This decision involved the New Zealand Court of Appeal considering an appeal against two decisions of Justice Morris in the High Court. The revocation decision is Novartis New Zealand Limited & Cyanamid of New Zealand Limited v Ancare New Zealand Limited CP480/97, Auckland High Court, 19 June 1998, (unreported). The case involved anthelmintic compositions suitable for administration to farm animals. In an earlier decision, Justice Morris found that the patent was invalid on the basis of obviousness and anticipation and in the second decision that the specification could not be amended to cure the defect. The defendant appealed both decisions, which were heard together by the Court of Appeal.

One issue that was decided by the same judge was that when looking at the ground of obviousness, the so-called “diligent searcher” test applied. That is, the prior art forming part of the obviousness enquiry needed to be art that would have been found by a diligent searcher. It had been thought by some commentators that this test had been discarded following the decision in the Windsurfer case (Windsurfing International Inc v Tabur Marine (Great Britain) Ltd [1985] RPC 59 (CA). Nevertheless, Justice Morris applied the diligent searcher approach and considered how a diligent searcher would operate in the particular circumstances of the case.

In the appeal, the Court of Appeal was asked to rule on whether the diligent searcher test formed or still formed part of the law and procedure in New Zealand. Unfortunately, the court did not decide the issue, on the basis that it did not need to do so. This means it remains, to some extent, at large and Justice Morris’s decision remains the last word on the topic.

One issue the Court of Appeal did deal with was the procedure adopted by the patentee during amendment of the patent specification. The court was quite firm in its view that it would have been preferable if Ancare, the appellant, had undertaken all amendments prior to the hearing, so as to distinguish the cited prior art. That is, so that the issue of validity could have been determined in the light of the ruling on the amendments.

The court in particular was dismissive of any attempt to support at trial two different versions of the patent. That is, on the basis that it is contrary to the fundamental requirements that a patent clearly define an invention. It is expected that this directive will dissuade patentees from filing amendments late in the piece and trying to run different versions of the patent, in the alternative.

Also on the basis of Windsurfing International Inc v Tabur Marine (Great Britain) Limited [1985] RPC 59 at 73, the Court of Appeal held that the inventive step has to be found in the language of the specification and it cannot be found elsewhere. At the time of going to press, this decision is under appeal to the Privy Council in London.