the grant date of the reissue patent and not of the "original" patent from which the reissue was obtained.  The Federal Circuit weighed in on this argument and found it unavailing (at least under the circumstances of these patents) in its Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc. decision handed down earlier this month.

The case arose in ANDA litigation between Plaintiffs Merck Sharp & Dohme B.V and Merck Sharp & Dohme LLC and a variety of Defendants over sugammadex (6-per-deoxy-6-per-(2-carboxyethyl)thio-γ-cyclodextrin), the active ingredient in Merck's Bridion drug, which is used to "assist[] patients' recovery of muscle function after a form of paralysis induced during surgery":

The patent at issue was U.S. Reissue Patent No. RE44,733** having claims expressly reciting the active ingredient and methods of use thereof without cancelling any of the claims of U.S. Patent No. 6,670,340 from which it originated.  Importantly, the '340 patent issued on December 30, 2003 and had an original expiration date of January 27, 2021.  The reissue patent was granted on January 28, 2014, 686 days before FDA approval on December 15, 2015, and Merck applied for patent term extension (PTE) on the reissue patent.  The USPTO granted to RE '733 the maximum PTE of five years (until January 27, 2026) due to nearly 12 years of FDA delay as calculated from the December 30, 2002 grant date of the '340 patent.

Defendants did not challenge Merck's assertion that their generic sugammadex would infringe but instead argued that the portion of the term extending after December 14, 2022 was improperly granted.  According to Defendants, the plain meaning interpretation of the statutory language of § 156(c) regarding proper calculation of PTE was from "the date the patent issued," and because the patent whose term was extended was RE '733, not the '340 patent, the proper length of PTE should be 686 days, not five years (or 1,825 days).  Their argument was that the PTO improperly interpreted the statute and they moved that the District Court determine the correct, shorter PTE term based on their statutory interpretation.

Merck argued against Aurobindo's position by relying on § 251 and § 252 (regarding the effects of reissue), and § 156 of the Patent Act, as well as provisions in the MPEP (amended close upon this litigation) at § 2766:

With respect to calculating the amount of extension to which the reissued patent is entitled to receive, so long as the original patent claimed the approved product and the reissued patent claims the approved product, the original patent grant date would be used to calculate the extension to which the reissued patent would be entitled.

(which constitutes current Office policy).  While the PTO's position was not dispositive, the District Court stated that "the Court may 'take notice of public reports and filings, such as those prepared by an administrative agency or pursuant to government regulation, to extent they have indicia of authenticity," citing In re Plum Baby Food Litig., No. 21-2417, 2022 WL 16552786, at *3 (D.N.J. Oct. 31, 2022) (citing Sturgeon v. Pharmerica Corp., 438 F. Supp. 3d 246, 259 (E.D. Pa. 2020)).

The District Court held that, "when read in its proper context alongside the provisions of the Patent Act addressing reissues," the use by the USPTO of the grant date of the '340 patent instead of the reissue RE '733 patent was proper "unambiguously," inter alia, because it did not create a conflict with either § 251 or § 252 regarding the effect and characteristics of reissue applications, was consistent with established USPTO practice, and did not contravene the policy choices evinced by Congress in passage of the Hatch-Waxman Act.  These policy provisions and considerations included that PTE established in the Act "provides the holders of patents on approved patented products with an extended term of protection under the patent to compensate for the delay in obtaining FDA approval," citing Merck & Co., Inc. v. Kessler, 80 F.3d 1543, 1547 (Fed. Cir. 1996).  The District Court opinion characterized Defendants' position as being "an untenable reading of the statutory scheme on the whole, creating conflict with various provisions of the Patent Act as well as unintended results."  And on policy grounds, the opinion asserted that Defendants' "plain meaning" of the statute "would undermine the purpose of the Hatch-Waxman Act, in contrast to Merck's interpretation, which aligns with it."  Finally, the opinion held that in the face of an ambiguity the District Court did not recognize but Defendants' contend has arisen in the statute, the District Court held that consistent PTO practice of using the grant date of the original patent deserves deference under Skidmore v. Swift & Co., 323 U.S. 134 (1944).  This appeal followed.

The Federal Circuit affirmed the District Court's determination that PTE was properly calculated from the grant date of the '340 patent, in an opinion by Judge Dyk joined by Judges Mayer and Reyna (a substantial percentage of which opinion was set forth in extensive footnotes).  The panel differed with the parties on the relevant statutory term, stating that it was not the word "issue" but rather the term "the patent" with regard to which patent's issue date should be used under § 156(c):

The term of a patent eligible for extension under subsection (a) shall be extended by the time equal to the regulatory review period for the approved product which period occurs after the date the patent is issued[.]  35 U.S.C. § 156(c) [emphasis added].

The Court agreed with the Patent Office that § 156(c) is ambiguous with regard to whether it is the original or the reissue patent that is "the patent."  Relying on the Supreme Court's opinion in Caraco Pharm. Lab'ys, Ltd. v. Novo Nordisk A/S, 566 U.S. 399, 412 (2012), the Court assessed the meaning of the term by the statutory text in the context in which it is used (wherein in Caraco the Court interpreted the meaning of 21 U.S.C. § 355(j)(5)(C)(ii)(I))) regarding the distinctions, if there were any, between "not an" and "not any" for counterclaims a generic drugmaker could raise in ANDA litigation).  In Caraco, the Court held that "[w]ithin [the Hatch-Waxman Act's] framework, the counterclaim naturally functions to challenge the brand's assertion of rights over whichever discrete use (or uses) the generic company wishes to pursue."  Here, the panel assessed the statutory meaning with regard to the "specific" context in which it was used and the "broader" context of the statute "as a whole," citing Robinson v. Shell Oil Co., 519 U.S. 337, 341 (1997); Dep't of Homeland Sec. v. MacLean, 574 U.S. 383, 393 (2015); and Centripetal Networks, Inc. v. Cisco Sys., Inc., 38 F.4th 1025, 1031 (Fed. Cir. 2022).  That "broader" context involved Congressional intent to "compensate pharmaceutical companies for the effective truncation of their patent terms while waiting for regulatory approval of new drug applications" according to the opinion, citing Glaxo, Inc. v. Novopharm, Ltd., 110 F.3d 1562, 1568 (Fed. Cir. 1997); Merck & Co. v. Hi-Tech Pharmacal Co., 482 F.3d 1317, 1323 (Fed. Cir. 2007); PhotoCure ASA v. Kappos, 603 F.3d 1372, 1374 (Fed. Cir. 2010); and Merck & Co. v. Kessler.

