Background

In a decision handed down on 14 July 2023, the Federal Court of Australia (the Court) has upheld a decision of the Commissioner of Patents in opposition proceedings against the grant of Australian Patent Application No. 2013335451 (the Application) filed by ToolGen Incorporated (ToolGen). The Court held that ToolGen was not entitled to claim priority from the first filed application, US Provisional Patent Application No. 61/717,324 (P1) as the claimed invention was not sufficiently disclosed in P1. As a result, the claims were held to be invalid for lack of novelty and inventive step.

Following this decision, ToolGen has been provided with an opportunity to amend the claims of the Application to address the identified defects. While these amendments will be considered by the Court, the respondents have already indicated they will oppose any amendments. As such, it is unlikely this matter will be resolved in the near future. In the meantime, however, the reasoning of Justice Nicholas in this decision provides useful guidance with respect to the disclosure requirements to establish entitlement to priority in accordance with sections 43(2) and (2A) of the Patents Act 1990 (Cth).

The Opposition Proceedings and Appeal

A "strawperson" opponent, Grant Fisher, was successful in opposing the grant of the Application on the grounds of lack of novelty, inventive step and clarity. Central to the submissions made by the Opponent was the allegation that ToolGen was not entitled to rely on the earliest claimed priority date on the basis that the first filed application, P1, did not sufficiently disclose the claimed invention. A Delegate of the Commissioner of Patents agreed with the Opponent in finding that claims 1-8 and 10-19 were invalid (Fisher v ToolGen Inc [2018] APO 65). ToolGen appealed the opposition decision pursuant to section 60(4) of the Patents Act.

At the outset of the Appeal, there were a number of concessions made by the parties, which had the effect of narrowing the substantive issues for the Court to consider, despite the fact that appeals from the Australian Patent Office are heard de novo as original proceedings. Specifically, the parties agreed that if claims 1-8 and 10-18 were not entitled to priority from P1, these claims were not novel and lack an inventive step. Moreover, neither party made any submissions in relation to the other two priority documents, US Provisional Patent Application No. 61/803,599 (P2) and US Provisional Patent Application No. 61/837,481 (P3), implying agreement that P2 and P3 were irrelevant, or could not be relied upon for claiming priority.

Claiming priority – what level of disclosure is sufficient according to Australian law?

Under section 43(2) of the Patents Act, the priority date of a claim may be the filing date of an earlier filed application (e.g., provisional application, PCT application), or the filing date of the application. When determining if the priority date of a claim is the filing date of an earlier filed application, the invention of the claim 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 (section 43(2A) of the Patents Act; regulation 3.12 of the Patents Regulations 1991).

Accordingly, the test for determining entitlement to an earlier priority date is equivalent to the sufficiency test of section 40(2)(a) of the Patents Act. In particular, and under the changes introduced by the Raising the Bar legislation, a patent specification is required to provide sufficient information to enable the whole width of the claimed invention to be performed by the skilled person without undue burden, or the need for further invention. The growing body of case law considering the operation of these provisions is effectively harmonising the Australian approach to support and enablement with UK and European law (see, e.g., TCT Group v Polaris, which we previously summarised here).

P1 and the complexities of CRISPR/Cas9 systems

When considering the nature of the disclosure of P1, and although not mentioned in the decision, it is important to note that the specification of P1 is somewhat unusual, as it is essentially an academic manuscript that has been filed as a provisional application. The manuscript, which has since been published as Cho et al. (2013, Nature Biotechnology, 31(3): 230-232), was submitted for peer review on 20 November 2012, just one month after the filing of P1 on 23 October 2012. The short window of time between the filing of P1 and the submission of the manuscript provides some indication of the pressures faced in the filing of the specification of P1. Balancing the competing need to publish academic research with the preparation and filing of patent applications will be familiar to patent attorneys and patent applicants alike. Nonetheless, failure to define the invention derivable from the Cho et al. manuscript, or any embodiments of the invention that may have been reasonably extrapolated from the data presented in Cho et al. had direct implications for establishing entitlement to priority from P1 in this decision.

