Patent Law - Methods Already Employed
in Practice Cannot Be Inventive Steps

The Judicial Committee of the Privy Council (PC) in Ancare New Zealand Limited v Fort Dodge New Zealand Limited [PC Appeal No 32 of 2001, 28 February 2002] decided that doing something which is common practice but which does not accord with scientific opinion is not necessarily an inventive step for the purposes of patent law. In that case, an appeal from New Zealand, the PC gave an admirably succinct judgment on the question of "obviousness" in respect of a patent which was challenged on the ground that the invention did not involve an inventive step.

For all intents and purposes the question of obviousness as it relates to patents is the same in New Zealand as in the UK under the Patents Act 1977, which provides that an invention, in order to be patentable, must not only be "new" (i.e., it does not form part of the state of the art), but must involve an inventive step, in that when compared with what is already known, it would not be obvious to someone with a good knowledge and experience of the subject.

In this case the patent in suit was for a liquid anthelmintic composition suitable for administration to farm animals which contained praziquantel (a compound active against tape worms) and one or more other compounds, such as levamisole or benzimidazole, which were active against roundworms.

The trial judge found that praziquantel was a well known compound which had been used to eradicate tapeworms in humans and small animals for a number of years. It had been patented by Bayer but the patent expired while the inventee was engaged in developing its product. It was therefore an obvious choice for the tapeworm element in the composition. Moreover, Levasimole was well known for treating roundworms. It would therefore have been obvious to anyone familiar with the prior art that if one wanted a combined treatment for tapeworms and roundworms , praziquantel and levasimole were well worth trying.

The inventee's position, when appealing to the PC, was that the idea behind the patent was in the face of scientific hostility to the very notion of treating tapeworms (as opposed to roundworms) in sheep as they were not seen as dangerous. However, since the priority date (the date of the patent application), research had shown that tapeworms were harmful to sheep. Thus, the inventive step was, therefore, to stand out against received scientific opinion and show prescience in realising that treating sheep for tapeworm was a sensible thing to do.

However, Lord Hoffman found - despite the inventee's clever argument - that the patent specification did not purport to identify a need for the treatment of tapeworms which had not been previously recognised.

Moreover, it was held that even if one could identify the inventive step as the idea of finding a compound to treat tapeworms as well as roundworms, it was not new. This was because at the priority date, most New Zealand farmers were treating their sheep for tapeworm and compounds for doing so were something known or used before the priority date of the claim in New Zealand. Just because the scientific community had thought it was perfectly useless does not mean that practising it, or having the idea of making a preparation to do it, was an inventive step. Otherwise anyone who adopted an obvious method for doing something which was widely practised but which the best scientific opinion thought was pointless could obtain a patent. To ignore what is being done in the market because it does not accord with scientific opinion would lead to the grant of a patent for what is already in use - or obvious extensions.

Accordingly the Privy Council agreed that the inventee's patent should be revoked.