Introduction

In what has been referred to as the most important UK patent infringement decision in over a decade, the UK Supreme Court in Actavis UK Limited v Eli Lilly ([2017] UKSC 48) confirmed that the doctrine of equivalents is part of UK law when considering patent infringement. One of the key pieces of legislation considered in the judgment was Article 2 of the Protocol on the Interpretation of Article 69 of the European Patent Convention, as amended in 2000, which specifically requires that "due account shall be taken of any element which is equivalent to an element specified in the claims".

In light of this judgment, it is timely to consider the situation in South Africa in relation to patent litigation cases in the pharmaceutical field.

National case law

The seminal South African case on the doctrine of equivalents is Stauffer Chemical Co v Safsan Marketing and Distribution Co (Pty) Ltd (1987 (2) SA 331 (A)). This case concerned the agricultural chemical field, which is closely related to the pharmaceutical chemical field.

The doctrine of equivalents was founded on the theory that "if two devices do the same work in substantially the same way, and accomplish substantially the same result, they are the same, even though they differ in name, form, or shape".

Although initially formulated in mechanical terms, the doctrine was considered equally relevant in respect of equivalent chemical compounds. In Stauffer, the court considered a number of earlier cases relating to the doctrine of equivalents and held that the doctrine of infringement by the substitution of equivalents applied only in respect of unessential features or integers of a claim. As part of its rationale, the court stated that the difficulty of explaining the behaviour of chemical compositions and predicting how different chemical substances in combination will behave under varying circumstances are often obstacles for patentees seeking to establish a case of infringement based on chemical equivalence. For many years, this decision was the relatively limiting authority that patent owners in the pharmaceutical field had to follow in product infringement litigation in South Africa.

However, as is evident in the more recent case law relating to pharmaceutical product infringement, such as the Supreme Court of Appeal judgment in Pharma Dynamics (Pty) Ltd v Bayer Pharma AG ((468/13) [2014] ZASCA 123), South African patent law has developed beyond such a strict consideration of the doctrine of equivalents to a far more holistic approach.

In Pharma Dynamics, the court referred to a number of seminal South African patent cases in interpreting the scope of the claims of the patent in suit. Summarising the various precedent cases, the court held that the meaning of the words used in the claims should be construed grammatically and in their ordinary sense (and not in isolation), but within the context of the specification as a whole. The interpretation of the scope of the claims should be performed by way of purposive construction, rather than a purely literal interpretation, so that the court does not overlook an infringement which takes the substance of the invention by peering too closely at the language of a claim. In addition, the court went a step further and held that:

  • the meaning of terms used in the specification and claims should be considered in the context of a person who is skilled in the art when the patent application is filed; and
  • evidence from relevant expert witnesses should be considered in order to place the court in as close a position as possible to such a skilled person when performing the interpretation.

Comment

South African pharmaceutical product litigation case law provides no particular test that refers to the doctrine of equivalents, as was the case in Actavis. However, when interpreting the scope of patent claims, with the assistance of expert witness testimony, the courts may hold that a claim extends to obviously substituted equivalents in the infringing product or process that are not literally provided for in the specification and claims. As such, a pharmaceutical product or process with chemical equivalents may also be considered to constitute infringement, provided that there is evidence that such chemical equivalents could be expected to be successfully substituted for the claimed variant in a patent at the time of the patent application priority date. Recent case law may therefore be a welcome development for originator pharmaceutical companies, although it is probably less so for generics manufacturers.

For further information on this topic please contact Joanne van Harmelen at ENSafrica by telephone (+27 21 410 2500) or email (jvanharmelen@ensafrica.com). The ENSafrica website can be accessed at www.ensafrica.com.

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