Legal Forum: Literal Claim Scope and After-Arising Technologies

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?

Judy M. Mohr, Ph.D.

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 (www.chiron.com) 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 (www.gene.com), 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

At trial, the issue under contention was whether Chiron's earlier-filed applications satisfied the written description and enablement requirements for claims covering monoclonal antibodies that bind selectively to human breast cancer cells. With respect to the 1984 priority application, the Chiron court noted that the 1984 application was not required to enable chimeric or humanized antibodies because these antibodies were not known at the time of filing the 1984 application.

According to the court, new technology that arises after an application filing date is by definition outside the bounds of the enablement requirement, and an inventor cannot be held responsible for enabling nonexistent technology. However, because chimeric or humanized antibody technology did not exist at the time of filing the 1984 application, the inventors cannot be said to "possess and disclose this technology," thereby failing to satisfy the written description requirement.

With respect to chimeric antibodies, the court noted that they were known at the time of filing the 1985 and 1986 applications, having been reported in June 1984. Yet, the court referred to chimeric antibodies as "nascent technology," with respect to the 1985 and 1986 applications, and required that a patent specification provide a "specific and useful teaching" of nascent technology.⁴ Because neither priority application provided such a teaching, the applications did not enable the claimed subject matter in the later-filed patent.

A different outcome has been reached in cases related to computer, electronic, or software arts. In Superguide Corporation v. DirecTV Enterprises, Inc.,⁵ at issue were the scope of claims related to interactive electronic program guides. Super-Guide owned several patents claiming ownership of a device that allows a television user to display on a television screen only the program information desired. The device stored electronic television program information in a microcontroller's memory to allow a user to search the stored information. When SuperGuide sued DirecTV asserting infringement of its patents, at issue was whether the literal claim scope was limited to analog signals, or whether the claims also encompassed digital signals. At the time of filing the applications in 1985, video data were predominantly communicated in an analog format, with the digital format emerging as a new technology.⁵

The SuperGuide court ruled that the law does not require that an applicant describe every conceivable and possible future embodiment of his invention in the specification. In contrast to the Chiron court's ruling that a specific and useful teaching must be provided for an emerging technology, the SuperGuide court did not require a detailed description of digital technology for the claims to encompass a digital video format.

The dramatically different results reached by the courts when applying the same legal rules are explained, at least in part, by the underlying technology. The courts currently regard the biotechnological field as being filled with a high level of unpredictability. Unpre-dictability in biotechnology exists, for example, in the complexity of cellular systems used for study and unknown changes in function upon structure variation. These factors are not present in the electronic, computer, and software arts. Hence, patent claims in the biotechnological field typically do not capture an after-arising technology, whereas patent claims in these other fields often do. Perhaps as the biotechnological industry continues to mature, the alleged level of unpredictability from a judicial perspective will decrease, permitting biotechnology-related claims to capture after-arising technologies.

Judy M. Mohr, Ph.D. Perkins Coie, LLP, 101 Jefferson Drive Menlo Park, CA 94025, 650.838.4402,fax 650.838.4350, jmohr@perkinscoie.com

REFERENCES

1. Ward, ES, Gussow, D, Griffiths AD, Jones PT, and Winter, G. Binding activities of a repertoire of single immunoglobulin variable domains secreted from Escherichia coli. Nature 1989; 341:544.

2. 35 U.S.C. § 112, first paragraph.

3. In re Wands, 858 F.2d 731 (Fed. Cir. 1988).

4. Chiron Corporation v. Genentech, Inc., 363 F.3d 1247 (Fed. Cir. 2004).

5. SuperGuide Corporation v. DirecTV Enterprises, Inc., 358 F.3d 870 (Fed. Cir. 2004).