Amgen Inc. v. Sanofi

LII note: The U.S. Supreme Court has now decided Amgen Inc. v. Sanofi .


Should the enablement requirement of a patent claim focus on whether the disclosures simply enable skilled people in the field to “make and use” the claimed invention or whether the disclosures accurately enable the “full scope” of the invention – all variations of the invention that fall within the patent claim’s description of the invention; and, would a relatively easy trial-and-error procedure equate to undue experimentation?

Oral argument: 
March 27, 2023

This case asks the Supreme Court to clarify whether Amgen’s disclosure of common techniques – a trial-and-error procedure and amino acid substitution technique – is sufficient to satisfy the enablement requirement for Amgen’s patent claim over all antibodies that bind to PSK9 protein and block PSK9 protein’s ability to bind to LDL receptors. Amgen argues that the focus of the enablement standard should be on whether the disclosure leads people to “make and use” the claimed invention and that common techniques do not amount to undue experimentation. Sanofi counters that the disclosures should be specific for broad patent claims and that Amgen’s trial-and-error techniques amount to undue experimentation. This case has significant implications on future innovation in the pharmaceutical industry and the patent law system.

Questions as Framed for the Court by the Parties 

Whether enablement is governed by the statutory requirement that the specification teach those skilled in the art to “make and use” the claimed invention, or whether it must instead enable those skilled in the art “to reach the full scope of claimed embodiments” without undue experimentation—i.e., to cumulatively identify and make all or nearly all embodiments of the invention without substantial “time and effort.”


Heart disease and cholesterol named elevated low-density lipoprotein (“LDL”) are correlated. Amgen Inc. v. Sanofi, Aventisub LLC. at 1082. When cholesterol is in the blood stream, the LDL receptors remove LDL cholesterol. Id. And the degradation of LDL receptor is regulated by an enzyme named proprotein convertase subtilisin/kexin type 9 (“PCSK9”). Id. at 1082–83. When PCSK9 binds to LDL receptors, it decreases the number of LDL receptors on a cell’s surface. Id. at 1083. In other words, PCSK9 may hinder LDL cholesterol control. Id. Monoclonal antibodies bind to PCSK9’s “sweet spot” where PCSK9 bind LDL receptors. Brief for Petitioner, Amgen Inc. at 10. As a result, PCSK9 cannot bind to the LDL receptors and LDL receptors can regulate the LDL cholesterol in the blood stream. Id. at 9–10.

Amgen owns the patents describing such antibodies. Amgen at 1083. Patents relevant in this case are ’165 and ’741 patents. Id. These two patents describe amino acid sequences for twenty-six antibodies. Id. Amgen named one of the antibodies (“21B12”) Repatha®. Id. More specifically, these patents claim antibodies that bind to one or more of fifteen amino acids of the PCSK9 protein and allow LDL receptors to regulate LDL cholesterol. Id. The patents define the claimed antibodies based on their function: binding to combinations of amino acids of the PCSK9 and blocking the PCSK9 from interacting with LDLR. Id.

On October 17, 2014, Amgen Inc., Amgen Manufacturing, Ltd., and Amgen USA, Inc. (collectively, “Amgen”) filed suit against Sanofi, Aventisub LLC, Regeneron Pharmaceuticals Inc., and Sanofi-Aventis U.S. LLC (collectively, “Sanofi”) in the United States District Court for the District of Delaware. Id. Amgen alleged that Sanofi infringed patents including the ’165 and ’741 patents by using a roadmap Amgen disclosed, and creating a new antibody that competes with Amgen’s antibodies. Brief for Petitioner at 15. Amgen and Sanofi stipulated to infringement, but Sanofi claimed the patent claim is invalid. Id. at 16. The district court granted Motion for Judgment as a Matter of Law (“JMOL”) of non-obviousness and of no willful infringement. Amgen at 1084. The jury determined that the patents are valid. Id.

