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Zoetis Vaccine Patent Survives Opposition Appeal by the Hair of its Chinny Chin Chin

Boehringer Ingelheim Animal Health USA Inc v Zoetis Services LLC
[2023] FCA 1119


21 September 2023

Federal Court of Australia

Rofe J


Another Australian Federal Court decision highlights that disclosure deficiencies in a patent specification, here a lack of description of the best method for performing the invention in particular, may result in invalid claims.


This decision relates to an appeal by Boehringer Ingelheim Animal Health USA Inc. (Boehringer) after it unsuccessfully opposed three patent applications owned by Zoetis Services LLC (Zoetis) before the Australian Patent Office 1 (Zoetis Applications).  The applications in question were directed to vaccines for treating enzootic pneumonia (also known as mycoplasmal pneumonia), a chronic respiratory disease in pigs caused by a species of bacteria known as Mycoplasma hyopneumoniae (M. hyo).

The Zoetis Applications were each filed on 3 April 2013, claiming a priority date of 4 April 2012, and have substantially the same specification except for introductory statements of the field, the consistory statements and examples.  In brief:

  • 535 is to “Mycoplasma hyopneumoniae vaccine”, a platform vaccine for protecting pigs against enzootic pneumonia;
  • 537 is to a “PCV/Mycoplasma hyopneumoniae combination vaccine” for protecting pigs against both enzootic pneumonia and Post-weaning Multisystemic Wasting Syndrome (PMWS) caused by porcine circovirus (PCV); and
  • 540 is to a “PCV/Mycoplasma hyopneumoniae/PRRS combination vaccine” for protecting pigs against each of enzootic pneumonia, PCV and thirdly porcine reproductive and respiratory syndrome (PRRS) virus.

While other vaccines were commercially available, a key difference between the Zoetis Applications and the prior art is the use of a soluble portion derived from M. hyo culture, separated from insoluble cellular material and substantially free of impurities.

Before the Patent Office, most claims of the 535 application were found to lack inventive step, whereas the 537 and 540 applications were allowed.  In this Federal Court appeal heard by Justice Rofe Boehringer pressed the following grounds for each application: lack of inventive step, lack of support, lack of sufficient disclosure, lack of disclosure of best method and that the invention claimed in certain “kit” claims is not patent eligible subject matter.  As examination was requested after 13 April 2013 the Patents Act 1990 (Cth) (Act) in its post-RTB form applied.

An appeal from a decision of the Patent Office is heard by the Federal Court as an original hearing de novo on all grounds, and may involve new evidence.  The onus remains on the opponent (in this case Boehringer) to establish each ground.  Justice Rofe found all claims of the Zoetis Applications invalid in the de novo appeal, with the exception of one claim of the 535 application.   The Court’s decision has not been further appealed to the Full Federal Court.

Key Issues

When an expert knows too much

The Court provided insight for parties considering expert selection, underscoring the pitfalls of engaging an “independent expert” with a longstanding contractual relationship with a litigant.  Her Honour found that Boehringer’s lack of a detailed description about its retainer with the expert whose evidence it led to be “unfortunate”.  The expert’s use of information that was not part of the common general knowledge (CGK) in the field “undermined the weight” that would otherwise be given his evidence on inventive step evidence  – Rofe J stated she was “unable to disentangle” the “infected” parts of his evidence on inventive step from that based on CGK.

When the meaning of “comprising” yields to context

The Court considered anew the construction of the word “comprising.  Importantly, her Honour found the use of “comprising” yielded to context, an analysis which is specific to the specification in each case.  Justice Rofe found that prior authorities establish that:

a definition of ”comprise” in a specification ”cannot give the word ‘comprise’ and its variants an unbridled operation” to contort a claimed invention into a substantially different invention to that described in the specification….Whether a definition of ”comprise” may need to yield to the context of the description of the invention in the specification will be specific to the particular specification in each case.

Justice Rofe construed claim 1 of the 535 application to cover an immunogenic composition with one or more M. hyo antigens limited to those antigens exemplified in the application as having been isolated from the soluble portion of an M. hyo culture.  The specification supports this interpretation by describing embodiments of the composition as just the M. hyo supernatant.  Here the claims do not extend the claim scope to include antigens for other diseases or any antigens beyond those mentioned in the specification but yielded to context, such that:

the immunological composition of the invention is not limited to only the essential integers listed, but also includes elements which the skilled person would understand to be required for an immunological composition, but not to be an essential part of the invention.

Similar constructions were applied to the claims in the 537 and 540 applications, with specific focus on the inclusion of PCV-2 and PRRS antigens, and with the antigens included within the claim scope by virtue of the word “comprising” limited to only the antigens specified in the specification.

