Abbey Laboratories Pty Ltd v Virbac (Australia) Pty Ltd (No 3)
[2025] FCA 1179
•24 September 2025
FEDERAL COURT OF AUSTRALIA
Abbey Laboratories Pty Ltd v Virbac (Australia) Pty Ltd (No 3) [2025] FCA 1179
File number(s): NSD 698 of 2024 Judgment of: JACKMAN J Date of judgment: 24 September 2025 Catchwords: PATENTS – application for revocation of certain claims of patent on basis that claims are neither novel nor involve inventive step within meaning of s 18(1)(b) of the Patents Act 1990 (Cth) (Patents Act) when compared to prior art base – cross-claim for infringement of patent – where specification is a pour-on anthelmintic formulation for cattle involving a selected levamisole active ingredient and a macrocyclic lactone dissolved in a non-aqueous system that is stable – where prior art base existed before priority date – where expert witness relies on greater knowledge than common general knowledge (CGK) attributable to a person skilled in the art (PSA)
PATENTS – whether claims of patent lack inventive step – legal principles concerning prior art base, common general knowledge and obviousness considered – where expert witnesses required to undertake task of developing anthelmintic, using knowledge as at priority date – where applicant’s expert evidence does not reflect position of PSA – where comparison of other similar patents – inventive step found
PATENTS – whether claims of patent lack novelty – whether necessary to consider a notional set of claims, in valid form, which would be fairly based, as set out in Du Pont (defined in reasons) – where language of Patents Act does not require Court to determine hypothetical validity of notional claim – where notional claim requirement adds unnecessary complexity which was not intended by legislature – notional claim requirement is unnecessary – comparison of prior art document with patent in suit undertaken, claim by claim – each of contested claims held to be novel
HIGH COURT AND FEDERAL COURT – decision whether or not to follow previous judge’s decision should not be based on ‘judicial comity’ – where compelling reason to depart from previous judge
EVIDENCE – whether a Ferrcom inference (as defined in reasons) can apply to expert evidence – where difficulty determining whether there has been ‘fear’ of evidence being given or whether the significance of the evidence was simply not appreciated when the evidence in chief was prepared much earlier – where features of contemporary practice require expert reports to declare that all appropriate inquiries have been made and no matters of significance omitted – where no room left to tactically seek to avoid subject matter – Ferrcom inference superseded
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Division: General Division Registry: New South Wales National Practice Area: Intellectual Property Sub-area: Patents and Associated Statutes Number of paragraphs: 220 Date of last submission/s: 10 September 2025 Date of hearing: 2–10 September 2025 Counsel for the Applicants: Mr A Ryan SC with Ms S Yates Solicitors for the Applicants: Bird & Bird Counsel for the Respondents: Mr N Murray SC with Mr J Elks Solicitors for the Respondents: Ashurst ORDERS
NSD 698 of 2024 BETWEEN: ABBEY LABORATORIES PTY LTD
(ACN 156 000 430)Applicant/First Cross-Respondent
ABBEY ANIMAL HEALTH PTY LTD
(ACN 164 159 764)Second Cross-Respondent
AND: VIRBAC (AUSTRALIA) PTY LTD
(ACN 003 268 871)Respondent
ORDER MADE BY:
JACKMAN J
DATE OF ORDER:
24 SEPTEMBER 2025
IN THESE ORDERS:
(a)Patent means Australian Standard Patent No. 2012227241 entitled Veterinary Topical Formulation.
(b)Levamox Duo means the Cross-Respondents’ product known as Levamox Duo Pour-On for Cattle.
THE COURT DECLARES THAT:
1.The Cross-Respondents have infringed each of claims 1 to 10, 13, 15, 16 and 18 of the Patent.
2.Claims 19, 20 and 21 of the Patent are, and at all material times have been, invalid.
THE COURT CERTIFIES THAT:
3.Pursuant to s 19 of the Patents Act 1990 (Cth), the validity of each of claims 1 to 10, 13, 15, 16 and 18 of the Patent was questioned unsuccessfully in this proceeding.
THE COURT ORDERS THAT:
4.From 22 October 2025, each Cross-Respondent, whether by itself, its directors, officers, servants or agents, or otherwise be restrained, from infringing each of claims 1 to 10, 13, 15, 16 and 18 of the Patent, including by engaging in any of the following acts within Australia during the term of the Patent without the licence or authority of the Cross-Claimant:
(a)manufacturing in Australia, or importing into Australia, Levamox Duo;
(b)selling, supplying or otherwise disposing of Levamox Duo in Australia;
(c)offering to manufacture, sell, supply or otherwise dispose of Levamox Duo in Australia; and
(d)authorising, procuring, inducing or joining in a common design with any other person to engage in any of the acts referred to in sub-paragraphs (a) to (c) above.
5.By 22 October 2025, the Cross-Respondents destroy or deliver up to the Cross-Claimant on oath all Levamox Duo, together with all advertising, promotional and packaging material relating to such products, in the possession, custody, power or control of each Cross-Respondent in Australia.
6.Claims 19, 20 and 21 of the Patent be revoked pursuant to s 138(3) of the Patents Act 1990 (Cth).
7.There be an inquiry as to damages or an account of profits.
8.The Originating Application otherwise be dismissed.
9.The Respondent/Cross-Claimant file and serve any affidavits and written submissions in relation to costs by 17 October 2025.
10.The Applicant/Cross-Respondents file and serve any affidavits and written submissions in relation to costs by 31 October 2025.
11.The Respondent/Cross-Claimant file and serve any affidavits and written submissions in reply in relation to costs by 14 November 2025.
12.The matter be listed for case management in relation to the question of the assessment of pecuniary remedies on 31 October 2025 at 9.30 am.
Note: Entry of orders is dealt with in Rule 39.32 of the Federal Court Rules 2011.
REASONS FOR JUDGMENT
JACKMAN J:
Glossary
The following defined terms have been used in these reasons with the corresponding meaning:
Defined Term Meaning 040 Patent New Zealand Patent No. NZ 20060552040 filed on 13 December 2006 in the name of Bomac Research Ltd (CB129) 041 Patent Australian Patent No. 2004228041 in the name of Merial Ltd published on 21 October 2004 (CB130) 154 Patent New Zealand Patent No. NZ 761154 in the name of Elanco New Zealand with a filing date of 23 June 2011 (Exhibit 1) 242 Patent Patent No. WO 2004/069242 A1 in the name of Jurox Pty Ltd (CB13) 600 Patent Patent No. 2009222600 filed on 5 October 2009, taking priority from NZ 571920 in October 2008 in the name of Bomac Research Ltd (Exhibit 2) 789 Patent New Zealand Patent No. 606789 in the name of Elanco New Zealand filed on 20 December 2017 (Exhibit 3) 984 Patent Australian Patent No. 2011234984 A1 in the name of Boehringer Ingelheim Animal Health USA Inc with priority date of 2 April 2010 and filed on 11 April 2011 (CB9, 133, 136) Abbey Abbey Laboratories Pty Ltd, the applicant and first cross-respondent in these proceedings Act Patents Act 1990 (Cth) as at the Priority Date; that is, prior to the enactment of the amendments made by the Intellectual Property Laws Amendment(Raising the Bar) Act 2012 (Cth) Agnew 1 Dr Kim Agnew’s first affidavit, dated 19 August 2024 Agnew 2 Dr Kim Agnew’s second affidavit, dated 25 September 2024 Agnew 3 Dr Kim Agnew’s third affidavit, dated 8 October 2024 Agnew 4 Dr Kim Agnew’s fourth affidavit, dated 21 March 2025 Alawi 1 Dr Fadil Alawi’s first affidavit, dated 21 August 2024 Alawi 2 Dr Fadil Alawi’s second affidavit, dated 5 October 2024 Alawi 3 Dr Fadil Alawi’s third affidavit, dated 7 October 2024 Alawi 4 Dr Fadil Alawi’s fourth affidavit, dated 12 October 2024 Alawi 5 Dr Fadil Alawi’s fifth affidavit, dated 24 March 2025 Alawi 6 Dr Fadil Alawi’s sixth affidavit, dated 8 April 2025
anthelmintic
also known as antiparasitic or parasiticide, being a product used to treat parasites, comprising endoparasites (those most commonly affecting cattle in Australia being gastrointestinal nematodes, lung worm, tapeworm, coccidia and liver fluke) and ectoparasites (those most commonly affecting cattle in Australia being lice (biting and sucking), ticks, mites, nuisance fly and buffalo fly) API or active active pharmaceutical ingredient, being an ingredient which has the desired therapeutic effect Appendix Abbey’s submission comparing the claims in the Patent in suit with the alleged disclosures of the 984 Patent, being an appendix to these reasons APVMA Australian Pesticides and Veterinary Medicines Authority BHT butylated hydroxytoluene, being an antioxidant Bunt 1 Professor Craig Bunt’s first affidavit, dated 24 February 2025 Bunt 2 Professor Craig Bunt’s second affidavit, dated 12 June 2025 CGK common general knowledge Cydectin Platinum Virbac’s combination moxidectin and levamisole product launched in late 2020, an embodiment of the invention of the Patent in suit DEP diethyl phthalate DGME or DGBE diethylene glycol monobutyl ether, also known as butyl carbitol DMP dimethyl phthalate DMA dimethyl acetamide DMI dimethyl isosorbide Eclipse a combination macrocyclic/levamisole topical formulation manufactured by Merial Eclipse Pour-On Data Sheet the “Eclipse” Pour-On safety data sheet (CB10) EE Injection Label the “Eclipse E” Injection Label (CB12) EE Injection Data Sheet the EE Injection Safety Data Sheet (CB11) Formulation JER the Joint Experts’ Report by Dr Alawi and Professor Bunt dated 24 April 2025 IGR insect growth regulator Levamox Duo the anthelmintic product sold by Abbey and Abbey Animal Health Pty Ltd in Australia since 9 January 2025, known as “Levamox Duo Pour-On for Cattle” levamisole an active ingredient used in anthelmintics as at the Priority Date, being a nicotinic agonist lipophilic soluble in fats, oils and lipids in living organisms Liu 1 Mr Roger Liu’s first affidavit, dated 21 February 2025 macrocyclic lactones a group of active anthelmintic ingredients used at the Priority Date NMP 1-methyl-2-pyrrolidinone; or N-Methyl pyrrolidone, a solvent non-aqueous system a system that does not use water Outlaw a combination macrocyclic lactone/levamisole formulation manufactured by Bayer, being the same formulation used in the Saturn product Patent Australian Patent No. 2012227241 in the name of Virbac, being the patent in suit (CB1) PEG polyethylene glycol Priority Date 23 September 2011 PSA person skilled in the art RH relative humidity Saturn a combination macrocyclic lactone/levamisole formulation manufactured by Bayer, being the same formulation used in the Outlaw product Specification the complete specification of the Patent Task to develop as a team as at 23 September 2011 a combination product with acceptable shelf-life stability containing a macrocyclic lactone and levamisole for use in relation to cattle, and being a pour-on formulation Team JER the Joint Experts’ Report by Dr Agnew, Dr Alawi and Professor Bunt dated 24 April 2025 triacetin a type of glyceryl acetate (a solvent) Virbac Virbac (Australia) Pty Ltd, the respondent and cross-claimant in these proceedings Introduction
Abbey seeks an order revoking certain claims of the Patent under s 138 of the Patents Act on the basis that the invention claimed is not a patentable invention. Abbey contends that the claims in question, when compared with the prior art base as it existed before the Priority Date, is neither novel nor involves an inventive step within the meaning of s 18(1)(b).
Virbac cross-claims for infringement of claims 1–10, 13, 15, 16 and 18–21. They are the claims which Abbey seeks to have revoked. If the Patent is valid, there is no issue as to Abbey having infringed the Patent by offering to sell and supply in Australia its product Levamox Duo since about 4 December 2024 and actually selling, supplying and keeping for those purposes Levamox Duo since about 9 January 2025.
Abbey commenced these proceedings on 29 May 2024, well before it launched Levamox Duo. On 17 December 2024, I declined to grant Virbac an interlocutory injunction restraining the launch and sale of Levamox Duo, on the basis that the balance of convenience did not favour an injunction: Abbey Laboratories Pty Ltd v Virbac (Australia) Pty Ltd [2024] FCA 1488. A final hearing was scheduled to commence on 12 May 2025, but was adjourned by consent because of the personal circumstances of one of the expert witnesses. As is conventional in intellectual property litigation, the question of pecuniary remedies is to be heard and determined subsequently.
