In South African patent law, “selection patents” relate to inventions that involve selecting particular elements or subgroups from a broader known class of compounds, processes, or materials, where the selected subgroup or element demonstrates special properties or unexpected advantages compared to the larger class from which they are chosen.  

This niche category of patents has a tailored scope of protection and the validity depends on meeting particular criteria that set it apart from the wider class. 

Whilst the South African Patents Act 1978 does not contain provisions supporting a particular approach to selection patents as falling within a special category, understanding the subtleties of selection patents requires a closer look at the criteria and case law that shape this area of intellectual property law.  

A selection patent must satisfy the standard patentability criteria of novelty, inventive step, and utility.  

While there is limited case law specifically addressing selection patents in South Africa, broader principles of patent law and influential precedents from English law often play a role. Here, the meaning of and conditions for the validity of selection patents in England were enunciated in the case of IG Farbenindustrie AG’s Patents [1930] 47 RPC 289 where the court held that for a selection patent to be valid, it must be based on some substantial advantage to be secured by the use of the selected members; that the whole of the selected members must possess the advantage in question; and that the selection must be in respect of a quality of a special character which can fairly be said to be peculiar to the selected group. From this decision, it is clear that the selection cannot be an arbitrary choice; the selected elements must demonstrate a surprising result or have unexpected properties compared to the larger class from which they are chosen.  

A selection that merely identifies a known subset without revealing any surprising characteristics does not meet this threshold, in other words, the selection must not be obvious in the light of the state of the art. The selection must be specific, clearly defined, ensuring that it does not encompass the entire broader class previously disclosed. 

Novelty: It is not enough that the selected subgroup is not directly disclosed in the prior art; it must offer new and distinctive qualities that were not previously recognized. For example, if a known class includes a variety of chemical compounds, a selection patent might protect a specific compound from that class that exhibits an unexpected therapeutic effect. 

Inventive step: The choice of the specific subgroup should not be obvious to a person skilled in the field, based on prior knowledge of the larger group. The selected subgroup should represent a leap in understanding or application that is not readily apparent. If a person skilled in the art could easily predict the properties or benefits of the selected subgroup, then the selection lacks inventiveness. 

In South Africa, there is no basis for what the form of a specification for a selection patent should take. Thus, the selection patent would, at the very least, need to sufficiently describe, ascertain and where necessary, illustrate or exemplify the invention and the manner in which it is to be performed in order to enable the invention to be performed by a person skilled in the art of the invention.   

This means that the patent specification must explain why the selection was made and what unexpected benefits or properties the selection offers. This ensures that the patent specification is sufficiently detailed to enable others skilled in the field to understand and replicate the invention. This requirement aligns with the broader patent principle of enabling disclosure (Merial and Others v Cipla Vet (Pty) Ltd [2016] ZASCA 57), which is fundamental to maintaining the balance between protecting innovation and sharing knowledge. 

Selection patents in South Africa provide a pathway for protecting specific innovations within a known class provided that they demonstrate that the chosen elements or subgroups offer something unexpected or surprising.  

This distinctive characteristic makes selection patents both a powerful tool for innovators and a complex area of patent law. By carefully navigating these criteria, inventors can secure valuable protection for their discoveries, even within well-trodden scientific fields.