HealthLawProf Blog

Editor: Katharine Van Tassel
Case Western Reserve University School of Law

Monday, February 20, 2023

USPTO's Lax Policy Leads to Biologic Formulation Thicket

Bernard Chao (University of Denver), USPTO's Lax Policy Leads to Biologic Formulation Thicket (2023):

Biosimilar drugs enter the United States market well after they enter the European market. That is likely due to high patent assertion rates in the U.S. and stronger patent portfolios in this country. But why are patent thickets protecting biological drugs in the United States an American phenomenon? Presumably, biological drug companies seek extensive patent coverage everywhere.

By comparing the U.S. and EU prosecution histories of formulation patents covering Abbvie’s blockbuster Humira drug, the current study seeks to answer this question. This study found two differences in the way that that the United States Patent Office (USPTO) and European Patent Office (EPO) treated formulation patent applications. First, the primary difference between the two patent offices is that they treat prophetic examples dramatically differently. The written description for the Humira formulation patents contained both working examples with data, and a laundry list of ingredients (i.e. prophetic examples) that had no accompanying test results. The USPTO allowed broad claims that covered far more than the working examples. The claims covered the prophetic examples and perhaps even more. In contrast, the EPO requires independent claims to contain the “essential features” of invention. In practice, this meant that the EPO only allowed claims that were narrowly tailored to cover the working examples. Claim limitations in the EU patents corresponded to the specific excipients found in the working examples.

The second difference was how the two offices treated functional claims. These are claims that include limitations that are drafted to describe a result or function as opposed to the structure (e.g. a chemical compound) that the applicant used to achieve the function. Functional claims can be extremely broad because a whole range of known and unknown compounds may satisfy the functional limitation. During the prosecution of the Humira formulation patents, the U.S. patent office often allowed functional claim limitations. However, when the EPO was faced with the same kind of language, it objected stating “that these features are results to be achieved” which “lacks clarity under Article 84 of the European Patent Convention (EPC).” While this policy difference undoubtedly led to broader patents in the U.S. than the EU, the EPO’s essential features requirement was probably the larger factor.

The upshot is that a combination of these two policy differences led to vastly different patent portfolios in the U.S and EU. The U.S. patents did not just have greater claim scope than their EU counterparts, the U.S. patents were also far more numerous (22 U.S. formulation patents vs. 2 EU formulation patents) than their EU counterparts. As a result, Abbvie had a substantially greater ability to prevent biosimilar competition in the United States than in Europe.

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