Accordingly, the opinion states that Congressional purpose was for PTE to be granted to patents ("and only those patents") that claimed drugs for which regulatory approval delayed the benefit of patent exclusivity.  Finding for Merck, the opinion states, satisfies this Congressional intent, whereas agreeing with Aurobindo would "den[y] Merck compensation for all but a small period of the delay."  "There is no reason why the Hatch-Waxman Act's purpose would be served by disabling extensions of the unexpired term solely based on a patent holder's decision to seek reissue, and Aurobindo offers none," according to the panel.

The opinion addresses Aurobindo's argument that it would be improper statutory construction to use the original patent grant date for calculating PTE term because that original '340 patent was "dead" upon reissue, citing case law interpreting the effects of reissue including Seattle Box Co. v. Indus. Crating & Packing, 731 F.2d 818, 827 (Fed. Cir. 1984), and others extending back into the 19th Century.  The distinction the Court drew in rejecting this argument was that the status of the original patent was "irrelevant" because "the reissued patent inherits 'the unexpired part of the term of the original patent'" under 35 U.S.C. § 251(a) and mentioning that this date is unambiguous (albeit stating in a footnote that the panel did not find the parties' reliance on this portion of the status to be helpful because "it does not shed any light on the meaning of the term "the patent'" ).  "[A] 'reissue patent does not simply replace an original patent nunc pro tunc'" according to the opinion, citing Intel Corp. v. Negotiated Data Sols., Inc., 703 F.3d 1360, 1364 (Fed. Cir. 2012).

The opinion holds further that the panel's conclusion is consistent with § 156(a) regarding the provision that "the term of a patent . . . shall be extended . . . from the original expiration date of the patent" (emphasis added) (stating this is "the most natural reading" of this statutory language to refer to the original patent) as well as § 154(a)(2) regarding calculation of patent term.

The opinion concludes by acknowledging that the panel's interpretation is also consistent with how the PTO has construed the statute (in the overwhelming number of cases in which the issue has arisen) and, in the face of Aurobindo's argument, expressly revised the MPEP in this regard (consistent with the Court's assessment of the Hatch-Waxman statutory scheme).

* The complete roster of ANDA defendants before the District Court in consolidated actions were Aurobindo Pharma USA, Inc.; Aurobindo Pharma, Ltd.; Eugia Pharma Specialties Ltd.; Gland Pharma Ltd.; Mankind Pharma Ltd.; Lifestar Pharma LLC; Mylan API US LLC; Mylan Pharmaceuticals Inc.; Mylan Inc.; Sandoz Inc.; LekcPharmaceuticals d.d.; Sun Pharmaceutical Industries, Inc.; Sun Pharmaceutical Industries Ltd.; Fresenius Kabi USA, LLC; Dr. Reddy's Laboratories, Inc.; Dr. Reddy's Laboratories, Ltd.; and USV Private Ltd.

** In a footnote, the panel noted that Merck filed its reissue application only after the Federal Circuit held that the addition of narrower claims could provide a proper basis for a reissue filing, in In re Tanaka, 640 F.3d 1246, 1251 (Fed. Cir. 2011).

Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc. (Fed. Cir. 2025)
Panel: Circuit Judges Dyk, Mayer, and Reyna
Opinion by Circuit Judge Dyk

Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)

Note: This post addresses a Federal Circuit decision that issued on March 14, 2025.  This appeal involved Plaintiff-Appellant Regeneron Pharmaceuticals, Inc., Defendant-Appellee Amgen Inc. (Case 24-2351).  At trial, this case also included Defendants Mylan Pharmaceuticals Inc.; Amgen USA, Inc.; Biocon Biologics Inc.; Celltrion, Inc.; Formycon AG; and Samsung Bioepsis Co.; as well as the Defendants-Appellee.

By Kevin E. Noonan --

The Defendants in biosimilar litigation involving Regeneron's EYLEA biologic drug got off the schneid last week (see "Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)," involving Defendant-Appellant Celltrion), when one of the Defendants (Amgen) obtained a decision affirming the District Court's denial of a preliminary injunction under the litigation provisions of the BPCIA.

As in the earlier appeals, Regeneron's injunction motion was based on infringement of U.S. Patent No. 11,084,865 by Amgen's EYLEA biosimilar (designated ABP 938) and the appeal was limited to the propriety of the District Court's denial thereof to Regeneron.  The basis for the District Court's denial was that Regeneron had not satisfied the burden for being granted a PI, that they were likely to succeed on the merits, and this determination was based on differences between Regeneron's approved formulation and Amgen's biosimilar version of it.

Regeneron's '865 patent recited in representative claim 1 the components of its formulation of its EYLEA biologic drug (aflibercept):

1.  A vial comprising an ophthalmic formulation suitable for intravitreal administration that comprises:
    a vascular endothelial growth factor (VEGF) antagonist,
    an organic co-solvent,
    a buffer,
    and a stabilizing agent,
    wherein said VEGF antagonist fusion protein is glycosylated and comprises amino acids 27-457 of SEQ ID NO:4; and
    wherein at least 98% of the VEGF antagonist is present in native conformation following storage at 5° C. for two months as measured by size exclusion chromatography.

(wherein the italicized limitations were important to the district court's denial of the PI).

The specific ingredients that differed in Amgen's formulation and Regeneron's patented formulation was the absence of the buffer recited in the '865 patent claims.  As produced by Amgen, the opinion explains that "Amgen had discovered a way to prepare and formulate the active ingredient, aflibercept, in a manner that eliminates the need for a separate buffer component—i.e., the aflibercept itself provides sufficient buffering capacity to stabilize the formulation."

