In Australia, the inquiry whether a combination of integers is patentable subject matter may be deeply influenced by the way the claim preamble and objects of the invention are drafted. Failure to appreciate this can result in inadvertent invalidity, as a series of decisions by the Federal Court of Australia demonstrates.

It has long been the law in Australia that a mere collocation of integers (i.e. integers without a working interaction to achieve a result) is not patentable subject matter. More recently, it has been held that in some circumstances including an ‘orphan’ integer in a claim can, by itself, invalidate an otherwise good patent. The Federal Court of Australia draws a distinction between orphan integers that are:

  1. on the one hand, a mere optional addition to a combination claim which was not an element of the invention and served only to limit the claim (which would not affect the validity of the claims for lack of patentable subject matter) and
  2. on the other hand, an integer which was an element of, and said to limit, the invention (which would affect the validity of the claim for lack of patentable subject matter).

(Smith & Nephew Pty Ltd v Wake Forest University Health Sciences [2009] FCAFC 142; Wake Forest University Health Sciences v Smith & Nephew Pty Ltd (No 2) [2011] FCA 1002)

In the Wake Forest University cases, the Federal Court considered a claim directed to 

An apparatus for applying negative pressure to a wound beneath a fluid-impermeable seal... 

The claim had a number of integers with a working interaction to result in the application of negative pressure and the last integer of the claim was that the ‘apparatus is in an aseptic package’.

The Federal Court acknowledged that the aseptic packaging may play a part in wound healing, but noted that the claim was instead directed to applying negative pressure to a wound. It was not in dispute that the aseptic package plays no part in the application of negative pressure to a wound. In light of this and a finding by the court that the patentee had advanced a construction that the aseptic package was an essential part of the invention for other aspects of patentability, the claim was in the second category above and was found invalid. 

The dicta of the Federal Court suggests that the result in the Wake Forest University cases would have been different if the claim was directed instead to 

An apparatus for facilitating the healing of wounds…

The Wake Forest University cases therefore highlight the importance of having a carefully considered claim preamble in combination claims, so as to not inadvertently create an orphan integer.

The importance of the claim preamble has been reiterated in the December 2014 decision of Streetworx Pty Ltd v Artcraft Urban Group Pty Ltd [2014] FCA 1366. In Streetworx, Justice Beach considered claims directed to ‘A lighting assembly…’ (i.e. the claims did not include an explicit indication of the what the lighting assembly was for). Justice Beach distinguished Wake Forest on the basis that the claims in that case specifically identified the desired result, namely applying negative pressure to a wound.

Justice Beach held that the result that the integers of a combination claim must interact to produce “is to be identified by reference to the specification as a whole, and in particular, the objects of the invention”. After citing the explicit object statements from the patent specification, which referred to easier, faster, safer and less frequent maintenance and servicing of the lighting assembly, the judge held that all integers of the claim interacted to achieve this result. The combination claim was therefore found to define patentable subject matter.

From the Wake Forest University and Streetworx cases, it is apparent that those involved in drafting and prosecuting patents with combination claims need to pay particular attention to claim preambles and object statements. Failure to do so may result in inadvertent invalidity through lack of patentable subject matter.