This is the first article in a two part series exploring particular issues in relation to the validity and infringement of second medical use claims in Australia with reference to two recent decisions by the Patent Office and Federal Court. Part 2, which relates to the infringement of second medical use claims with reference to the Australian Patent Office decision in Neurim Pharmaceuticals (1991) Ltd v Generic Partners Pty Ltd (No 5) [2024] FCA 360 (Neurim) can be found here.
This article considers the recent Australian Patent Office decision in Zoetis Services LLC v Boehringer Ingelheim Vetmedica GmbH [2024] APO 4 (Zoetis). In particular, the Zoetis decision provides useful guidance on the construction of method treatment claims, and the differences between the assessment of inventive step and innovative step of method treatment claims in view of clinical trial disclosures and prior “off-label” (non-approved) use, in Australia.
We have previously discussed the validity risks associated with clinical trial disclosures in Australia here and here. We have also discussed the validity of Swiss-style claims in view of clinical trial disclosures here in the context of the Full Federal Court decision in Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd [2020] FCAFC 116 (Mylan). The Zoetis decision further emphasises that premature disclosures relating to clinical trials, particularly the results or anticipated results, can pose a significant threat to patent validity in Australia.
Inventive step vs innovative step
An invention will be taken to involve an inventive step in Australia unless it would have been obvious to a skilled person in light of the common general knowledge in the art (CGK) considered separately or together with one, or a combination of two or more, prior art documents or acts. Where the invention addresses a problem to be solved (as is often the case), the High Court has endorsed the following test for inventive step:[i]
Would the notional research group at the relevant date, in all the circumstances … directly be led as a matter of course to try [the claimed invention] in the expectation that it might well produce a [useful desired result]?
In contrast, an invention will be taken to involve an innovative step unless it would, to a skilled person in light of the CGK, only differ from the information made publicly available in a single document or act (or single source of information) in ways that make no substantial contribution to the working of the invention.
The distinction between inventive step and innovative step was considered by the Full Federal Court in Dura-Post (Aust) Pty Ltd v Delnorth Pty Ltd [2009] FCAFC 81, which endorsed the approach of the lower court as follows:
There is no need to search for some particular advantage in the art to be described as an innovative step which governs consideration of each claim. The first step is to compare the invention as claimed in each claim with the prior art base and determine the difference or differences. The next step is to look at those differences through the eyes of a person skilled in the relevant art in the light of common general knowledge as it existed in Australia before the priority date and ask whether the invention as claimed varies from the kinds of information set out in s7(5) in ways that make no substantial contribution to the working of the invention …
The phrase ‘no substantial contribution to the working of the invention’ involves quite a different kind of judgement from that involved in determining whether there is an inventive step. Obviousness does not come into the issue … Indeed the proper consideration of s 7(4) is liable to be impeded by traditional thinking about obviousness.
Construction of method of treatment claims
The proper construction of method of treatment claims was considered by the High Court in Apotex Pty Ltd v Sanofi-Aventis Australia Pty Ltd [2013] HCA 50; 253 CLR 284 (Apotex HC) in the context of indirect infringement (i.e., contributory infringement). In construing a claim directed to a method of treating psoriasis by administering leflunomide, the High Court affirmed the conclusion reached by the Full Federal Court in Apotex Pty Ltd v Sanofi-Aventis Australia Pty Ltd (No 2) (2012) 204 FCR 494 (Apotex FC) as follows:
This new method of treatment, as a patentable invention, can only be realised or expressed through the deliberate administration of leflunomide to prevent or treat psoriasis. It will not be realised or expressed by its administration with some other object or end in view that happens to achieve the result of preventing or treating psoriasis accidentally or as an unsought consequence. To construe the claim as simply requiring the administration of leflunomide that achieves a therapeutic or biological result that includes the prevention or treatment of psoriasis is, in our view, effectively to ignore the governing characteristic incorporated into the express words of the claim that the invention is a method directed to preventing or treating psoriasis – the claimed advance in the art.