The District Court construed the '865 patent claims to require that the aflibercept and buffer were separate components ("[w]here a claim lists elements separately, the clear implication of the claim language is that those elements are distinct components of the patented invention" (emphasis in the opinion)), relying on Becton, Dickinson & Co. v. Tyco Healthcare Grp., LP, 616 F.3d 1249, 1255 (Fed. Cir. 2010), for the principle that "[t]here can be no literal infringement where a claim requires two separate structures and one such structure is missing from an accused [product]."  But this is just a presumption, and the District Court then considered whether there was a basis to overcome the "clear implication" it applied in its initial claim construction (it did not).  In coming to this conclusion, the District Court assessed both intrinsic and extrinsic evidence, which the opinion asserts "only reinforced the implication that the 'VEGF antagonist' and 'buffer' must be separate components of the claimed formulation."  The Court was careful to note that while the term "buffer" had been construed in earlier litigation with co-defendant Formycon (see "Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)"), the issue on claim construction before the District Court here was different to the extent that the issues raised by Amgen in this litigation were different (if only because the Court was tasked to determine whether the buffer was a distinct component of the claimed formulation under the Court's Becton precedent).  The District Court decided that Becton controlled and Amgen had raised "a substantial question of noninfringement" that precluded Regeneron from demonstrating there was a likelihood of success on the merits for its infringement action.  On this basis, the District Court denied Regeneron's motion for a preliminary injunction and this appeal followed.

The Federal Circuit affirmed, in a decision by Judge Lourie joined by Chief Judge Moore and Judge Stark.  The panel relied not only on Becton but on follow-on cases coming to the same conclusions, including Kyocera Senco Indus. Tools Inc. v. Int'l Trade Comm'n, 22 F.4th 1369, 1382 (Fed. Cir. 2022), and Schindler Elevator Corp. v. Otis Elevator Co., 593 F.3d 1275, 1282 (Fed. Cir. 2010), on the principle that where a claim recites limitations separately the clear implication is that each recited limitation is a "distinct component" of the claimed invention.  Reviewing how the District Court applied this principle, the panel asserted that "claim 1 plainly recites a pharmaceutical formulation, comprising four separately listed components."  (The opinion in a footnote is careful to say that this is not a per se rule but raises a presumption that "may always be rebutted in the context of a particular patent," citing Google LLC v. Ecofactor, Inc., 92 F.4th 1049, 1058 (Fed. Cir. 2024).)

Here, the panel found that the plain meaning of the claims raises the "separate elements" presumption, and the opinion states that Regeneron's arguments to the contrary are "misplaced."  In particular, the Court rejected Regeneron's argument that the District Court's previous construction of the term "buffer" with regard to the PI granted against Defendant Formycon precluded Becton from applying here.  One basis for this decision was that the District Court in fact did apply established principles of claim construction, specifically Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc), to determine whether the elements are separate and that the buffer cannot be substituted with aflibercept.

In addition, the opinion states that the proper way to construe the claim is to determine "whether a formulation is claimed in a way that clearly implies it requires distinct components."  Regeneron's proposed construction analysis was directed to whether the term "VEGF antagonist" overlaps with the term "buffer," the opinion saying that these inquiries are independent of each other.  This assessment provided the Court another basis for rejecting Regeneron's argument that the prior construction from the Formycon decision should be binding.

Having concluded that the District Court properly applied Becton, the panel then turned to the evidence for whether Regeneron had rebutted the Becton presumption.  The panel's basis for deciding that they had not done so began with the determination that the '865 patent's claims and the specification supported the District Court's decision that the terms at issue were separate.  The opinion turned first to the claims, and the requirement for rebuttal that there was "evidence that shows that the impliedly distinct components, instead, can be satisfied by a single component" (the Court reminding that extrinsic evidence cannot alter the meaning found in the intrinsic evidence under Intel Corp. v. VIA Techs., 319 F.3d 1357, 1367 (Fed. Cir. 2003)).  The panel found the intrinsic evidence supported the District Court's determination that the two claim elements were separate under Becton.  This intrinsic evidence included the plain meaning of the claims, wherein all the '865 patent claims made the separateness distinction found by the District Court here, including the use of "different concentrations and different units of measurement" (emphasis in opinion).  Turning to the specification, the panel agreed with the District Court that "the specification of the '865 patent uniformly describes the 'VEGF antagonist' and the 'buffer' as separate and distinct components of the formulation" (providing examples and in particular the lack of any instances where the buffering capacity of aflibercept was taught as a substitute for buffers disclosed therein).  "'Nothing in the specification indicates' that the VEGF antagonist 'might' also satisfy the distinct 'buffer' component" according to the opinion.

Concluding their review of the intrinsic evidence considered by the District Court, the panel held that the lower court "correctly concluded that the only reasonable construction of the claim language, in light of the specification (which does nothing to rebut the presumption of separateness), is that the 'VEGF antagonist' and 'buffer' are distinct components."

The Federal Circuit then considered whether extrinsic evidence asserted by Regeneron rebutted the District Court's conclusions regarding Becton separateness of the recited elements, concluding that such evidence did not do so.  The panel noted that the District Court could have refused to consider extrinsic evidence under the circumstances arising here where the intrinsic evidence is "clear and unambiguous."  Having considered the extrinsic evidence presented by Regeneron "for completeness," the Federal Circuit found no clear error in the District Court's analysis that such evidence (consisting of expert testimony and citation of a prior art reference explaining the buffering capacity of polypeptides) did not rebut the Court's conclusions based on intrinsic evidence.

In sum, the Federal Circuit held that on this record there was "at least a substantial question of noninfringement" raised by Amgen's formulation differences and accordingly Regeneron had not established the requisite likelihood of success for the District Court to grant a preliminary injunction, citing as an example Genentech, Inc. v. Novo Nordisk A/S, 108 F.3d 1361, 1364 (Fed. Cir. 1997).

It remains to be seen, of course, whether Amgen will launch "at risk" (that risk being a finding of willful infringement under 35 U.S.C. § 284 and enhanced damages including attorneys' fees for doing so).  Under the circumstances behind the Federal Circuit's decision (including non-infringement) Amgen may decide it is worth the risk, which then raises the possibility that Regeneron will settle with Amgen or other defendants.  Those decisions will likely be based on considerations to which others outside the parties are unlikely to be privy and thus remain to be seen.

Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)
Panel: Chief Judge Moore and Circuit Judges Lourie and Stark
Opinion by Circuit Judge Lourie

DNA Genotek Inc. v. Spectrum Solutions LLC (Fed. Cir. 2025)

By Kevin E. Noonan --

Sometimes important contributions to innovation can come from the mundane rather than the extraordinary.  One (perhaps apocryphal) example comes from the story of the early development of television by Philo Farnsworth (the story, but not the apocrypha, is set forth in Evan Schwartz's book The Last Lone Inventor).  In this aspect of the tale, Farnsworth's brother-in-law, wanting to help but knowing nothing about electronics, learned to blow glass television tubes which he realized were necessary components of Farnsworth's invention.  This story comes to mind in a recent nonprecedential Federal Circuit decision regarding methods for isolating DNA from biological samples (such as sputum), found not to be infringed in DNA Genotek Inc. v. Spectrum Solutions LLC.

The case arose over U.S. Patent No. 10,619,187 that claimed a device for "preserving nucleic acids at room temperature for extended periods of time and for simplifying the isolation of nucleic acids" according to the opinion.  Claim 1 is set forth in the opinion as being representative:

A device for receiving and preserving nucleic acid in a biological sample, said device comprising:
    one or more walls defining a containment vessel having a top having an opening, and a closed bottom having a sample receiving area for holding said biological sample, said opening for receiving a liquid sample and for sealably receiving a sealing cap, said top having an opening for receiving a biological sample from the mouth of a user and further comprising at least one marking on said one or more walls which corresponds to a fluid volume in the sample receiving area;
    a reagent compartment having a barrier, said barrier sealing and containing reagents in said reagent compartment and capable of disestablishment to release said reagents into the sample receiving area;
    reagents in the reagent compartment for preserving nucleic acids potentially present in the sample wherein said reagents comprise a denaturing agent, a chelator and a buffer agent; and,
    the sealing cap, whereby the device is configured such that, when sealably closing said opening with said sealing cap, the barrier mechanically disestablishes to release said reagents to form a mixture of reagents and said biological sample wherein said buffering agent maintains a pH of said mixture equal to or above 5.0 to preserve nucleic acids potentially present in the sample.

As explained in the opinion, the device contains a first region for collecting a biological sample and a second region containing reagents for preserving the nucleic acid in the sample, with a barrier between the two regions; the device further comprises means for "disturbing the integrity" of the barrier so that the reagents in the second region and the biological sample is mixed.  Said second region also contains reagents for disrupting cells in the sample, "liberating" nucleic acids, solubilizing the lipid components, stripping [proteins] from DNA and digesting proteins therein," wherein the liberated nucleic acid is stably preserved at room temperature for later analysis.  Benefits of the claimed devices and methods for using them include eliminating the need for refrigeration between biological source and clinical or analytical laboratories.

Genotek sued Spectrum for infringement by the latter company's SDNA home saliva-collection kit for providing COVID-19 PCR testing.  The District Court granted Spectrum summary judgment of non-infringement based, according to the opinion, on construction of the term "reagent compartment."  This appeal followed.

The Federal Circuit affirmed, in an opinion by Judge Rodney Gillstrap,* sitting by designation, joined by Judges Lourie and Hughes.  The opinion focused on the District Court's construction of the term "reagent compartment" to mean "a region or section of the containment vessel" and that the '187 patent specification provided "clear guidance" regarding the location of that compartment in the device.  Specifically, the District Court construed the location of the reagent compartment to be within the containment vessel of the device.  This construction was supported by the prosecution history and the record of an inter partes review (IPR) proceeding in which the '187 patent was involved, according to the opinion.  In particular, the District Court held and the Federal Circuit affirmed that Genotek had intentionally deleted "any explicit disclosure of the reagent compartment being in the cap/lid," which evinced "a clear intent to limit the final scope of the invention to a device with the reagent compartment in the containment vessel."

Genotek argued on appeal that the District Court erred in its construction by importing limitations from the specification into the claims and that the plain language of the claims contained no limits on the location of the reagent compartment.  The Federal Circuit disagreed, citing several portions of the specification that consistently supported the District Court's construction and that these portions described the invention "as a whole" and not merely preferred embodiments, citing Regents of Univ. of Minnesota v. AGA Med. Corp., 717 F.3d 929, 936 (Fed. Cir. 2013), for the principle that "[w]hen a patent thus describes the features of the 'present invention' as a whole, this description limits the scope of the invention."

Equally unavailing was Genotek's argument that a provisional application from which the '187 patent claimed priority (and which was incorporated by reference) disclosed an embodiment where the reagent compartment was in the cap.  The panel found support in the prosecution history for the District Court's construction excluding the cap location for the reagent compartment.  According to the opinion, "[w]hen Genotek filed its non-provisional application, it intentionally deleted all references to that embodiment and included only embodiments with the reagent compartment in the container."  Such deletions have been held to "contribute[ to] understanding . . . the intended scope of the final application," citing MPHJ Tech. Invs., LLC v. Ricoh Ams. Corp., 847 F.3d 1363, 1369 (Fed. Cir. 2017), and thus the Federal Circuit agreed with the District Court that the properly construed claims of the '187 patent did not include embodiments where the reagent compartment was in the cap or lid.

Finally, Genotek objected to the District Court relying on distinctions between the device claimed in the '187 patent and prior art patents having a reagent compartment in the lid on the grounds that those statements were made with regard to preferred embodiments of the invention claimed in the '187 patent and not the invention as described a whole.  The panel noted that these statements were not dispositive but also understood the District Court's consideration of them as permissively "informing the district court's construction" of the claims to the device.

On these bases, the Federal Circuit affirmed the District Court's grant of summary judgment for Spectrum that their SDNA devices did not infringe the asserted claims of the '187 patent.

*Chief Judge of the U.S. District Court for the Eastern District of Texas.

DNA Genotek Inc. v. Spectrum Solutions LLC (Fed. Cir. 2025)
Nonprecedential disposition
Panel: Circuit Judges Lourie and Hughes, and Chief District Judge Gilstrap
Opinion by Chief District Judge Gilstrap

Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)

By Kevin E. Noonan --

Completing a recent jurisprudential "hat trick,"* the Federal Circuit affirmed a District Court grant of a preliminary injunction against a biosimilar applicant for Regeneron's EYLEA biologic drug in Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc.

