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By: Maxwell H. Terry, Volume 107 Staff Member

While the technical subject matter of a patent can grow inordinately complex, the predominant theory underlying patent law is relatively straightforward. In exchange for the right to exclude others from making, using, or selling the invention claimed by a patent, the inventor must disclose the invention to the public.[1] While the inventor enjoys a limited monopoly over the invention,[2] the published patent inures to the benefit of the public through the dissemination of knowledge.[3] Such disclosure promotes further innovation by empowering subsequent inventors to “stand on the shoulders of giants” and build upon the foundation established by earlier inventors.[4] This quid pro quo is largely embodied in § 112(a) of the Patent Act, which defines patent law’s “enablement requirement.”[5] Section 112(a), however, says very little about exactly how much disclosure is required to obtain a patent. The Supreme Court granted certiorari in Amgen Inc. v. Sanofi, Aventisub LLC to clarify the scope of disclosure necessary to satisfy the patent bargain,[6] the outcome of which could immensely heighten a patentee’s disclosure obligation.


Pertinently, § 112(a) states that a patent specification must contain a written description of the invention in such exact terms as to “enable any person skilled in the art” [7] to make and use the same.[8] This disclosure obligation is dubbed “enablement.” The Federal Circuit has consistently held that a patent must enable a person skilled in the art to practice the claimed invention without “undue experimentation.”[9] In determining what constitutes undue experimentation, the Federal Circuit typically applies the Wands factors,[10] which posit that the scope of a patent’s disclosure should be roughly commensurate with the scope of the claimed invention.[11]

Enablement issues are most prominent when a patent claims a broad genus of subject matter.[12] Traditionally, the Federal Circuit required the disclosure of a representative number of species within a genus rather than of the genus in its entirety.[13] Recently, however, the Federal Circuit has stated that “[a] claim is not enabled when, at the ‘effective filing date of the patent, one of ordinary skill in the art could not practice their full scope without undue experimentation.’”[14] Thus, if the Federal Circuit’s language is taken to its logical extreme, a patent must disclose each operable embodiment of a genus to satisfy the enablement standard if undue experimentation would be required to reach a specific species within it.[15]

While broad claims should, in theory, be accompanied by equally broad disclosures, the “full scope” enablement standard may be impossible to meet. Take chemistry, for example, where sequences of compounds can interact in millions of different ways. Testing and adequately disclosing such a plethora of species would be difficult or impossible within the time and resource constraints of a company.[16] Further, § 112(a) itself makes no mention of a “full scope” enablement standard.[17]


The pivotal question in Amgen Inc. v. Sanofi, Aventisub LLC  is whether § 112(a) requires a patent specification to enable those skilled in the art to merely “make or use” the invention, or whether it must instead enable the “full scope” of claimed embodiments without undue experimentation.[18] Answering the latter in the affirmative would mean a patent must enable a person of ordinary skill to make and identify all—or nearly all—embodiments of the invention without substantial “time and effort.”[19]

At issue in Amgen are two patents directed to monoclonal antibodies that function to bind with amino acids on a protein (PCSK9) to block binding with low-density lipoprotein (LDL) cholesterol receptors which regulate LDL cholesterol, thereby helping prevent heart disease.[20] The patents share a common specification, which discloses twenty-six antibodies that can bind to one or more of fifteen amino acids of the PCSK9 protein.[21] However, rather than claim the antibodies themselves, the patents claim the functionality of the antibodies.[22] Thus, though the patent describes twenty-six specific antibodies, there are potentially millions of antibodies which fit within the bounds of the claim.[23]

The Federal Circuit held that Plaintiff Amgen’s patents were invalid for lack of enablement.[24] Applying the Wands factors, though the type of experimentation would be common in the art, the sheer amount of experimentation required to enable the “full scope” of the claims constituted undue experimentation.[25] While this outcome seems reasonable, § 112(a) never previously required a comprehensive listing of species within a genus.[26] Many commentators, including Amgen, have argued that the “undue experimentation” requirement has historically been directed at the type of experimentation rather than the quantity.[27] According to this argument, enablement would be met if the experimentation required is routine in the relevant industry so long as the patent enables a subset of species representative of the entire genus.[28]


