May 22, 2023

Supreme Court Affirms Amgen Patents’ Invalidity in Closely Watched Enablement Case

The U.S. Supreme Court has decided a closely watched case regarding patent law’s enablement requirement, Amgen Inc. v. Sanofi. The Supreme Court affirmed the Federal Circuit’s decision that Amgen’s patent claims were invalid, holding that the patents’ disclosures “offer[ed] persons skilled in the art little more than advice to engage in ‘trial and error.’”

The Court’s decision was unanimous. Although Amgen and various amici had urged the Court to adjust the standard for enablement in ways that would favor patent validity, the Court’s decision announced no major changes to the doctrine.


The relevant provision of the Patent Act requires a patentee to describe its invention “in such full, clear, concise, and exact terms as to enable any person skilled in the art... to make and use the [invention].” 35 U.S.C. § 112(a). The Federal Circuit has held that this language requires enablement of the “full scope” of the invention, without “undue experimentation.”

The Amgen case involves functional claims to monoclonal antibodies. Each of the claims at issue in Amgen’s patents is directed to “an isolated monoclonal antibody” that “binds to” particular “residues” of an enzyme (what the Supreme Court described as the “sweet spot”). The claims are not limited by sequence or structure of the antibody. 

The enablement dispute was over whether the patents disclosed enough to enable a skilled artisan to make antibodies that successfully achieve the claimed binding effect. The patent specifications gave 26 examples of antibodies within the scope of the claims. But as the Supreme Court described the case, there were potentially millions of antibodies within the scope of the claims that were disclosed not by sequence or structure, but by the ability to bind to the sweet spot. Amgen contended that the specification enabled skilled artisans to make these antibodies using either of two approaches, one called a “roadmap” (which entailed generating a range of antibodies and testing them) and one called “conservative substitution” (which entailed starting with the 26 examples, making small substitutions likely not to impair functionality, and testing the results).

A jury rejected the defendants’ enablement challenge to Amgen’s patent claims. The district court, however, granted judgment as a matter of law to the defendants, and the Federal Circuit affirmed that decision.

Amgen sought review by the Supreme Court. Although Amgen’s position raised multiple issues for review, the relevant “question presented” disputed the Federal Circuit’s precedent holding that a patent must enable skilled artisans to practice the “full scope” of the invention without “undue experimentation.” 

The Supreme Court initially asked the United States for its views. The government filed a brief urging the Court to deny Amgen’s petition and contending that Amgen’s claims are not enabled. The Court granted Amgen’s petition—limited to the “full scope” enablement question—nonetheless.

The Court’s Decision

In a unanimous opinion by Justice Neil Gorsuch, the Supreme Court affirmed the Federal Circuit and held the patent claims not enabled. 

At the threshold, the Court agreed that “the specification must enable the full scope as defined by its claims.” Slip Op. 13. It made clear, however, that “a specification may call for a reasonable amount of experimentation to make and use a patented invention,” and that “what is reasonable in any case will depend on the nature of the invention and the underlying art.” Slip Op. 15. These holdings are consistent with existing Federal Circuit precedent.

The Court began by summarizing the key enablement cases over centuries of Supreme Court doctrine, from the telegraph to the incandescent lamp. The Court distilled from these cases the principle that when an inventor seeks to claim “an entire class of processes, machines, manufactures, or compositions of matter,” and not just its own invention within that category, “the patent’s specification must enable a person skilled in the art to make and use the entire class.” In other words, the Court cautioned: “The more one claims, the more one must enable.” Slip Op. 13.

The Court nevertheless reaffirmed that “a specification may call for a reasonable amount of experimentation to make and use a patented invention.” Slip Op. 15. The Court also emphasized that in some cases, a patentee may disclose a “general quality [that] may reliably enable a person skilled in the art to make and use all of what is claimed” and thereby satisfy the enablement requirement. Slip Op. 13-14. 

The Court then held, in a relatively short discussion, that Amgen’s claims, “defined by their function,” were not enabled. Slip Op. 15-19. The Court dismissed the “roadmap” and the “conservative substitution” method as instructing the artisan to just engage in “trial-and-error”—“‘painstaking experimentation’ to see what works.” To be sure, the Court noted, “methods like a ‘roadmap’ or ‘conservative substitution’ might suffice to enable other claims in other patents—perhaps because … the inventor identifies a quality common to every functional embodiment,” but the Court concluded that in the context of this case, they did not. Slip Op. 17 (emphasis added).

The Court agreed with the patentee that “enablement is not measured against the cumulative time and effort it takes to make every embodiment within a claim.” Slip Op. 18. But where there is no guidance about how to make embodiments that function as claimed, the patent is not enabled.