The recent Full Federal Court decision in Zoetis Services LLC v Boehringer Ingelheim Animal Health USA Inc [2024] FCAFC 145 (Zoetis) yet again demonstrates why “best method” is such a problematic ground of invalidity in Australia. This case, which concerns vaccines against diseases affecting pigs, highlights how “heart-bacon” the draconian best method requirement in Australia can be for applicants and patentees because it can invalidate an entire application or patent despite there being a sufficient disclosure of the invention.
We have previously discussed the problems with the best method requirement, including here and here.
Background
In April 2013, Zoetis Services LLC (Zoetis) filed three Australian patent applications, all of which were broadly directed to vaccines against diseases affecting pigs (collectively, the Applications):
- AU 2013243535 (AU ‘535), directed to a Mycoplasma hyopneumoniae( hyo) vaccine;
- AU 2013243537 (AU ‘537), directed to a multivalent hyo and porcine circovirus type 2 (PCV-2) vaccine; and
- AU 2013243540 (AU ‘540), directed to a trivalent hyo, PCV-2 and porcine reproductive and respiratory syndrome virus (PRRSV) vaccine.
The Applications were accepted by the Australian Patent Office (APO) and Boehringer Ingelheim Animal Health USA Inc (Boehringer) opposed the grant of each of the Applications. The APO found that several claims in AU ‘535 did not involve an inventive step and upheld, in part, Boehringer’s opposition towards AU ‘535. However, AU ‘537 and AU ‘540 were considered valid. Boehringer appealed the APO’s decision to the Federal Court, and Zoetis cross-appealed with respect to AU ‘535.
On appeal, Rofe J found that, other than claim 2 of AU ‘535, all claims of the Applications were invalid and should not proceed to grant on the grounds that, inter alia, Zoetis had failed to disclose the best method known to it of performing the claimed inventions.[1] Rofe J also found that certain dependent claims of the Applications lacked support because they “comprised” embodiments that extended beyond Zoetis’ contribution to the art (see our discussion of this issue here). Both parties requested that Rofe J provide further reasons in relation to the dependent claims on other grounds of invalidity in question. In Rofe J’s supplementary decision,[2] her Honour held that claim 2 of AU ‘535 was also invalid on the ground that Zoetis had not disclosed the best method known to it of performing the invention defined in that claim.
The best method issue
Under Australian law, a patent specification must disclose the best method of performing the invention that was known to the applicant at the time of filing (the “best method” requirement).[3]
In relation to best method, Boehringer argued that, prior to filing the Applications, Zoetis had formulated several experimental vaccines (termed investigational vaccine products (IVPs)), which were exemplified in the specifications. However, some IVPs performed better than others, for example, in terms of their efficacy. Moreover, Zoetis had only disclosed the antigen concentrations of the IVPs relative to a reference vaccine, however, the antigen concentration of the reference vaccine was not disclosed in the specifications. Accordingly, the absolute antigen concentrations of the IVPs were allegedly known by Zoetis but had not been disclosed in the specifications of the Applications as filed.
Rofe J considered that one IVP must have been the most efficacious out of all those generated by Zoetis, and that the method of manufacturing that IVP was known to Zoetis at the time of filing the Applications but was not disclosed in the specifications as filed. Accordingly, Zoetis had failed to disclose the best method of performing the inventions.
Zoetis appealed Rofe J’s findings with respect to best method (as well as inventive step).
Appeal decision confirmed best method not disclosed
While the Full Court confined their attention to AU ‘535, the parties agreed that any findings in respect of AU ‘535 could be applied equally to AU ‘537 and AU ‘540.
