The recent Full Federal Court decision in Zoetis Services LLC v Boehringer Ingelheim Animal Health USA Inc [2024] FCAFC 145 has highlighted fundamental flaws in the Australian patent law’s ‘best method’ requirement. While the court's application of existing principles appears sound, the resulting analysis reveals that the requirement is not only arbitrary in its operation, but potentially counterproductive to innovation.
The Australian Patents Act 1990 sets out requirements for patent specifications in section 40. These include that the specification must: disclose the invention in a manner clear enough and complete enough for the invention to be performed by a person skilled in the relevant art (the enablement requirement); disclose the best method known to the applicant of performing the invention (the best method requirement); and that the claims must be supported by matter disclosed in the specification (the support requirement). While failure to satisfy enablement or support might affect only certain claims, failure to disclose the best method is fatal to the entire patent. It is, in effect, a ‘nuclear’ ground of invalidity that cannot be remedied by amendment or partial revocation.
The Zoetis case concerned three patent applications for pig vaccines that were found invalid for failing to disclose the best method of performing the inventions. While the applications disclosed ranges of antigen concentrations that would work, they did not reveal the specific concentrations used in Zoetis's successful experimental vaccines. The court’s analysis of why this was fatal to the applications exposes deep problems with the requirement itself.