Enablement and Plausibility – is a guess good enough?


The Australian enablement requirement was introduced with the IP Laws Amendment (Raising the Bar) Act 2012 that came into effect on 15 April 2013. However, some seven years later there is still little jurisprudence on Australian support requirements. The Raising the Bar amendments on this issue were meant to bring Australian law in line with European law, and this does appear to be the direction in which IP Australia and the courts are heading. The Australian Patent Office has looked to Europe, and particularly the UK, for a framework with which to apply Australian enablement requirements (which are also commonly referred to as “sufficiency requirements”).

This article looks at Australian Patent Office decisions over the past couple of years and the application of a plausibility test to ostensibly prevent speculative claiming under Australian enablement requirements.

By way of background, Section 40(2)(a) of the Patents Act (1990) stipulates that a complete specification must disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art.

The Explanatory Memorandum that accompanied the Raising the Bar Act (2012) which introduced the enablement requirement explains that this provision is ostensibly to require enablement of the invention across the full scope of the claims, without undue burden, or the need for further invention. The question is, what level of disclosure is needed to meet this threshold and enable the claims across their full scope? In other words, based on a given disclosure, how broadly are you entitled to claim your invention, e.g. by extrapolating claim scope beyond what is specifically disclosed or exemplified in the specification?

To address this, the Patent Office has adopted a plausibility test, that is, based on the disclosure of the specification, it must be plausible that the invention can be worked across the full scope of the claims. But what does plausible mean?

Background of the plausibility test

The spectre of plausibility first raised its head in Australia in the Evolva Patent Office decision which was published on 14 November 2017 in which the Patent Office adopted a low threshold test based on the approach outlined by the UK Courts in Human Genome Sciences Inc v Eli Lilly & Co [2011] UKSC 51; [2012] RPC 6 (Eli Lilly). However, recent developments in UK jurisprudence (see Warner-Lambert v Generics & Anr [2018] UKSC 56) have raised the threshold for the plausibility test, and it appears that the Australian Patent Office (“APO”) is following suit. In a more recent APO decision (BASF Corporation [2019] APO 34 (19 July 2019)), the Delegate confirmed the approach applied in the Warner-Lambert case. This suggests that, in the absence of Australian Court decisions, the Patent Office will continue to be guided by the UK approach.

The Evolva Decision

The Evolva decision (Evolva SA [2017] APO 57 (14 November 2017)) concerned Australian patent application no. 2012342114.

Australian patent application no. 2012342114 was directed to a method of producing a mogroside compound that comprised contacting and glycosylating mogrol with recombinant polypeptides having at least 90% sequence identity with certain amino acid sequences.

During prosecution, the examiner raised support and enablement objections against certain claims. Specifically, the examiner was of the view that there was no general principle of application that would enable the invention across its full scope since:

“The present claims recite peptides with at least 90% sequence identity to any one of 5 reference sequences. It is not reasonable to assume (and the applicant admits in their response, by indicating the need to test such peptides for the desired activity) that every single peptide having the recited sequences will have the recited transferase activity.

As such, the present claims are not considered to have a principle of general application. Therefore, in order to work the invention across its full scope (i.e. to say for the PSA to reasonably know which of the recited peptides are encompassed by the claims), the PSA would need to produce every single peptide recited and then take the additional step of assaying each to see which have the desired activity…”

The Applicant was unable to resolve the objection through written responses, and as such, requested to be heard before the Patent Office.

In the hearing, the Delegate referred to earlier UK and European jurisprudence to resolve the question of what constitutes a clear enough and complete enough disclosure and advocated the following test1:

  1. What is the scope of the invention as claimed?
  2. What does the specification disclose to the skilled person?
  3. Does the specification provide an enabling disclosure of all the things that fall within the scope of the claims, and in particular:
    1. Is it plausible that the invention can be worked across the full scope of the claims?
    2. Can the invention be performed across the full scope of the claim without undue burden?

With regard to this case, the Delegate was of the view that the “only issue in question here is whether it is plausible that polypeptides which have as low as 90% identity would be capable of catalysing the defined glycosylation reaction”2. To answer this question, the Delegate adopted a plausibility test based on the UK approach in the Eli Lilly case, where it was decided that the threshold for plausibility was “a low one, and may be based on the slimmest of evidence”, and in some cases plausibility could be established by a “reasonably credible” claimed use or an “educated guess”3.