It was accepted by the Court that P1 discloses a CRISPR/Cas9 system comprising Cas9 derived from Streptococcus pyrogenes in combination with a specific single guide RNA (sgRNA +48), and includes data demonstrating that this CRISPR/Cas9 system is effective for cleaving target DNA sequences in mammalian cells. Based on these data, ToolGen submitted that P1 discloses an invention involving the use of a Type II Cas9 endonuclease comprising a nuclear localisation sequence (NLS) and a single guide RNA (sgRNA) comprising portions of CRISPR RNA (crRNA) and transactivating RNA (tracrRNA) of variable lengths to generate site-specific double stranded breaks in a target DNA sequence adjacent to a protospacer adjacent motif (PAM), consistent with the claims of the Application.

In rejecting ToolGen's submissions, the Court held that while P1 discloses a CRISPR/Cas9 system derived from S. pyrogenes, which comprises a "naked" or "isolated" sgRNA, there was no disclosure of a principal of general application that would support a claim directed to the use of any Type II CRISPR/Cas9 system in eukaryotic cells, which encompasses the delivery of a gRNA via a nucleic acid intermediate (e.g., DNA or viral RNA) encoding the gRNA. This finding was based on extensive expert evidence, which was relied upon to define the phrase "nucleic acid encoding a gRNA" and establish that, based on the disclosure of P1 and the common general knowledge at the filing date, the person skilled in the art would be subject to undue burden to identify alternative Type II CRISPR/Cas9 systems that would be reasonably expected to work in the same way as the CRISPR/Cas9 system disclosed in P1. The nature of the experiments required to identify such alternative Type II CRISPR/Cas9 systems were detailed at length by Nicholas J, including the need to screen and identify Cas9 endonucleases from bacterial species other than S. pyrogenes, determining endogenous crRNA and tracrRNA sequences of the alternative Cas9 endonucleases, identifying and characterising the nature crRNA and tracrRNA sequences, identifying and validating the PAM sequences targeted by the alternative Cas9 endonucleases, and designing and constructing the sgRNA. In view of the significant experimental work required to identify and validate alternative Type II CRISPR/Cas9 systems in eukaryotic cells, the Court held that the skilled addressee would need to undertake a significant research project to perform the invention of the claims, which would not be straightforward or routine. As a result, P1 did not sufficiently disclose the invention as claimed, and none of the claims was entitled to a priority date derived from P1.

While there was no specific consideration as to whether the claims enjoyed partial priority to P1 in accordance with section 43(3), the decision suggests that claims that limit the gRNA to a "naked" or "isolated" sgRNA (e.g., claim 19, sgRNA +48) and S. pyrogenes Cas9 (e.g., claim 3) may be entitled to enjoy priority from P1, at least to the extent that it is was accepted that P1 discloses a Type II CRISPR/Cas9 system with these features. Recognition of partial priority would allow the relevant part of the disclosure to predate the disclosure of Wang et al., 2013, Cell, 153: 910-918, which the Court considered to anticipate the in vitro transcribed sgRNA of claim 19.

Internal support from the Application

Although not relevant to priority entitlement, the Court also made some remarks on the internal support requirements, responsive to the respondent's submissions that the claims lacked support as a result of the combined operation of the support requirement under section 40(3) and the sufficiency test of section 40(2)(a).

Under section 40(3) of the Patents Act, the claims must be supported by the matter disclosed in the specification, and the scope of the claims must not exceed the extent of the applicant's contribution to the art. In assessing whether the claims are supported by the specification, the approach adopted by the Court (and the Patent Office) is to construe the claims and determine the scope of the invention as claimed, construe the description to determine the technical contribution to the art, and then decide whether the claims are supported by the technical contribution to the art. In making this assessment, the Court referred to Warner-Lambert LLC v Generics (UK) Ltd t/a Mylan [2018] UKSC 56, pointing out that the facts of that case showed how a claim may be enabled by the specification, yet not meet the support requirement under section 40(3). The Court further observed that it is difficult to see how a claim to an invention that was not enabled could meet the support requirement.