Sanofi filed an appeal to the United States Court of Appeals for the Federal Circuit. Id. The Federal Circuit remanded for a new trial on issues including the district court’s evidentiary rulings and jury instructions regarding Sanofi’s defenses. Id. The federal circuit also vacated the permanent injunction. Id.

On remand, Amgen and Sanofi tried the issues of a written description of the patents and enablement before a jury. Id. Sanofi failed to prove that the claimed patents were invalid. Id. Sanofi then moved for JMOL, and alternatively, a new trial. Id.

The Delaware district court granted the JMOL motion for lack of enablement but denied the motion for lack of written description. Id. The court conditionally denied Sanofi’s motion for a new trial. Id. Amgen appealed to the Federal Circuit, and the Federal Circuit upheld the ruling. Id.

On November 18, 2021, Amgen filed a petition for a writ of certiorari with two questions presented. Petition for a writ of certiorari. The United States Supreme Court granted certiorari on November 4, 2022, limited to Question 2 presented by the petition.



Petitioner Amgen understands that the Federal Circuit provides a more onerous enablement standard for a genus patent claim, which covers a broad group of potential products derived from the central patented feature. Brief for Petitioner, Amgen Inc. at 24. Amgen explains that, while the Federal Circuit typically looks to whether a claim enables a person to make and use the invention without undue experimentation, the Federal Circuit has elevated this standard for genus claims by asking whether the claim enables a person to make the “full scope” of claimed embodiments. Id. at 24–25. Amgen specifies that, in this case, the “full scope” standard means that Amgen’s disclosure should teach a person how to make every possible antibody, the embodiments, that could fit the description of Amgen’s claimed antibodies. Id. at 25, 28. Amgen argues that an elevated standard is unwarranted under 35 U.S.C. §112(a) (“Section 112(a)”). Id. at 25. Amgen notes that Section 112(a) provides a single enablement standard and does not suggest the standard should change according to the type of invention or claim. Id.

Amgen protests the Federal Circuit’s elevated standard because the standard is too burdensome upon patent applicants. Brief for Petitioner, Amgen Inc. at 27. Amgen interprets the Federal Circuit’s “full scope” elevated standard as a requirement for courts to consider the cumulative time and effort required to make nearly all potential embodiments. Id. at 26­­–27. Amgen contends that the Federal Circuit’s “full scope” approach makes it near impossible to submit a valid genus claim because a patent claimant would be required to identify, test, and describe how to create and use every potential variation of a claimed central invention. Id. at 27–28. Amgen claims that the law has been clear that patent applicants are not burdened to describe all potential outcomes and that the Supreme Court in Mowry had suggested it would be extremely difficult to meet such a burden. Id. Amgen advocates that the Federal Circuit should simply apply the Section 112(a) enablement standard and focus on whether Amgen’s disclosures enable a skilled person to make Amgen’s claimed antibodies. Id. at 41.

Respondent Sanofi refutes that the Federal Circuit has employed a different elevated standard for genus claims, disagreeing that Federal Circuit opinions support Amgen’s reading of an elevated standard for genus claims. Brief for Respondent, Sanofi at 35. Sanofi maintains that the Federal Court had applied the “undue experimentation” standard against Amgen’s claims as it does with all other patent claims. Id. at 36. Moreover, Sanofi argues that Amgen’s understanding of the Federal Circuit’s enablement standard is mistaken because the Federal Circuit has clearly rejected enablement standards that solely depend on the effort required to discover all possible embodiments and attempt to quantify and compare effort. Id. at 32–33. Sanofi further rebuts Amgen’s characterization of the Federal Circuit’s decision and expounds that the Federal Circuit evaluated the cumulative effort in this case only because Amgen did not provide a helpful enablement disclosure that efficiently taught how to recreate the claimed antibodies, not because the Federal Circuit was applying a different standard. Id. at 34.

