A Double Blow for Moderna – Seqirus Topples Two mRNA Patent Applications

Introduction

Seqirus has successfully opposed Moderna’s:

• AU2015249553 patent application (AU553) for nucleic acid vaccines; and
• AU2017326423 (AU423) for high purity RNA compositions and methods for preparation of these compositions.

Seqirus invalidated all of the AU553 claims and claims 1-8 and 11-20 of AU423 on the grounds of obviousness, insufficiency and lack of support.

Moderna was given two months from the date of each decision to file amendments to overcome the deficiencies identified in the decisions. Moderna applied to amend AU533 but IP Australia considered that, while allowable, the proposed amendments did not overcome the deficiencies identified in the decision. Moderna subsequently withdrew AU553 in December 2025, leaving one live divisional application in the same patent family. As no amendments were filed on AU423, the Commissioner of Patents refused AU423 on 24 September 2025, again leaving one live divisional application in the same patent family.

Background

AU553’s only independent claim, claim 1, claimed:

A nucleic acid vaccine comprising one or more mRNA polynucleotides having an open reading frame encoding an antigenic polypeptide, formulated in a cationic lipid nanoparticle having a molar ratio of about 20-60% cationic lipid: about 5-25% non-cationic lipid: about 25-55% sterol; and about 0.5-15% PEG-modified lipid.

AU423 included two independent claims (claims 1 and 16) as follows:

1.  A method of producing a messenger ribonucleic acid (mRNA) that is suitable for administration as a vaccine to a human subject, wherein the mRNA comprises an open reading frame encoding a vaccine antigen, the method comprising incubating a reaction mixture comprising a deoxyribonucleic acid (DNA), an RNA polymerase that initiates with a GTP or GDP, a buffer, adenosine triphosphate (ATP), cytidine triphosphate (CTP), uridine triphosphate (UTP), and guanosine triphosphate (GTP), thereby producing the mRNA, wherein:

(i) the concentration of GTP is greater than the concentration of one or more of ATP, CTP, and UTP, and two or more of ATP, CTP, and UTP are in equimolar concentrations; and/or

(ii) the reaction further comprises guanosine diphosphate (GDP), the concentration of GTP plus GDP is greater than the concentration of one or more of ATP, CTP, and UTP, and two or more of GTP, ATP, CTP, and UTP are in equimolar concentrations.

16.  A method of producing a messenger ribonucleic acid (mRNA) that is suitable for administration as a vaccine to a human subject, wherein the mRNA comprises an open reading frame encoding a vaccine antigen, the method comprising incubating a reaction mixture comprising a deoxyribonucleic acid (DNA), a T7 RNA polymerase, a buffer, adenosine triphosphate (ATP), cytidine triphosphate (CTP), uridine triphosphate (UTP), and guanosine triphosphate (GTP), thereby producing the mRNA,

wherein the concentration of GTP is greater than the concentration of one or more of ATP, CTP, and UTP, and two or more of ATP, CTP, and UTP are in equimolar concentrations,

wherein the UTP is a modified UTP comprising 2’-O-methylribose, pseudouridine (ψ), N1-methylpseudouridine (m1ψ), 2-thiouridine, 4-thiouridine, 2-thio-1-methyl-1-deaza- pseudouridine, 2-thio-1-methyl-pseudouridine, 2-thio-5-aza-uridine , 2-thio-dihydropseudouridine, 2-thio-dihydrouridine, 2-thio-pseudouridine, 4-methoxy-2-thio-pseudouridine, 4-methoxy-pseudouridine, 4-thio-1-methyl-pseudouridine, 4-thio-pseudouridine, 5-aza-uridine, dihydropseudouridine, or 5-methoxyuridine.

Key Issues

Seqirus pressed the same five grounds of invalidity in its oppositions to AU553 and AU423: lack of novelty, obviousness, insufficiency, lack of support and inutility. Notably, Moderna did not file any evidence in answer in the opposition to AU423.

AU553 and AU423: Lack of Novelty

Seqirus alleged that the claims of AU533 were anticipated by three prior art patent applications. The Delegate determined that none of the cited prior art anticipated the claimed invention, as none of the cited prior art provided clear and unmistakeable directions to make the claimed invention.

