Intervet inventive step in a veterinary injectable formulation holds on appeal from patent office

Boehringer Ingelheim Animal Health USA Inc. v Intervet International B.V. [2022] FCAFC 88

18 May 2022

Full Federal Court of Australia

Perram, Nicholas and Burley JJ

Background

Opposition and primary court proceedings

Boehringer initially opposed the grant of Intervet’s patent application before the Patent Office in 2016.  The application relates to injectable formulations for controlling parasites in animals, and claims a formulation comprising two active ingredients in an oily non-aqueous solvent system: a macrocyclic lactone in solution, and a levamisole salt in particulate form.  Both active ingredients had previously been used individually for the same purpose.  

Following rejection of its opposition, Boehringer appealed to the Federal Court in respect of inventive step.  Since such an appeal is a proceeding de novo, involving a rehearing of the case, Boehringer was required to establish that it was clear or practically certain that the patent is invalid (the test applicable to patent applications governed by pre-Raising the Bar legislation).  The appeal was dismissed by the primary judge.  

Key Issues

Despite finding that the two active ingredients were known to be chemically incompatible, stable under different pH conditions and to have very different solubilities in water, the primary judge held that it was common general knowledge at the priority date that it would be desirable to combine the two active ingredients into a single formulation.  An expert in formulation chemistry called by Boehringer gave evidence that the differing characteristics of the two active ingredients would have led him to consider a suspension formulation (as in the claimed invention), to keep the two active ingredients separate from each other.  However the product development expert called by Intervet gave evidence that use of a suspension, where the levamisole was in particulate form, could affect the release profile of levamisole as compared to known formulations comprising levamisole in solution.  The judge accepted it was common general knowledge that the release profile of levamisole was important to its efficacy and that the effect of using levamisole in particulate form on that profile would require investigation.  His Honour also found that resolution of the uncertainties relating to the claimed formulation would require more than routine testing.  He therefore was not satisfied that the notional skilled addressee would be directly led to try the formulation as claimed. 

His Honour found that Boehringer had not made out its lack of inventive step case for three reasons: (i) the known chemical incompatibility of the two active ingredients and the uncertainties created by formulating them together, (ii) the fact that the formulation chemist had not considered the impact on release profile when proposing his formulation approach, and (iii) secondary considerations – in particular the lack of commercially available formulations of levamisole in oily formulations or particulate form and prior unsuccessful attempts at combined formulations. 

His Honour considered two prior art documents, concluding they did not help Boehringer’s obviousness case.  The first, a patent application to a combination formulation without the use of a suspension, identified by way of background the difficulty of formulating these types of active ingredients together in a suspension.  The primary judge found that Boehringer had led no evidence that this difficulty had been overcome between the date of the prior art document and the relevant priority date.  The second disclosed a macrocyclic lactone and levamisole formulated in a suspension, but without any discussion of stability issues or any material detail as to the manufacture or practical description of the formulation itself, and no evidence that the formulations exemplified were made or tested.  In fact His Honour concluded that the authors appeared to have been unaware of the chemical incompatibility of the two active ingredients.

Appeal – application of Cripps question

The majority of Boehringer’s grounds for appeal related to the primary judge’s application of the Cripps question.  This test is commonly applied as an aid to analysing obviousness, and essentially asks whether the skilled addressee would, in all the circumstances, be directly led as a matter of course to try the claimed invention in the expectation that it might well produce a useful or better alternative. 

Boehringer submitted that the primary judge erred by failing to limit his consideration to the invention as claimed (that is, the form and relative quantities of the active ingredients), and instead taking into account issues which did not form part of the integers of the claims: efficacy of the formulation and the release rate of levamisole.  Intervet submitted that the problem to be solved was to create a stable formulation with at least some efficacy, and that these considerations were relevant to the characterisation of the invention that the Cripps question addressed. 

The Full Court held that a meaningful anti-parasitic effect was an essential feature of the invention, and that uncertainty as to the effect of using a particulate form on the levamisole release rate should be taken into account in applying the Cripps question.  Given the known issue of resistance to the active ingredients when used individually this uncertainty would teach away from the claimed formulation.  This conclusion was not affected by the fact that a specified release rate did not expressly form part of the claims, since a formulation within the scope of the claims nevertheless needed to be safe and efficacious. 

The Cripps question does not involve an assessment of secondary considerations, such as evidence that practical difficulties were overcome in reaching the invention.  Rather, secondary considerations may be indicative the presence of an inventive step where the invention might otherwise be considered obvious.  Therefore Boehringer’s submissions that there was no such evidence were rejected as not relevant to the application of this question.  Furthermore, the Full Court in fact specifically identified prior unsuccessful attempts by Boehringer to overcome the formulation problem. 

The fact that the stability of the formulation could be assessed by routine testing did not of itself make the invention obvious.   The Full Court approved the application of the approach used in Alphapharm , in which the Court distinguished between testing and experimentation required to reach the invention and subsequent routine testing and checking.  Consistent with this, the Full Court held that the evidence had not established that any testing which led to the invention was routine. 

Outcome

The Full Court concluded that it was open to the primary judge to dismiss the obviousness case, emphasising that the onus was on Boehringer was to establish an error of principle by the primary judge.

Implications

When applying the Cripps question in an obviousness case, consideration should be given to factors which are not specifically claimed but which go to the nature of the invention, at least where it can be argued that they are implicit in the claims.  In this case, the problem purported to be solved by the invention was relevant to the characterisation of the invention to which the Cripps question was addressed.   

When assessing the nature of testing associated with the invention, parties should be aware of the distinction between testing required to move from the common general knowledge or relevant prior art to the invention, and confirmatory testing after the invention.  The fact that the latter may be routine does not necessarily make the steps to reach the invention routine. 

_______

¹ as reformulated by Graham J in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd [1970] RPC 157

² Aktiebolage Hassle v Alphapharm Pty Ltd (2002) 212 CLR 411

About Pearce IP

Pearce IP is a boutique firm offering intellectual property specialist lawyers, patent attorneys and trade mark attorneys to the pharmaceutical, biopharmaceutical and life sciences industries.  Pearce IP is the 2021 ‘Intellectual Property Team of the Year’ (Lawyers Weekly Australian Law Awards) and was shortlisted for the same award in 2022.  Pearce IP is ranked in IAM Patent 1000 and Managing IP (MIP) IP Stars, in Australasian Lawyer 5 Star Awards as a ‘5 Star’ firm, and the Legal 500 APAC Guide for Intellectual Property.  Pearce IP leaders are well recognised as leading IP practitioners.

Our leaders have been recognised in virtually every notable IP listing for their legal, patent and trade mark excellence including: IAM Patent 1000, IAM Strategy 300, MIP IP Stars, Doyles Guide, WIPR Leaders, 5 Star IP Lawyers, Women in Law Awards – Partner of the Year, Best Lawyers and Australasian Lawyer 5 Star Awards, Women in Business Law Awards – Patent Lawyer of the Year (Asia Pacific), Most Influential Lawyers (Changemaker), among other awards.