Sanofi submits that Amgen’s broad patent claim is why the “undue experimentation” standard seems to be a high standard in this case. Brief for Respondent, Sanofi at 35. Sanofi elaborates that Amgen had submitted a very broad claim by claiming all embodiments of antibodies with the function to bind to specific PSK9 residues and the function to block LDL receptors from connecting to PSK9. Id. at 10, 35 Sanofi contends that the Federal Court, in accordance with the longstanding principle that a patent claim must enable as much as it claims, justly scrutinized Amgen’s enablement disclosures and found that Amgen’s disclosures did not enable as much as Amgen claimed in its patent claim. Id. at 35. Sanofi suggests that Amgen could have satisfied the “undue experimentation” standard if Amgen had claimed a narrower scope of antibodies or if Amgen had provided a more helpful enablement disclosure that predictably generated desired antibodies instead of common trial-and-error antibody production techniques. Id. at 33.


Petitioner Amgen posits that Section 112(a) clearly states that an enablement disclosure is meant to guide a skilled person to successfully make and use the invention. Brief for Petitioner, Amgen Inc. at 41. Amgen emphasizes that Section 112(a) and this Court’s precedent Nautilus, Inc. has clarified that an enablement disclosure is sufficient if it guides a skilled person with reasonable certainty. Id. Amgen highlights that the trial court proceedings show that Amgen’s instructions provided in the enablement disclosures will not only produce the 26 example antibodies described by Amgen but also always produce an antibody capable of binding to PCSK9 proteins and blocking binding with LDL receptors ­– Amgen’s claimed antibodies. Id. at 48–49. Amgen provides that the full range of claimed antibodies can be produced according to Amgen’s instructions too. Id. Amgen notes that the focus of enablement has always been providing a method that successfully teaches how to recreate an invention; the vast and potentially unknown range of potential variations of the invention is not relevant in evaluating an enablement disclosure. Id. at 42, 44.

Amgen recognizes that an accurate enablement disclosure can still be invalidated if it requires a skilled person to undergo undue experimentation. Brief for Petitioner, Amgen Inc. at 25. Amgen asserts that Amgen’s instructions do not require elaborate experimentation because the two shared techniques – (1) testing antibodies on mice and identifying successful antibodies and (2) substituting chosen amino acids with alternative amino acids with similar properties ­– are common, simple, and cheap. Id. Amgen notes that the Federal Circuit in Wands has already acknowledged antibody testing on mice was not burdensome in other patent claims. Id. Amgen underscores that their technique is also not unpredictable, citing their amino substitution technique because scientists can substitute amino acids in Amgen’s 26 identified antibodies to predictably produce desired antibodies. Id. at 49–50.

Respondent Sanofi posits that Section 112(a) and Supreme Court precedents, like O’Reilly v. Morse, Lamp, and Corona Cord Tire Co. which have interpreted Section 112(a), require enablement disclosures to describe how to make the invention, not a subset of the invention. Brief for Respondent, Sanofi at 23. Sanofi describes that such Supreme Court precedents have consistently required patent applicants to specify their inventions and have rejected broad patent claims that encompassed unspecified inventions. Id. at 25–26. Sanofi argues that Section 112(a) provides no support to Amgen’s idea that enablement is sufficient if it teaches people to create and use the variation of the invention they need at the time. Id. at 37–38. Sanofi quotes Federal Circuit precedent McRO, Inc. that enablement must describe how to make the entire invention without undue experimentation. Id. at 28. Sanofi adds that, considering the special monopoly power given to patent holders, the more a patent claim attempts to claim, the more the patent claim must enable. Id. at 29.

Sanofi emphasizes that a legitimate enablement disclosure allows a skilled person to predictably produce the claimed invention. Brief for Respondent, Sanofi at 43–44. Sanofi criticizes Amgen for mischaracterizing Amgen’s enablement instructions as capable of producing predictable outcomes because, while it may predictably produce a functional antibody, Amgen’s instructions simply produce a random embodiment of the desired antibody. Id. at 43. Sanofi contends that this random production equates to undue experimentation. Id. at 49. Sanofi expands that, because Amgen’s techniques would provide a big pool of candidate antibodies, a scientist would have to test every candidate to see if it falls within Amgen’s claims, and that there are millions of potential antibodies that fall within Amgen’s claim even though Amgen has only specifically identified 26 antibodies. Id. Sanofi adds that Amgen’s instructions do not teach the scientific community any new or improved method of making antibodies and, hence, is inconsistent with the spirit of the enablement disclosure. Id.