Thus, where the deliberate administration for the treatment of a condition not covered by a valid method of treatment claim unintentionally treats a condition encompassed by the claim, the claim would not be indirectly infringed by the supply of the drug. It follows that anticipation requires disclosure of deliberate administration to achieve the claimed therapeutic purpose in the prior art.
While not relevant to the Zoetis decision, we discussed the proper construction of Swiss-style claims arising from the Mylan decision here.
Inevitable results and method of treatment claims
The High Court’s findings in Apotex HC are also consistent with the obiter dicter comments of the Full Federal Court in AstraZeneca AB v Apotex Pty Ltd (2014) 226 FCR 324 (AstraZeneca) in relation to an “inevitable result” as follows:
… it is important to note the cautionary observations of Bennett and Yates JJ in [Apotex FC]… at [165] that there is a question whether the unyielding logic of the “inevitable result” cases can be applied uncritically in every case of alleged anticipation, particularly where the invention in suit is claimed as a new method of medical treatment involving the administration of a known compound for a hitherto unknown and unexpected, but nevertheless useful, therapeutic use.
In Neurim, Nicholas J considered whether the “inevitable result” exception discussed in AstraZeneca applies in the case of a subset of a previously disclosed use or method. In that case, the claims at issue are directed to a prolonged release formulation of melatonin treatment of “primary insomnia characterized by non-restorative sleep and improving the restorative quality of sleep in said patient”, whereas the prior art relates to use of prolonged release formulations of melatonin for treating various indications, including insomnia and improving sleep quality.
Nicholas J rejected the respondent’s characterisation of the claims directed to a narrower use than the prior art as “parameteritis” (i.e., an attempt to re-patent the prior art by limiting the claims by reference to a parameter not specifically mentioned but nonetheless encompasses in the prior art). Rather, his Honour considered that the newly claimed features “have a technical effect, are part of the invention, and are directly related to a claimed advantage of the invention” (i.e., were more akin to a selection invention). Accordingly, his Honour considered that the claims are novel (and involve and inventive step) because they are directed to a new therapeutic use and “it was not an inevitable result of the prior use of melatonin that it had been or would be used as such a treatment”.
The claims at issue in Zoetis
The Zoetis decision concerns an opposition to a standard patent application (Parent) and a divisional innovation patent thereof (Divisional). Claim 1 of the Parent is as follows:
A method for treating a patient with asymptomatic (occult, preclinical) myxomatous mitral valve disease (MMVD), the method comprising administering to the patient an effective amount of a pharmaceutical composition comprising pimobendan so as to effect a reduction of the heart size of an already pathologically enlarged heart of the patient in combination with delaying the onset of clinical symptoms of heart failure in the patient.
The Divisional claims are in similar terms, further specifying that the patient is a dog and that the MMVD “is of a stage ISACHC Class IB or ACVIM stage B2”.
In construing these claims, the Delegate concluded:
- to the extent the claims define features based on a population of patients (i.e., derived from a clinical trial), the results of a clinical trial would be understood by a skilled person as providing a basis for extrapolation to individual patients within a patient population;
- the clinical outcomes of a reduction of the heart size of an already pathologically enlarged heart of the patient in combination with delaying the onset of clinical symptoms of heart failure are essential features of the claims and not merely “parameteritis”; and
- the term “effective amount” simply reinforces that the purpose of the method of treatment is to achieve the claimed clinical outcomes.
Accordingly, the Delegate concluded: “It follows that the claims define methods of treatment comprising the administration of pimobendan to individuals in a particular patient group … in order to achieve the defined clinical outcomes”.
The Zoetis decision
The Zoetis decision considers, inter alia, the novelty, inventive step and innovative of method of treatment claims in view of a press release referring to a clinical trial disclosure (EPIC Press Release) and clinical records relating to off-label use of pimobendan in dogs (NCSU Records).
EPIC Press Release
While the EPIC Press Release mentions there is “clear evidence of benefit of the administration of pimobendan in [delaying the onset of congestive heart failure]”, it does not disclose the feature of a reduction in heart size. Accordingly, the claims of both the Parent and the Divisional were found to be novel.