Seqirus again alleged that the claims of AU423 were anticipated by three prior art documents (a patent application and two journal articles), with the Delegate finding that that none of the cited prior art anticipated the claimed invention, as none of the cited prior art provided clear and unmistakeable directions to make the claimed invention.

AU553 and AU423: Obviousness

AU553: Seqirus alleged that the claimed invention in AU553 was obvious when considered in light of the common general knowledge (CGK), either alone or separately with a number of prior art documents.

Based on the evidence before him, the Delegate found that, in light of the CGK alone, a skilled addressee would not be directly led as a matter of course to formulate a nucleic acid vaccine comprising a mRNA encoding an antigenic polypeptide, formulated in a lipid nanoparticle (LNP) having the four components in the defined ratios, as defined in AU553’s claim 1, with a reasonable expectation of success. The Delegate provided the following reasons for this decision:

• First, the CGK taught away from using mRNA LNP vaccines, instead teaching that either self-amplifying RNA (saRNA) or mRNA and protamine was required to achieve an immune response.
• Secondly, there was no motivation in the CGK for the skilled addressee to replace protamine with LNPs. The Delegate did not consider that the skilled addressee would be directly led as a matter of course to combine the use of mRNA with an LNP in a vaccine, as it was CGK that LNPs used with small interfering RNA (siRNA) gave an undesirable inflammatory response associated with a transient IgM response.
• Thirdly, while it was known that an LNP formulation with the four claim 1 lipid components could be used to encapsulate siRNA, there was still considerable uncertainty in the CGK as to whether such an LNP could successfully encapsulate mRNA encoding an antigenic polypeptide and produce a meaningful antigen specific immune response.  As a result, the Delegate did not consider that there would be a reasonable expectation of success that an LNP could successfully encapsulate mRNA encoding an antigenic polypeptide and produce a meaningful antigen specific immune response.
• Fourthly, it was considered surprising when siRNA/LNP technology was in fact applied to mRNA.

The Delegate then went on to consider obviousness in light of the CGK and a number of prior art documents (each considered separately). Seqirus ultimately proved obviousness in light of the CGK and each of WO 2013/151736 A2 (“In Vivo Production of Proteins”, which was also cited for novelty) and WO 2013/185069 A1 (“Pulmonary Delivery of mRNA to Non-Lung Target Cells”). The Delegate found:

• In respect of CGK + WO 2013/151736 A2, that a skilled addressee would be directly led as a matter of course and with a reasonable expectation of success, to develop an mRNA LNP vaccine encoding an antigenic polypeptide. WO 2013/151736 A2 disclosed compositions and methods for the preparation, manufacture and therapeutic use of polynucleotides, primary transcripts and mRNA molecules. Although the expert evidence noted that a functional immune response required a certain level of translation from mRNA to antigen, the word “vaccine” as it was used in AU553 merely required a composition that improved immunity. Accordingly, there would be the requisite expectation of success as the level of translation would be sufficient to produce an antigen specific immune response. This expectation of success did not require an immune response at the level of a commercially successful vaccine.
• In respect of CGK + WO 2013/185069 A1, that a skilled addressee would also be directly led as a matter of course and with a reasonable expectation of success, to develop an mRNA LNP vaccine encoding an antigenic polypeptide. WO 2013/185069 A1 disclosed compositions comprising mRNA formulated for pulmonary administration and related methods for the delivery of mRNA, that a suitable lipid carrier vehicle included a lipid nanoparticle, and an IT spray experiment in mice with firefly luciferase (FFL) mRNA lipid nanoparticle formulation of HGT5001:DOPE:Cholesterol:DMG-PEG2K at a molar ratio of 40:20:35:5.

AU423: Seqirus also alleged that the claimed invention in AU423 was obvious when considered in light of the CGK, either alone or separately with three prior art documents. Based on the evidence before her, the Delegate found that, although in vitro-transcription (IVT) reaction methods were known and it was also known that many factors could affect the resulting product, Seqirus had not established that the claims were obvious in light of the CGK alone.

