Legal Insights

Patent priority date issues under the Raising the Bar regime

By Ben Miller, Stephen Rohl, Katie Pryor

• 22 December 2023 • 7 min read
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In brief

Under the “Raising the Bar” (RTB) regime, in order to obtain the benefit of an earlier priority date, the claimed invention must be disclosed in a manner that is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art. This new requirement has been awarded fairly minimal judicial consideration to date.

ToolGen Incorporated v Fisher (No 2) [2023] FCA 794 provides a detailed assessment of the post-RTB law of priority in the context of the exciting early-2010s race to apply CRISPR-Cas9 technology to the genetic editing of human and animal cells.


ToolGen is the applicant for Australian patent application number 2013335451, which relates to a system for implementing CRISPR/Cas9 in eukaryotic cells. The patent application claims an earliest priority date of 23 October 2012 based on a US provisional patent application (P1).

The patent application comprises 21 claims, including independent claim 1 for a composition and independent claim 10 for a method. The claims are directed to systems comprising a nucleic acid encoding a Cas9 polypeptide and a nucleic acid encoding a guide RNA that hybridises to a target nucleic acid sequence in a eukaryotic cell.

During opposition proceedings in the Patent Office, claims 1-8 and 10-18 were found to lack novelty and lack an inventive step in circumstances where none of the claims was entitled to priority from P1. Claims 19 and 21 were found invalid on the basis of lack of clarity and lack of inventive step, respectively.

ToolGen appealed to the Federal Court. The opponent, Fisher, and a related party cross-appealed in relation to claims 9 and 20.

This update considers the Federal Court’s findings in relation to the priority claim only.

The law of priority

Under s 43(2) and (2A) of the post-RTB Patents Act, a claim will be entitled to an earlier priority date if the relevant document discloses “the invention in the claim in a manner that is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art”.

Nicholas J stated that this language “is essentially the same” as the language of s 40(2)(a) (which reflects “classical sufficiency”).[1] Under the umbrella of “the disclosure requirement”, his Honour went on to consider the UK and European law on these grounds, as well as the Explanatory Memorandum to the RTB Act.

ToolGen submitted that an important difference between the European law and s 43(2A) of the Patents Act is that the latter imposes no requirement that the priority document and the patent application be “in respect of the same invention”.[2] Nicholas J observed that the implication of this submission is that a claim may be entitled to an earlier priority date based on a document directed to a different invention to the claim in question.[3]

Nicholas J rejected ToolGen’s argument, finding that although there was no such express requirement in s 43(2A) of the Patents Act, it did not follow that the priority document need not disclose the invention claimed.[4] His Honour noted that “it is not sufficient for the priority document to provide a starting point from which the person skilled in the art may transition from one invention to another by use of the common general knowledge”.[5]

His Honour went to consider these principles in the context of P1.


Nicholas J characterised P1 as “a relatively short document which resembles an unpublished journal article”.[6] The document states that it describes “a novel genome editing technology based on RNA-guided endonucleases”.

In what could perhaps be viewed as a bad omen for ToolGen’s priority claim, Nicholas J found that the skilled addressee of P1 was different to that of the patent application – while P1 was addressed to a molecular biologist, the patent application was directed to a team comprising both a molecular biologist and a microbiologist.

One of the issues in dispute was the extent to which various aspects of P1 disclosed technology for use in vivo rather than in vitro. For example, Nicholas J found that P1 only disclosed DNA templates suitable for in vitro preparation of a guide RNA and that there was no disclosure of any system in which nucleic acids were introduced into the cell to transcribe the guide RNA in vivo.

Another question before his Honour was whether P1’s disclosure in the context of a particular bacterial species enabled the performance of the invention more broadly. Nicholas J rejected ToolGen’s argument that P1 discloses a principle of general application. His Honour found that the inventors of P1 tested the technology on components derived only from a specific species of bacteria and that there was nothing in the document to suggest that this species was likely to be representative of other bacterial species with a Type II CRISPR/Cas system, or that these results could be generalised to eukaryotic cells.[7] Further, there was evidence of uncertainty associated with predicting in vivo effectiveness of a CRISPR/Cas9 system from in vitro assays at the priority date.[8]

As to whether the compositions and methods of the claims were otherwise enabled beyond the particular bacterial species disclosed in P1, his Honour concluded that the skilled team would be required to carry out “prolonged research and experimentation and would most likely encounter significant difficulties along the way”. Further, “[m]uch of the work would be non-routine and would be carried out in circumstances where P1 provided no meaningful guidance or direction and no assurance of success”.[9] His Honour found that none of the claims of the patent application was entitled to priority based on P1.

After considering the arguments relating to other grounds of invalidity, Nicholas J concluded that each of the claims would, if granted, be invalid. ToolGen has sought to amend the patent application, with a hearing scheduled for March 2024.

Key takeaways

This case provides some much-anticipated judicial guidance on the “new” s 43 of the Patents Act and serves as a reminder of the higher standard imposed by the requirement that a priority document clearly discloses an invention, compared to the pre-RTB external fair basis requirement. The makeup of the skilled team may be central to this assessment.

The Prescription - December 2023 Edition

The Prescription is a biannual publication addressing legal developments and trends in the healthcare and life sciences spaces in Australia.

[1] [166].
[2] [182].
[3] [183].
[4] [193].
[5] [193].
[6] [52].
[7] [320].
[8] [325].
[9] [362].

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