The Specification
The Patent is entitled “Veterinary Topical Formulation”. It has a priority date of 23 September 2011.
The Specification states that the invention relates to the field of veterinary pharmaceuticals and in particular to the development of improved anthelmintic formulations containing a combination of active ingredients.
Under the heading “Background of the Invention”, the Specification states that the control of gastrointestinal parasites is an important aspect of modern livestock farming. It describes the five major classes of broad spectrum anthelmintic which have been developed over the previous 50–60 years, namely benzimidazoles, nicotinic agonists (which includes the imidazothiazole group, which in turn includes levamisole), macrocyclic lactones, amino-acetonitrile derivatives, and spiroindoles. The Specification states that compared to other anthelmintics, levamisole has the narrowest margin of safety, although toxicity is usually the result of excess dosage (page 3, lines 15–16). It is also stated that levamisole has a broad spectrum of activity and is effective against many larval stages of parasites, although not arrested larvae. As for macrocyclic lactones, it is stated that the first drug of that class, namely ivermectin, was introduced in the early 1980s. It is stated that macrocyclic lactones consist of two closely related chemical groups, avermectins and milbemycins: the avermectins include abamectin, ivermectin doramectin and eprinomectin, and the milbemycin group is represented by milbemycin oxime and moxidectin, introduced in 1997. It is said that macrocyclic lactones are the most potent killer of worms, and have the unique quality of also killing several types of external parasites, such as lice, mites and ticks. It is said that macrocyclic lactones have a wide margin of safety for livestock and are effective against all stages of worms, including inactive forms (page 4, lines 4–5). It is stated that all five major classes of anthelmintics have application in the control of a wide variety of ecto and endoparasites, and the group of worms known as helminths are of particular concern. Helminthiasis is said to be a prevalent and serious economic problem with domesticated animals, including cattle. Among the helminths, the group of worms described as nematodes is said to cause widespread, and at times serious, infection in various species of animals. A list of nematodes that are contemplated to be treated by the anthelmintics is then set out, and includes Cooperia and Ostertagia among the many genera.
The Specification notes that there have been many anthelmintics developed over the years, but there is concern over the development of resistance to anthelmintics belonging to the benzimidazole, nicotinic agonist and macrocyclic lactone classes. Resistance refers to the process by which exposure of the parasite population to an anthelmintic leads to genetic selection of those parasites able to tolerate it, and the problem is exacerbated by over-exposure of the parasite population to the anthelmintic or by sub-lethal dosing of the parasite through inaccurate dose administration. It is stated that of particular relevance to this application is the development of resistance to those classes of anthelmintic widely used in cattle. It is stated that resistance to the more recent macrocyclic lactone class is also becoming much more common, and this is particularly troublesome given that it is by far the most popular form of parasite treatment for farmed cattle (page 5, lines 25–27).
The Specification then refers to three strategies which farmers have relied on to prevent and manage the problem of anthelmintic resistance, the third of them being the use of combinations of anthelmintics from different classes to reduce the potential of parasites to survive the treatment. It is then said that the patent application describes practical solutions to aid farmers in the application of that strategy by providing an improved ready-to-use combination of anthelmintics selected from two different anthelmintic classes (page 6, lines 7–9). The specification then states the following (page 6, lines 10–16):
From the perspective of ease of administration it is most desirable that any combination is able to be applied topically. It would also be desirable that the formulation contained both a macrocyclic lactone active ingredient and levamisole, as both of these anthelmintics are used topically in cattle and such a combination would help ensure the widest spectrum of activity.
It would further be desirable that a combination solution of macrocyclic lactone and levamisole could be applied to the back of an animal in a form that would have a minimal tendency to run off the back of the animal before absorption had occurred.
Under the heading “Definitions”, it is stated that the formulations of the present invention must be stable to be of commercial use, and that a commercially acceptable anthelmintic formulation is one which is stable at room temperature for a period of at least three months (page 6, lines 19–21). The Specification states that, in conditions of accelerated testing at 40ºC, this requires the potency of the actives within the formulation to remain within specified and acceptable limits for six weeks (page 6, lines 21-23).
Under the heading “Prior References”, the Specification refers to several patents. Reference is made to NZ 336139 (Novartis), which is said to represent a recent attempt to formulate a combination product containing a macrocyclic lactone anthelmintic and levamisole. It is stated that the formulation described in that patent includes levamisole in an aqueous acidic phase and macrocyclic lactone in a lipophilic phase, and that a third active could potentially be suspended in particulate form in the aqueous phase. The disadvantage of that formulation is said to be the need for the formulation to be shaken or agitated into an emulsion, and that the product is chemically complicated, including two or three different phases. The complicated nature of the formulation is said to be due in part to the different formulation requirements of the actives. Macrocyclic lactone active ingredients are said to be substantially insoluble in water, whereas levamisole is water soluble, and macrocyclic lactone active ingredients are most stable at a pH of about 6.6 whereas levamisole is most stable at a pH of less than about 4 (page 7, lines 25–27).
The prior references also refer to NZ 520295 (Merial), which is said to be a more recent attempt to provide a stable formulation of a macrocyclic lactone anthelmintic combined with levamisole. It is stated that NMP was used to dissolve both active ingredients, resulting in a formulation that was simple to prepare and demonstrated much improved stability of the two actives. Pausing there, I note that the product marketed by Merial pursuant to that patent is the Eclipse Pour-On product.
Reference is also made to NZ 552040 (Bomac), in which the macrocyclic lactone and levamisole active ingredients are solubilised in a combination of triacetin and glycerol formal. It is stated, however, that this formulation does not offer improvement in shelf stability when compared to the prior art, and the data presented in the patent indicates that it is potentially more poorly absorbed when compared to the formulation described in NZ 520295. Pausing there, I note that the products marketed pursuant to that patent are the Saturn and Outlaw products, and that Dr Alawi is a co-inventor of that patent, being the 040 Patent.
The Specification then states that most of these solvent selections are unsuitable for combinations of macrocyclic lactones and levamisole, either because they do not promote long term stability of the formulation or because their presence in the formulation would promote severe skin site reactions on treated animals (page 8, lines 14–16). An additional problem with the formulations is said to be that they tend to have relatively low rates of transdermal absorption, which is said to be likely due to the fact that the solvents used have been selected primarily on the basis of minimising degradation of the active ingredients during storage rather than due to their ability to transdermally deliver both actives. It is also stated that the current combination topical formulations have a tendency to quickly run from the back of the animal, primarily because they are organic solvent based and therefore have the typically low viscosity of the solvent mix. The Specification then states the following (page 9, lines 1–3):
Accordingly, there remains a need for a stable topical formulation containing a macrocyclic lactone anthelmintic and levamisole, and that promotes improved transdermal absorption of the two anthelmintic active ingredients as well as reduced tendency for run-off.
Under the heading “Statement of Invention”, there appear a number of consistory clauses, corresponding to some of the independent claims. There then follows a verbatim recitation of claims 1–21.
Under the heading “Description”, the Specification states that a series of studies was undertaken in an attempt to improve on the shelf stability of currently available macrocyclic lactone/levamisole topical formulations, in which abamectin was used as the representative macrocyclic lactone active, while levamisole in its base form was used as the representative levamisole anthelmintic (page 10c, line 16–19). Under the sub-heading “Solvent Selection”, it is stated that a solvent selection process was initiated to determine which solvents might be suitable for inclusion in a series of stability studies, and all oily solvents were rejected based on previous knowledge of potential irritancy when combined with levamisole. It is stated that a selected series of topical solvents was tested to determine their basic ability to offer improvements from those currently used as the main solvents in the commercially available macrocyclic lactone/nicotinic agonist combination topical formulations known as Eclipse and Saturn. In the trials, formulations were prepared containing 1% abamectin, 20% levamisole base and 0.1% BHT (an antioxidant), with all materials dissolved in the selected solvent. A table of results from the trials is then set out (page 11), showing the results for 13 solvents, beginning with NMP (which I note is the solvent used in the Eclipse Pour-On product) and glycerol triacetate (which I note is the solvent used in the Saturn product).
It is then stated that, as might be expected, the two solvents used in the marketed products, Eclipse and Saturn, performed better than most of the other solvents tested, but surprisingly three other solvents performed equally well and one in particular, DMI, performed best of all in terms of enhancing the stability of abamectin. Those five solvents are then set out in order of performance as follows: DMI, NMP, DMA, glycerol acetate, and DEP. The Specification states that, surprisingly and quite unexpectedly, the best solvents for stability of the macrocyclic lactone active ingredient also were the easiest in which to dissolve the ingredients.
The Specification then states that, based on those results, the five preferred samples were then tested for stability enhancement of the levamisole active ingredient. It is stated that data indicated that in the case of the preferred solvents, the levamisole was more stable than the abamectin ingredient (although I note that that data is not presented in the Specification).
The Specification then states that, while it would appear that it would be most beneficial that DMI alone be used in the formulation, unfortunately it is a very expensive solvent, and for this reason a less expensive co-solvent would be desirable (page 12, lines 14–16). The choice of DMA and DEP is said to offer advantages in terms of potential cost reduction. It is then stated that further high temperature stress testing was conducted to determine whether a blend of solvents selected from the preferred solvents might offer cost savings without unacceptably compromising the stability of the active ingredients. DMI and DMA in varying proportions from 40 to 60% were used, and the samples were subjected to long-term storage of 55ºC. The reduction in the abamectin potency of all samples was such that it is said to be demonstrated that the co-solvent system could meet the objective of cost saving while maintaining stability to at least the standard set with the group of preferred solvents. It is then said that additional tests were performed in which DMI/DMA solutions were tested against DMI/DGME solutions containing 1% abamectin and 20% levamisole base, and that results for accelerated testing at 55ºC for seven days indicated that for all batches there was a slight but completely unexpected improvement in abamectin stability for the DMI/DGME solvent combination. It is then said that use of DGME as a co-solvent would have the additional benefit of reducing the flash point of the formulation.
The Specification then provides fifteen example formulations, together with a method of preparation.
The Specification then states that, surprisingly during the experiments, it was found that it was possible to solubilise triclabendazole (which I note is another anthelmintic) within the same formulation as the macrocyclic lactone and levamisole (page 18, lines 1–2). It is stated that a particularly preferred formulation incorporates a combination of DMI and DMA or DGME at a ratio of around 80/20 to 20/80 (page 18, lines 10–11). It is also stated that various combinations of the preferred invention were then applied to test animals, and in no case was there any apparent skin reaction to the formulations (page 18, lines 12–13).
The Specification then states that a second aspect of the invention is the addition of one or more viscosity modifying agents to solvent based topical macrocyclic lactone/levamisole formulation systems. It is said that a number of such agents have been tested and found to be suitable for this application at levels low enough that they have no discernible influence on the shelf-life stability of the formulation. It is said that of particular usefulness are, among others, polymers, including linear, branched or cross-linked polymers, acrylic polymers, cross-linked acrylic polymers, and a list of examples is then given which includes polyvinyl pyrrolidone and polyethylene glycols. It is stated that a variety of topical formulations were tested, both including and excluding the viscosity modifying agent, to test the effectiveness of the preferred materials. A laboratory simulation is then described as having been undertaken, using a substrate mounted on an inclined board, and various samples were poured onto the top portion of the board with measurements taken as to how far down the board each formulation would run. It is then stated that of particular usefulness in the formulation were viscosity modifiers comprised of polyvinyl pyrrolidone and/or cellulose acetate butyrate (page 20, lines 19–20). It is stated that in all cases, the addition of the viscosity modifier resulted in a considerable reduction in the tendency of the formulation to run, and that typically formulations in which the material was added (at levels from 2–5%) resulted in a reduction in run length on the inclined board of between 50 and 70%.
Under the heading “Advantages”, the Specification says that the invention provides stable formulations including a macrocyclic lactone anthelmintic in combination with levamisole, and the formulations retain each active in solution. The formulations are said to be monophasic and suitable to manufacture on a commercial scale, and as both actives are in solution, the formulations are physically stable in that they do not separate out into separate phases, thereby enabling the formulations to be used without requiring agitation or shaking before use, and greatly reducing the risk of differing concentrations of actives through the drum or other storage container (page 21, lines 4–9). In addition, it is stated that, as the formulation excludes water, the issue of incompatible pH requirements is alleviated (page 21, lines 10–11).