As in the earlier appeals, the injunction was based on infringement by Celltrion's EYLEA biosimilar (designated CT-P42) of U.S. Patent No. 11,084,865 and the appeal limited to the propriety of the District Court granting a preliminary injunction (PI) to Regeneron (as well as some jurisdictional issues).  The opinion dealt summarily with those issues resolved in the earlier appeals, including whether the District of West Virginia could exercise jurisdiction against Celltrion, a Korean company.  Based on the Court's earlier decisions, in this opinion the panel held that Defendant-Appellant Celltrion had sufficient minimum contacts with the West Virginia forum to satisfy the jurisdictional standard in the Fourth Circuit.  The opinion also set forth the Court's determination that Regeneron satisfied its burden for being granted a PI, specifically that "(1) it is likely to succeed on the merits, (2) it is likely to suffer irreparable harm in the absence of preliminary relief, (3) the balance of equities tips in [its] favor, and (4) an injunction is in the public interest," citing BlephEx, LLC v. Myco Indus., Inc., 24 F.4th 1391, 1398 (Fed. Cir. 2022).  Once again, the panel held that questions of the nexus between Celltrion's sales of its EYLEA biosimilar and irreparable harm to Regeneron had been established in the earlier appeals and applied here.

The only issue recognized by the Federal Circuit to be before it in this appeal was whether Celltrion had raised a "substantial question of invalidity" against Regeneron's '865 patent, specifically on obviousness-type double patenting (ODP) grounds.  This challenge was based on Claim 5 of an earlier-issued Regeneron patent, U.S. Patent No. 9,340,594:

5.  [A pre-filled syringe suitable for intravitreal administration comprising a 1 mL luer glass syringe fitted with a plunger and a stable ophthalmic formulation of a vascular endothelial growth factor (VEGF) trap, which consists of (i) a receptor component consisting essentially of an immunoglobulin-like domain 2 of a first VEGF receptor and an immunoglobulin-like domain 3 of a second VEGF receptor, and (ii) a multimerizing component, wherein the stable ophthalmic formulation comprises:
    (a) 1-100 mg/ml a VEGF antagonist;
    (b) 0.01-5% of one or more organic co-solvent;
    (c) 5-40 mM of buffer; and
    (d) optionally comprising 1.0-7.5% of a stabilizing agent[,
    wherein the first VEGF receptor is Flt1, and the second VEGF receptor is Flk1 or Flt4, wherein the VEGF trap is stable for at least 4 months, and] wherein the VEGF trap consists of amino acids 27-457 of SEQ ID NO:4, wherein the stable ophthalmic formulation comprises 40 mg/mL of the VEGF trap, 10 mM phosphate, 40 mM NaCI, 0.03% polysorbate 20, 5% sucrose, at pH 6.2-6.4,

Wherein the italicized limitations were recited in independent claim 1 and intermediate dependent claims 2 through 4.

The District Court had held that the patentable distinctions between this claim and the claims of the '865 patent included "(1) the stability requirement that 'at least 98% of the VEGF antagonist is present in native conformation following storage at 5° C. for two months as measured by size exclusion chromatography'; (2) the requirement that aflibercept [the EYLEA active ingredient] is glycosylated; and (3) the use of a vial versus a pre-filled syringe."  The panel set forth in the opinion the specific distinctions between claim 5 and claim 4 of the '865 patent to be that claim 5 requires stability of the VEGF trap to be maintained for "at least 4 months," whereas claim 4 of the '865 patent recites that "at least 98% of the VEGF antagonist is present in native conformation following storage at 5° C. for two months as measured by size exclusion chromatography."  The District Court concluded (and the Federal Circuit agreed) that the 98% limitation was "neither inherent nor obvious" in what was claimed in claim 5 of the '594 patent.  Celltrion's specific challenges to this determination were the District Court's claim construction of the term "stable," wherein the District Court did not construe the term to mean the specific requirement recited in claim 4 of the '865 patent, instead holding that the term "stable" had "a broader meaning than the particular SEC measurements of aggregation and threshold levels (98%) to which Celltrion attempts to limit the term."  The District Court rejected Celltrion's assertions that such stability was sparsely reported in the '594 specification, finding "numerous descriptions of stability beyond simply 98% native conformation as measured by SEC."  The Federal Circuit agreed with the District Court's construction of the term "stable" and accordingly rejected Celltrion's argument that claim 5 of the '594 patent "expressly anticipates the stability limitations in the asserted claims [of the '865 patent]."

Celltrion's second challenge was that the "98% native conformation claim limitation" in claim 4 of the '865 patent was inherent in the stability limitation recited in claim 5 of the '594 patent.  According to the District Court:

Celltrion's reliance on the native conformation data in Examples 3 and 4 [of the '594 patent] is legally inadequate to prove inherency.  That the practice of '594 claim 5 sometimes results in 98% native conformation is insufficient; inherency requires that the 98% native conformation limitation be present necessarily, not just possibly or probably [emphasis in original].

The Federal Circuit rejected as a contradiction of the plain meaning of the claims Celltrion's arguments that the skilled artisan would have interpreted the stability limitations of "at least 98% [to] define[] a rate of aggregation over a particular time, under particular conditions" because the claim recites that the 98% of the VEGF antagonist be "present in native conformation following storage . . . for two months" which in no way implicates calculation of a rate of aggregation as argued by Celltrion.

Third, the panel rejected Celltrion's argument of error by the District Court in deciding that the 98% native conformation limitation was not obvious, which was based on expert testimony.

Finally, the Court briefly turned to Celltrion's arguments regarding the glycosylation limitations, which the District Court had rejected based on the extent of glycosylation of aflibercept.  Celltrion argued that claim 5 of the '594 patent anticipated the asserted claims of the '865 patent because it covers "a genus with only two species – glycosylated and non-glycosylated."  The District Court held that, in view of the "five distinct glycosylation sites," "there are at least thirty possible glycosylated forms of aflibercept . . . in addition to the nonglycosylated form."  In view of the Court's determination that "one patentably distinct limitation [i.e., the stability limitation] is enough" to support the District Court's rejection of Celltrion's assertion of invalidity for ODP, and Celltrion's opportunity to pursue this invalidity argument at trial, the Court held that there was no need to address the issue here and affirmed the District Court's determination that Celltrion had not rebutted Regeneron's evidence of there being a likelihood of success on the merits to support its motion for a preliminary injunction.