The Delegate then went on to consider obviousness in light of the CGK and the three prior art documents (each considered separately). Seqirus ultimately proved that claims 1-8 and 11-20 were obvious in light of the CGK and the prior art article: “Self-coded 3’-Extension of Run-off Transcripts Produces Aberrant Products during in Vitro Transcription with T7 RNA Polymerase”, Triana-Alonso et al., Journal of Biological Chemistry, 1995, vol. 270, iss. 11, pp. 6298-6307. The Delegate noted that:

• the AU423 claims were directed to methods of producing mRNA by IVT where the reaction mixture had been modified to reduce the production of contaminants; and
• the prior art article taught that the preferential reduction of UTP concentration relative to the other nucleotides (NTPs) “leads to faithful transcription and good yields, irrespective of the nucleotide composition of the template.”

Accordingly, the Delegate was satisfied that the expert evidence supported a conclusion that simply encoding a known vaccine antigen in place of the model peptides of the prior art article did not require further invention, and that AU423’s claims 1-8 and 11-20 were obvious. The Delegate considered that features of the IVT process, such as the use of modified NTPs, choice of polymerase and reaction temperature, were routinely chosen by the skilled addressee depending on the nature of the desired product and components used in the reaction mixture, with well-defined reaction conditions and components known in the art. The Delegate did, however, consider that claims 9 and 10 were inventive over the CGK and the prior art article as the article did not teach maintaining GTP, CTP and ATP in equimolar concentrations.

AU 553 and AU423: Inutility

Seqirus’ AU553 utility challenge failed as the Delegate considered that Seqirus had failed to provide any evidence of a formulation within the scope of claim 1 that did not attain the result promised for the invention by the patentee, the promise being that a composition comprising an mRNA encoding an antigenic polypeptide formulated in a LNP having the components in the molar ratios as defined in claim 1 would function as a vaccine (i.e. would produce an antigen specific immune response).

Seqirus’ AU423 utility challenge also failed as the Delegate considered that Seqirus had raised doubts and concerns regarding the likely outcomes of the claimed process, but that this amounted to mere speculation rather than any evidence to show that the claims included within their scope any particular embodiment that would not be useful or would not achieve at least some aspect of the benefits promised in the specification.

AU553: Insufficiency: Clear and Complete Enough Disclosure

The Delegate noted that, to satisfy the sufficiency requirement, the skilled person must be able to perform the invention across the scope of the claim without undue burden or inventive skill. The Delegate considered that the claimed invention defined a nucleic acid vaccine (or a composition that improves immunity) comprising one or more mRNA polynucleotides having an open reading frame encoding a polypeptide that is capable of stimulating an antigen specific immune response, formulated in a cationic lipid nanoparticle having a molar ratio of about 20-60% cationic lipid: about 5-25% non-cationic lipid: about 25-55% sterol: and about 0.5-15% PEG-modified lipid. The Delegate further considered that the specification disclosed:

• the formulation of modified mRNA using lipidoids;
• mRNA LNP vaccines having a molar ratio of 50% cationic lipid (DLin-KC2-DMA or DLin-MC3-DMA), 10% non-cationic lipid (DSPC), 38.5% sterol (Cholesterol) and 1.5% PEG-modified lipid (PEG-DOMG), and the use of those vaccines to express antigenic polypeptides (influenza haemaglutinin antigen and MRSA); and
• a number of examples analysing the immunogenicity of mRNA vaccines encoding a variety of antigenic polypeptides (See Example 17-21), but that none of these examples disclosed the use of an LNP. The Delegate also note that none of the LNP examples disclosed varied the composition of the LNP other than varying the cationic lipid between KC2 and MC3.

The Delegate assessed the issue of sufficiency by asking two questions:

• Whether it was plausible that the invention could be worked across the full scope of the claim; and
• Whether the invention could be performed across the full scope of the claim without undue burden.

The Delegate answered the first question in the affirmative and the second question in the negative, leading the Delegate to conclude that the patent was invalid for insufficiency.