Under the heading “Variations”, it is said that although a number of macrocyclic lactone anthelmintics have been described in the examples, other macrocyclic lactones may be used in place of those described. Similarly, although a levamisole base has been used in the examples, other forms of levamisole may be used.
The Claims are then set out as follows:
CLAIMS
1.A stable formulation including a levamisole active ingredient and at least one active selected from the group known as macrocyclic lactones, with both of said actives being dissolved in a non-aqueous system including one or more solvents selected from dimethyl acetamide, dimethyl isosorbide, diethyl phthalate and dimethyl phthalate; wherein the formulation is a topical formulation for administration to cattle.
2.A formulation as claimed in claim 1 in which one or more solvents selected from dimethyl acetamide, dimethyl isosorbide, diethyl phthalate and dimethyl phthalate are present at a level of from 20% to 85% w/v.
3.A formulation as claimed in any one of the above claims in which the levamisole active ingredient and the at least one macrocyclic lactone active ingredient are dissolved in a system including a blend of dimethyl isosorbide and a second solvent selected from dimethyl acetamide, diethyl phthalate, dimethyl phthalate and glycol ethers.
4.A formulation as claimed in any one of the above claims which additionally includes at least one co-solvent selected from glyceryl acetates, pyrollidones, glycol ethers, glycol esters, glycerol formal, and alcohols.
5.A formulation as claimed in any one of the above claims, wherein the at least one macrocyclic lactone active ingredient is selected from abamectin, ivermectin, doramectin, eprinomectin, moxidectin, and selamectin.
6.A formulation as claimed in any one of the above claims wherein the at least one macrocyclic lactone active ingredient and the levamisole active ingredient remain within 10% of their initial specification for at least 3 months when stored at 25ºC or below and at ambient humidity.
7.A formulation as claimed in any one of the above claims, wherein the macrocyclic lactone active ingredient is present in the range of between 0.01–5% w/v.
8.A formulation as claimed in any one of the above claims, wherein the levamisole active ingredient is in the base, hydrochloride or phosphate form.
9.A formulation as claimed in any one of the above claims, wherein the levamisole active ingredient is in the base form.
10.A formulation as claimed in any one of the above claims wherein the levamisole active ingredient is present in the range of between 1–30% w/v.
11.A formulation as claimed in any one of the above claims wherein the formulation additionally includes an additional anthelmintic selected from: benzimidazoles (including albendazole, fenbendazole, mebendazole, oxfendazole, oxibendazole, triclabendazole), clorsulon, closantel, derquantel, febantel, monepantel, morantel, netobimin, nitroxynil, oxyclozanide, praziquantel, pyrantel and rafoxinide.
12.A formulation as claimed in any one of the above claims which includes a macrocyclic lactone, levamisole and triclabendazole at a concentration of from 5 to 50%.
13.A formulation as claimed in any one of the above claims wherein the formulations additionally include antioxidants and/or stabilizers.
14.A formulation as claimed in any one of the above claims wherein the formulation additionally includes at least one further medicament selected from anthelmintics, dietary supplements, vitamins, mineral and other beneficial agents.
15.A method of treating or preventing infection of cattle with Cooperia or Ostertagia by administering a formulation as claimed in any one of claims 1 to 14.
16.A method of preparing a formulation containing a levamisole active ingredient and at least one macrocyclic lactone active ingredient by the steps of:
(a)dissolving at least one of either the levamisole active ingredient or the macrocyclic lactone active ingredient in at least one solvent selected from dimethyl isosorbide, dimethyl acetamide, diethyl phthalate and dimethyl phthalate
(b)adding a co-solvent or co-solvents if desired, and then the second active ingredient if not already dissolved in the solution.
17.A method of preparing a formulation containing a levamisole active ingredient and at least one macrocyclic lactone active ingredient by the steps of:
(a) dissolving at least one of either the levamisole active ingredient or the macrocyclic lactone active ingredient in at least one solvent selected from glyceryl acetates, pyrollidones, glycol ethers, glycol esters, glycerol formal, and alcohols
(b) adding a co-solvent or co-solvents selected from dimethyl isosorbide, dimethyl acetamide, diethyl phthalate and dimethyl phthalate
(c) adding the second active ingredient if not already dissolved in the solution.
18. A method of preparing a formulation as claimed in claim 16 or 17 in which further medicaments, antioxidants, viscosity modifiers or stabilizers are added at any time.
19.A solvent based topical formulation containing a macrocyclic lactone and a levamisole active ingredient dissolved in one or more organic solvents which further contain a viscosity modifier designed to increase the viscosity of the formulation.
20.A formulation according to claim 19 in which the viscosity modifier is added at a rate of less than 10% w/v.
21.A formulation according to claim 19 or 20 in which the viscosity modifier is selected from polymers (including Linear, Branched or Cross-linked polymers, Acrylic Polymers, Cross-linked Acrylic Polymers, Cellulose & Cellulose derivatives, Organoclays, Oligomer, Aluminium stearates/isostearates/myristates/laurates/palmitates, inorganic polymer and its modified silicate materials, natural waxes and glycerides.
22.A stable formulation suitable for topical administration to cattle substantially as herein described with references to any one of the examples.
Claims 1–14 and 19–22 are formulation claims. Claim 15 is a method of treatment claim, concerning the administration of a formulation of Claims 1–14. Claims 16–18 are method claims for preparing a formulation. Claims 1, 16, 17, 19 and 22 are independent claims.
It is useful to identify specifically the integers of Claim 1 numerically as follows:
1.1A stable formulation including
1.1(a) a levamisole active ingredient and
1.1(b) at least one active selected from the group known as macrocyclic lactones
1.2with both of said actives being dissolved in a non-aqueous system, including solvents selected from DMA, DMI, DEP and DMP
1.3wherein the formulation is a topical formulation for administration
1.4to cattle
The Expert Witnesses
Dr Kim Agnew
Dr Agnew is a veterinarian with more than 20 years’ experience in the development of products in the animal health industry, including those for treating ectoparasites. From 1987 to 1995, he practised as a vet specialising in dairy and beef cattle, pigs and sheep. His professional experience in the veterinary pharmaceutical industry, from 1995 through to September 2011, was principally in managing and supervising teams conducting all phases of product development, including products for the treatment of parasites in livestock. In terms of the early phases of product development (ie, coming up with the formulation itself), he had an active role in terms of the selection of an active for development and the administration method, including directing that particular actives and products be developed for particular administration methods. In 1995, Dr Agnew became the Veterinary Technical Manager for Elanco Animal Health New Zealand, being the New Zealand business of the US-based Elanco group which had a significant global cattle product portfolio. In 2006, Dr Agnew became the Research and Regulatory Manager for Elanco Animal Health Australia, where he worked on the “Spinosad” project, being a novel ecto-parasiticide for sheep and cattle, and was responsible for ensuring completion of the research studies and regulatory submissions to the APVMA in relation to those products. In 2009, Dr Agnew became the Innovations Business Unit Manager for Elanco in Australia. In that role, Dr Agnew managed product development work, among other things, including new product development where Spinosad was investigated in combination with other parasiticides to broaden the efficacy of Spinosad in sheep and the development of the Spinosad portfolio for cattle, involving both formulation work and clinical assessment of initial formulations. In 2011, Dr Agnew became the Emerging Markets Regional Regulatory, Research and Product Development Manager of Elanco. Although after the Priority Date, it is worth noting that from 2015 to 2020, Dr Agnew was the R&D Leader for Australia and New Zealand for Merial/Boehringer-Ingelheim, and was responsible for a team of fourteen full-time employees developing a portfolio of innovation projects for Australia and New Zealand and executing the tasks required to commercialise the portfolio. One of the key functions of the team was ground-up formulation development in areas including topical endo-parasiticides, internal endo-parasiticides and topical ecto-parasiticides for sheep and cattle. Dr Agnew accepts that he is not a formulator and that he would defer to the formulators in terms of the approach to take to the formulation of products of the kind arising in this case: T112.15–24; Agnew 3 at [3].
Dr Agnew gave direct answers to the questions put to him in his oral evidence, and I accept him as a reliable and credible expert witness on matters within his field of expertise, which does not include questions of how a formulator would go about his or her work, or the CGK of formulators of the relevant kind of products.
Dr Fadil Alawi
Dr Alawi is a pharmaceutical formulator with more than 23 years’ experience in developing pharmaceutical formulations in the animal health industry in Australia and New Zealand, including parasiticides. In 1978 he was awarded a PhD in Pharmaceutical Sciences from the University of Dundee in Scotland. Between February 2001 and April 2005, he was employed by Amdel Labs as a Product Development & Stability Manager. He was responsible for developing formulations for veterinary products, mainly for cattle and sheep, and for personal care and cosmetics. In that role, he provided advice to clients on solving manufacturing problems involving pharmaceutical formulations and was also responsible for managing the stability of products. In April 2005, Dr Alawi began employment at Bomac Research Ltd as a Technical Manager. In 2010, Bayer NZ acquired Bomac and Dr Alawi became Head of Chemistry, Formulation and Technology Transfer. In 2015, Dr Alawi became the Head of Pharmaceutical Development, and remained in that role until January 2019. Since April 2019, Dr Alawi has been a private consultant and trainer at Pharminnovation Ltd, which is his own business, providing consulting services to animal health companies in relation to new product development and technology transfer.
As to the work which Dr Alawi performed in his roles at Bomac and Bayer from April 2005 to January 2019, while his title changed his role was effectively the same. Dr Alawi was responsible for overseeing the carrying out of formulation and process development of veterinary products for cattle, sheep, equine, pig and poultry, aquaculture and companion animals. Dr Alawi oversaw a team of chemists who assisted him with developing new formulations and drug delivery methods, conducting stability testing and developing and validating analytical methods. From time to time, Dr Alawi conducted those activities when his personal involvement was needed, however he was primarily responsible for managing the team and reviewing the results. The products that Dr Alawi developed during that period included injectables, intramammaries, orals, pour-ons, dips and tablets for use as: mastitis control, anthelmintics, nutritional and metabolism supplements, antibiotics, reproductive health treatments and hormone replacements. In those roles, Dr Alawi also assisted the registration team who were responsible for obtaining regulatory approvals for the products that his team formulated. In particular, Dr Alawi and his team were responsible for preparing the chemistry dossier to be submitted to the Australian and New Zealand regulatory authorities, which included information regarding the formulation, manufacturing instructions, release and expiry specifications, specifications and certificates of analysis of the raw materials to be used in manufacturing a product, stability data and supportive technical arguments. As at 23 September 2011, Dr Alawi was working in New Zealand, but kept on top of developments in the Australian market for animal health products to see if those products were relevant to the formulation of the products that he was developing for Bayer NZ. In Dr Alawi’s experience, the same veterinary pharmaceuticals were generally available in New Zealand and Australia, although there were some differences in the active ingredients used in products sold in Australia in order to account for different species of parasites that were more prevalent in Australia than in New Zealand. Dr Alawi says, and I accept, that formulators including himself, as at September 2011, ensured that they were aware of formulation development work that was happening in both Australia and New Zealand, as well as the available products.
Dr Alawi accepted that as at June 2011 (being the filing date of the 154 Patent), he was at
the forefront of research into the formulation of macrocyclic lactones and levamisole (T171.1–17, 185.43–186.3). Dr Alawi was the inventor or co-inventor named in ten patents or patent applications before the Priority Date dealing with macrocyclic lactones, four of which were in combination with levamisole (Exhibit 4 and T182.14–184.34). In some respects, which I discuss below, Dr Alawi was shown to have relied on greater knowledge than the CGK attributable to the PSA, especially on the question whether the PSA would adopt a non-aqueous solvent system. I therefore approach his evidence with considerable caution and reservation.