Trial against this defendant, and the remaining defendants** is ongoing.

* See "Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)" and "Regeneron Pharmaceuticals, Inc  v. Formycon AG"
** In addition to Mylan Pharmaceuticals Inc. and Formycon AG these include Amgen USA, Biocon Biologic Inc., Samsung Bioepsis Co. Ltd, and Amgen Inc.

Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. (Fed. Cir. 2025)
Nonprecedential disposition
Panel: Circuit Judges Prost, Wallach, and Chen
Opinion by Circuit Judge Prost

 

Five Years Ago Today . . .

By Donald Zuhn –-

On March 11, 2020, World Health Organization Director-General Tedros Adhanom declared that the COVID-19 outbreak "can be characterized as a pandemic," and cautioned that the WHO has "rung the alarm bell loud and clear."  At the time of the announcement, the WHO noted that there were 118,000 cases reported globally in 114 countries.  As of February 13, 2025, when it issued its most recent report, WHO reported 777,291,317 cases globally, regrettably resulting in 7,083,769 deaths.  When the Director-General declared that the COVID-19 outbreak had become a pandemic, he noted that "[t]his is not just a public health crisis, it is a crisis that will touch every sector -- so every sector and every individual must be involved in the fight."  The WHO, which declared the COVID-19 outbreak a public health emergency of international concern (PHEIC) on January 30, 2020, ended the PHEIC on May 5, 2023; whether the outbreak remains a pandemic is the subject of some debate.  According to the Wikipedia page on the COVID-19 pandemic, it ranks as the fifth-deadliest pandemic or epidemic in history.

The COVID-19 pandemic had a profound impact on patent practice, as it had for nearly every single industry.  The pandemic changed how most of us work, where most of us work, and what many of us work on.  Two years after the pandemic was declared, the Pharmaceutical Research and Manufacturers of America (PhRMA) noted that "[p]erhaps more than any other time in history, society is seeing and benefiting from the innovation supported by intellectual property."  For example, the U.S. Food and Drug Administration granted an Emergency Use Authorization (EUA) for Gilead Sciences' remdesivir 123 days after the virus was first detected in a patient sample, granted an EUA for convalescent plasma 237 days after the virus was first detected, granted an EUA for Eli Lilly's antibody treatment 315 days after the virus was first detected, granted an EUA for the Pfizer-BioNTech vaccine 347 days after the virus was first detected (and then followed with two more EUAs for Moderna's vaccine and Johnson & Johnson's vaccine), and approved Pfizer's antiviral PAXLOVID 723 days after the virus was first detected.

Five years after the WHO declared that the COVID-19 outbreak had become a pandemic, its effects on the global economy and global politics are still being felt.

Additional information regarding the COVID-19 pandemic that has appeared on Patent Docs can be found here:

• "International Trade Commission Issues Report of COVID-19 IP Waiver," November 8, 2023
• ""Zero Draft" of WHO CA+ Released," February 7, 2023
• "WTO TRIPS Council Recommends That General Council Extend Waiver Deadline," December 18, 2022
• "Nine Countries Seek Extension of WTO Waiver to COVID-19 Therapeutics and Diagnostics," December 11, 2022
• "Status of Proposed Extension of TRIPS Waiver in WTO," December 8, 2022
• "C4IP Presents Webinar on COVID Waiver Extension," December 5, 2022
• "Moderna Sues Pfizer and BioNTech over mRNA Vaccine Technology," August 31, 2022
• "U.S. Trade Representative Releases 2022 Special 301 Report," April 28, 2022
• "U.S. Chamber of Commerce Supports House and Senate Legislation Prohibiting Biden Administration from Negotiating Modifications to WTO TRIPS Agreement Without Congressional Authorization," April 24, 2022
• "Senators Send Letter to Commerce Secretary Regarding WTO Waiver Compromise," March 28, 2022
• "The Proposed WTO IP Waiver: Just What Good Can It Do? -- An Analysis," March 24, 2022
• "IP Associations "Concerned" by Reports of TRIPS Waiver Compromise," March 24, 2022
• "More on Leaked WTO COVID-19 Vaccine Patent Waiver Compromise," March 21, 2022
• "Compromise Reportedly Reached on COVID-19 Vaccine Patent Waiver," March 16, 2022
• "Sen. Tillis Writes to U.S. Trade Representative (Again) Regarding TRIPS Waiver," December 12, 2021
• "U.S. Trade Representative Responds to Letters from Senators Regarding TRIPS Waiver," November 14, 2021
• "U.S. Chamber of Commerce Urges Administration to "Double Down" on Global Vaccine Distribution," November 3, 2021
• "Is This the WTO Waiver End Game?" July 25, 2021
• "BIO Declaration on Global Access to COVID-19 Vaccines and Treatments and Role of IP," June 24, 2021
• "GOP Legislators Write in Opposition to Proposed TRIPS Waiver," May 16, 2021
• "Science Does Not Support the Latest COVID Hysteria," May 13, 2021
• "Population of Patents at Risk from Proposed WTO Patent Waiver," May 12, 2021
• "Sen. Daines Urges Biden Administration to Withdraw Support for COVID-19 IP Waiver," May 12, 2021
• "Pfizer CEO Pens Open Letter on COVID-19 Vaccine IP Waiver," May 10, 2021
• "If the Devil of the WTO IP Waiver Is in the Details, What Are the Details?" May 9, 2021
• "The Road to Hell Is Paved with What Everybody Knows," May 6, 2021
• "BIO & IPO Issue Statements on Biden Administration's Support for Proposed WTO Waiver," May 6, 2021
• "Biden Administration Supports Waiver of IP Protection for COVID-19 Vaccines," May 5, 2021
• "Suspending IP Protection: A Bad Idea (That Won't Achieve Its Desired Goals)," April 26, 2021
• "Sen. Tillis Asks Biden Administration to Oppose WTO Waiver Proposal," April 21, 2021
• "IP Organizations Support Continued Opposition to Waiver Proposal," April 5, 2021
• "Evolution of SARS-CoV-2 from Bat to Human Pathogen," March 31, 2021
• "Industry Coalition Supports Continued Efforts to Oppose Waiver Proposal," March 29, 2021
• "Neanderthal Ancestors Can Be Human Guardian Angels for COVID Infection, Too," March 18, 2021
• "BIO and PhRMA Urge Biden Administration to Oppose Proposed WTO TRIPS Waiver," March 11, 2021
• "Do mRNA-based COVID Vaccines Have an Achilles Heel?" January 26, 2021
• "Going from Bad to Worse: Evidence for Neuro-COVID Infections," January 17, 2021
• "USPTO Provides Update on COVID-19 Prioritized Examination Pilot Program," January 3, 2021

