We can all be guilty of promising more than we can deliver – but for a patentee, that can be fatal for the validity of your patent. Under Australian patent law, inventions must be ‘useful’ in order to be patentable, and one of the complex elements of this requirement is whether any promises made with respect to the invention in the specification are satisfied. If you promise more than your invention can deliver, your invention will be found inutile. But how is the ‘promise’ of an invention to be characterised – and what if your patent specification makes many promises?
The Full Court of the Federal Court of Australia (FCAFC) recently confirmed the applicability of the ‘Promise Doctrine’ under Australian patent law – particularly as it applies to patents that disclose ‘composite’ promises. In its decision in ESCO Corporation v Ronneby Road Pty Ltd, the FCAFC. held that the invention as claimed in each and every claim of a patent must achieve the promise set out in the specification – including ‘composite’ promises that may comprise multiple features or parts.
The ‘Promise Doctrine’
The requirement that an invention should be useful before it can support the grant of letters patent predates the Statute of Monopolies and, along with novelty, is one of the earliest requirements of patent validity. 
Over time, courts have developed several rules for assessing the utility of an invention. One of these rules requires that an applicant or patentee delivers on any promise for the invention which was made in the specification. This rule is sometimes referred to as the ‘Promise Doctrine’.
The Doctrine finds its roots in the “False Promise Doctrine” from the United Kingdom, which developed in the early part of the 20th Century when the grant of a patent resulted from the Crown exercising its own discretionary power. There was a presumption that the Crown granted patents on the entirety of the disclosure in the application being true.
Although the requirement that a patentable invention should be useful is now a specific statutory requirement, the application of the Promise Doctrine as an element of the utility requirement, continues to persist in Australia. The approach taken by the FCAFC in this case is notably in contrast to the position in jurisdictions such as Canada, where the Supreme Court of Canada, in the recent decision of AstraZeneca Canada Inc v Apotex Inc (2017) SCC 36, declared that the promise doctrine is no longer good law as it undermines the interpretation of utility under Canadian patent law.
This case – Application of the Promise Doctrine and the question of composite promises
The patent application in this matter concerned an invention that “pertains to a wear assembly for securing a wear member to excavating equipment”. The invention was described in the abstract of the patent as:
A wear assembly for excavating equipment which includes a wear member and a base each with upper and lower stabilising surfaces that are offset and at overlapping depths to reduce the overall depth of the assembly while maintaining high strength and a stable coupling. The nose and socket each includes a generally triangular-shaped front stabilising end to provide a highly stable front connection between the nose and wear member for both vertical and side loading. The lock is movable between hold and release positions to accommodate replacing the wear member when needed, and secured to the wear member for shipping and storage purposes.
Relevantly, paragraph 6 in the “Summary of the Invention” section, stated:
The present invention pertains to an improved wear assembly for securing wear members to excavating equipment for enhanced stability, strength, durability, penetration, safety and ease of replacement. (emphasis added)
Ronneby (who sought to challenge the validity of the patent application) argued that the promise of the invention, being “the consideration for the grant of the monopoly”, lies in attaining, in each of the claims of the patent, each and every one of the features said to produce the improved or enhanced wear assembly. That is, every claim of the patent application should provide a wear assembly that has enhanced:
- stability, and
- strength, and
- durability, and
- penetration, and
- safety, and
- ease of replacement.
A failure of any claim to achieve all of these promises, Ronneby argued, would render that claim invalid.
But what was the promise?
The Federal Court at first instance declared Esco’s patent invalid for lack of utility, finding that although a number of the claims delivered one or more of the promised advantages, none delivered on all six of the promises.
The FCAFC took the view that where a composite promise has been made with respect to an invention, a failure to attain any one of the elements of that composite promise in any claim will render that claim inutile. However, the FCAFC found that on a proper construction of the Esco’s patent application, the promise of the Esco invention as claimed was not that it would achieve each of the enhanced features identified in paragraph 6 of the ‘Summary of the Invention’.
It was noted that the standard or ‘orthodox’ approach in applying the Promise Doctrine is to look first to the body of the specification to determine what the promise(s) of the invention are, and then turning to the claims to see whether those promise(s) have been attained. However, the FCAFC considered that in cases like Esco where the claims are variously directed to different aspects of the invention, including the different enhanced features identified in paragraph 6 of the specification, a ‘heterodox’ approach is more apt. This involves looking at the body of the specification and then at the claims and then back at the specification. Regardless of which approach is used, it was the FCAFC’s view that the construction of the specification (when read as a whole) should not produce discontinuity or asymmetry.
While it has been suggested that Australian courts should follow their Canadian brethren by abandoning the Promise Doctrine, the FCAFC’s decision in this case shows that, at least for now, it remains a key element in assessing whether an invention has met the statutory “usefulness” threshold. Whether the orthodox or ‘heterdox’ approach to patent construction is adopted, the conclusions reached by the FCAFC in this case highlights the importance of ensuring that care is taken when describing outcomes said to be achievable by the invention as claimed.
The author wishes to thank Sally Knowles-Jackson and Veg Tran for their assistance in the preparation of this article.
 McEniery, Ben, ‘Patent Eligibility and Physicality in the Early History of Patent Law and Practice’ (2016) 38(2) UALR 175, 181.
 2017 SCC 36 [AstraZeneca] at paras 34, 35.
 Section 18(1)(c) of the Patents Act 1990 (Cth) for standard patents and section 18(1A)(c) for innovation patents. As in the case of the Patents Act, 1952 (Cth), lack of utility was not a ground for pre-grant opposition. Lack of utility was introduced as a ground for pre-grant opposition by the US Free Trade Agreement Implementation Act 2004 (Cth). Following the passage of the Intellectual Property Laws Amendment (Raising the Bar) Act 2012, it has also become a ground for re-examination.
 ESCO Corporation v Ronneby Road Pty Ltd  FCAFC 46.