There are two potential outcomes to Amgen. First, the Supreme Court could hem closely to the language of § 112(a) and reject the “full scope” approach to enablement for unreasonably constraining the statute. This would likely rein in application of the Wands factors to permit patents which disclose a representative number of species but fall short of disclosing a genus in its entirety. Some amicus briefs have argued that such an outcome is not only warranted, but is the exact conclusion the Federal Circuit reached below.[29] The American Intellectual Property Law Association, for example, stated Amgen “did not rewrite or create a new test for determining the sufficiency of an enablement disclosure” and that § 112(a) “does not require disclosure of ‘all’ possible embodiments to enable genus claims.”[30] Under this reasoning, the Federal Circuit’s “full scope” standard is not a new test, but rather a familiar one presented through different terminology.

Second, the Supreme Court could accept a “full scope” enablement reading under the statute, thereby heightening the level of disclosure required to obtain a patent. If the higher enablement standard is approved, patentees might adapt their drafting strategy to include more limited claims. While this would increase certainty for the patentee, it would restrict the patentee’s exclusionary rights and stifle the dissemination of information. Furthermore, if it is too expensive to enable each embodiment in a genus claim, and if a narrow patent would not be desirable, then there could be a net loss in innovation.

Finally, the outcome of Amgen could affect several industries. There are many terms of art which exist in other technological fields that could introduce uncertainty. For example, if a software invention requires implementation on a generic “processor,” then perhaps under the “full scope” enablement standard the inventor must literally list each type of processor which would work or not.[31] Though pedantic, this example goes to show the absurd results of a literal “full scope” enablement standard. While this example is a far cry from the millions of antibodies at issue in Amgen, the Federal Circuit certainly has not established a clear line.


[1] See 35 U.S.C. § 112(a); J.E.M. Ag Supply, Inc. v. Pioneer Hi-Bred Intern., Inc., 534 U.S. 124, 142 (2001) (“The disclosure required by the Patent Act is ‘the quid pro quo of the right to exclude.’”) (citation omitted).

[2] The maximum term of a patent is generally twenty years from the date of application. 35 U.S.C. § 154(a)(2).

[3] S. Comm. on the Judiciary, 90th Cong., Rep. of the President’s Commission on the Patent System 2 (1966) (“[B]y affording protection, a patent system encourages early public disclosure of technological information, some of which might otherwise be kept secret.”).

[4] See Suzanne Scotchmer, Standing on the Shoulders of Giants: Cumulative Research and the Patent Law, 5 J. Econ. Persps. 29, 29 (1991) (“[A]lmost all technical progress builds on a foundation provided by earlier inventors.”).

[5] 35 U.S.C. § 112.

[6] Amgen Inc. v. Sanofi, Aventisub LLC, 987 F.3d 1080 (Fed. Cir. 2021), petition for cert. granted in part, 214 L. Ed. 2d 196 (Nov. 4, 2022). Oral argument is scheduled for March 27, 2023. Eileen McDermott, Amici for Sanofi Add Their Two Cents as Amgen’s Day in High Court Approaches, IPWatchdog (Feb. 12, 2023), [].

[7] The mythological “person having ordinary skill in the art” is a term used throughout the Patent Act to refer to a hypothetical person of reasonable skill and knowledge in the relevant field. See, e.g., Jonathan J. Darrow, Note, The Neglected Dimension of Patent Law’s PHOSITA Standard, 23 Harv. J.L. & Tech. 227 (2009).

[8] 35 U.S.C. § 112(a).

[9] See In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988) (“Enablement is not precluded by the necessity for some experimentation . . . . However, experimentation needed to practice the invention must not be undue experimentation.”) (emphasis added).