President Nominates John Squires to be Next USPTO Director

By Donald Zuhn –-

On Monday, President Trump's nomination for Under Secretary of Commerce for Intellectual Property and Director of the U.S. Patent and Trademark Office, John A. Squires, was submitted to the U.S. Senate for confirmation.  Mr. Squires is currently a partner at Dilworth Paxson LLP in New York.  His Dilworth Paxson biography indicates that Mr. Squires' practice area is litigation, that he is a graduate of the University of Pittsburgh School of Law, and that he has a B.S. in Chemistry from Bucknell University.

Mr. Squires' firm biography also indicates that he is "globally recognized as one of the world's leading attorneys in advanced technologies and intellectual property, including AI, Blockchain, Fintech/Regtech Cybersecurity, and Risk," "led the creation of the United States' first patent asset-backed finance platform for one of the world’s leading funds," and "co-founded, launched, and sits on the board of numerous IP and risk-related businesses, including Regulatory DataCorp, the Risk Assistance Network + Exchange (RANE), and FinClusive."  His biography further notes that in response to the 9/11 attacks, he helped establish an anti-money laundering, anti-terrorist financing information, and analytics business.

According to his LinkedIn page, Mr. Squires served as Chief IP Counsel for Goldman Sachs from 2000 to 2009, was co-chair of the IP Group at Chadbourne & Parke LLP from 2009 to 2012, was a partner at Perkins Coie LLP from 2012 to 2016, has been a Strategic Advisor to the Risk Assistance Network + Exchange (RANE) since 2013, has been a Board Member and Corporate Secretary and Co-Founder of FinClusive since 2016, and has been a partner at Dilworth Paxson since 2017.

If confirmed, Mr. Squires would become the twelfth person to serve as Director or Acting Director (or perform the duties of the Director) since July of 2004.  Three Directors have been nominated by new incoming Administrations over that time:  David Kappos, who served as Director from August 13, 2009 to January 31, 2013; Andrei Iancu, who served as Director from February 8, 2018 to January 19, 2021; and Kathi Vidal, who served as Director from April 13, 2022 to December 16, 2024.  Given yesterday's nomination, Mr. Squires, once confirmed, could begin his tenure as Director earlier than two of those three former Directors.

Additional information regarding Mr. Squires' nomination can be found at IPWatchdog, Reuters, and Bloomberg Law.

Immunogen, Inc. v. Stewart (Fed. Cir. 2025)

By Kevin E. Noonan --

After creating something of a frisson due to the apprehension that the Federal Circuit might be convinced to re-evaluate whether it was a necessary element for establishing obviousness for the skilled artisan to have had a reasonable expectation of success (see "U.S. Patent Office Challenges the Reasonable Expectation of Success Prong of Obviousness Law Precedent in Immunogen v. Vidal")*, cooler (or perhaps more conventionally doctrinal) heads prevailed in the Court's recent decision in Immunogen, Inc. v. Stewart (albeit by ignoring the argument while nevertheless affirming the District Court's obviousness determination).

The technology at issue (in U.S. Patent Application Publication No. US 2015/0132323 A1) was directed to methods for treating ovarian and peritoneal cancer patients using an antibody-drug conjugate ("ADC") called IMGN853 (mirvetuximab soravtansine).  The molecule is a conjugate of "an antibody known as 'huMov19,' . . . a toxic maytansinoid payload known as 'DM4,' and . . . a charged chemical linker known as 'charged sulfo-SPDB linker.'"  However, as set forth in the opinion, the drug had the deleterious side-effect that it was capable of causing ocular toxicity, including keratitis and blurred vision; this side effect was not recognized in the prior art.  The methods recited in the rejected claims specify that the administered dose be calculated from the adjusted ideal body weight (or "AIBW"), which will vary from patient to patient and will also likely vary for the same patient during the course of the treatment; claim 1 is set forth as being representative (wherein the limitation in italics was at issue here):

1.  A method for treating a human patient having an FOLR1-expressing ovarian cancer or cancer of the peritoneum comprising administering to the patient an immunoconjugate which binds to FOLR1 polypeptide,
    wherein the immunoconjugate comprises an antibody or antigen-binding fragment thereof that comprises the variable light chain (VL) complementarity determining region (CDR)-1, VL CDR-2, VL CDR-3, variable heavy chain (VH) CDR-1, VH CDR-2, and VH CDR-3 of SEQ ID NOs: 6-9, 11, and 12, respectively, and a  maytansinoid, and
    wherein the immunoconjugate is administered at a dose of 6 milligrams (mg) per kilogram (kg) of adjusted ideal body weight (AIBW) of the patient.

The standard for determining the amount of ADC to be administered is different from the total body weight (or "TBW") standard used in the prior art.  Using the TBW standard led to an unacceptable level of ocular toxicity which was not recognized in the art, and such ocular toxicity was significantly alleviated if this drug was dosed using the AIBW approach.

This is the second time Immunogen has come before the Federal Circuit to appeal rejections for indefiniteness and obviousness from the Patent Office for the '809 application.  In the first case, Immunogen challenged the rejections by filing suit under 35 U.S.C. § 145 and the District Court held for the Office on summary judgment.  The Federal Circuit (before a panel of Judges Newman, Stoll, and Clevenger) vacated and remanded; see "ImmunoGen, Inc. v. Hirshfeld").  With respect to obviousness, the Court's prior judgment was based on factual errors appreciated by the panel, finding that there were genuine issues of material fact in dispute mandating reconsideration by the District Court on remand.