In the context of the Application, the Court considered that the deficiencies identified in the disclosure of P1 carried across to the Application, notwithstanding that the Application more comprehensively disclosed the invention, including alternative embodiments and configurations of the CRISPR/Cas9 system, which were not disclosed in P1 (e.g., a gRNA and a nucleic acid encoding a gRNA). In particular, the Court held that the claims lacked support as they were too broad, at least insofar as they encompassed the use of any Type II CRISPR/Cas9 system (i.e., not limited to S. pyrogenes) and any chimeric guide RNA of any length (i.e., not limited to sgRNA +48).

Harmonisation with European and UK law

As mentioned above, the changes introduced by the Raising the Bar legislation were intended to bring sections 40(2)(a) and 40(3) of the Patents Act into closer alignment with corresponding provisions under European and UK law. However, the Court's finding with respect to priority in this decision is contrary to that of the European Patent Office (EPO) when considering European applications in the same patent family as the Application (i.e., derived from PCT/KR2013/009488).

Interestingly, during the examination of European Patent Application No. 13849670.8, the EPO considered the validity of the earliest priority date and identified defects in the priority claim to P1 (and P2). In the European Search Opinion issued on this application, the Examiner alleged that P1 did not disclose any generalisations relating to a Cas9 polypeptide comprising a NLS. Therefore, the priority claim was only considered partially valid, with respect to the specific Cas9 polypeptide and the specific NLS. The Applicant successfully argued against the Examiner's objection, resulting in the grant of claims directed to a Type II CRISPR/Cas9 system comprising a Cas9 protein with one NLS at the C-terminus, not limited to any particular bacterial ortholog. These granted claims were opposed by multiple parties, including on grounds relating to the lack of entitlement to priority from P1. However, EP 13849670.8 was revoked for administrative reasons prior to the opposition hearing.

A related divisional application, EP 20164644.5, is currently under opposition at the EPO. The granted claims of this application are directed to methods of using a Type II CRISPR/Cas9 system comprising a Cas9 protein with one NLS at the C-terminus in eukaryotic cells, again, not limited to any particular bacterial ortholog. Unlike the parent application, the EPO did not identify any defects in the priority claim to P1 during examination. Nonetheless, multiple opponents are contending (inter alia) that the granted claims are not entitled to the earliest priority date conferred by P1. While there is some variation in the nature of the arguments that have been presented for this ground of opposition, there is significant overlap with the priority issues considered in the Australian opposition and appeal proceedings. As such, the outcome of the European opposition should provide a useful indication of how harmonised the approach to support and enablement is between Europe and Australia.

Key takeaways and practical guidance

  • When filing a provisional application, it is important that high quality and comprehensive specifications are prepared based on the experimental data that is on hand, rather than simply reproducing a manuscript. Failure to define the invention with claims, or to incorporate embodiments of the invention that reasonably extrapolate data in view of the common general knowledge in the art may result in the provisional application being construed as limited to the exemplified embodiments only, which may not accurately reflect the applicant's contribution to the art.
  • While it is generally recognised that the specification need not exemplify each and every embodiment of the invention, it is possible to extend the scope of the disclosed invention by incorporating as much experimental data as possible. Such data may not be suitable for publication in an academic journal article, but may nonetheless provide useful support for broader claim scope (g., different Cas9 orthologs, gRNA configurations / sequences, cell types, optimisation results, comparative data, etc.).
  • It is unlikely that patent examiners are going to be in a position to grapple with priority issues to the level of detail of the Court in this decision. Therefore, entitlement to priority based on the sufficiency of disclosure may present opportunities to challenge the validity of Australian patents / patent applications where relevant prior art has been published before the deferred priority date, for example, by the submission of third party observations, opposition proceedings and revocation proceedings.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.