Whole Hog or Nothing: Federal Court Reinforces Best Method Obligations in Pig Vaccine Patent

Zoetis Services LLC v Boehringer Ingelheim Animal Health USA Inc [2024] FCAFC 145

Background

The Full Court of the Federal Court of Australia has dismissed Zoetis Services LLC’s (Zoetis) appeal against Justice Rofe’s two decisions upholding Boehringer Ingelheim Animal Health USA’s (Boehringer) opposition to the grant of three patent applications relating to pig vaccines.  We reported on Justice Rofe’s two decisions here and here.

The three patent applications in issue were:

• AU2013243535 entitled “Mycoplasma hyopneumoniae vaccine” (the ‘535 Application);
• AU2013243537 entitled “PCV/Mycoplasma hyopneumoniae combination vaccine” (the ‘537 Application); and
• AU2013243540 entitled ‘PCV/Mycoplasma hyopneumoniae/PRRS combination vaccine” (the ‘540 Application).

In her Honour’s first decision, Justice Rofe held that the claims of all three patent applications were invalid on various grounds apart from claim 2 of the ‘535 Application.  In her Honour’s second decision, Justice Rofe held that specific combination claims which had not been addressed in her first decision were also invalid and that claim 2 of the ‘535 Application was invalid for failure to disclose the best method of performing the claimed invention.

In dismissing Zoetis’ appeal with costs, the Full Court has again provided valuable guidance on the scope of the patentee’s obligation to disclose the best method of performing the invention known to it, as well as on the level of expectation which must be shown to prove lack of inventive step.

Key Issues 

The Full Court was required to determine the following two issues in the appeal:

1. whether the three applications disclosed the best method known to Zoetis of performing the inventions; and

2. whether specific claims in the applications which related to single dose vaccines (the single dose claims) involved an inventive step.

Best Method

The ‘535 Application disclosed a composition which provided immunity to mycoplasmal pneumonia, a common disease in pigs.  This composition was made by growing M. hyo in pig serum, and then separating the resulting culture into soluble and insoluble parts.  Claim 2 of the ‘535 Application provided a method of removing the immunoglobulin G (IgG) and other immune complexes which remained in the soluble part (supernatant) after the separation step. It was the supernatant which had immunogenic qualities, the efficacy of which was reduced by the presence of IgG and other immune complexes via a phenomenon called “interference”.  IgG and other immune complexes were present in the supernatant because the pig serum came from pigs which would most likely have been exposed to disease.

The ‘537 Application disclosed a bivalent composition made from the ‘535 Application M. hyo supernatant (treated with Protein A and Protein G) to which an antigen of the pig circovirus type 2 (PCV-2) had been added.  PCV-2 causes Post-weaning Multisystemic Wasting Syndrome (PMWS) in pigs.

The ‘540 Application disclosed a trivalent composition made from the ‘535 Application supernatant to which antigens of both PCV-2 and porcine reproductive and respiratory syndrome virus (PRRSV) had been added.  PRRSV causes Porcine Reproductive and Respiratory Syndrome (PRRS).

The Full Court considered the best method challenge as it applied to the ‘535 Application, on the basis that Boehringer’s best method challenge was identical for all three applications and so the outcome of the appeal on best method for the ‘535 Application would apply equally to the ‘537 and ‘540 Applications.

In upholding Justice Rofe’s decision on best method, the Full Court noted that:

• The best method requirement necessitates disclosure of the best method known to the patentee of performing the invention.  The nature and extent of the disclosure required depends on the nature of the invention itself.
• In deciding whether the best method has been disclosed, it is necessary to look at the invention disclosed in the specification as a whole, not merely the claims.  On this point, the Full Court considered the Full Court’s best method reasoning in Firebelt Pty Ltd v Brambles Australia Ltd [2000] 51 IPR 531, in which the Full Court focused on the form of the claims in reaching the conclusion that there had not been a failure to disclose the best method.  The Full Court in Zoetis v Boehringer stated:

…[w]ith respect to their Honours, if they are to be taken as saying that the form of the claims is determinative, we do not agree. The fact that none of the claims in that case was to a lid opening device operating at any particular time could not of itself be an answer to the best method challenge if the timing of such operations was advantageous to the working of the combination or the quality of the outcomes achieved from its use.

• The patentee has an obligation to include aspects of the method of manufacture that are material to the advantages it is claimed the invention brings.

The Full Court went on to note that Justice Rofe had summarised the invention in the ‘535 Application as an improved immunogenic composition or vaccine to elicit a protective response in pigs against the disease caused by M. hyo, using an M. hyo supernatant which can also be used as a base or platform for a combination vaccine with at least one additional antigen protective against selected microorganisms (other than PCV-2, as there are no claims to an M. hyo/PCV-2 combination).  The Full Court agreed with Justice Rofe’s characterisation of the invention, noting that the two key advantages of the invention were:

1. the ability of the vaccine to be administered in a single dose; and

2. he suitability of the hyo composition to be used as part of a combination vaccine conferring immunity against both M. hyo and one of a number of other pig viruses.

