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Amgen v. Sanofi before the US Supreme Court and in Europe


In late May, the US Supreme Court published its opinion in Amgen v. Sanofi (Amgen, Inc. v. Sanofi, et al. 598 U.S. ____ (2023)). At issue was whether the specifications of Amgen’s US patents (US 8,829,165 and US 8,859,741) met the enablement requirement of the US statute, as outlined in 35 U.S.C. . § 112(a) — that is to say, whether the patents described the invention “in such full, clear, concise and exact terms as to enable any person skilled in the art…to make and use [the invention].”

As background, Amgen’s patent claims were directed to cholesterol-lowering monoclonal antibodies. Levels of low density lipoprotein (LDL) (so-called ‘bad cholesterol’) are regulated in the human body by cellular receptors for LDL, which bind LDL, bring it into the cell and remove it from circulation, thereby lowering serum cholesterol. A protein called PCSK9 binds to the LDL receptor on the cell, causing the receptor to degrade, resulting in an increase in LDL in circulation. Blocking or inhibiting PCSK9 with an antibody prevents the degradation of the LDL receptor and allows LDL to be downregulated.  The disputed claims in Amgen’s patents were directed to “the entire genus” of antibodies that (1) “bind to specific amino acid residues on PCSK9” and (2) “block PCSK9 from binding to [LDL receptors].”

The litigated claims covered Amgen’s drug Repatha® as well as Sanofi’s competing drug Praluent®, and Amgen sued Sanofi for infringement in 2014. Sanofi counterclaimed invalidity of the patents for not meeting the enablement requirement, among other issues. The District and Federal Circuit Courts both sided with Sanofi, citing earlier case law on enablement in the US (primarily in re Wands, 858 F.2d 731, in which the Federal Circuit laid out factors when determining whether patent claims are enabled or require the skilled person to engage in “undue experimentation”).

The Federal Circuit concluded that Amgen’s claims were broad but the guidance and examples presented were narrow, and thus the claims were not enabled by the specification. In appealing to the Supreme Court, Amgen alleged that, in its decision on whether Amgen’s specification was enabling, the Federal Circuit was unfairly holding Amgen’s patents to a higher standard than what was required by the statute.

Amgen’s appeal asked specific legal questions of the Supreme Court:

  • Whether enablement is governed by the statutory requirement that the specification teach those skilled in the art to “make and use” the claimed invention under 35 U.S.C. § 112 or
  • Whether, as the Federal Circuit had decided, the specification must instead enable those skilled in the art “to reach the full scope of claimed embodiments without undue experimentation” – that is to say, to cumulatively identify and make all or nearly all embodiments of the invention without substantial “time and effort”

The description of Amgen’s patents identified 26 antibodies that performed the binding and blocking functions and described them using their amino acid sequence. The description also provided crystal structures for two antibodies (one of which was Repatha®) and showed the binding location of Repatha® within PCSK9. In the specification of the patents Amgen described two methods the skilled person could use to make antibodies performing these functions: (1) the “roadmap” method, in which the skilled person generates hybridoma cell lines and tests the resulting monoclonal antibodies for the two functions, and (2) “conservative substitution,” in which the skilled person starts with antibodies known to bind and block PCSK9 and substitutes amino acids with other similar amino acids before testing the resulting monoclonal antibodies.

In authoring a unanimous decision for the Supreme Court, Justice Gorsuch affirmed the Federal Circuit’s decision. The Supreme Court’s decision cited several historical US cases on enablement, among them O’Reilly v. Morse, 15 How. 62 (1854); The Incandescent Lamp Patent 159 U.S. 465 (1895); and Holland Furniture Co. V. Perkins Glue Co. 277 U.S. 245 (1928).

The general principles relied upon in these cases will be familiar to practitioners of patent law. Foremost among these principles is that “The more a party claims…the more it must enable.”

According to the Court, “if a patent claims an entire class of processes, machines, manufactures or compositions of matter, the patent’s specification must enable a person skilled in the art to make and use the entire class. In other words, the specification must enable the full scope of the invention as defined by its claims.”

It may suffice to give one (or a few examples) of the invention in the specification, if the specification also discloses “some general quality…running through” the class that gives it “a peculiar fitness of the particular purpose.”  

A specification is not necessarily not enabling because the skilled person must engage in “some measure of adaptation or testing.” It may “call for a reasonable amount of experimentation to make and use a patented invention. What is reasonable in any case will depend on the nature of the invention and the underlying art.”

Key takeaways from the Court’s reasoning for practitioners of patent law are to include as many examples in the specification as possible, as well as to include rationales that can expand to undisclosed species by identifying features that they have in common and their specific function.

According to the Court, Amgen’s patent claims vastly exceeded the scope enabled by its specification. Amgen sought “to monopolize an entire class of things defined by their function – every antibody that binds to particular areas of the sweet spot of PCSK9 and blocks PCSK9 from binding to LDL receptors…this class of antibodies does not include just the 26 that Amgen has described by their amino acid sequences, but a vast number of additional antibodies that it has not.” Amgen’s “roadmap” and “conservative substitution” approaches amounted “to little more than two research assignments.”

Amgen’s argument that application of the law on enablement in this manner disincentivises breakthrough innovation fell upon deaf ears. The Supreme Court noted the policy issue inherent in the “patent bargain:” that a patent contain enough information such that when it expires, the public has sufficient knowledge to be enabled to practice it without restriction. According to the Court, “striking the proper balance between incentivizing inventors and ensuring the public receives the full benefit of their innovations is a policy judgement that belongs to Congress.”

The Supreme Court thus upheld the Federal Circuit decision, agreeing that Amgen’s patents offered the skilled person little more than advice to engage in “trial and error.”

The Court’s opinion is perhaps not surprising to practitioners of patent law, and is historically consistent with longstanding principles on enablement under US law. Surprisingly, however, the Supreme Court made no mention of the Wands factors, which lower courts and the USPTO have frequently considered when determining whether patent claims are enabled or require the skilled person to engage in undue experimentation. According to Wands, “whether undue experimentation is needed is not a single, simple factual determination, but rather is a conclusion reached by weighing many factual considerations,” namely: 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. There is therefore now ambiguity as to the applicability of these factors in the future by the lower courts and patent office.

Turning now to how Amgen has fared in Europe, there is a requirement under Article 83 EPC is that the patent application “disclose the invention in manner sufficiently clear and complete for it to be carried out” by the skilled person. However, the sufficiency hurdle for functional antibody claims is significantly lower than the enablement requirement for such claims in the US. Instead, the main hurdle for the grant and validity of such claims is inventive step, as the EPO sees generating antibodies that bind to specific amino acid residues in a known target antigen as a matter of routine.

Amgen’s equivalent patent EP 2215124 was limited by the EPO following opposition and appeal proceedings for lack of inventive step and added subject-matter. The patent was maintained in a much narrower amended form than the litigated US claims. In the amended independent claim of the European patent as maintained, the claimed antibody competes with Repatha® or another specific antibody and blocks PCSK9’s ability to bind to the LDL receptor.

This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.

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