Full scope enablement in functional limitation claims

Two recent Federal Circuit decisions in the Amgen Inc. v. Sanofi patent infringement litigation suggested the demise of antibody genus claims, but the Supreme Court has decided to weigh in on the Federal Circuit’s unfavorable enablement doctrine precedent, granting Amgen’s petition for certiorari for review of those standards.¹

Amgen's patents at issue² functionally “claim antibodies that bind to one or more of the fifteen amino acids . . . of the PCSK9 protein and block PCSK9 from binding to LDL receptors.”³ These receptors are responsible for removal of LDL cholesterol from blood to naturally help reduce the risk of heart disease. Amgen sued Sanofi for infringement, and despite district court juries twice deciding that Sanofi failed to carry its burden of invalidating the patents for either lacking enablement or written description, the district court granted Sanofi’s motion for judgment as a matter of law (JMOL) for lack of enablement.⁴ On appeal, the Federal Circuit affirmed, holding the claims invalid for lack of enablement because “undue experimentation would be required to practice the full scope of the claims.”⁵

To reinforce Amgen’s expert’s testimony on appeal that “a person of skill in the art can make all antibodies within the scope of the claims by following a roadmap . . . described in the specification,” Amgen pointed to Sanofi’s inability to cite any particular antibody to prove otherwise.⁶ Amgen also contended that “the effort required to discover and make every embodiment of the claims” was the wrong measuring stick for the undue experimentation calculus.⁷

The Federal Circuit rejected Amgen’s arguments emphasizing instead “the conspicuous absence of nonconclusory evidence that the full scope of the broad claims can predictably be generated by the described methods.”⁸ The Federal Circuit also  determined that several Wands factors significantly contravened Amgen’s arguments, including factors that consider the substantial breadth of the claims and the invention’s “unpredictable field of science with respect to satisfying the full scope of the functional limitations.”⁹ The Federal Circuit focused heavily upon the fact that “[e]ach appealed claim in this case is a composition claim defined, not by structure, but by meeting functional limitations.”¹⁰

In its petition for certiorari, Amgen contended that “The Federal Circuit’s decision in this case defies more than a century of” Supreme Court precedent on this issue and “invades the jury’s role.”¹¹ Amgen argued that the Federal Circuit erred in requiring the specification to “enable those skilled in the art to reach the full scope of the claimed embodiments without undue experimentation."¹² By imposing these standards Amgen contends that the Federal Circuit’s decision has an “impact on innovation that is devastating, particularly for critical biotech and pharmaceutical industries . . .[by] invalidat[ing] genus claims based on perceived size alone."¹³

Despite the Solicitor General’s recommendation not to grant Amgen’s petition, the Supreme Court granted certiorari on November 4, 2022. The Supreme Court’s decision has the potential to make clear what a patentee must teach in the specification to support genus-type claims with functional limitations, including functionally-defined antibody genus claims.