The Antibody Patent Paradox

Mark A. Lemley, Jacob S. Sherkow

Research output: Contribution to journalArticle


Antibodies constitute a staggering $145 billion annual market—an amount projected to almost double by 2026. Consequently, patents covering antibodies are among the most valuable in the patent system. But antibody patents are being struck down left and right, victims of the Federal Circuit’s recent shift to strengthen two doctrinal areas of patent law—enablement and the written description requirement. For each, the Federal Circuit has heightened requirements that patentees disclose or teach how to make and use the “full scope” of their inventions.<br><br>There are good reasons to be skeptical of the Federal Circuit’s attack on genus claims in chemistry generally. But it seems to be a particular problem for antibodies. Applying the Federal Circuit’s reinvigorated written description and enablement requirements to antibodies and their chemical structure fits poorly with the science underlying the molecules themselves. Immune receptor production—a semi-random and galactically expansive process—produces antibodies that are startingly different in both structure and function. There is no way to genus claims to antibodies that satisfy the court’s current tests. The science simply doesn’t allow it. At the same time, this change in the Federal Circuit’s jurisprudence is a legitimate reaction to some of the problems with the long-standing (and long-permitted) practice of claiming antibodies in functional terms. Functional claiming can lead to overbroad patents that stifle future innovation, as it has done in the software industries. Perhaps the Federal Circuit is wary of a similar result in biotechnology.<br><br>Fortunately, we think there is a middle ground—a new (or, really, quite old) form of patent claim drafting that gives inventors effective control over true substitutes without giving them the power to block real improvements: means-plus-function claims and infringement by the equivalents. Those doctrines limit patentees to claiming only the specific structural features of antibodies they both possessed and described, but also entitle them to assert their patents against antibodies with equivalent functions but different structural characteristics. If the economics of intellectual property center on balancing a need for protection beyond the literal invention and allowing improvements, this seems a step in the right—or, at least doctrinally permissible and economically sensible—direction.<br><br>Whether patentees go for such a solution remains to be seen. Recent empirical evidence on antibody claims has yet to document such a shift. Patent attorneys may need to get over their historical reluctance in writing their claims in such a fashion. Our solution won’t give patentees everything they want. But they just might find it gives them what they need.<br>
Original languageEnglish (US)
JournalYale Law Journal, Forthcoming
StatePublished - Feb 15 2022


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