Jie Yang


Abstract After two jury trials, two trips to the Federal Circuit, and two petitions to the Supreme Court, the Court this past term decided Amgen Inc. v. Sanofi without much controversy. In a unanimous decision, the Court affirmed the invalidation of Amgen’s functional antibody claims for lack of enablement. As a result, inventors down the road, not just life sciences companies, may find it more difficult to obtain broad patents. Although the Court was clear that Amgen may not “monopolize an entire class of things defined by their function,” the opinion fell short of guiding lower courts on how to address enablement of genus claims going forward. Genus claims are claims that cover multiple, related embodiments, or species, of an invention. Genus claims offer a broad scope of protection for a patentee, but they also present a particular problem to the carefully crafted patent bargain—how broad is too broad? Too much protection for genus claims may block future innovations in the entire field, while too little could discourage inventors from disclosing the inventions or even investing in innovations. Enablement is a powerful limitation the patent system placed on the scope of genus claims: the accompanying patent document (i.e., specification) must enable a skilled artisan to make and use the invention without undue experimentation. In this paper, I propose a bifurcated approach to evaluation of enablement of genus claims. This approach recognizes two different types of genus claims, one containing only functional limitations (without physical characteristics or chemical properties), and the other containing at least some structural limitations. I argue that, for functional genus claims, means-plus-function (MPF) claiming should apply, which limits a functional claim to the particular means of implementation (i.e., structure, material, or acts) disclosed in the specification and its equivalents. Under this approach, a patentee is allowed to claim an invention based on functionality, but not the function regardless of how it is implemented. On the other hand, I argue that, for structural genus claims, the inoperative embodiments doctrine applies. Accordingly, a claim does not fail for nonenablement simply because some of the covered embodiments are not operative or screening of candidates is necessary. Instead, a patent challenger carries the burden to demonstrate that it is not reasonably likely that a skilled artisan, by following the patent disclosure, can reach operative embodiments of the invention across the full scope without undue experimentation. It is essential that experimentation is evaluated based on the entire attempt to make and use the invention, instead of only on screening, which is routine in the unpredictable arts. This approach dissuades patentees from claiming with pure functional terms, leaves room for experimentation in unpredictable arts, and helps achieve a balance between incentivizing inventors and ensuring that the public enjoy the full benefits of the inventions.