Professor Craig Bunt
Professor Bunt is the Professor of Agricultural Innovation at the University of Otago in New Zealand. Professor Bunt completed a PhD in Pharmaceutical Sciences at the University of Otago in 1995, where his studies focused on formulation of animal pharmaceutical products. Between 1992 and 1995, Professor Bunt also worked for the New Zealand National Poisons Centre, where his roles included advising consumers on the risk of safety and toxicity issues in respect of pharmaceutical products, including veterinary formulations. After completing his PhD, he worked for 10 years as a Research Officer with InterAg, which is a veterinary pharmaceutical company based in Hamilton, New Zealand, where his role involved developing and testing controlled release veterinary formulations for farm and other animals. On leaving InterAg in 2005, he took up a position as a Senior Lecturer in Pharmaceuticals at the University of Auckland. The teaching component of his work focused on pharmaceutical formulations for animals and humans, and the research component focused on veterinary formulations, including anthelmintics for cattle. In 2007, Professor Bunt took up a position as a Senior Research Scientist at AgResearch, a New Zealand Crown research institute in Christchurch, where his duties focused on devising and developing agri and veterinary formulations for use, particularly in cattle and sheep. On leaving AgResearch in 2011, Professor Bunt accepted a position as Senior Lecturer in Animal Science at Lincoln University in New Zealand, and in 2015 he was promoted to Associate Professor. In those roles at Lincoln University, Professor Bunt had a mixture of scientific agri-biologicals, pest-control and veterinary pharmaceutics research and teaching duties, and his research program explored new ways to formulate difficult-to-deliver molecules for veterinary pharmaceuticals, agricultural and nutraceutical applications. From 2019 to 2022, he was an Honorary Associate Professor in Pharmaceutics at the University of Auckland. In 2021, he was appointed as the Inaugural Professor of Agricultural Innovation at the University of Otago.
Professor Bunt describes his work over his career as having been predominantly in the field of formulating veterinary pharmaceuticals, including but not limited to anthelmintic formulations for cattle. He regards himself, among other things, as a veterinary pharmaceutical formulation scientist. He has authored over fifty research publications, and has served on the editorial boards of six journals. He has also authored several textbook chapters. In addition to his academic publications, he is named as an inventor on sixteen patents.
Throughout his career, Professor Bunt has formulated a wide variety of veterinary pharmaceutical products, both before and after the Priority Date. This includes products which seek to control the breeding cycle of cattle, sheep and pigs; various different injectable formulations, in particular injections of hormones for livestock; and various anthelmintic formulations. Professor Bunt performed screening of a range of different formulations of anthelmintic agents (in particular, anthelmintic formulations containing ivermectin as the active ingredient) in different solvents to test the solubility of the active ingredient in different water-miscible solvent mixtures. The aim of those studies was to determine whether the ivermectin active ingredient could be formulated into an injectable, but ultimately that project did not progress upon closer review of the business case. Professor Bunt acknowledged that as at September 2011, he had not formulated an anti-parasiticide for cattle which had reached the market, nor has he done so since then (T276.14–21). In fact, the only veterinary pharmaceutical product which has resulted from Professor Bunt’s product development work referred to in his evidence is a bovine progesterone releasing device (T275.32–276.12).
Professor Bunt has also regularly assisted in clinical trials, where he was responsible for performing, compounding of test samples, administration of dosage forms, blood collection, and pharmacokinetic analysis of the data from the trials. In other words, Professor Bunt reviewed the data to determine how and how well the active ingredient(s) was absorbed. He also made any changes required to the formulation as a result of those studies. That role also entailed liaising with regulatory bodies to obtain approval for the trials and for the product to be brought to market.
I regard Professor Bunt as a reliable and credible expert witness. I generally prefer the evidence of Professor Bunt to that of Dr Alawi where their evidence is in conflict.
Do the claims lack an inventive step?
Legislative Provisions and Legal Principles
Section 18(1)(b)(ii) of the Act provides in effect that among the requirements of an invention being “a patentable invention” is the requirement that, when compared with the prior art base as it existed before the priority date of the relevant claim, the claim “involves an inventive step”. Section 7(2) of the Act at the relevant time, provides as follows:
For the purposes of this Act, an invention is to be taken to involve an inventive step when compared with the prior art base unless the invention would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed in the patent area before the priority date of the relevant claim, whether that knowledge is considered separately or together with the information mentioned in subsection (3).
Section 7(3) then provides that:
The information for the purposes of subsection (2) is:
(a) any single piece of prior art information; or
(b) a combination of any 2 or more pieces of prior art information;
being information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood, regarded as relevant and, in the case of information mentioned in paragraph (b), combined as mentioned in that paragraph.
The term “prior art base” is defined in Sch 1 of the Act relevantly as follows:
(a)in relation to deciding whether an invention does or does not involve an inventive step or an innovative step:
(i)information in a document that is publicly available, whether in or out of the patent area; and
(ii)information made publicly available through doing an act, whether in or out of the patent area.
The term “common general knowledge” (or CGK) refers to that which is known or used by those in the relevant trade, being the background knowledge and experience which is available to all in the trade in considering the making of new products or the making of improvements in old products, as used by an individual as a general body of knowledge: Minnesota Mining and Manufacturing Co v Beiersdorf (Australia) Ltd [1980] HCA 9; (1980) 144 CLR 253 (Minnesota) at 292 (Aickin J, with whom Barwick CJ, Stephen, Mason and Wilson JJ agreed). It refers to knowledge which is generally accepted and assimilated by “the formulating community”: Aktiebolaget Hässle v Alphapharm Pty Ltd [2002] HCA 59; (2002) 212 CLR 411 (Alphapharm) at [31] (Gleeson CJ, Gaudron, Gummow and Hayne JJ). Put differently, it is the “knowledge generally known and accepted by ‘the bulk of those who are engaged in the particular art’”: Alphapharm at [173] (Kirby J).
The “person skilled in the art” (or PSA) is a non-inventive skilled worker in the relevant field: Minnesota at 293 (Aickin J, with whom Barwick CJ, Stephen, Mason and Wilson JJ agreed); Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd [1981] HCA 12; (1981) 148 CLR 262 (Wellcome) at 270 (Aickin J, with whom Gibbs CJ, Stephen, Mason and Wilson JJ agreed). Evidence as to the knowledge of the PSA must be directed to what the “notional skilled worker” would have known, not what a leading expert in the field would have known; hence, the expert should not be overqualified and should be able to depose to the state of the common general knowledge in Australia at the priority date: JMVB Enterprises Pty Ltd v Camoflag Pty Ltd [2005] FCA 1474; (2005) 67 IPR 68 at [91] (Crennan J); Globaltech Corporation Pty Ltd v Reflex Instruments Asia Pacific Pty Ltd [2022] FCA 797; (2022) 167 IPR 515 at [277] (Jagot J). The PSA may have the composite skills of a team of people: General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 at 485 (Sachs LJ); Otsuka Pharmaceutical Co Ltd v Generic Health Pty Ltd (No 4) [2015] FCA 634; (2015) 113 IPR 191 at [124] (Yates J).
As to obviousness, the principles relevant to the issues in the present case may be stated as follows:
(a)the question is whether the invention itself is obvious, not whether a diligent searcher might find pieces from which there might have been selected the elements which make up the patent, otherwise there could never be a valid patent for a new combination of old integers: Minnesota at 293 (Aickin J, with whom Barwick CJ, Stephen, Mason and Wilson JJ agreed);
(b)in the case of a combination patent, it is the selection of the integers out of perhaps many possibilities, which must be shown to be obvious: Minnesota at 293;
(c)it is important to avoid the misuse of hindsight, especially where what is claimed is a new and inventive combination for the interaction of integers, some or all of which are known: Alphapharm at [21] (Gleeson CJ, Gaudron, Gummow and Hayne JJ);
(d)inventiveness must be determined by considering the combination as a whole: Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [2007] HCA 21; (2007) 235 CLR 173 (Lockwood) at [69] (Gummow, Hayne, Callinan, Heydon and Crennan JJ);
(e)the test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be steps of the inventor or not: Wellcome at 286 (Aickin J, with whom Gibbs CJ, Stephen, Mason and Wilson JJ agreed);
(f)the tracing of a course of action which is complex and detailed, as well as laborious, with a good deal of trial and error, with dead ends and the retracing of steps is not the taking of routine steps to which the hypothetical formulator is taken as a matter of course: Alphapharm at [58] (Gleeson CJ, Gaudron, Gummow and Hayne JJ);
(g)it is not sufficient that a claimed invention in a combination patent was “worth a try” or “obvious to try” or resulted from trying out various known possibilities until a correct solution emerged: Alphapharm at [72]–[76] and [78] (Gleeson CJ, Gaudron, Gummow and Hayne JJ);
(h)the test of whether an expectation that an experiment may well work (falling short of knowing that the steps will, would or even may well work) is applicable to characterising steps as routine and to be tried as a matter of course: Nichia Corporation v Arrow Electronics Australia Pty Ltd [2019] FCAFC 2; (2019) 175 IPR 187 (Nichia v Arrow) at [88]–[89] and [99] (Jagot J, with whom Besanko and Nicholas JJ agreed), citing Generic Health Pty Ltd v Bayer Pharma Aktiengesellschaft [2014] FCAFC 76; (2014) 222 FCR 336 at [71];
(i)it is not sufficient to establish that the claimed invention, or the steps leading to it, would be one of a number of possibilities rather than one that would be taken as a matter of routine or one to which the skilled addressee would be directly led as a matter of course to try: Pharmacia LLC v Juno Pharmaceuticals Pty Ltd [2022] FCAFC 167; (2022) 168 IPR 431 at [145] (Jagot, Yates and Downes JJ);
(j)an obvious solution to a given problem may be contrasted with the speculative possibility of a solution which is presently unknown and, perhaps, unattainable: Bristol-Myers Squibb Company v Apotex Pty Ltd (No 5) [2013] FCA 1114; (2013) 104 IPR 23 at [346] (Yates J);
(k)“obvious” means “very plain”: Alphapharm at [34] (Gleeson CJ, Gaudron, Gummow and Hayne JJ); Lockwood at [51] (Gummow, Hayne, Callinan, Heydon and Crennan JJ);
(l)a “scintilla of invention” is sufficient in Australian law to support the validity of a patent: Lockwood at [52] (Gummow, Hayne, Callinan, Heydon and Crennan JJ); and
(m)if a particular route is an obvious one to take or try, it is not rendered any less obvious merely because there are other obvious routes as well: Nichia v Arrow at [92]–[93].
Uncontroversial Expert Evidence
There is a very large measure of agreement on a number of topics between Dr Agnew, Dr Alawi and Professor Bunt. Those matters are set out in the Team JER, which I summarise below.
First, the three experts agree that the development of a pour-on veterinary pharmaceutical product requires a multidisciplinary team combining commercial and technical expertise. Key roles include marketing, finance, regulatory affairs, clinical research, formulation chemistry, analytical chemistry, and manufacturing. Collaboration between commercial and technical teams is essential from concept to market launch to ensure both scientific integrity and commercial viability: Team JER at [1].
Second, the three experts agree that the development of a new anthelmintic product relies on a wide range of information sources, including scientific literature, patents, regulatory guidelines, market intelligence, and technical data from existing products. These sources are essential for understanding the competitive landscape, ensuring regulatory compliance and informing product design: Team JER at [6]. The sources include the Merck Index: Team JER at [7(f)].
Third, the experts agree that, as at September 2011, non-aqueous solvent systems were the predominant choice for pour-on anthelmintic products used for cattle in Australia and New Zealand. These lipophilic formulations were preferred due to their compatibility with active ingredients and perceived superior performance in terms of skin absorption and stability. Macrocyclic lactones are readily formulated in non-aqueous solvents (Team JER at [11(a)]), and unlike levamisole have very poor solubility in water (Professor Bunt in Formulation JER at [16], and at T122.16–17). The salt forms of levamisole are more soluble in water than the base form: Alawi 5 at [80]; Bunt at T140.31–39. However, aqueous-only systems also existed in formulations other than pour-ons and were considered based on formulation requirements and product goals. While non-aqueous formulations dominated the pour-on market in 2011, aqueous pour-on formulations did exist: Team JER at [8] and [12].
Veterinary pharmaceutical pour-on products are topical formulations applied to livestock, typically along the animal’s back, for systemic absorption and/or local action against parasites. As at September 2011, the majority of pour-on anthelmintic products available in Australia and New Zealand for cattle were non-aqueous. These lipophilic formulations were preferred as there was a common understanding that they enhanced skin absorption for systemic effects and ensured the active ingredient remained on the animal’s surface for ectoparasite treatment. Examples included macrocyclic lactone and levamisole-based products.: Team JER at [10].
