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The Supreme Court Invalidates Functional Genus Claims

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In a unanimous opinion in Amgen Inc. v. Sanofi, the Supreme Court held that two functional genus patent claims were not enabled under 35 U.S.C. § 112(a).1 In doing so, it affirmed both the Federal Circuit’s previous decision and that court’s well-established practice of almost always invalidating genus claims for lack of enablement.

The relevant patents in Amgen Inc. v. Sanofi (U.S. Patent Nos. 8,829,165 and 8,859,741) both concern a genus of antibodies that help reduce the levels of low-density lipoprotein cholesterol (“LDL cholesterol”). Specifically, these patents claim any antibody that performs the following two functions: (1) binding to specific amino acids on the PCSK9 protein and then (2) blocking that PCSK9 protein from then impeding the body’s mechanism for removing LDL cholesterol from the bloodstream. So, while the patents claimed any such antibody that performed those two functions, the patent specifications only identified and disclosed 26 specific antibodies that performed those two necessary functions.

The Court held that the patents did not enable a skilled artisan to “make and use” the full scope of the invention, as required by § 112(a) of the Patent Act. The Court noted that if “a patent claims an entire class of . . . composition of matter, the patent’s specification must enable a person skilled in the art to make and use the entire class.” To the Court, the patents at issue did not satisfy this requirement.

Along with disclosing 26 antibodies in its specifications, Amgen offered a skilled artisan two distinct methods to then discover other antibodies in the claimed genus. First, it offered a “roadmap” that instructed a skilled artisan on how to generate from scratch antibodies in a lab and then test to see whether they performed the two necessary functions of blocking and binding. Second, and in the alternative, the specifications suggested “conservative substitution.” Here, a skilled artisan could start with an antibody known to perform the blocking and binding functions, replace certain amino acids with similar amino acids, and then test the resulting antibody to determine if it performed those two functions.

But these two methods were inadequate to enable the full scope of the claims. The Court found that the methods “amount[ed] to little more than two research assignments.” Both merely required an artisan to undergo a “trial-and-error method for finding functional antibodies.” Regarding the conservative substitution method, the Court noted that such a trial-and-error method was “an uncertain prospect given the state of the art,” which it observed was “unpredictable.” The Court, however, noted that a “specification [is not] necessarily inadequate just because it leaves the skilled artist to engage in some measure of adaptation or testing.” And determining whether such adaptation or testing “is reasonable . . . will depend on the nature of the invention and the underlying art.”

The Court further cautioned against reading its opinion as holding that a specification must always describe “how to make and use every single embodiment within a claimed class.” Indeed, for some inventions, the Court noted that only a few examples may be sufficient to enable an entire class if there was “some general quality . . . running through” that class. So, while the law does not require a court to look at the “cumulative time and effort” it takes to enable every species within a genus, offering skilled artisans “little more than advice to engage in ‘trial and error’” was not sufficient to survive an enablement challenge in this case.

Finally, the Court briefly dismissed Amgen’s argument that holding its patents invalid for lack of enablement would “destroy incentives for breakthrough inventions.” According to the Court, this was a “policy judgment that belong[ed] to Congress.”

What This Means For You

This decision falls in line with the Federal Circuit’s trend of invalidating genus claims when they are challenged for lack of enablement. In fact, the Federal Circuit has almost always invalidated such claims on enablement grounds, finding that whatever the patent owner had included in its specifications to justify a broad genus claim was not enough to enable the claim’s full scope.2 The Supreme Court’s affirmance of this practice serves as a reminder of the precarious positions that functional genus claims occupy in the legal field today. To ensure these genus patents survive an enablement challenge, patent applicants should make certain that their specifications sufficiently describe how a skilled artisan can make and use the full scope of the claim. And while what is required to satisfy enablement is a highly fact-specific inquiry, merely recommending that the artisan partake in “trial and error” when the art in question is unpredictable is likely not enough to survive an enablement challenge.

1 598 U.S. ___ (2023).

2 See Dmitry Karshtedt, Mark A. Lemley, Sean B. Seymore, The Death of Genus Claims, 35 Harvard J. of Law & Tech. 1, 4 (2021)


This information is provided by Vinson & Elkins LLP for educational and informational purposes only and is not intended, nor should it be construed, as legal advice.