The Full Court reaffirmed that the nature and extent of the disclosure required to fulfil the best method requirement depends on the nature of the invention itself,[4] which must be discerned from the invention as described in the whole of the specification, including the claims.[5]
In particular, the Full Court reaffirmed that “where a patent applicant knows of a method which permits the invention to be more satisfactorily performed, the patent applicant must disclose that method in the specification”.[6] Further, the Full Court considered that where a method of manufacture is material to the advantages achieved by a claimed invention, the patentee has an obligation to include such methods.[7]
At the core of the Full Court’s consideration were the purported advantages (i.e., “promises”) of the claimed invention, namely:[8]
- the efficacy of the hyo vaccine when administered as a single dose to pigs; and
- the suitability of the hyo vaccine when used as part of a combination vaccine.
The Full Court agreed with Rofe J that the concentrations of the M. hyo and PCV-2 antigens in the claimed vaccines, and the balance between such antigens, were material to these advantages being achieved.
In its appeal, Zoetis attempted to argue that by virtue of the specification disclosing a range of absolute antigen concentrations in micrograms per millilitre, it had fulfilled the best method requirement. In other words, Zoetis was of the view that the best method for making the claimed vaccine was to make it within a range of antigen concentrations, as any vaccine made with the antigen concentrations within such a range would deliver the promises of the invention. Zoetis also contended that it was not obliged to state which specific antigen concentration within the disclosed range was the best.
The Full Court rejected Zoetis’ appeal, noting that while a patent applicant is not obliged to indicate which embodiment in a specification constitutes the best method, they are “bound to disclose the method fairly”.[9] Specifically, the patent applicant may be required “to do more than identify a range from within which the best method may be found”.[10] Accordingly, in view of the IVPs disclosed in the specifications of the Applications demonstrating fluctuating levels of efficacy by virtue of comprising different antigen concentrations, the Full Court found that Zoetis had not disclosed the best method known to it at the time of filing the Applications, as persons skilled in the art would be left to discover for themselves what the appropriate antigen concentrations were to deliver the promises of the invention, and the particular methods to produce vaccines with such antigen concentrations.
Key Takeaways
The Zoetis decision serves as an important reminder that failure to disclose the best method of performing a claimed invention can be fatal to an entire patent. It also highlights that the “promises” of the invention are key to assessing best method (in addition to utility, as we discussed here). Further, it is now well-established in Australia that even when a claimed invention is directed to a product (e.g., a vaccine, as in the Applications), it is likely to be necessary to disclose the best method of making such a product known to the applicant at the filing date.
Unlike other grounds of invalidity, which in some instances can be resolved by amendment and/or partial revocation, there are very few mechanisms available to patentees to remedy a failure to disclose the best method, particularly where examination was requested on or after 15 April 2013. Therefore, it is paramount that patent applicants in Australia (and New Zealand, which also imposes a best method requirement) ensure that the best method known to them of performing the invention is included in the patent specification at the time of filing to avoid the best method requirement coming back to bite them.
If you have any questions in relation to the best method requirement or other aspects of Australian (or New Zealand) patent law, please contact Riley Morrow (RMorrow@dcc.com) or Claire Gregg (CGregg@dcc.com).
[1] Boehringer Ingelheim Animal Heath USA Inc v Zoetis Services LLC [2023] FCA 1119
[2] Boehringer Ingelheim Animal Health USA Inc v Zoetis Services LLC (No 2) [2024] FCA 291
[3] Patents Act 1990 (Cth), s40(2)(aa)
[4] Zoetis at [15]; with reference to the Full Court’s findings in Sandvik Intellectual Property AB v Quarry Mining & Construction Equipment Pty Ltd [2017] FCAFC 138 (Sandvik) at [115(c)] and Les Laboratoires Servier v Apotex Pty Ltd [2016] FCAFC 27 (Servier) at [108]
[5] Zoetis at [15], citing Sandvik at [115(d)] and Servier at [124]
[6] Zoetis at [15]; citing Servier at [64]
[7] Zoetis at [16]; citing Servier at [135]
[8] Zoetis at [62]
[9] Zoetis at [56]
[10] Zoetis at [56]