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.
Enablement vs Best Method
The court emphasised that enablement and best method are distinct requirements. As the judgment explains, at [48]:
There is nothing in Zoetis’s submission that the fact that the person skilled in the art was enabled to make vaccines with any desired antigen concentration had implications for the best method issue. The two grounds are distinct in s 40(2) and are to be kept that way. There is no conceptual difficulty in concluding that an invention is enabled across a range (as here of antigen concentrations) but, at the same time, concluding that the best method of making the composition has not been disclosed.
The court proceeded to reject Zoetis’s argument that disclosing a range of workable embodiments was sufficient at [57]:
Zoetis’s submission is that the specification ‘disclose[d] a range of embodiments’ because it disclosed that the invention could be satisfactorily performed over the disclosed range of antigen concentrations. If this is correct, then the specification disclosed a large number of embodiments …. With such a number of embodiments, a fair disclosure of the best method known to Zoetis of making the vaccine required Zoetis to indicate which was the most efficacious to its knowledge from the trials it had conducted on that issue through the assay of the various IVPs.
Enablement requires that an applicant provide sufficient information for the skilled person to work the invention across the full scope of the claims. You cannot validly claim a range unless you can enable others to work the invention across that entire range. Best method, by contrast, creates an obligation based purely on what the applicant happens to know at the filing date (presumably – but see further discussion below). An applicant who knows certain values within the range work better than others must disclose this information, while an applicant who has not yet done the optimisation work faces no such obligation.
The Timing Question – Filing vs Grant
Interestingly, the court noted (at [15]) that there remains ‘a controversy in the authorities as to whether the relevant date at which this question is to be posed is the date of the filing of the application or the date of the grant’.
However, this controversy – assuming it is real – appears to be largely academic under the current Act. Following the Raising the Bar reforms in 2013, section 102 prohibits the addition of any matter not disclosed in the specification as filed. This means that even if the best method requirement theoretically applied at grant, it would be impossible to comply with any obligation to disclose improvements discovered after filing. The specification simply cannot be amended to add such information. It follows that any question of when the best method known to the applicant must be disclosed can now only be resolved in favour of the filing data. Anything else runs counter to the existing legislative scheme.
A Fundamentally Flawed Requirement
This analysis reveals the best method requirement to be fundamentally flawed in several ways. First, it is essentially arbitrary – the extent of mandatory disclosure is determined not by what others need to know to work the invention, but by the timing of the application relative to the applicant’s own development work. An applicant who files an application without having conducted optimisation must still enable the full scope of any claimed ranges, including disclosing methods for producing values across those ranges, and providing sufficient justification for why the person skilled in the art would expect the invention to work throughout the claimed scope. But having satisfied those requirements, the applicant faces no additional obligation to disclose optimal values within those ranges. By contrast, an applicant who has done the hard work of testing and optimisation before filing must disclose those insights in full detail – insights that may have value well beyond the patent term.
Second, the best method requirement creates perverse incentives. It effectively penalises successful development work completed before filing. This has the potential to encourage earlier filing with less experimental validation, rather than conducting thorough pre-filing testing and development work. Ironically, once the application is filed, the applicant is then free to conduct optimisation work without any obligation to disclose the results, even though any improvements discovered during prosecution might be just as valuable to the public as those known at filing.
Third, and perhaps most significantly, the requirement cannot achieve its intended purpose. The goal is presumably to ensure that the public receives disclosure of the best method of performing the invention in exchange for the patent monopoly. But since the disclosure is limited to what was known at filing, and improvements cannot be added later, there is no guarantee that the disclosed method will actually be the best method by the time the application is published or, subsequently, when the patent is granted.
International Perspective – Is Australia Becoming an Outlier?
The strictness of Australia’s approach stands in marked contrast to a number of other major jurisdictions. In Europe, there is no best method requirement at all – enabling disclosure that supports the claims is sufficient. The United States has effectively neutered its equivalent ‘best mode’ requirement through the America Invents Act. While the requirement remains in the statute it is, in practice, unlikely to arise during examination, and a failure to disclose best mode can no longer be used to invalidate an issued patent.
These jurisdictions appear to have recognized that an overly strict best method requirement can upset the delicate balance between encouraging innovation through the patent system and preserving legitimate trade secrets. The fact that sophisticated patent systems such as that created by the European Patent Convention can function effectively without a best method requirement at all suggests that Australia’s approach may be unnecessarily severe.
Commercial Reality vs Legal Theory
The current Australian approach seems to rest on a theoretical view of the patent bargain that doesn’t align well with commercial reality. In many cases, the truly valuable know-how in implementing an invention lies in details that go beyond what is necessary to enable its practice. Forcing disclosure of these details may actually discourage use of the patent system, particularly in industries where such implementation knowledge represents significant competitive advantage.
Moreover, it’s often possible for competitors to discover optimal implementation parameters through their own trials or reverse engineering of commercial products. The patent system’s primary goal is to enable others to practice the invention, not to save them routine development work that they are perfectly capable of performing themselves.
A Better Way Forward
If the concern is preventing deliberate concealment or deception in patent applications, Australia already has a more appropriate tool in section 138(3)(d) of the Patents Act, which allows revocation of patents obtained by fraud, false suggestion or misrepresentation. These are serious allegations requiring clear evidence, and courts are rightly cautious about making such findings without direct proof rather than mere inference.
The Zoetis decision highlights the reasons why it may be time for Australia to reconsider its approach to the best method requirement. At minimum, courts should recognise that there’s a difference between enabling disclosure necessary to practice the invention and the kind of implementation details that legitimately belong in the realm of trade secrets. The European approach demonstrates that a patent system can function effectively without requiring disclosure of every optional implementation detail known to the applicant.
While some form of best method requirement may serve a useful purpose, its application should focus on preventing deliberate concealment of information necessary to practice the invention effectively, not forcing disclosure of every implementation detail that might provide commercial advantage. Until this balance is restored, Australian patent applicants face unnecessary uncertainty and risk from what has become an increasingly problematic requirement.
Naturally, I am not the first to raise these concerns, and I know that they are shared by other practitioners in Australia. IP Australia maintains a Policy Register that it describes as a ‘snapshot of issues’ that have come to its attention from various sources. The Register includes a proposal to repeat the best method requirement, which has been ‘on hold’ since September 2017, despite being flagged as ‘medium priority’. Maybe it is time to take this proposal off hold?