The choice of solvent systems is influenced by a number of factors, including:
(a)the solubility and stability of the active ingredients;
(b)the desired rate of absorption and the understanding of the need to achieve appropriate spreading and penetration of the animal’s skin;
(c)the formulator’s expertise and experience; and
(d)in the case of product lifecycle extensions, formulators often aim for minimal alteration to the original formulation to reduce regulatory risk.
(Team JER at [11])
Fourth, the three experts agreed that the primary active ingredients used in pour-on treatments for ecto and/or endoparasites in cattle as at 2011 fell within a limited number of well-established anthelmintic families: macrocyclic lactones, benzimidazoles, imidazothiazoles, and others targeting specific parasites such as liver flukes. These were used individually or in combination depending on the intended spectrum of activity: Team JER at [13].
Fifth, the three experts agreed that existing veterinary pharmaceutical products on the market are a critical reference point in the development of new anthelmintics. Evaluating current products helps identify gaps, guide formulation decisions, and ensure competitive positioning. This evaluation draws on a variety of sources, including product labels, regulatory databases, sales data, and reverse engineering of samples: Team JER at [16].
Sixth, the three experts expressed agreement in the Team JER (at [19]–[20]) that a known technical issue with existing macrocyclic lactone and levamisole combination pour-on products was chemical instability, primarily due to the differing pH stability requirements of the two actives. Macrocyclic lactones typically require a neutral pH for stability, while levamisole is more stable at a lower pH. This instability resulted in shorter shelf-lives and necessitated overages to compensate for degradation, and was widely acknowledged within the industry.
In Bunt 2 at [6]–[7], Professor Bunt said that, on reviewing that aspect of the Team JER, he realised that he had misunderstood the question, which he had understood to be directed to the technical properties of macrocyclic lactones and levamisole. Professor Bunt said that he intended to state that the active ingredients were widely known in the industry to have different physicochemical properties (for example, different pH), and combining these two active ingredients with different properties could give rise to stability issues. However, as at 23 September 2011, Professor Bunt was not aware of any commercial macrocyclic lactone and levamisole combination products (that is, products already available in the market) that had stability issues, such as chemical instability leading to undesirably short shelf-lives, including the Eclipse Pour-On product. Dr Agnew and Dr Alawi explained that the shelf-life of the Eclipse Pour-On product was 15–18 months, which was acceptable, but a shelf-life approved by regulators of 24 months would enable suppliers to align their stock with commercial use and would thus be commercially advantageous: Dr Agnew at T145.42–146.11; Agnew 3 at [13]; Dr Alawi at T149.17–150.17. However, Dr Agnew volunteered that, as the market leader, the Eclipse Pour-On product sold out every year, so it was not much of an issue commercially (T146.3–5), and was an internal concern for the company (T143.27). In light of that evidence, I do not accept Dr Alawi’s evidence that the Eclipse Pour-On product was well-known as at 23 September 2011 as having a short shelf-life: see Alawi 5 at [93] and [137]. The expert evidence therefore does not go so far as to establish that an aspect of the CGK was that the issue of chemical instability arising from the differing pH requirements of the two APIs was known to have caused shortened shelf-life of products in the market which was commercially unacceptable or problematic. In relation to the Eclipse Pour-On product in particular, Professor Bunt says that he was not aware of any disadvantages or concerns with the product as at the Priority Date (Bunt 1 at [153], misnumbered and following [411]), and I accept that evidence as reflecting the CGK.
I note at this point that Professor Bunt explained that when a macrocyclic lactone was solubilised in an aqueous solution in which it would degrade, it could be refrigerated in order to slow down the degradation process to a rate that was not a problem: T249.39–41. Although there does not appear to be any direct evidence on the point, I infer that the smaller quantities of formulation required for injections could be refrigerated by farmers in that way, whereas it would have been impractical for the larger volumes of solution required for pour-ons to be refrigerated.
Although not stated in the Team JER, it is not in dispute between the expert witnesses that combination anthelmintics had advantages in: (a) enabling farmers to target different families of parasites at the same time, thus avoiding the need to apply multiple products containing separate actives (Alawi 1 at [36]); and (b) overcoming antiparasitic resistance (Alawi 1 at [37]; Agnew 1 at [45]–[47]; Bunt 1 at [53] and [104]).
Further, as to administration methods as at September 2011, there were three main administration routes used in relation to cattle, namely: (a) oral administration, such as an oral drench; (b) topical administration (that is, using a pour-on product, where administration is to the outside of the animal); and (c) injectables. As at 23 September 2011, the topical route was the preferred administration method for farmers, having regard to the ease of that administration method (namely, application to the back of the animal), followed by the injectable route, with oral dosing largely confined to calves: Alawi 1 at [42]; Agnew 1 at [59]; Bunt 1 at [50]–[51]. A topical formulation is relatively easier and safer for a farmer or veterinarian to administer to animals of a large size, like cattle, however there is a risk that the efficacy of such formulations could be reduced if there was heavy rain immediately after the formulation was administered that may cause the formulation to be washed off the animal: Alawi 1 at [42]; Agnew 1 at [62].
The first combination anthelmintic product for cattle, Eclipse Pour-On, was developed in around the early 2000s and registered by Ancare in 2003, being an anthelmintic product involving the combination of a macrocyclic lactone (namely abamectin) and levamisole: Agnew 1 at [48]. Levamisole was known to demonstrate excellent efficacy against Cooperia, and companies responded to the development of resistance in the Cooperia species to macrocyclic lactones by developing combination products (both pour-on and injectable) of macrocyclic lactones with levamisole, such as the Eclipse Pour-On, which effectively treated all worm species with a single application method: Agnew 1 at [50]. As at 23 September 2011, the Eclipse Pour-On product was the market leading pour-on on the market, with the Saturn product (also known as Outlaw) being behind it in terms of market share: Dr Agnew at T133.1–18; and see Dr Alawi at T149.10–13.
Disputed Expert Evidence
In preparing Alawi 2, Dr Alawi was set the Task, in which he was asked to assume that, as at 23 September 2011, a team that he was a part of had been asked to develop a combination product with acceptable shelf-life stability containing a macrocyclic lactone and levamisole for use in relation to cattle, and being a pour-on formulation. Dr Alawi noted that he had not been told which specific macrocyclic lactone the business would like to use, or whether the formulation could contain a combination of one or more macrocyclic lactones plus an anthelmintic from another family (such as triclabendazole) in addition to levamisole: Alawi 2 at [8].
Senior Counsel for Virbac criticised the elements of the Task as being improperly leading and effectively confining the issues to the question of solvent selection. Virbac submitted that Dr Alawi should have been given an open question as to approaches for new or improved products in the market generally, such as: having regard to the existing products on the market, if you were considering launching a new product or an improved product, what steps would you have undertaken? (T52.1–20). I reject that submission. There is, and was at 23 September 2011, a greater preference at pharmaceutical companies and among cattle farmers for pour-on products, followed by injectables and lastly oral products: Agnew 1 at [59]. In light of the fact that the market-leading products at the time were the anthelmintic pour-on products involving the combination of a macrocyclic lactone and levamisole, namely Eclipse and Saturn (or Outlaw), it is likely that the expert evidence would not have differed materially if the question had been posed in the more open-ended way suggested by Virbac. As Dr Agnew said in his unchallenged evidence, if one was seeking as at 23 September 2011 to develop a new product, one would consider the state of the market, the preference for pour-on products in the market generally and the business’s goals, and having regard to the state of the existing products, the simplest way forward to develop a product in this market would be to develop a new pour-on product containing a macrocyclic lactone and levamisole: Agnew 2 at [38]–[39]. Dr Agnew points out that the existing market-leading pour-on product on the market at the time was the combination macrocyclic lactone (abamectin) and levamisole combination product, namely the Eclipse Pour-On, so in his experience it would be unsurprising that the business would look to develop a new macrocyclic lactone/levamisole dual combination pour-on product. Further, the way in which the Task was framed left the choice of the particular macrocyclic lactone and levamisole open. That is particularly significant in terms of the choice between levamisole in its base form and levamisole in its salt form (such as levamisole hydrochloride), which has a direct bearing on the question whether to use water in the solvent system.
Dr Alawi described the formulation process in Alawi 1 at [45]–[71], before having been given the Task. In the initial phase, Dr Alawi would receive information regarding the product that the business wished to develop, including information provided by the marketing and sales teams. He would expect that macrocyclic lactones would be the preferred family of anthelmintics because as at September 2011 they were recognised as effectively treating a broad range of parasites: Alawi 1 at [53]. He would then use this information to work with the business to identify the goals to be targeted in developing the new product and would analyse the results of literature and patent searches carried out by someone in the formulation team that identified documents that may contain information that could assist in developing the product: Alawi 1 at [54]–[55]. He would then consider whether it would be suitable to proceed with the active identified by the business: Alawi 1 at [56]. After selecting candidates for the active ingredient(s), he would begin to develop a prototype formulation using a number of set pre-formulation activities to determine the “most suitable candidate” formulation: Alawi 1 at [56]. Dr Alawi would then undertake pre-formulation compatibility tests in solvents, or a combination of solvents, noting that it is sometimes necessary to use a co-solvent for reasons including improving stability and/or improving penetration of the active: Alawi 1 at [59]. He would then consider the addition of the other excipients, such as antioxidants, antimicrobial preservatives, colourants/dyes, viscosity modifiers, aerosols, and waxes. Short term stability tests would then be conducted by the chemists in the formulation team using a few possible prototype formulations, and if the results were satisfactory, safety and efficacy would be considered by veterinarians working in the business (in the clinical team) to see which candidate performed better: Alawi 1 at [61]. Based on the results, the formulation team would then select a preferred formulation by considering the objectives supplied by the business, taking into account effectiveness, safety, cost and manufacturing steps: Alawi 1 at [62]. Once the formulation was selected, the team would produce lab scale batches and develop analytical test methods to test the chemical parameters of the formulation and the suitability of the methods for use as a stability indicating method (ie, as a procedure to detect any degradation products from the API and ensure that they stay within the specification limits during the product’s shelf life): Alawi 1 at [63]. After conducting these initial tests, the product would be put on an accelerated stability trial to ensure the physicochemical stability of the developed formulation, after which the team would then finalise the finished product specification and develop the analytical method that will be validated prior to or during the process of undertaking animal trials or scaling up production: Alawi 1 at [64]. Professor Bunt adds that in his experience, more than half the formulations that were put through stability studies were found to be unsuitable due to chemical or physical instability: Bunt 1 at [140(f)]. As to pour-on formulations generally, such formulations as at 23 September 2011 were typically prepared with lipophilic excipients to ensure that the active ingredient was spread around the outside of the cow’s body to treat the ectoparasites and also to allow it to be absorbed and move through the skin to have a systemic effect on the endoparasites: Alawi 1 at [65]. Professor Bunt adds that non-lipophilic excipients can also be used through the use of viscosity modifiers: Bunt 1 at [150].
Dr Alawi states that as at September 2011, a typical topical formulation would include the following ingredients (at Alawi 1 at [68]):
(a)the APIs;
(b)a solvent (or solvents) suitable for solubilising the APIs, such as benzyl alcohol, isopropyl alcohol, NMP, triacetin, Crodamol GTCC, dimethyl sulfoxide, DMA, butyl carbitol, dipropylene glycol methyl ether and dimethyl isorboside (some of which are contested by Professor Bunt, as discussed below);
(c)surfactants;
(d)stabilisers, such as MPG and butyl dioxitol; and
(e)other excipients, such as antioxidants (BHT, BHA, Vit E), antimicrobial preservatives (parabens), colourants/dyes (Macrolex yellow, Patent blue V85), viscosity modifiers (Xanthum gum), Aerosols, waxes (bees and castor).