The Delegate concluded that since each of the recited amino acid sequences contained the same consensus sequence, and that the skilled person would understand the role of this consensus sequence in the glycosylating reaction, it was plausible that the claims could be performed across their full scope to produce a mogroside compound.

The BASF decisions

More recently, the question of plausibility was considered in BASF Corporation [2019] APO 34 (19 July 2019).

Patent Applications: 2017204400 & 2017204506 were directed to synergistic fungicidal or insecticidal mixtures comprising either a fungicide or insecticide selected from a particular group of fungicides or insecticides in combination with particular bacteria.

During prosecution, the Examiner raised support and enablement objections against certain claims. Specifically, the Examiner was of the view that there was limited exemplification of synergy, and in the absence of a general principle of application, the claims were not enabled across their full scope.

The Applicant substantially narrowed the claims and argued that given the reduced number of potential combinations, there was no undue burden of experimentation to perform the claimed invention. The Examiner acknowledged that this amendment resolved the “undue burden of experimentation” but maintained that the claimed invention failed the plausibility test given the lack of exemplification. Relevantly, neither the ‘400 nor the ‘506 specifications provided experimental data evidencing synergy of the claimed compositions. To address this shortcoming, the Applicant sought to rely on post-filing evidence of synergy.

The Examiner maintained the enablement objection, and in response, the Applicant requested to be heard before the Patent Office.

As part of the Hearing submissions, the Applicant filed an expert declaration in which a person skilled in the art expressed their view that they would consider it likely that synergism would occur in the claimed combinations based on the information provided in the specifications as filed.

In considering whether the invention was plausible across the full scope of the claims, the Delegate again referred to UK jurisprudence noting that subsequent to Eli Lilly, the UK Supreme Court had issued a more recent decision, Warner-Lambert Company LLC v Generics (UK) Ltd [2018] UKSC 56 (the UK Warner-Lambert decision).

There were two key decisions that came out of the UK Warner-Lambert decision:

  1. the UK Supreme Court overturned earlier decisions in relation to the plausibility threshold noting that plausibility tests outlined in these earlier decisions were too low and could be “satisfied by a ‘prediction … based on the slimmest of evidence’ or one based on material that was ‘manifestly incomplete’.”; and
  2. it was made clear that sufficiency of disclosure must be met at the filing date of the specification, specifically: “Sufficiency of disclosure must be satisfied at the effective date of the patent, i.e. on the basis of the information in the patent application together with the common general knowledge then available to the skilled person. Acknowledging sufficiency of disclosure on the basis of relevant technical information produced only after this date would lead to granting a patent for a technical teaching which was achieved, and, thus, for an invention which was made, at a date later than the effective date of the patent.”

Turning to the plausibility threshold, the Delegate stated that while “the specifications, given what they present as the invention, can be understood to assert that it would be expected that synergistic combinations would result… they do not provide any underpinning explanation for this assertion”4, thus highlighting the potential importance of disclosing a principal of general application or underlying mechanism that can be applied across the full claim scope.

Turning to the sufficiency of disclosure requirements, the Delegate dismissed the post-filing evidence filed by the Applicant5.

Neither of the above were determinative since ultimately the Delegate decided that the claims were enabled on the basis of the statements made in the expert declaration, and that in the absence of any contradictory evidence, the enablement objection could not be maintained6.


The Australian enablement test as applied by the Australian Patent Office continues to evolve in view of UK jurisprudence. However, the test for plausibility has not yet been considered in the Australian Courts.

These decisions highlight that presently:

  • The plausibility threshold is relatively low, although the threshold has increased beyond speculation or mere assertion. Disclosing a principal of general application or underlying mechanism that applies across the full scope of the claims provides strong basis for plausibility.
  • Plausibility should be considered based on the specification at the filing date of the specification. Lack of enablement cannot be rectified by post-filed data.
  • Narrowing claim scope to avoid an “undue burden of experimentation” by limiting the number of potential permutations of the invention does not necessarily remedy the issue of plausibility since these are two different arms of the enablement test.

A Declaration from a skilled person that they would consider plausible, based on the information in the specifications as understood at the filing date, can be highly persuasive in establishing plausibility.

1 Evolva SA [2017] APO 57 (14 November 2017) at 45

2 Ibid at 59

3 Ibid at 59

4 BASF Corporation [2019] APO 34 (19 July 2019) at 79

5 Ibid at 68

6 Ibid at 86

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