In Australia, one strategy that can be implemented by opponents to establish a claimed invention is obvious, is to retain one or more experts and provide them with a ‘hypothetical task’. The hypothetical task typically involves presenting an expert with a problem and asking the expert to solve it using only information that was common general knowledge in their field at the priority date of the subject patent. If an expert provides a solution that maps onto the claims of the subject patent, the evidence obtained can be used to demonstrate that the claimed invention lacks an inventive step.
Recent Australian patent oppositions from 2023 and 2024 provide valuable insights on how to instruct experts to perform the hypothetical task and avoid the common pitfalls, such as hindsight bias. These oppositions also underscore the importance of conducing the hypothetical task appropriately and the consequences of failing to do so. We have reviewed these substantive oppositions to highlight some of the common issues that arise when preparing inventive step evidence and provide practical tips to avoid them.
As discussed in a previous article on Australian Patent Oppositions (Lessons from Australian patent opposition trends in 2023), of the 22 substantive patent oppositions in 2023, only four involved a hypothetical task (around 18%). In 2024, only two out of the 28 substantive patent oppositions involved a hypothetical task (around 7.1%). As the data suggests, the hypothetical task is rarely used in Australia. This may be due to the complexities associated with preparing the evidence, the perception amongst practitioners that hypothetical task evidence is not useful for patent oppositions, and the cost associated with preparing the evidence. However, as we discuss below, when hypothetical task evidence is prepared carefully, it can be a valuable tool for opponents.
Inventive step evidence
Section 7(2) of the Patents Act 1990 (the Act) provides that an invention is to be taken to involve an inventive step unless it would have been obvious to the person skilled in the art in the light of the common general knowledge, either considered alone or together with one or more prior art documents. As such, in Australian patent disputes, it is very common for opponents and applicants to retain and lead evidence from an expert as to the inventive step of a claimed invention.
An expert’s hypothetical task evidence can be compromised for various reasons. For example, it can be infected by hindsight where the expert was already aware of the solution as a result of prior knowledge or the manner in which they were briefed. Other common issues involve the expert not having the appropriate technical expertise in the field, practitioners not establishing with the expert that the starting point (e.g. a problem) for the hypothetical task was common general knowledge and the formulation of the hypothetical task by practitioners leading the expert towards the invention. Some of these common issues are discussed below in light of recent opposition decisions of the Australian Patent Office.
Structured approach to the hypothetical task
To mitigate some of the risks associated with preparing hypothetical task evidence, practitioners instructing an expert on questions of inventive step can adopt the following set sequence.
First, practitioners could ask the expert about the common general knowledge in the relevant field at the priority date. In doing so, practitioners should carefully ask the questions in a manner that avoids any suggestions from the other side that the expert was "primed" with questions before undertaking the hypothetical task. In Alistair Mann v Electronic Pain Assessment Technologies (epat) Pty Ltd [2023] APO 1 (12 January 2023) (Alistair Mann), MinterEllison (representing Alistair Mann) conducted a hypothetical task that was challenged by the Applicant. In the decision, the Delegate deemed the common general knowledge questions (directing the expert to provide evidence as to the state of the art as it related to automated methods of facial expression recognition) appropriate because the questions pertained to the common general knowledge itself. The relevant extract of the opposition decision states:
[95] … And even if it could be said that [the expert] was “primed” by prior questions from the Opponent’s counsel, to consider recognition of facial expressions as a possible solution to the problem, I am satisfied that this starting point is consistent with the knowledge of a hypothetical skilled team that I have previously found to comprise clinicians, pharmacists, pain psychologists and computer scientists.
Second, practitioners could ask the expert to identify well-known problems in the field at the priority date, one potentially serving as the starting point of the hypothetical task. The expert could then receive a hypothetical task based on their evidence of well-known problems. In response, the expert could explain how they would have solved the problem at the priority date. If the solution provided by the expert doesn't align with the claims of the opposed patent, practitioners could then present the expert with a prior art document to supplement the common general knowledge to see if it would impact the expert's solution.
Importantly, the expert should not receive the prior art documents or opposed patent before undertaking the task, as this may influence them with information that was not common general knowledge (or in the case of the opposed patent, by the actual solution).
In Alistair Mann, the Delegate endorsed this set sequence for conducting the hypothetical task, noting:
[100] … Indeed, [the expert] appeared to have been appropriately briefed: first summarising his own experience, then giving his understanding of common general knowledge in the field of pain, then being presented with the hypothetical task, and only after that being presented with prior art documents and thereafter being shown the opposed application.
Common problems with hypothetical task evidence and how to avoid them
1. Expert exposed to the opposed patent or invention prematurely
The most obvious way evidence is tainted by hindsight is if the expert is provided with the opposed patent, or knows of the invention, before being tasked with the hypothetical task. In such cases, hypothetical task evidence may be afforded little weight as the expert was already aware of the invention.
For this reason, before formally engaging the expert, practitioners could try to determine if the expert is already aware of the product or method associated with the opposed patent without disclosing it. However, there are instances where it is difficult to find an expert in a particular field who is not already familiar with the invention. For example, some inventions (e.g. blockbuster drugs) may be so well-known that finding an appropriate expert without prior knowledge could be impossible.
Ingredion Incorporated v Tate & Lyle Solutions USA LLC and Tate & Lyle Technology Limited [2023] APO 63 (11 December 2023) related to food and beverage products containing allulose syrups. The Delegate found that the expert’s evidence was tainted by hindsight because the expert was initially shown the opposed patent, and knew the opposed patent concerned allulose syrups. Delegate K. Wagg was mindful of this hindsight and observed:
[30] The Applicant’s criticism of the process in which [the expert's] declaration was collected relates to the fact that with the knowledge of the allulose syrups in mind, [the expert's] evidence would be tainted with hindsight. [The expert] provides information on the syrups he had worked on and then does indeed go straight to discussing allulose. I will be mindful of this hindsight bias through the usual weighing of evidence which is part of the role of the Commissioner in patent oppositions.