Turning to the Task, and formulating a pour-on product responsive to the Task, Dr Alawi would start the “solvent selection process”, which includes solubility tests, followed by brief stress testing stability trials, carried out to identify the optimal pharma grade solvents that dissolve the required amount of macrocyclic lactone and levamisole and provide a stable matrix for a pour-on pre-formulation: Alawi 2 at [11]. His goal in carrying out the solvent selection process at 23 September 2011 would be to confirm which solvent(s) provides better or comparable stability compared to those used in commercially available formulations, that are also safe and cost effective: Alawi 2 at [12]. His steps would not change based on the relevant macrocyclic lactone(s) involved (Alawi 2 at [13]), which Professor Bunt finds surprising and oversimplistic, and says that it is important to determine the specific active ingredients as that will dictate the remaining steps, including the choice of solvents and other excipients (Bunt 1 at [230] and [232]). I accept that evidence by Professor Bunt. I do not regard Professor Bunt’s evidence on that point as materially weakened by his generalised evidence that members of the same chemical family (such as the macrocyclic lactone family) often share similar chemical properties, and if one member of the family is soluble in a particular vehicle, he would expect the other members of the family are likely to share this characteristic: Bunt 1 at [178]. Dr Alawi says he would take abamectin (1%) and levamisole base (20%), and test each solvent in the list below for its ability to dissolve the required amount of the actives, and provide a stable matrix for a pour-on pre-formulation, and he would include 0.1% BHT or BHA as a chemical preservative to minimise or delay API oxidative degradation, particularly for the mectin: Alawi 2 at [13]. As at 23 September 2011, the candidate solvents that Dr Alawi says he would have used in his solvent selection process for this Task were the following nine solvents (in no particular order): benzyl alcohols, benzyl benzoate, DMI, DGME, NMP, DMA, triacetin, glycerin formal, and DEP: Alawi 2 at [14].
During this process, Dr Alawi would look for how easy it is (and how long it takes) for each of the two APIs to dissolve in the solvent, and if heat is required to accelerate the solubility; if any solvent did not solubilise the actives, it would be excluded from his next step (being the initial stress stability testing at 4ºC and 54ºC): Alawi 2 at [15]. Dr Alawi says that as at 23 September 2011, he would have had every reason to believe that at least some, if not most, of the solvents identified would solubilise a combination of macrocyclic lactone and levamisole, because macrocyclic lactones and levamisole bases are lipophilic and the solvents that he identified are lipophilic: Alawi 2 at [16]. Once he had confirmed that the APIs dissolved in the solvents, initial stress testing would be carried out, which as at 23 September 2011 involved routine testing carried out at 4ºC and 54ºC over a period of a minimum of one week to confirm the best solvent candidates to take forward to the next step in the development process, as this step confirmed that the formulation was viable from a stability point of view: Alawi 2 at [17].
From the initial stress testing, Dr Alawi would select the best performing solvents to formulate two to four pre-formulations for short-term stability tests, being routine testing carried out over a period of 12 weeks at 25ºC/60% RH and 40ºC/65% RH, aimed at identifying the most suitable candidate formulation (or preferably two candidates) to take forward to clinical screening trials: Alawi 2 at [18]. At this stage, Dr Alawi would consider whether to use a co-solvent in a formulation in combination with another of the best performing solvents, to formulate stable, safe and cost-effective pre-formulation candidates to take forward, as some solvents that offered the best stability were more expensive than others: Alawi 2 at [18]. Dr Alawi would expect, based on his experience, that these pre-formulations would contain a minimum of 1% macrocyclic lactone, 20% of levamisole base, and 0.1% BHT: Alawi 2 at [20]. The amount of the solvent(s) in these pre-formulation candidates would be “qs” (quantity sufficient) to the three main ingredients (being the two APIs and BHT), which would amount to around 78% solvent (whether it is one solvent or a combination of solvents): Alawi 2 at [20].
In preparing Alawi 4, Dr Alawi was shown the Patent for the first time. Dr Alawi said the following in relation to each of the claims of the Patent (omitting his analysis of the claims which are no longer in issue).
As to claim 1, Dr Alawi says that the use of a non-aqueous system as at September 2011 was the usual approach taken by a formulator for dissolving lipophilic molecules, including levamisole base and at least one active selected from the group of macrocyclic lactones: Alawi 4 at [30]. Dr Alawi does not understand the patentee to suggest that there is anything inventive in the combination of macrocyclic lactones and levamisole in a pour-on for use on cattle; rather, it is the solvent system that is the purported inventive step. In Dr Alawi’s opinion, there is no invention in the selection of a solvent system that produces a stable formulation, referring to the use of each of DMA, DMI and DEP (being three of the four solvents referred to in claim 1), plus other solvents, in the solvent selection process that he would have undertaken as at 23 September 2011 (as stated in Alawi 2 at [14]): Alawi 4 at [32]. In relation to the claim to DMA as the solvent system, Dr Alawi points out that this was the solvent in the EE Injection Data Sheet, and says that DMA was a common excipient used in veterinary drug formulations (including pour-ons) that was lipophilic and capable of solubilising both eprinomectin and levamisole: Alawi 4 at [33]. I deal with these matters below.
Paragraph 13 refers to the topical veterinary composition of paragraph 1, wherein the pharmaceutically acceptable carrier is one of four options, including glycerol formal and DMI (page 73, line 16–18).
Paragraph 14 refers to the topical veterinary composition of paragraph 1, wherein the at least one 1–arylpyrazole is fipronil, the at least one macrocyclic lactone is one of seven compounds, the at least one IGR is one of seven options, and the at least one anthelmintic is one of sixteen options including levamisole (page 73, lines 19–26).
Paragraph 15 refers to the composition of paragraph 1 or paragraph 13, wherein the at least one 1–arylpyrazole is fipronil, the at least one macrocyclic lactone is eprinomectin, the at least one IGR is (S)–methoprene, and the at least one anthelmintic is praziquantel (which I note has been chosen rather than levamisole) (page 73, lines 27–29).
Paragraph 16 refers to the topical veterinary composition of paragraph 1 or 15, wherein the composition is in the form of a spot-on or a pour-on formulation.
Paragraph 17 refers to a method for the treatment or prevention of a parasitic infestation or infection in an animal comprising administering to the animal in need thereof an effective amount of the topical veterinary composition of paragraph 1.
Paragraph 18 refers to the method of paragraph 17, wherein the at least one 1–arylpyrazole is fipronil, the at least one macrocyclic lactone is eprinomectin, ivermectin or moxidectin, the at least one IGR is one of two options, and the at least one anthelmintic is febantel, pyrantel or praziquantel (noting again, that levamisole was not chosen as one of the anthelmintics).
Paragraph 19 refers to the method of paragraph 17, wherein the parasite is an ectoparasite.
Paragraph 20 refers to the method of paragraph 17, wherein the parasite is an endoparasite.
The claims are then set out, corresponding to each of the twenty paragraphs referred to in the specification (pages 69–74).
Professor Bunt provides a detailed comparison of the Patent Claims and the 984 Patent: Bunt 1 at [461]–[491]. It is sufficient for present purposes to refer to Professor Bunt’s treatment, which I accept, of claim 1 of the Patent and the following reasons which he provides for why the formulation referred to in claim 1 of the Patent is not disclosed by the 984 Patent (Bunt 1 at [463]), as follows:
(a)The 984 Patent broadly provides a very generalised disclosure of a wide range of different combinations of active ingredients from four classes of compound, different methods of administration, numerous different solvents, and different types of formulations. Professor Bunt considers the 984 Patent as being directed at teaching the combination of these four classes of compound into single formulations but does not teach how to formulate such compositions. As Professor Bunt puts it, the 984 Patent provides several “shopping lists” of potential active ingredients, potential target parasites, potential modes or forms of administration, potential target animals, and potential excipients (including solvents), but provides little assistance in identifying any specific combinations within such extensive lists that are shown to work in a combined formulation.
(b)Specifically, the 984 Patent claims combinations of at least four active ingredients, and does not claim combinations of only two active ingredients, and in particular, one that requires levamisole. Claim 1 of the Patent, by contrast, specifically requires levamisole and a macrocyclic lactone.
(c)Professor Bunt says there are different considerations that apply when formulating with four active ingredients from four different classes of compounds, as against the formulation with levamisole and one (or more) macrocyclic lactones. For example, Professor Bunt says that one cannot simply add two additional active ingredients from different classes into an existing combination formulation of levamisole and macrocyclic lactones and expect it to be compatible, efficacious and safe. Similarly, Professor Bunt says that a formulator cannot simply remove two active ingredients from a combination product comprising four different actives, and expect it to operate in a similar manner.
(d)Further, Professor Bunt notes that while levamisole is disclosed in the 984 Patent as an active ingredient that may be included in the formulation, it need not be included, whereas the Patent requires the presence of levamisole in claim 1 and all other claims of the Patent.
(e)Professor Bunt also notes that where the 984 Patent claims do require a specific macrocyclic lactone and a specific anthelmintic within a single claimed formulation (for example, claim 15), that anthelmintic is not levamisole but is praziquantel. Professor Bunt says that praziquantel and levamisole belong to different groups of compounds and therefore have different chemical properties and necessarily very different formulation considerations.
(f)Similarly, Professor Bunt notes that the only method claim in the 984 patent that requires a specific combination of active ingredients (being claim 18) again does not include levamisole, and the preferred anthelmintic agent is instead praziquantel.
(g)The 984 Patent also refers to a wide range of possible formulations, including emulsions, suspensions and aqueous formulations, whereas all of the claims of the Patent are limited to non-aqueous solutions.
(h)Professor Bunt points out that claim 1 of the Patent requires that the formulation be dissolved in one or more of the solvents from the group including DMA, DMI, and the two phthalates, whereas claim 1 of the 984 Patent only specifies a “pharmaceutically acceptable carrier” (which may be aqueous, and may comprise any number of different solvents).
(i)Further, Professor Bunt notes that, while claim 12 of the 984 Patent refers to DMA and DMI within a list of over twenty-five solvents, it does not require that it be a non-aqueous system, and the solvents are also to be used in a formulation containing four different categories of active ingredients, that need not include levamisole. In other words, Professor Bunt says that the 984 Patent (including claim 12) does not disclose a combination of active ingredients and solvents claimed in any of the claims of the Patent. Professor Bunt says that if, contrary to his understanding of the 984 Patent, the 984 Patent discloses the possibility of formulating a combination of active ingredients and solvents claimed in any of the claims of the Patent, then that possibility would be only one of thousands of other potential formulations which do not include a combination of active ingredients and solvents claimed in any of the claims of the Patent, and there is nothing in the 984 Patent that points him to use of that one combination compared with the thousands of other potential formulations.
(j)Professor Bunt points out that, while the 984 Patent claims formulations that can be administered to a wide range of animals, the Examples of the 984 Patent are all conducted on cats. This demonstrates to Professor Bunt that, where the 984 Patent teaches a particular formulation, it is directed towards a specific spot-on formulation for use on cats. By contrast, the Patent specifically teaches (and claims) pour-on formulations for use on cattle. In Professor Bunt’s experience, the market requirements and therefore the formulation requirements for products which are for domesticated animals are different to products which are for livestock. As a formulator, Professor Bunt would be able to obtain little assistance from information regarding a formulation to be administered as a spot-on formulation for cats if he was tasked with formulating a pour-on product for cattle.
Dr Alawi made a detailed comparison of the claims of the Patent with the disclosures in the 984 Patent: Alawi 4 at [53]. Senior Counsel submitted that Dr Alawi’s analysis has been superseded by the comparison made by Abbey’s legal representatives which I have reproduced in the Appendix to these reasons. However, I note the comparison by Dr Alawi as it led to responsive evidence by Professor Bunt. Professor Bunt made the overall observation that Dr Alawi’s comparison of the 984 Patent and the Patent appeared to be limited to separating the constituent parts of each claim of the Patent and then seeking to identify any reference to each of those constituents in different parts of the 984 Patent specification: Bunt 1 at [552]. As another overall observation, Professor Bunt says that Dr Alawi did not mention the fundamental difference in the teaching of the two patents, in that: (a) the Patent teaches specific formulations comprising at least two active ingredients (levamisole and a macrocyclic lactone) in the form of a pour-on formulation for use in cattle, incorporating very specific solvents in a non-aqueous system; whereas (b) the 984 Patent discloses combinations of at least four different active ingredients from four different classes of compounds in a variety of different solvents in aqueous and non-aqueous systems for use in a wide range of animals, and in particular cats: Bunt 1 at [553]. I regard those criticisms as well-founded, and applicable also to Abbey’s analysis set out in the Appendix. It is not necessary to deal in detail with the particular criticisms which Professor Bunt makes of Dr Alawi’s analysis of each of the claims in the Patent by way of comparison to the 984 Patent, but it is sufficient to say that I accept Professor Bunt’s evidence on those matters.
I also re-iterate the point made above that I accept Professor Bunt’s evidence that the 984 Patent would not assist him in preparing a formulation for any animal other than the formulations discussed in the Examples, which are all applied to cats: Bunt 1 at [293].