However, the Parent claims were found to lack an inventive step because determination of a suitable dosage to provide a delay in the onset of congestive heart failure was considered by the Delegate to be a matter of routine, and the reduction of heart size of an already pathologically enlarged heart was considered to be an inevitable outcome of administering that dosage. In other words, the EPIC Press Release provided an expectation that pimobendan delays onset of congestive heart failure, and there was no evidence to suggest the existence of dosages that would achieve a delay in onset of congestive heart failure but not a reduction of heart size.
In contrast, the Divisional claims (which rely on the same features for patentability as the Parent Claims) were found to involve an innovative step. In that regard, the Delegate considered that “reducing the size of an already pathologically enlarged heart clearly makes a substantial technical or functional contribution and is a significant aspect of the operation of the invention over the prior art disclosures”. Determining an appropriate dosage regimen was also considered “an additional factor that would make a functional contribution to the invention over the disclosure by the EPIC Press Release”.
NCSU Records
The NCSU Records include both the acts of diagnosing and treating seven different dogs with pimobendan by various veterinarians in a single clinic (prior off-label use), and the associated discharge instructions provided to the dog owners. The Delegate considered the NCSU Records to be of a nature that constitutes a single source of information (and therefore relevant for both novelty and innovative step), and the dog owners to be members of the public who did not have any obligation of confidentiality with respect to the NCSU Records.
However, in considering what the NCSU Records disclose, the Delegate had a number of reservations, including the hearsay nature of the evidence of the relevant expert about cases he was not directly involved in, and the hindsight assessment of the circumstances surrounding the administration of pimobendan to the dogs. In that regard, the Delegate cautioned against drawing conclusions beyond the specific circumstances of each of the individual cases.
Of particular relevance was the lack of any disclosure in the records of the therapeutic purpose for which pimobendan was administered to the dogs (i.e., the claimed clinical outcomes) and the lack of generalisability of the specific off-label uses to the general population. These factors were determinative in finding that both the Parent and Divisional claims are novel, and involve an inventive and innovative step, over the NCSU Records.
Key takeaways
The Zoetis and Neurim decisions provide some important insights into the validity of method of treatment claims in Australia as follows.
- The claimed therapeutic outcomes are essential features of method of treatment claims and must be disclosed in the prior art for the claims to lack novelty and an innovative step.
- The inevitable achievement of a therapeutic outcome in the prior art is not sufficient to destroy the novelty or innovative step of a claim in the absence of a disclosure of the deliberate administration to achieve that therapeutic outcome.
- A claim directed to a narrower therapeutic purpose of an active agent may not be anticipated (or rendered obvious) by prior art directed to use of the same active agent for a broader therapeutic purpose where the narrower therapeutic purpose is associated with a new technical effect or advantage.
- On the other hand, where the claims include multiple therapeutic outcomes and those outcomes are inevitably linked, the prior art need only provide the expectation of success in relation to one of those outcomes to render the claims obvious.
- Prior “off-label” use of a drug in individual patients has limited relevance for novelty, inventive step and innovative step.
- The low bar for assessing innovative step in Australia may still provide opportunities to obtain robust protection for pharmaceutical innovations. While the phase out of Australia’s second-tier innovation patent system commenced on 26 August 2021, innovation patents will remain in effect in Australia up until 25 August 2029, and it is still possible to file innovation patent applications as divisionals of certain standard patent applications (see our previous article).
Please contact Claire Gregg (cgregg@dcc.com) or Paul Dewar (pdewar@dcc.com) if you have any questions.
To read part 2 of this article, please click here.
[i] Aktiebolaget Hässle v Alphapharm Pty Ltd [2002] HCA 59; first set out in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd [1970] RPC 157 at 187–188 per Graham J, referred to as a reformulation of the “Cripps question” set out in Sharp & Dohme Inc v Boots Pure Drug Company Ltd (1928) 45 RPC 153 at 173