Functional Claiming – A Desired Result for Applicants?

Published April 27th, 2012

Commissioner’s Decision 1319

Summary – This decision deals with the Patent Appeal Board’s (“PAB”) review of the final rejection of Canadian Patent Application No. 2,268,812 (“`812 Application”), directed to methods for producing transgenic animal models for Alzheimer’s Disease (“AD”).  The PAB reversed rejections by the Examiner that the claims were merely directed to a desired result, not enabled, and lacked utility, resulting in issuance of the application.  In assessing whether the claims were directed to a desired result, the PAB analyzed the claims as a whole, with reference to the description.  The PAB’s reversal indicates that functional definitions of individual features of a claim do not necessarily render the claim unpatentable for being directed to a desired result.

Analysis – It is well-accepted claim drafting practice to couch an invention in terms of its structural features.  However, a mere structural definition of an invention, particularly in the life sciences or chemical fields, is often unduly narrow.  For example, a structural definition of a gene would be the sequence of that gene and nothing more.  If an Applicant wishes to claim a gene more broadly, functional language may be used in the claim to define the gene in terms of its exerted effect or its characteristic properties.  In this way, other genes that act in the same way to accomplish the same result may be included within the scope of the claim.

While functional claiming is certainly acceptable in Canada, it is impermissible to define an invention solely in the sense of a desired result.  The line between functional claiming and claiming in the sense of a desired result has become a contentious issue between Applicants and Examiners, with Examiners often raising claim rejections on the grounds that a claim is directed to a desired result.  Such a rejection was the subject of Commissioner’s Decision 1319.

Claim 1 of the `812 Application was directed to a method of preparing a transgenic animal that contains a mutant presenilin polypeptide and a mutant amyloid precursor polypeptide.  The claim recited, among other things, the expression “wherein upon expression the mutant presenilin polypeptide has the same phenotypic effect as presenilin M146L, and wherein upon expression the mutant amyloid precursor protein has the same phenotypic effect as APP695 K670N, M671L”.  During prosecution, the Examiner rejected the claim on the basis that this functional recitation rendered it directed to a desired result and therefore unpatentable.

The PAB disagreed with the Examiner and reversed the rejection, stating that the desired result of the claim was not the identification of mutant transgenes per se but, rather, the production of transgenic animal models of AD that possess the phenotype of accelerated AD pathology.  The PAB found that, in order to achieve that result, the Applicant had identified and expressed a combination of mutant transgenes associated with AD in a transgenic animal.  The PAB also found that, in view of the teachings of the description, a skilled person would have been able to identify mutant transgenes other than those specifically exemplified therein.

The Examiner had also rejected certain claims for lacking enablement and utility.  These rejections were also reversed by the PAB and the application has since issued to patent.

Practice Point – In this decision, the PAB determined that the functional language used in the claims did not direct them to a desired result.  This decision may assist Applicants in successfully overcoming desired result rejections when claimed features are defined functionally but when the functional definition is not directed to the desired result of the claim.

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