Salient Legal Principles
In General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 (General Tire) at 485–86, Sachs, Buckley and Orr LJJ said that:
(a)if the prior inventor’s publication contains a clear description of, or clear instructions to do or make, something that would infringe the patentee’s claim if carried out after the grant of the patentee’s patent, the patentee’s claim will have been shown to lack the necessary novelty;
(b)if carrying out the directions contained in the prior inventor’s publication will inevitably result in something being made or done which, if the patentee’s patent were valid, would constitute an infringement of the patentee’s claim, this circumstance demonstrates that the patentee’s claim has in fact been anticipated;
(c)if, on the other hand, the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee’s claim, but would be at least as likely to be carried out in a way which would not do so, the patentee’s claim will not have been anticipated; and
(d)to anticipate the patentee’s claim the prior publication must contain clear and unmistakable directions to do what the patentee claims to have invented.
Those statements of principle have been described by the Full Court as the “touchstone” for determining whether a prior publication anticipates a claimed invention: AstraZeneca AB v Apotex Pty Ltd [2014] FCAFC 99; (2014) 226 FCR 324 (AstraZeneca v Apotex) at [293] (Besanko, Foster, Nicholas and Yates JJ). Their Honours emphasised (at [300]) that the reverse infringement test is not applied by simply asking whether something within the prior art document would, if carried out after the grant of the patent, infringe the invention as claimed. It must be shown not merely that something described in an earlier specification could have been used to produce a particular result, as it must also be shown that the specification contains clear and unmistakable directions so to use it: at [300]. Their Honours described sufficiency of disclosure as a cardinal anterior requirement in the analysis of whether a prior art document anticipates a claimed invention, and that it is only after the stage of assessing the sufficiency of disclosure that the notion of reverse infringement comes into play as the final and resolving step of the required analysis: at [302].
The UK Court of Appeal in General Tire at 486 also used a metaphor as follows:
A signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee.
There are those who find the metaphor helpful (including the Full Court in AstraZeneca v Apotex at [294] and [302]), but I am not among them. On the one hand, an effective signpost typically does give clear and unmistakable directions to a desired destination, which the ordinary addressee will successfully follow to reach that destination. That is its very purpose. On the other hand, when a flag-staff was erected and the Union Jack was raised in the evening of 26 January 1788 at Sydney Cove in Port Jackson, those who planted the flag had very little knowledge of the territory they were claiming, other than its unfamiliarity. In my view, there is no need to resort to metaphors when the fundamental principle is well-expressed in the literal language of whether the prior publication contains clear and unmistakable directions to do what the patentee claims to have invented.
Abbey relies on the statement in Bristol-Myers Squibb Company v FH Faulding & Co Ltd [2000] FCA 316; (2000) 97 FCR 524 at [67] (Black CJ and Lehane J), to the effect that a prior publication, if it is to destroy novelty, “must give a direction or make a recommendation or suggestion” which will result, if the skilled reader follows it, in the claimed invention. Abbey’s preference for the notion of a “recommendation” as an alternative to a “direction” is reflected at numerous points in the Appendix and in its oral submissions. However, as the Full Court observed in Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd [2020] FCAFC 116; (2020) 279 FCR 354 at [89] (Middleton, Jagot, Yates, Beach and Moshinsky JJ), Black CJ and Lehane J were not stating a statutory test, but were seeking to capture and explain the notion conveyed by the cases of the sufficiency of the disclosure that a prior art document must make before it can deprive an invention of novelty, and that notion is not elucidated by exploring the linguistic limits of words such as “recommend” and “suggest” as ordinary English words. Their Honours treated the reasoning of Black CJ and Lehane J as turning on an evaluation of the facts of the case, and not on any new or modified principle of anticipatory disclosure: at [102].
Abbey also submits, and I accept, that a prior publication can anticipate even where it gives directions in relation to other matters that would not necessarily fall within the claims of the patent in suit. The proposition is illustrated by the reasoning of the Full Court in AstraZeneca v Apotex, especially at [262]–[263] and [287], in that the fact that the anticipatory document gave directions that the compound was effective in treating two other diseases that were not the subject of the claims in suit did not in itself establish an insufficiency of disclosure for the purpose of anticipation. The Full Court distinguished the case before it from the kind of case where the claimed compound is buried among other compounds in the anticipatory document so as to be akin to a leaf hidden in Sherwood Forest or a book to be found in the Bodleian Library: at [285]–[286], adopting the illustrations given by Jacob LJ in Dr Reddy’s Laboratories (UK) Ltd v Eli Lilly and Company Ltd [2010] RPC 9 at [26] and [28]. The aspect which was fatal to the novelty objection was a different point concerning the insufficiency of the disclosure in the alleged anticipatory document concerning dosages: at [288]–[290]. However, the question must depend on the particular circumstances of the case, especially as to the breadth of the range of matters disclosed in the earlier specification and the number and significance of the variables which it discloses.
Application of principles
I have set out above at [186]-[188] some of the most salient aspects of Professor Bunt’s evidence, which I accept, in Bunt 1 at [463], [552]–[553] and [293]. That evidence demonstrates that in the present case, the 984 Patent discloses a vast range of alternative formulations, and does not contain clear and unmistakable directions to do what the Patent claims to have invented. As Professor Bunt said, even if the 984 Patent is read as disclosing the possibility of formulating a combination of active ingredients and solvents claimed in any of the claims of the Patent, then that possibility would be only one of thousands of other potential formulations: Bunt 1 at [463(i)]. Abbey’s submissions merely identify any reference to the constituent parts of the Patent in different parts of the specification for the 984 Patent, as Professor Bunt said of Dr Alawi’s comparison: Bunt 1 at [552]. As Professor Bunt said, the disclosure in the specification for the 984 Patent is so broad as to provide no assistance in preparing a formulation for any animal other than the formulations discussed in the Examples which are all applied to cats: Bunt 1 at [293].
Turning from those general findings to the particular claims of the Patent which are in contest and comparing them with the disclosures in the 984 Patent, there is no sufficient disclosure of the specific claim 1 composition of the Patent in the 984 Patent. As Virbac submits, the defects in Dr Alawi’s (and Abbey’s) approach were exposed during the concurrent evidence. Dr Alawi said in relation to the 984 Patent that he can explain as a skilled formulator what he could use from the 984 Patent, and he would apply his ability as a skilled formulator to make choices about how he would proceed if he read the 984 Patent: T256.41–257.1. However, while the prior art is to be read by the PSA in light of the CGK, it is impermissible to add CGK to fill gaps between what is disclosed in the prior publication and the claimed invention: BlueScope Steel Ltd v Dongkuk Steel Mill Co Ltd (No 2) [2019] FCA 2117; (2019) 152 IPR 195 at [1029] (Beach J); AstraZeneca v Apotex at [352]; Merck Sharp & Dohme Corporation v Wyeth LLC (No 3) [2020] FCA 1477; (2020) 155 IPR 1 at [230] (Burley J). Dr Alawi’s approach effectively treated the analysis as if the 984 Patent was another s 7(3) document that he could deploy, despite the fact that novelty and obviousness are two separate enquiries. It is clear that the addressee of the 984 Patent must use his or her ability as a formulator to make many choices about how to proceed in trying to formulate a specific combination, including the choice of animal, the choice of anthelmintic agent, the choice of mode of administration, the choice of aqueous versus non-aqueous systems, the choice of solvents and the criteria to be adopted for stability.
Dealing with those choices individually, the first is the choice of animal. Claim 1 of the Patent requires the treatment to be for cattle. In the 984 Patent, however, animals are defined very broadly, even including humans (page 9, lines 23–27), and lengthy lists of different kinds of animals are given in numerous places in the 984 Patent.
As to the choice of anthelmintic agent, claim 1 of the Patent requires the use of levamisole. Abbey relies on para 10 of the 984 Patent, but that includes levamisole in a list of sixteen options. Further, para 15 of the 984 Patent specifically identifies each of the active ingredients in an example composition, and is dependent on para 13, thereby narrowing the specific solvents that might be used. However, para 15 specifies the anthelmintic agent as praziquantel, rather than levamisole. As Virbac submits, when the 984 Patent does specifically identify an anthelmintic agent in combination with specific solvents, it does not identify levamisole but specifically identifies a different anthelmintic agent. Praziquantel is also the anthelmintic agent selected for each of the formulations used in the Examples in the 984 Patent (rather than levamisole), although it should be noted that those example formulations are for spot-on formulations for cats.
As to the choice of mode of administration, claim 1 of the Patent requires it to be a topical formulation, and one that is a solution (as it refers to “both of said actives being dissolved”). Dr Alawi agreed that there are compositions that would fall within para 1 of the 984 Patent that will not necessarily be a solution in which ingredients are dissolved: T256.21–24. He also agreed that para 1 can include emulsions, gels and pastes and that choice is available: T257.2–23, 258.10–16.
As to the choice of an aqueous versus a non-aqueous system, claim 1 of the Patent requires a non-aqueous solvent system. Dr Alawi explained that the composition of para 1 could include an aqueous system (and would then fall outside the scope of claim 1): T257.29–33. Dr Alawi also explained that if one wants to make a paste, gel or cream then one would have to use water: T258.1–3. The specification for the 984 Patent expressly says that when the composition is in the form of a liquid solution or suspension, the pharmaceutically acceptable carrier may include aqueous or organic solvents or mixtures of solvents (page 39, lines 8–11).
As to the choice of solvents, the 984 Patent includes within its scope any pharmaceutically acceptable carrier and, as referred to above, does not exclude an aqueous solvent system or an aqueous co-solvent. Dr Alawi accepted that the composition of para 1 of the 984 Patent could include a solvent other than DMA, DMI or a phthalate: T258.21–24. Further, para 12 of the 984 Patent (which does refer to DMA and DMI among twenty-seven options), is only dependent on para 1, and does not require combination with para 10 which specifies the anthelmintic agent (including levamisole as one of sixteen possibilities). Accordingly, a PSA taking a para 12 solvent in the composition of para 1 need not combine it with a levamisole-containing composition. Paragraph 13 of the 984 Patent refers to DMI as one of four solvents, but again is dependent only on para 1, which does not specify levamisole.
As to the choice of criteria for stability, the Patent provides a specific definition of a stable formulation, namely one which is stable at room temperature for a period of at least three months, and in conditions of accelerated testing at 40ºC. This requires the potency of the actives within the formulation to remain within specified and acceptable limits for six weeks (page 6, lines 19–23). The paragraphs describing the invention of the 984 Patent do not specifically require a stable formulation at all. The only stability study in the 984 Patent is in Example 5, and it is tested at 30ºC, as opposed to either the tests at 25ºC or the stress tests performed at 55ºC disclosed in the Patent. Further, the stability test in the 984 Patent is of a formulation that does not contain levamisole, but rather tests a formulation containing fipronil, (S)-methoprene, eprinomectin and praziquantel.
Those comments in relation to claim 1 apply equally to the dependent claims of the Patent, but some additional points should be made in relation to them.
As to claim 2 of the Patent, Abbey relies on the preferred embodiments of the 984 Patent on page 50, and undertakes an arithmetic analysis whereby the cumulative total of the API percentages listed within those embodiments are subtracted from 100% to leave a putative solvent system percentage. However, those embodiments do not refer to the claim 1 solvents at all, and they do not specify the use of levamisole. Accordingly, there is no clear and unmistakable direction to make a formulation within claim 2 of the Patent.
As to claim 3 of the Patent, the additional key integer for claim 1 is that the solvent system must include DMI, and also a co-solvent selected from DMA, the phthalates or glycol ethers. Abbey relies on para 12 of the 984 Patent, but para 12 is dependent only on para 1 (and not also on para 10), and thus a composition of para 12 will not necessarily include levamisole (and will not necessarily be a composition for cattle, in the form of a topical solution). Further, para 12 does not require the use of DMI with one of the specified co-solvents; rather, the 27 solvents are simply listed without preference and the paragraph permits “any combination thereof” but does not specify what the combination might be. The same applies to para 13, where the list is smaller, but it does not specify (and merely encompasses) the specific solvent system required by claim 3 of the Patent. Accordingly, there is no clear and unmistakable direction to make a formulation for cattle in a solution for topical administration, incorporating levamisole and a macrocyclic lactone, that includes DMI as one solvent and a further solvent identified from claim 3.