Here, the Office once again prevailed at the District Court on Immunogen's § 145 action and once again Immunogen appealed to the Federal Circuit.  Once again, the District Court found the claims to be invalid for indefiniteness under § 112(b) and obviousness under § 103 (as well as obviousness-type double patenting, which was not at issue in the appeal).  The indefiniteness judgment was based on the specification "fail[ing] to define AIBW . . . anywhere in its claims" which was significant because the District Court also found that "there are various formulas for AIBW from which a person of ordinary skill in the art could have chosen."  The District Court also held that method of treatment claims using this drug were obvious in view of Immunogen's earlier disclosure of IMGN853 administration using total body weight (TBW) dosing and AIBW dosing for other drugs.  The specific bases for the District Court's obviousness determination set forth in the opinion was that "(i) the problem of ocular toxicity was known, (ii) skilled artisans understood that changing the dose was a possible solution for adverse side effects such as ocular toxicity, and (iii) the prior art disclosed AIBW dosing as a potential means to eliminate or ameliorate ocular toxicity."

The Federal Circuit affirmed, in an opinion by Judge Lourie, joined by Judges Dyk and Prost.  Regarding obviousness, the panel addressed Immunogen's argument that the District Court erred in its motivation to combine analysis.  According to Immunogen, the ocular toxicity motivating use of AIBW was not recognized in the art.  The Federal Circuit made the distinction that, while the solution to an unappreciated problem may be non-obvious "it does not follow that a claimed solution to an unknown problem is necessarily non-obvious" (emphasis in opinion).  According to the Court, what matters (under KSR Int'l Co. v. Teleflex Inc) is "the objective reach of the claim," i.e., "any need or problem known in the field of endeavor at the time of invention and addressed by the patent can provide a reason for combining the elements in the manner claimed," citing KSR, Janssen Pharms., Inc. v. Teva Pharms. USA, Inc., 97 F.4th 915, 929 (Fed. Cir. 2024), and Alcon Rsch., Ltd. v. Apotex Inc., 687 F.3d 1362, 1368 (Fed. Cir. 2012).  Accordingly, the opinion rejected Immunogen's argument because specific problems not recognized in the prior art do not mandate a finding of non-obviousness under KSR in the Court's view.  The opinion credits the District Court's determination that ocular toxicity was a "well-known adverse event in administration of immunoconjugates" comprising the maytansinoid component of IMGN853 (despite such effects not being seen in experimental animals).  Lack of knowledge does not prevent the skilled worker from being motivated to monitor for the unknown side effects according to the panel (which seems to smack at least a little of hindsight and special pleading).

The panel similarly rejected Immunogen's contentions that the specific use of AIBW in place of TBW would not have been obvious.  The District Court held that the skilled worker would have been motivated to try to solve the unrecognized ocular toxicity problem by using alternative methods for determining an effective dose known in the art (as was AIBW, known for avoiding ocular toxicity in drugs such as antibiotics, radioimmunoconjugates, and other anticancer drugs).  These facts formed the bases for the District Court in finding motivation for using AIBW as a dosing metric and the Federal Circuit found no clear error in this determination.  This decision was based on the panel's apprehension that, while not having been used to determining dosing for an ADC in the prior art, it "would have been within the range of knowledge of a person of ordinary skill in the art when confronted with dosing-induced toxicities, and particularly when confronted with dosing-induced ocular toxicity" (despite ocular toxicity for IMGN853 not being appreciated in the prior art).  The District Court (and the Federal Circuit) supplemented the art with Immunogen's own U.S. Patent Application Publication No. 2012/0282282 (ImmunoGen's own publication) that disclosed both IMGN853 and ocular toxicity.

Turning to the question of the specific dose (6 mg/kg) set forth in the claims, a seemingly important factor (for both the District Court and the Federal Circuit) was that "patients who weigh exactly their ideal body weight receive an identical dose of IMGN853 when dosed based on either AIBW or TBW."  There was specific disclosure in the art for administering "about" 6 mgkg (5 mg/kg or 6 mg/kg) of IMGN853.  In addition to these facts, the panel was concerned that in finding the claimed method non-obvious the Court could be "prevent[ing] doctors from practicing what is already disclosed in the prior art for patients at their ideal body weight" (which would occur even if the doctor did not know the amount to be administered using AIBW dosing).  This outcome should be sufficient to support the District Court's obviousness conclusion according to the opinion, citing PAR Pharm., Inc. v. TWI Pharms., Inc., 773 F.3d 1186, 1196 (Fed. Cir. 2014), quoting In re Oelrich, 666 F.2d 578, 581 (CCPA 1981).

Finally, turning to the question of reasonable expectation of success that the Patent and Trademark Office had argued should not be a consideration in this and similar cases, Immunogen's argument was focused on the lack of such reasonable expectation for the 6 mg/kg dose.  The absence of any limitation in the claims relating to avoiding ocular toxicity formed the basis for the panel to reject this argument; specifically what the District Court was required to do (and did under these circumstances according to the Court) was to determine whether "a person of ordinary skill in the art would have had a reasonable expectation that dosing a human at 6 mg/kg AIBW would have been effective in treating ovarian and peritoneal cancers," citing Teva Pharms. USA, Inc. v. Corcept Therapeutics, Inc., 18 F.4th 1377, 1381 (Fed. Cir. 2021).  The Court again relied on this dosage being the same using AIBW as was found using TBW to provide the requisite reasonable expectation of success to support the District Court's obviousness holding.

For Immunogen, the outcome was the same as in the earlier appeal, but for the rest of us some comfort can be taken that the Court did not take the USPTO's suggestion that it fundamentally rewrite how obviousness is properly determined.

* In its briefing, the Office took the position that claims to methods for administering drugs (particularly ones subject to independent patent protection) that rely, as do Immunogen's, on dosing regimens are (almost per se) obvious.  This position included an attack on Immunogen's argument that the claims were non-obvious because the unpredictability of these claims would preclude the skilled worker from having the requisite reasonable expectation of success.  The Office decried this argument, asserting that "ImmunoGen should not be able to use 'unpredictability' as talisman for getting a patent.  Otherwise, drug companies may be able to get patent protection on any follow-on pharmaceutical development no matter how obvious to try - because the result of pharmaceutical experiments are nearly always somewhat unpredictable."

Immunogen, Inc. v. Stewart (Fed. Cir. 2025)
Panel: Circuit Judges Lourie, Dyk, and Prost
Opinion by Circuit Judge Lourie