[10] See id. (“They include (1) the quantity of experimentation necessary, (2) the amount of direction or guidance presented, (3) the presence or absence of working examples, (4) the nature of the invention, (5) the state of the prior art, (6) the relative skill of those in the art, (7) the predictability or unpredictability of the art, and (8) the breadth of the claims.”).

[11] See Crown Operations Int’l, Ltd. v. Solutia Inc., 289 F.3d 1367, 1379 (Fed. Cir. 2002) (“The purpose of the enablement requirement is to ‘ensure[ ] that the public knowledge is enriched by the patent specification to a degree at least commensurate with the scope of the claims.’”) (citation omitted).

[12] “Genus” claims are typically broad claims that “cover[] a group of structurally related products that incorporate the basic advantage of the patented invention.” Dmitry Karshtedt, Mark A. Lemley & Sean B. Seymore, The Death of the Genus Claim, 35 Harv. J.L. & Tech. 1, 3 (2021). If the genus is “clothing,” then a “species” would be “socks.”

[13] D Three Enters. v. SunModo Corp., 890 F.3d 1042, 1047 (Fed. Cir. 2018) (“[T]o claim a genus, a patentee must disclose ‘a representative number of species falling within the scope of the genus or structural features common to the members of the genus so that [a PHOSITA] can visualize or recognize the members of the genus.’”) (citation omitted).

[14] See Idenix Pharms. L.L.C. v. Gilead Sciences Inc., 941 F.3d 1149, 1154 (Fed. Cir. 2019) (emphasis added) (quoting Wyeth & Cordis Corp. v. Abbott Labs., 720 F.3d 1380, 1384 (Fed. Cir. 2013)).

[15] Id.

[16] See Karshtedt et al., supra note 12, at 63 (“No matter how much testing the patentee does, there will always be untested species, and because those species aren’t tested, the PHOSITA won’t know whether they are properly included in the genus, so the claim would fail . . . .”).

[17] See 35 U.S.C. § 112(a).

[18] Brief for the United States as Amicus Curiae at 1, Amgen Inc. v. Sanofi, Aventisub LLC, 987 F.3d 1080 (Fed. Cir. 2021), petition for cert. granted in part, 214 L. Ed. 2d 196 (Nov. 4, 2022).

[19] See id. at 6 (stating lower courts looked at whether experimentation necessary to enable full scope of inventions took “substantial amount[s] of time and effort”).

[20] See Amgen, 987 F.3d at 1083–84 (describing patents at issue).

[21] Id. at 1083.

[22] See id. (“The claimed antibodies are defined by their function . . . .”).

[23] Id. at 1085 (“Sanofi contends that there are millions of antibody candidates within the scope of the claims.”).

[24] Id. at 1088.

[25] Id.

[26] See Karshtedt et al., supra note 12, at 62 (“In effect, courts have converted the full-scope enablement inquiry from ‘did I teach you enough such that you can make use of the full scope of the invention?’ to ‘did I give you enough information to assess the full list of what works and what doesn’t without undue experimentation?’”).

[27] See Brief for Petitioners at 26, Amgen, 987 F.3d 1080 (No. 21-757) (“Instead of focusing on the depth of information the patents provided, and whether skilled artisans could ‘produce from it alone a practically operative invention,’ . . . the court turned enablement into a numbers game.”).

[28] Id. at 20 (“The Federal Circuit’s test fundamentally alters the basic patent bargain, denying an inventor a patent based sheerly on the number of possible embodiments, even if the patent’s disclosures teach the world how to ‘make and use’ the claimed invention.”).

[29] See, e.g., Brief for the American Intellectual Property Law Association as Amicus Curiae Suggesting Affirmance at 2, Amgen, 987 F.3d 1080 (No. 21-757) (“The Federal Circuit’s patent invalidity decision in this case was based on established law for judging the enablement of genus claims that use functional language.”).

[30] Id.

[31] Example derived from Thomas J. Campbell, Jr., SCOTUS Takes on Scope of Enablement Inquiry in Amgen v. Sanofi: Implications for Pharma/Biotech and Beyond, IPWatchdog (Nov. 13, 2022), [].