A statutory obligation

In Australia, the patent applicant has an obligation to disclose the best method of performing the invention known to the applicant at the time of filing the patent application – section 40(2)(aa) of the Patents Act 1990 (Cth).

This obligation does not exist in other major jurisdictions, such as in Europe and the United States.

Failure to meet this obligation is a ground for revocation. It can be an effective ground because it is difficult to remedy and success results in all the claims of the patent being invalidated.

What have the courts said?

In Zoetis Services LLC v Boehringer Ingelheim Animal Health USA Inc (2024) FCR 19 (Zoetis) it was held that the “invention” refers to the “embodiment which is described and around which the claims are drawn. “It is necessary to consider both the description of the invention and the claims” to determine whether the best method has been disclosed

In Zoetis the Full Court considered the earlier Full Court decision of Firebelt Pty Ltd v Brambles Australia Ltd (2000) FCA 1689 (Firebelt), to illustrate how the law has changed. The relevant claim in Firebelt was directed to a side loading refuse vehicle that included a lid opening device. There was evidence that the invention would not work without a lid opening device. The court set out that there was no statutory obligation to describe which of the contemplated lid opening devices was considered to be the best. In Zoetis the court set out that the form of the claims is not determinative. The fact that none of the claims in Firebelt was to a lid opening device operating at any particular time could not of itself be an answer to whether the best method is disclosed if the timing of the operation was advantageous to the working or the quality of the achieved outcomes.

In Les Laboratoires Servier v Apotex Pty Ltd [2016] FCAFC 27 (Servier), the claims were directed to a compound. Servier argued that the best method requirement was met because the patent specification identified the best compound, which was claimed. The court accepted that there are cases where the claim is to a product or class of products and the “best method requirement is satisfied by a description of the best embodiment known to the patentee at the relevant time”. However, “the nature and extent of the disclosure required to satisfy the best method requirement will depend on the nature of the invention itself. Accordingly, a distinction between products and processes that ignores the specific features of the invention claimed is unhelpful.”

Referring to the obligation described above, the court described the best method requirement as: “…where an inventor in fact knows of a method at the time of filing the complete patent application, which has taken the methodology to a more satisfactory stage or provides more certainty so that the public may more quickly and easily utilise the invention for which a monopoly is granted, the inventor is under an obligation to disclose that method”. Furthermore:

“If Servier knew of a method that provides a form of the salt with the characteristics exemplified in the Patent, which characteristics provided the stated advantages of the invention over the prior art, it was incumbent on it to provide that method. This would relieve the skilled worker from making the choices within those necessarily made or available in a classical salification. The disclosure of the method known to Servier would not only have relieved the skilled addressee of confronting blind alleys and pitfalls which may not be uncommon in a general sense but also, and importantly, would tell the skilled addressee the methodology to achieve the form that obtains the result which constitutes the invention, that is increased stability and storage length.”

In GlaxoSmithKline Consumer Healthcare Investments (Ireland) (No 2) Ltd v Generic Partners Pty Ltd [2018] FCAFC 71, the court set out that the patent applicant is not entitled to withhold information that is necessary to enable the skilled addressee to perform the invention in accordance with the invention merely because the skilled addressee could ascertain such information by routine experimentation. Whether the applicant should disclose relevant information will depend on the importance of the information in question, the practicality of disclosing it, and the extent of the burden imposed on the skilled addressee who is left to rely upon routine experimentation. The question is to be addressed in a practical and common-sense manner.

In Dometic Australia Pty Ltd v Houghton Leisure Products Pty Ltd [2018] FCA 1573 (Dometic), the innovation patent in suit broadly related to an air conditioning system. Saliently, the innovation patent was filed as a divisional application. The defendant claimed that the innovation patent did not comply with the best method requirement as the divisional application specification did not disclose the best method for inducing and maintaining a Coandă effect. The inventor (also the defendant) found that the Coandă effect was instrumental to the working of the invention covered by the Patent and the improved method for inducing and maintaining a Coandă effect was developed between filing the parent case and the divisional application. The Court determined that the best method requirement must be fulfilled on the actual filing date of the patent application. That is, the relevant date for assessing best method with respect to a divisional application is the actual filing date of the divisional application, not the filing date of the parent case/s. In the case of Dometic, the patentee was saved as evidence demonstrated that the patentee did not have knowledge of the improved method at the time that the divisional application was filed. But for this fact, the Patent would have been deemed invalid and unenforceable due to lack of best method in light of the omission of a description of the method to achieve an important advantage of the invention.

Consider all information necessary to reproduce the invention

Generally, the more critical or necessary the information is to reproducing the invention, the more likely it is that the information should be included. This should be relatively easy to assess once the invention has been properly identified, including the particular advantages achieved by performing the invention. These should not necessarily be described as “advantages” specifically. However, the utility of the embodiments described in the specification can be highlighted with reference to improvements over the prior art. This can help to anticipate potential inventive step issues that may be raised by an examiner, allowing the applicant to refer to passages in the specification that support arguments.

Issues relating to disclosure in a patent specification should be addressed as early as possible in the drafting process.  Where possible, advantages over prior art and alternative embodiments of the invention should be described in the specification.

Safeguarding against best method attacks

It is difficult to remedy a failure to disclose the best method because an amendment to disclose the best method invariably results in the impermissible addition of new material to the specification.

Patent applicants should consider maintaining divisional patent applications so that they can pursue an additional divisional application if a corresponding granted patent is vulnerable to a best method attack.