Claiming priority: a matter of fact

Section 25(7) of the Patents Act No 57 of 1978 explained.

An invention can only be patented if it does not form part of the state of the art at the time of the application for the patent. The relevance of prior art, the Nemesis of any prospective patentee, is further defined in S25(7) of the Patents Act No 57 of 1978 - the state of the art includes matter not yet available to the public at the time of establishing an earliest priority date, provided that an application containing such matter became open to public inspection, and that the application’s priority date precedes that of the relevant application.

The reasoning behind this is sound: granting monopolies on the same subject matter to separate entities in the same country is nonsensical and would inevitably lead to absurd conflicts. It is critical, however, to understand the scope of the “matter” referred to in S25(7). Conflicting judgments have been handed down by the courts and generally there are two main schools of thought: The first, termed the “prior claims approach”, is based on the premise that the scope of protection of a patent is contained in the claims and therefore the fictitious publication date predated to the earliest priority date of the application should only be extended to the claimed invention. The second, termed the “whole contents approach”, believes that it is against public interest to grant a patent on matter that has already been publically disclosed in a prior application, albeit not yet published and not part of the claimed invention.

According to the Strasbourg Convention, a member country is free to adopt either approach. In South Africa, the argument was finally put to bed in the case of Deton Engineering (Pty) Ltd and another v John Paul McKelvey and others. The facts of this case revolved around two granted patents, and the invalidity of the second (the “Deton patent”), as a result of it being anticipated by the first (the “CMI patent”).

All of claims 1, 2, 4 and 7 of the Deton patent were disclosed in the body of the CMI patent, but, importantly, not in its claims. Even though not yet published at the time, the CMI patent’s earliest priority date preceded that of the Deton patent. Its relevance was thus unknown to Deton Engineering at the time of its application.

In the case that followed, Deton Engineering contended that, in accordance with S31(1)(b), South Africa was in support of the “prior claim approach” as, at the time, it related the priority date of the matter to the claim with the earliest priority date.

This argument was supported by S32(3)(d) which specifically stated that the ambit of the protection of an invention had to be contained in the claims.

Van Dijkhorst J held that the object of S25(7) was to avoid double patenting, that only claimed matter could have a priority date, and that the matter not claimed thus only formed part of the prior art from the day of publication. Judgment was handed down in favour of the validity of the Deton patent and the “prior claim approach.

The case was, however, brought before the Supreme Court of Appeal. Harms JA contested that S25(7) specifically mentions “matter” and not “claims”, which, he felt, pointed towards the “whole contents approach”.

Harms JA further emphasized the term “matter contained in an application” used in S25(7)(b), and held that, since S30, read with S32(2) prescribes that an application for a patent can be either in the form of a complete specification or a provisional specification, which does not need to have claims as long as it fairly describes the invention, S25(7) cannot be construed to exclude matter contained in a specification which is not claimed.

Further, the Patents Act generally relates “matter” to disclosures in the body of the specification that can support a claim. Obviously, if at a later stage, CMI were to, by way of amendment, include matter contained in the body of the specification into the claim, this would lead to double patenting, which destroys the object of creating a monopoly.

Harms JA thus concluded that it was never the intention of the legislature to follow the “prior claims approach” and that any inference to this end would be incorrect. The appeal was upheld with costs.

S33 had since been amended and no longer links priority to the claim with the earliest priority date, but rather to matter contained in the application from which priority is claimed. This clearly brings the Patents Act in line with the “whole contents approach”.