The ‘535 Application referred to investigational vaccine products (IVPs).  The ‘535 Application disclosed that the vaccine could be made with a given range of M. hyo antigens but did not identify the antigen concentrations of the IVPs other than by comparison to a reference vaccine (the antigen concentration of which was not disclosed in the specification).  Critically the different IVPs demonstrated different levels of efficacy within the range provided and the efficacy of the IVPs was measured against the reference vaccine.  This meant that it would not be possible for the skilled addressee to make any of the IVPs because the specification only stated the antigen concentration of each IVP by reference to the antigen concentration of the reference vaccine which was not disclosed.

As the advantages presented by the invention were the ability to deliver a composition conferring immunity against M. hyo in a single dose, and that the composition could be used as a platform to deliver immunity against other pig viruses, it followed that it would confer an advantage on the skilled addressee to know what antigen concentration would result in the composition being most effective when administered as a single dose and which balance between the antigens would result in a combination vaccine that could confer immunity against M. hyo and PCV-2.

Boehringer alleged that, prior to the filing of the ‘535 Application, Zoetis had formulated a number of the IVPs, each of which was a method of performing the invention in the ‘535 Application and one of which must be the best method.  The Full Court agreed, noting that the evidence showed that the IVPs varied in efficacy and the logic of this entailed that one of them was the most efficacious (i.e. the best method).  Accordingly, Zoetis had failed to disclose the best method in the ‘535 Application.  The Full Court also concluded that in the circumstances, and contrary to Zoetis’ submission, there was no need for Boehringer to identify which of the IVPs was best in order to prove its lack of best method case.

Inventive Step

Zoetis also appealed from Justice Rofe’s finding that the single dose claims did not involve an inventive step.

At first instance, Justice Rofe had held that the single dose claims were not inventive in light of the expert evidence that tests as to dosage and duration of protection would be routine in the course of developing an M. hyo supernatant.  Justice Rofe therefore considered that the skilled addressee would start with a single dose as part of those routine tests.

The Full Court agreed with Justice Rofe, dismissing Zoetis’ appeal against Justice Rofe’s lack of inventive step finding.  The Full Court stated:

It is an unremarkable proposition in the circumstances of this case that a person skilled in the art would undertake testing of a new vaccine product for the purposes of determining duration of protection. Among other things, it would be necessary to have such information for the purposes of determining the need for, and timing of, any second dose (if two doses were being contemplated) and whether the vaccine (in whatever dosage) would be effective for the intended lifespan of the pig. This is consistent with, and supported by, the expert evidence of Professor McVey.

 

…the person skilled in the art would thereby be directly led as a matter of course to the invention disclosed by the single dose claims. The experts agreed that it was desirable that any such product be administered as a single dose if that was feasible. The revelation that the composition could be administered in a single dose to achieve the requisite protective immune response during such tests would be no more than the direct outcome of what is essentially routine and non-inventive work to ascertain an appropriate dosage, which is consistent with a finding of obviousness…

 

Further, the person skilled in the art would directly be led, as a matter of course, to undertake such work in the expectation that it might well produce a useful alternative to, or a better vaccine than, existing (single dose) vaccines…

The Full Court distinguished between evaluating the character of the expectation and the steps the skilled addressee would have taken.  The Full Court stated that the relevant expectation was to be measured against the ordinary level of expectation and risk inherent in routine work in the particular field.  The relevant test was not knowing that steps will or would or even may well work, but merely expecting that the steps may well work.  The Full Court also considered that it was not always necessary that the skilled addressee knew, or even expected, a particular outcome at the outset of the hypothetical task.  This meant that, in the field of drug formulation, it might not be necessary that the skilled addressee would expect a specific known dose to provide adequate single dose protection if they would expect the routine and non-inventive work in which they are assumed to engage might well result in the identification of such a dose from within a range.

Outcome

So, the Full Court dismissed Zoetis’ appeal with costs, upholding both the lack of best method and lack of inventive step findings made by Justice Rofe at first instance.  Critically, all three applications were invalidated in their entirety as a result of the lack of best method finding.

Implications

The Full Court’s decision continues the line of cases in which patents are being invalidated in their entirety for lack of best method.  The Full Court’s decision illustrates the power of the lack of best method ground for parties seeking to invalidate patents and provides valuable guidance for patentees on the scope of their obligation to disclose the best method of performing the invention known to it.  The decision also provides valuable guidance on the level of expectation which must be shown to prove lack of inventive step.

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