On the question of plausibility, the Delegate noted that, while plausibility may be a low threshold, it was not satisfied by mere speculation or assertion. That said, while there was expert evidence doubting whether successful encapsulation of mRNA could occur across the full scope of the claims, a mere “doubt” was not sufficient to establish a lack of plausibility. Further, while the chemical structure of the cationic lipid might have an impact on transfection efficiency, this potential shortcoming was not enough to meet the threshold that the LNP mRNA vaccine over the scope of claim 1 would not be “technically credible” or “believable” in its ability to produce an immune response.

On the question of undue burden, the Delegate considered that the evidence showed that there would be an undue burden on the skilled addressee to test which cationic lipids would result in an LNP comprising mRNA encoding an antigenic polypeptide which results in an antigen specific immune response, and that, accordingly, claim 1 was not clearly and completely enough disclosed. The Delegate did not, however, agree with Seqirus’ submission that there was not a clear and complete enough disclosure for a mRNA LNP vaccine encoding any antigenic peptide or in relation to the potential toxicity of a particular cationic lipid component.

AU 553: Lack of Support

To determine whether the support requirements were satisfied, the Delegate construed the claims (to determine the scope of the invention as claimed) and the description (to determine the technical contribution to the art) and then formed a view on whether the claims were supported by the technical contribution to the art.

The Delegate ultimately determined that claim 1 lacked support as the scope of the cationic lipid component extended beyond the applicant’s technical contribution to the art, as the description only taught the use of the cationic lipid being either DLin-KC2-DMA or DLin-MC3-DMA. Claims 3-67 were dependent on claim 1 and did not introduce any features that remedied this lack of support. Claim 2, however, was supported with respect to the cationic lipid, as this claim was limited to DLin-KC2-DMA and DLin-MC3-DMA which were shown in the specification to provide suitable LNPs that provide an immune response.

AU423: Insufficiency: Clear and Complete Enough Disclosure + Lack of Support

The Delegate addressed the questions of insufficiency and lack of support together in the AU423 opposition.

The Delegate noted that AU423 specification only included data showing the effective suppression of contaminants with the alpha and GDP alpha reactions performed with 30 mM GTP, 15 mM ATP, 7.5 mM CTP and 7.5 mM UTP (4:2:1:1 ratio of GTP:ATP:CTP:UTP) or 30 mM GDP, 15 mM GTP, 15 mM ATP, 7.5 mM CTP and 7.5 mM UTP (4:2:2:1:1 ratio of GDP:GTP:ATP:CTP:UTP). AU423 did not provide any guidance, beyond the examples, regarding appropriately choosing the relative amounts of the NTPs to ensure improved RNA products were obtained. This meant that the skilled addressee was expected to work within the general bounds of IVT reactions to produce mRNA products with improved purity, with AU423 only teaching the use of a selected NTP, GTP or GTP plus GDP in the case of the claimed invention, in a greater concentration than at least one of the other NTPs with two or more other NTPs being equimolar.

While product purity was not certain with deviation from the alpha and GDP alpha reactions, given the expert evidence, the Delegate was prepared to accept that AU423 provided sufficient disclosure to enable a person skilled in the art to perform the invention of claims 9 and 10. However, the alpha and GDP alpha reactions did not extend to a general principle where the concentration of the GTP or GTP plus GDP need only be greater than one or more of the other NTPs with two or more of the other NTPs being in equimolar concentrations. Accordingly, there was insufficient disclosure to enable a person skilled in the art to perform the inventions of claims 1-8 and 11-20, and these claims lacked support as they extended beyond the applicant’s contribution to the art as disclosed in the description.

Outcome and Implications

These two decisions provide two recent examples of the power of strong prior art to knock out a patent application on the ground of lack of inventive step, as well as the power of the support and sufficiency grounds post the “Raising the Bar” amendments to the Australian Patents Act. While Moderna applied to amend AU553 to cure the identified deficiencies, IP Australia considered that the proposed amendments did not overcome these deficiencies. Moderna subsequently withdrew AU553 in December 2025, leaving one live divisional application in the same patent family. As no amendments were filed on AU423, the Commissioner of Patents refused AU423 on 24 September 2025, again leaving one live divisional application in the same patent family.

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