Intellectual Property Professors (“Professors”), in support of Amgen, argue that the heightened full scope enablement standard requires an inventor to conduct a limitless number of experiments until there are no untested species and thus frustrates patent protection in the chemical and life sciences industry. Brief of Amici Curiae Intellectual Property Professors (“Professors”), in support of Petitioners at 11–12. Especially in the pharmaceutical industry where large genus claims are common, this requirement is unreasonably demanding and discourages patent applications and innovation. Id. Professors criticize that this standard potentially exposes a pharmaceutical company with innovative drugs to a risk of imitation. Id. at 12. Further, the Alliance of U.S. Startups and Inventors for Jobs (“USIJ”) highlights that the heightened standard decreases patent enforceability and leads to an underinvestment in the biopharmaceutical industry which requires long-term investments. Brief Amici Curiae Alliance of U.S. Startups and Inventors for Jobs (“USIJ”), in support of Petitioners at 20.

Public Interest Patent Law Institute (“PIPLI”), in support of Sanofi, refutes that broad claim protection under the full scope enablement deters research and development of other types of antibodies. Brief of Amicus Curiae Public Interest Patent Law Institute, in support of Respondents at 10. Intellectual Property Law Professors and Scholars (“Scholars”), in support of Sanofi, add that narrow antibody claims have facilitated innovation. Brief of Amici Curiae Intellectual Property Law Professors and Scholars (“Scholars”), in support of Respondents at 10. Scholars claim that narrow antibody claims allow vigorous competition, encourage innovation, and thus increase the number of antibody patents and alternative therapies, and revenues. Id. at 11–12. Small and Medium Biotechnology Companies add that the undue experimentation standard promotes innovation while preventing certain innovators from taking excessive benefit from future innovators. Brief of Amici Curiae Small and Medium Biotechnology Companies, in support of Respondents at 17.


National Association of Patent Practitioners (“Practitioners”), in support of Amgen, explains that the United States patent system has granted patent protection based on the language of a claim, not based on provided examples and the contribution to the art. Brief of Amici Curiae National Association of Patent Practitioners, in support of Petitioners at 6. Practitioners argue that this approach makes it easier for the patent to encompass advances that were unforeseeable. Id. at 8. Practitioners claim that the full scope enablement standard will create a barrier to patent applications, thus discouraging public disclosure of inventions and technological advances. Id at 16–17. Practitioners add that the standard will influence technology industries. Id. at 5, 19. Additionally, Professors argue that a patent claim need not provide a rapid way to embody every single solution. Brief of Professors at 4. Rather, Professors argue that providing some working examples suffices as guidance to solutions, and the patent should protect the invention. Id. at 6.

Scholars suggest a fundamentally different view of what constitutes an invention, distinguishing narrow and broad inventions. Brief of Scholars at 18. Scholars argue that broad invention is when an inventor claims a principle that essentially “animates” a variety of solutions. Id. at 15–16. On the other hand, when a solution is found by “trial-and-error” without a general principle, the invention is a narrow one. Id. at 16–17. Scholars argue that granting Amgen’s “roadmap” patent protection will lead to granting broad protection to a narrow invention. Id. at 6–7, 19. Additionally, Professor Robin Feldman (“Feldman”), in support of Sanofi, adds that a full scope enablement standard polices overbroad claims. Brief of Amicus Curiae Professor Robin Feldman, in support of Respondents at 22–23. Feldman highlights that the U.S. patent system considers a patent as a reward for sharing inventions, and Amgen’s first come first served basis patent system contradicts the basis of the U.S. patent system. Id. at 33–34.


Written by:

Andrew Kim

Jade Lee

Edited by:

Renee Olivett


The authors would like to thank Professor Oskar Liivak for his guidance and insights into this case.