Legal Forum: Literal Claim Scope and After-Arising Technologies

What happens when a literal reading of a patent claim encompasses a technology developed after the patent's filing date?
Jul 01, 2006
Volume 19, Issue 7

Judy M. Mohr, Ph.D.
Rapid advances in technology pose special challenges to the US patent system. US patent laws are, in theory, technology blind and equally applicable to inventions in biotechnology and information technology. In practice, however, the patent system has applied the laws to different technologies unevenly. One example of an uneven application of the law has been the courts' view on the question: to what extent will claims in an issued patent encompass technology that is developed after the filing or issuance of the patent?

This comment considers this question, with particular focus on the situation where a literal reading of a patent claim encompasses an "after-arising" technology, i.e., a technology that is developed after the filing date of a patent application. The exclusivity conferred by a patent claim is determined by the literal meaning of the claim and, increasingly more rarely, by the meaning of the claim under the doctrine of equivalents. While one of the important objectives of the doctrine of equivalents is to accommodate after-arising technologies, the focus here is on the situation where an after-arising technology is within the scope of a literal reading of a claim.

Consider two illustrative examples. Suppose a patent application is filed before the discovery that immunoglobulin heavy chain variable domains bind antigen in the absence of a partner light chain, so-called single domain antibodies.1 Based on this application, imagine a granted patent claim that states, "An antibody or antibody fragment having binding specificity for a HER2 receptor on a breast cancer cell." Should the claim include within its scope, and thereby provide an exclusive position for, a single domain antibody having binding affinity for the HER2 receptor?

In another example, consider a patent claim on a system for storing electronic television program information in the memory of a microcontroller. Suppose the patent application was filed when analog technology was common in the industry, but before digital technology was viable. Should the granted claim provide an exclusive position for a later-developed digital system for storing electronic information in memory?

US patent law requires an applicant to provide a written description of the invention and a disclosure of how to make and use the claimed invention, the 'written description' and 'enablement' requirements, respectively.2 The written description requirement serves, inter alia, to demonstrate that an inventor was in possession of the claimed invention at the time the application was filed. The enablement requirement dictates that the description of the invention in the patent application be sufficient to teach a person of skill how to make and use the full scope of the invention without "undue experimentation."3

Of these two requirements, the written description requirement has been used to define the reach of claims, in some cases preventing a claim from encompassing after-arising technology, yet in other cases permitting a claim to capture an after-arising technology. In particular, the courts have used the written description requirement to limit the reach of claims in the biotechnological industry so that after-arising technology is not captured. Interestingly, however, the written description requirement has not been as rigorously applied to prevent claims related to computer, electronic, or software inventions from encompassing after-arising technology.

An example in the biotechnology field is the case involving Chiron Corporation's ( patent claims to a monoclonal antibody with binding affinity to the c-erbB-2 antigen, also known as the HER-2 antigen.4 Chiron brought suit against Genentech (, alleging infringement by Genentech's humanized antibody product, Herceptin. In response, Genentech asserted that Chiron's patent was invalid because of failure of the priority applications to satisfy the enablement and written description requirements. Chiron's patent claimed priority to three earlier-filed applications (1984, 1985, and 1986). At the time of filing the initial application in 1984, neither chimeric antibody technology nor humanized antibodies were known.4 Chimeric antibodies were identified at the time of filing the 1985 and 1986 applications, having been reported in literature in June 1984.4

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