As to claim 4 of the Patent, as that is dependent on each of claims 1 and 3, the matters referred to above also apply to claim 4. Abbey relies on para 13, but that paragraph is dependent only on para 1 and not para 10. Accordingly, a composition of para 13 will not necessarily include levamisole, nor will it necessarily be a composition for cattle, in the form of a topical solution. There is thus no clear and unmistakable direction to make a formulation for cattle in solution for topical administration, incorporating levamisole and a macrocyclic lactone, that includes DMI, DMA or a phthalate in addition to one of the co-solvents in claim 4.
Claims 5 and 7 of the Patent are dependent on the preceding claims, and thus the matters set out above apply also to why claims 5 and 7 are not anticipated by the 984 Patent. As to claim 5, Abbey relies on para 8 of the 984 Patent, but para 8 is dependent only on para 1, and in paras 1 and 8 (in combination) there is no specific disclosure of levamisole within the composition (which is required by claims 5 and 7 of the Patent). As to claim 7, Abbey refers to the embodiments of the 984 Patent on page 48 and following, but there is no embodiment on those pages with levamisole and the specific non-aqueous solvents of claim 1. There is thus no clear and unmistakable direction of a composition falling within claims 5 and 7 disclosed in the 984 Patent.
As to claim 6 of the Patent, again that is dependent on each of the preceding claims and thus the matters referred to above in relation to claims 1 to 5 apply also to claim 6. Abbey relies on Example 5, but Example 5 is a stability analysis of a formulation that is not identified to be for cattle, does not include levamisole at all (but includes the different anthelmintic agent, praziquantel) and the stability metrics in the analysis differ from those set out in claim 6 in terms of temperature and time period. There is no clear and unmistakable direction in the 984 Patent for a composition of claims 1 to 5 satisfying the specific stability requirements of claim 6, especially where there is no stability data for any composition that includes levamisole as an anthelmintic agent, and no stability data at all consistent with the claimed metric in claim 6.
Claims 8, 9 and 10 of the Patent relate to the form and proportion of levamisole used in the composition of the preceding claims. In addition to the points made above in relation to the preceding claims, there is no disclosure of the specific combinations claimed in the previous claims with a specific form of levamisole (whether that be the base form or one of its salt forms). There is thus no clear and unmistakable direction in the 984 Patent for a topical composition with the specified components in claim 1, let alone a specified form of levamisole used in such a composition. Rather, there are numerous permutations of modes of administration, active ingredients (including but not limited to levamisole of any form), solvents (including aqueous solvent systems), and target animal.
Claim 13 of the Patent is dependent on each of the preceding claims. Abbey refers to the passage of the 984 Patent on page 60 dealing with antioxidants and stabilisers by name, but they are not disclosed by the 984 Patent in the specific combinations required by claim 13 of the Patent. Claim 13 is dependent on the preceding claims of the Patent, which require (at least) a combination of a topical composition for cattle, including levamisole, a macrocyclic lactone and one or more of DMI, DMA and the phthalates. There is no clear and unmistakable direction in the 984 Patent (whether on page 60 or otherwise) for a topical non-aqueous composition with those components and an antioxidant or a stabiliser.
Claim 15 of the Patent is dependent on each of the preceding claims, and thus the points made above apply also to claim 15. Abbey relies on the references to parasitic infections of a wide range of animals on page 54, and the more specific references to nematodes on pages 2 and 3 of the 984 Patent. However, that is not a specific disclosure of Cooperia or Ostertagia. If that were the only problem, then an analogy may well have been available with AstraZeneca v Apotex, in which (as I have indicated above) the fact that the anticipatory document gave directions that the compound was effective in treating two other diseases that were not the subject of the claims in suit did not itself establish and insufficiency of disclosure. But that is not the only problem. There is no clear and unmistakable direction in the 984 Patent to treat cattle having the two specific parasitic infestations (being Cooperia and Ostertagia), nor is there any clear and unmistakable direction to use the specific formulations in claims 1 to 14 of the Patent.
The reasons given above in relation to claim 1, regarding the choice of anthelmintic agent and choice of solvents in the 984 Patent apply also to claim 16. Abbey relies on the passage in the 984 Patent (on page 60, lines 2–4), but that passage does not identify the specific active agents at all, nor does it require a solution and could take the form of tablets, pastes or collars. There is thus no clear and unmistakable direction in the 984 Patent (whether on page 60 or otherwise) to carry out a method of preparation of a formulation including levamisole, a macrocyclic lactone and one or more of DMI, DMA or the phthalates, where the active ingredients are dissolved.
Claims 18 to 21 of the Patent concern the use of viscosity modifiers. Claim 18 is dependent on claim 16. Abbey relies on the passage on page 60 of the 984 Patent referred to in relation to claim 16, but there is no clear and unmistakable direction in the 984 Patent (whether on page 60 or otherwise) to carry out a method of preparation of a formulation including levamisole, a macrocyclic lactone and one or more of DMI, DMA or the phthalates, where the active ingredients are dissolved, and also an antioxidant, viscosity modifier or stabiliser. Claims 19 to 21 also require choices to be made as to the anthelmintic agent, the mode of administration, the choice of a solution and the choice of an aqueous versus non-aqueous system in the 984 Patent. Further, in respect of each of claims 18 to 21, there is no disclosure of viscosity modifiers in the 984 Patent in the specific combinations in those claims of the Patent, and the 984 Patent does not refer to viscosity modifiers in the context of pour-on formulations. Abbey also relies on a passage at page 50, lines 20–24 of the 984 Patent, but there is no clear and unmistakable direction on page 50 of the 984 Patent to use polyvinylpyrrolidone or polyethylene glycols in a topical formulation including levamisole and a macrocyclic lactone that is dissolved (ie, not a paste or an ointment) in organic solvents. Accordingly, none of claims 18 to 21 is disclosed by the 984 Patent.
Accordingly, I reject Abbey’s contention that each of the contested claims of the Patent lacks novelty.
Can a Ferrcom inference apply to expert evidence?
In Commercial Union Assurance Company of Australia Ltd v Ferrcom Pty Ltd (1991) 22 NSWLR 389 (Ferrcom) at 418E–419F, Handley JA extended the principle of Jones v Dunkel (1959) 101 CLR 298 to the case of a party failing to ask questions of a witness in chief on a particular topic. His Honour said that where such a failure indicates as the most natural inference that the party fears to do so, that fear is then some evidence that such examination in chief would have exposed facts unfavourable to the party. Accordingly, inferences should not be drawn in favour of a party that called a witness who could have given direct evidence when that party refrained from asking the crucial questions. The High Court has endorsed that reasoning in the less strongly worded form that where counsel for a party has refrained from asking a witness whom that party has called particular questions on an issue, the court will be less likely to draw inferences favourable to that party from other evidence in relation to that issue: Kuhl v Zurich Financial Services Australia Ltd [2011] HCA 11; (2011) 243 CLR 361 at [63] (Heydon, Crennan and Bell JJ). That formulation better reflects the reasoning in Jones v Dunkel, whereby the relevant inference which may (not should) be drawn is that the evidence not called by a party would not have assisted the party (not that the evidence would have been adverse to the party).
In Ferrcom, Handley JA drew on a line of United States decisions, noting that there is extensive case law in the United States on this question. It should be noted, however, that there is a principle in federal courts and many state courts in the United States (embodied in r 611(b) of the Federal Rules of Evidence) that cross-examination should not go beyond the subject matter of the direct evidence (ie, evidence in chief) and matters affecting the witness’s credibility, although the court may allow inquiry into additional matters as if on direct evidence. By contrast, the applicable Anglo-Australian principle is that a witness may generally be cross-examined on any issue in the case: Heydon JD, Cross on Evidence (14th Australian edition, LexisNexis, 2024) at [17500]. There is thus a potential tactical advantage in the United States in limiting the scope of cross-examination by the simple expedient of a party not putting questions on an awkward subject to that party’s own witness, which is not available in Australia. In my professional experience, the natural inference most typically to be drawn in Australia from a party not leading evidence in chief on a particular subject is merely the innocuous one that the significance of the subject was not appreciated when the evidence in chief was prepared. That is especially so in the context of the modern practice of evidence in chief being given by affidavits, which are usually made and served weeks or months before the trial. Judges are not usually well placed to determine whether that is the appropriate explanation, rather than some supposed fear of the evidence being given. Accordingly, in my view, the appropriateness of drawing a Ferrcom inference needs to be approached with great caution.
In the present case, Abbey submitted in opening that a Ferrcom inference should be drawn on three matters which Professor Bunt had not addressed, although two of them fell away because certain claims of the Patent are no longer contested. The remaining matter concerns the issue of the obviousness of the range of concentration of the solvents in claim 2 of the Patent. I regard that as a misplaced criticism of Professor Bunt’s evidence. In the Formulation JER at [46], Professor Bunt explained that his response to the Task does not fall within claim 2 as he would not have selected the solvents referred to in claim 2, as he explained in his evidence concerning claim 1. There was therefore no need for him to deal with the concentration range of the nominated solvents in claim 2. Even on the widest possible view of Ferrcom inferences, such an inference could not be justified in the present case.
More fundamentally, in my view, there would rarely (if ever) be any scope for drawing a Ferrcom inference in the context of the contemporary practice in relation to expert evidence. I recognise that Ferrcom inferences have been drawn in relation to expert evidence in Ta Ho Ma Pty Ltd v Allen [1999] NSWCA 202; (1999) 47 NSWLR 1 at [11] (Handley JA); Gordon Martin Pty Ltd v State Rail Authority of New South Wales [2008] NSWSC 343 at [322] (Hall J); and Aristocrat Technologies Australia Pty Ltd v Global Gaming Supplies Pty Ltd [2009] FCA 1495; (2009) 84 IPR 222 at [417] (Jacobson J). The New South Wales Court of Appeal regarded a Ferrcom inference as available in principle in relation to expert evidence in Wiki v Atlantis Relocations (NSW) Pty Ltd [2004] NSWSC 174; (2004) 60 NSWLR 127 at [72]–[73] (Ipp JA, with whom Bryson JA and Stein AJA agreed), but the question was left open in DIF III – Global Co-Investment Fund LP v DIF Capital Partners Ltd [2020] NSWCA 124 at [142] (Bell P, with whom Bathurst CJ agreed).
In addition to the general reservations which I have already expressed in relation to Ferrcom inferences, there are particular features of contemporary practice concerning expert evidence which point strongly away from such inferences arising. The Federal Court’s Expert Evidence Practice Note (GPN–EXPT) is broadly representative of the practice throughout the Australian States and Territories, providing for conferences of experts and joint expert reports (section 7), concurrent oral evidence (section 8), and a declaration in expert reports that the expert has made all the inquiries which the expert believes are desirable and appropriate and that no matters of significance which the expert regards as relevant have, to the knowledge of the expert, been withheld from the Court (Annexure A, para 3(i)). Those elements are buttressed by clear restrictions on attempts by parties to interfere with the expert’s expression of opinion (section 3), and duties on the part of experts to provide relevant and impartial evidence (section 4). Contemporary practice thus does not leave any effective room for a party tactically to seek to ensure that certain subject matter is avoided by an expert witness engaged by that party, at least in circumstances where that subject matter is dealt with by a competing expert witness. Whatever scope there may once have been for the drawing of a Ferrcom inference in relation to expert witnesses, I regard that now as having been superseded.
Conclusion
Accordingly, Abbey’s challenge to the claims in the Patent has failed, except in relation to three claims, namely claims 19, 20 and 21. That very limited measure of success can only be described as a pyrrhic victory for Abbey. Abbey is liable for infringing the Patent, and Virbac is entitled to declarations and injunctions accordingly. Abbey should be granted a period of four weeks before the injunctions take effect in order to allow for an orderly wind-down. There will need to be a case management hearing to prepare for a subsequent hearing on pecuniary remedies.
I have not yet heard the parties on costs. My preliminary view is that Virbac is entitled to its costs of the proceedings. There may well be an application for special orders as to costs, such as indemnity costs arising from any offers of compromise and lump sum orders. Accordingly, I have set a timetable for affidavits and written submissions on the question of costs, which I anticipate deciding on the papers.
I certify that the preceding two-hundred and twenty (220) numbered paragraphs are a true copy of the Reasons for Judgment of the Honourable Justice Jackman. Associate:
Dated: 24 September 2025
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