Inventive step

Of key significance in the assessment of inventive step were prior art journal articles (the Okada Papers) that focus on inactivated M. hyo vaccines for pigs.  The vaccines described in the Okada papers included antigens extracted from M. hyo culture supernatants as well as inactivated whole-cell formulations.

Boehringer argued that the claimed inventions were obvious in light of CGK and the Okada publications, which suggested the potential advantages of a supernatant vaccine for M. hyo.  In relation to the modified Cripps question 2, Boehringer submitted that skilled individuals would have reasonably expected success in developing such vaccines.  In contrast, Zoetis submitted that the applications disclosed a culture supernatant purification step to remove unwanted contaminants which was not disclosed in the Okada Papers and which provided a useful solution that created a valuable M. hyo “platform” vaccine.

Justice Rofe agreed with Boehringer, finding that claim 1 of each of the Zoetis Applications lacked inventive step in view of the Okada Papers.  However, dependent claims to the purification step were found to be inventive (albeit some were held invalid for other reasons).


Expert evidence presented by Boehringer highlighted the complexity involved in developing vaccines, especially when combining antigens from different pathogen sources.  These challenges include choosing the appropriate vaccine type (live attenuated, killed virus, subunit, etc.), identifying suitable adjuvants, dealing with antigenic diversity and interference, determining safe and effective dosages, and conducting rigorous in vivo testing.  These were particularly significant for pathogens for which vaccines had not been identified or developed as of the priority date.

Her Honour concluded that the specifications did not provide specific and practical guidance for overcoming the challenges of combining vaccine antigens, and therefore the 535 and 537 claims which were to vaccines containing M.hyo antigens together with antigens to pathogens other than PCV and PRRS, lacked support.  Whilst the specifications mention the possibility of combining antigens and using the ‘M. hyo platform’, they do not offer detailed instructions or methodologies for doing so.  This lack of specificity makes it difficult for a skilled person to carry out the claimed combinations successfully.


Justice Rofe found that the Zoetis Applications provided an enabling disclosure of, and support for, claims to an immunogenic composition consisting of the M. hyo platform alone, or in combination with PCV and/or PRRS antigens.  However, the 535 and 537 applications were not found to provide an enabling disclosure for claims which include an immunogenic composition consisting of the M. hyo platform in combination with antigens other than those for PCV and PRRS (by contrast, the claims of the 540 application are limited to a trivalent composition comprising M. hyo, PCV and PRRS antigens).  Thus, these claims of the 535 and 537 applications were determined to have an insufficient disclosure.

Best method

Boehringer submitted that the Zoetis Applications did not disclose a best method known to Zoetis of performing the invention claimed.  Justice Rofe agreed, asserting that “Zoetis has chosen to hide the best method in plain sight in each of the Applications”.  So while formulations containing concentrations of antigens appear to be disclosed, they are disclosed in the form of relative concentrations, where the “key” to determining the relative concentrations is not provided.  Thus, the majority of the 535 application claims, and all those of the other two patents,  were found to lack best method.

Claims to “mere collocations” where all integers known – whether patent eligible

Where a claimed combination comprises individual elements without a purposeful and functional interaction between the elements to produce a new result or product (or lack the potential for a working interrelationship), the combination is considered to be a “mere collocation of separate parts” and is not eligible for patent protection as it is not a manner of manufacture as required by s18(1)(a) of the Act.

With the exception of claims directed to a kit comprising antigens in separate bottles prior to administration (in order to limit antigen interference), Justice Rofe found kit claims were not patent eligible as the features of claims to kits comprising either one bottle or instructions did not have the required “purposeful and functional interaction”.  This outcome appears to go against current Patent Office practice under which a collocation is only deemed unpatentable if all its integers are known, with the effect that an integer that is considered novel and inventive typically provides a patentable kit claim.


Other than claim 2 of the 535 application (directed to a culture supernatant purification step), all claims of the Zoetis Applications were held invalid, a decision which neither party has appealed to the Full Federal Court.


It is noteworthy that Zoetis did not have any pending members in this patent family – this would have provided alternative means to secure the broadest protection despite the outcome of the Boehringer opposition and Federal Court proceedings.  Patent specification disclosure deficiencies may be surgically rectified with post-filing amendments (whilst navigating added matter limitations) so for key patent assets, prudent prosecutors will recommend the maintenance of pendency via divisional applications.  In the absence of pending rights, Zoetis has closed the door on potentially the simplest path to redressing the disclosure deficiencies raised in this Federal Court decision.

[1] Boehringer Ingelheim Animal Health USA Inc. v Zoetis Services LLC [2020] APO 40
[2] Re-stated by the Australian High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd (2002) 212 CLR 411 at [53]

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