2. Ensuring the expert recognises the problem was well-known and the risk of practitioners oversharing information
Ideally, before a practitioner provides the expert with a hypothetical task, the expert should establish that the problem posed by the hypothetical task was well-known in the field at the priority date. Otherwise, it may create an unsuitable basis for addressing the inventive step question.
This may require practitioners to direct the expert through questioning, which can be difficult to do without tainting the expert's evidence with hindsight (we elaborate below on the importance of ensuring that the expert's evidence accurately reflects questions asked during evidence preparation). Practitioners should also avoid oversharing particular information prematurely, as the additional information could bias the expert’s evidence with hindsight. One way to navigate this issue could be to retain a 'dirty' expert to help clarify important questions before posing them to the expert.
3. Scope of the hypothetical task and questions put to the expert
Determining the scope of the hypothetical task can be challenging. Asking the expert a broad question without context can lead to the expert providing irrelevant information.
Conversely, practitioners should ensure that the hypothetical task provided to the expert is not narrower than the problem found in the common general knowledge. A narrow brief might lead the expert to overlook other factors that a skilled person would typically consider, or steer the expert towards addressing a specific issue.
In Renascor Resources Limited & Dorfner Anzaplan GmbH v Ecograf Limited [2024] APO 13 (18 March 2024), the Delegate observed that although the expert was asked a follow-up question that seemingly steered him towards using combinations of different purification processes, the expert's response demonstrated a broader consideration and therefore was acceptable:
[78] Renascor relied on this problem in their submissions at hearing. I also note that after [the expert] provided evidence as to the steps he would have taken in response to the hypothetical question, he was then asked what (if anything) he would have done if the graphite had not reached the desired level of purity. This subsequent question arguably directs [the expert] towards the use of combinations of different purification processes, rather than say replacement of the proposed solution (caustic bake) by a different process. However, given that his response included alternatives such as optimising the roast and leach steps I am satisfied that [the expert] considered the question more broadly than necessarily being limited to combinations.
Ideally, the expert should address key technical issues related to the opposed patent, likely to be raised by the other side, while answering the hypothetical task. If the expert does not proactively address these issues, practitioners should consider asking follow-up questions to gather evidence on those technical issues, as responding to those issues in reply evidence can be challenging.
4. Expert’s evidence must include key information
Many experts in patent oppositions state they have read and complied with the Federal Court
Expert Evidence Practice Note (GPN-EXPT), including the Harmonised Expert Witness Code of Conduct and the Concurrent Expert Evidence Guidelines (Expert Evidence Practice Note). The Expert Evidence Practice Note obligates the expert to include all significant matters in their evidence, stating that "...no matters of significance which the expert regards as relevant have, to the knowledge of the expert, been withheld from the Court."
It is crucial to thoroughly document the expert’s reasoning and any substantial questions or information provided by practitioners in the expert’s evidence, as the rationale behind an expert’s decision is often more significant than the decision itself. For instance, it is common for practitioners to direct the expert to specific parts of the common general knowledge. If this occurs, the expert’s evidence should reflect this guidance. This clarifies how the evidence was produced and assists the Delegate in understanding how the expert arrived at parts of their evidence.
In Rozenberg & Co Pty Ltd v Seattle Children’s Hospital d/b/a Seattle Children’s Research Institute; Fred Hutchinson Cancer Center [2023] APO 55, the Delegate was particularly surprised with the expert’s ability to quickly pinpoint the design target in circumstances where the question posed was much broader. The Delegate observed:
[168] When asked to provide comments on “any design features that may improve efficacy of the CAR-T cells and/or improve their safety profile when used in therapy”, Professor Brown drills down to the spacer being the IgG4 hinge with the CPPC mutation from the native CPSC with astonishing precision. He did not ponder on any other component, such as the scFv or any intracellular component, but immediately focused on the spacer as the sole design target. Professor Brown’s ability to pinpoint to a mutated IgG4 hinge spacer is particularly surprising given that the question was not specific to any particular scFv or even to a target antigen.
Consequently, the Delegate was cautious of the expert’s evidence regarding the task of designing CARs at the priority date, favouring the Applicant’s expert’s evidence on this point. Perhaps the Delegate's hesitancy towards the opponent’s expert evidence may have been avoided if the expert's evidence reflected in detail how they reached the design target and questions provided by the legal team.
Although it is a Federal Court decision, the case of Motorola Solutions, Inc. v Hytera Communications Corporation Ltd (Liability) [2022] FCA 1585 (23 December 2022) (Motorola) provides an example of persuasive hypothetical task evidence and a follow-up question being used appropriately. Justice Perram's first instance decision to invalidate a Motorola patent for lack of inventive step was recently challenged unsuccessfully by Motorola on appeal.
In Motorola, MinterEllison conducted a hypothetical task. When questioning the expert about addressing the problem of lost transmissions in the field of two-way radio systems, the expert initially omitted a claimed feature of the patent in their response. Consequently, MinterEllison's follow-up question was reflected in the expert's affidavit. The Judge deemed this follow-up question appropriate, enabling the expert to clarify that the particular feature was part of his solution and that using this feature to solve the problem was, in any case, obvious.
Take away about the hypothetical task
Preparing hypothetical task evidence requires specialist skill. Practitioners should exercise caution to avoid hindsight bias and other common pitfalls when preparing such evidence.
MinterEllison has a specialist patent opposition practice. If you require assistance with an active opposition, or would like to discuss the potential benefits of the Australian patent opposition process, please feel free to reach out.
