Abbey Laboratories Pty Ltd v Virbac [2025] FCA 1179 | Case summary

(2011) 284 ALR 309Abbey Laboratories Pty Ltd v Virbac [2025] FCA 1179 | Case summary | Zoe

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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):

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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):

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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:

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CLAIMS

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.

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.

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.

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.

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.

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.

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.

A formulation as claimed in any one of the above claims, wherein the levamisole active ingredient is in the base, hydrochloride or phosphate form.

A formulation as claimed in any one of the above claims, wherein the levamisole active ingredient is in the base form.

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.

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.

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%.

A formulation as claimed in any one of the above claims wherein the formulations additionally include antioxidants and/or stabilizers.

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.

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.

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.

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.

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.

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.

A formulation according to claim 19 in which the viscosity modifier is added at a rate of less than 10% w/v.

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.

A stable formulation suitable for topical administration to cattle substantially as herein described with references to any one of the examples.

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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.

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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

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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.

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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:

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(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].

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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:

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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.

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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]):

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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.
As to claim 2, Dr Alawi refers to the evidence in Alawi 2 at [20] that the amount of solvent(s) in the pre-formulation candidates that he would have developed as at September 2011 would be around 78%, which falls within the range in claim 2 of 20% to 85%: Alawi 4 at [34].
As to claims 3 and 4, Dr Alawi refers to his evidence in Alawi 2 at [18] where he describes the advantages of using a co-solvent (including stability, manufacturing, safety and cost-effectiveness benefits): Alawi 4 at [35]. Dr Alawi also refers to his evidence in Alawi 1 at [68] where he described solvents that were suitable for typical topical formulations at September 2011, including glycol methyl ether and alcohols, and says that the co-solvents listed in claims 3 and 4 are all solvents that were commonly known as at 23 September 2011: Alawi 4 at [36]. Dr Alawi also notes that DGME, which he listed in Alawi 2 at [14] as a solvent that he would use in his solvent selection process, is a glycol ether, but it was an expensive solvent and thus as at September 2011, he would have used it in combination with a cheaper solvent, such as NMP or DMA: Alawi 4 at [36].
As to claim 5, Dr Alawi says that he does not understand the patentee to suggest that the use of particular macrocyclic lactones is inventive, and each of the macrocyclic lactones in claim 5 was known to him at 23 September 2011 and was used in veterinary pharma formulations, including pour-ons: Alawi 4 at [37]. His approach to developing a formulation would not have been affected by the identity of the macrocyclic lactone that was proposed to be used in the formulation: Alawi 4 at [37].
As to claim 6, Dr Alawi says that the stability test referred to is a short-term stability test that is consistent with the tests that he described in Alawi 2 at [18]: Alawi 4 at [38]. Professor Bunt would also have used that stability metric: Bunt 1 at [447].
As to claim 7, Dr Alawi refers to the example given in Alawi 2 at [13] of a formulation containing 1% abamectin, which falls within the range of 0.01-5% in claim 7: Alawi 4 at [39]. Dr Alawi considers that this range encompasses the standard "chemically possible" quantities of macrocyclic lactone that could be included in the formulation to ensure that this active ingredient was present at a concentration that is efficacious and safe: Alawi 4 at [39]. Dr Alawi says that the selection of the upper end of the range value (5%) is a level that he would expect to be associated with no efficacy benefits (compared with much lower concentrations) and, more importantly, with adverse effects on animals treated with formulations containing this excessively high concentration: Alawi 4 at [39] (although I note Professor Bunt's disagreement with this point in Bunt 1 at [542] on the ground that the dosage volume would be adjusted to suit the concentration, which I prefer). By maintaining that the upper end of the concentration could be efficacious in Bunt 1 at [542], Professor Bunt's evidence is consistent with there being nothing inventive about the concentration range as such, which the two experts agreed upon in the Formulation JER at [60]-[61].
As to claims 8 and 9, Dr Alawi says that each of the forms of levamisole identified were known to him at 23 September 2011 as evidenced by his use of levamisole base in his response to the Task in Alawi 2: Alawi 4 at [40]. Dr Alawi says that levamisole hydrochloride is used in oral formulations, while levamisole phosphate is used in injections, and these forms of levamisole would not be used in a pour-on formulation: Alawi 4 at [40]. I deal with that point below.
As to claim 10, Dr Alawi refers to his evidence in Alawi 2 at [20] where he states that he would expect that the pre-formulations would include 20% levamisole base, and in his experience as at September 2011, this concentration would provide the optimal level of efficacy without the added risks of adverse effects that would be inevitable with formulations containing the maximum concentration in the range (namely 30%) referred to in claim 10: Alawi 4 at [41]. Dr Alawi says that the high upper value of 30%, as at September 2011, was at a level that he would expect to be associated with no efficacy benefits (compared with lower concentrations such as 20%) and, more importantly, with adverse effects on animals treated with formulations containing this excessively high concentration: Alawi 4 at [41]. Again, I prefer Professor Bunt's disagreement with Dr Alawi on the higher concentration: Bunt 1 at [542]. If anything, that assists Abbey's case, and in any event, Professor Bunt appears to agree that there is nothing inventive about the concentration range of levamisole as such: Formulation JER at [70].
As to claim 13, Dr Alawi refers to his evidence in Alawi 2 at [13] that he would include 0.1% BHT or BHA as a chemical preservative to protect or minimise and delay API oxidative degradation (especially for the mectin): Alawi 4 at [44]. Dr Alawi says that antioxidants and stabilisers were routinely used in such formulations as at 23 September 2011 and there is nothing inventive about their inclusion: Alawi 4 at [44]. Professor Bunt accepts that viscosity modifiers, stabilisers and antioxidants were commonly used: Bunt 1 at [48], [91] and [531].
As to claim 15, as at 23 September 2011, Cooperia and Ostertagia were common parasites in cattle that were known to be able to be treated with macrocyclic lactones and levamisole: Alawi 4 at [46]. Resistance of these parasites to one or other of the suggested active ingredients was well known as at 23 September 2011, as was the effectiveness of combination anthelmintics (containing the suggested active ingredients) to treat resistant strains of these parasite species: Alawi 4 at [46].
As to claim 16, Dr Alawi says that the method of preparing a formulation by dissolving the actives in the selected solvent and adding a co-solvent if required were ordinary formulation steps as at 23 September 2011, following his solvent selection process: Alawi 4 at [47]. If Professor Bunt were to have chosen one of the solvents required by claim 16 (contrary to his evidence), then he accepted that there would have been nothing special about the method in claim 16: T252.20-23.
As to claim 18, Dr Alawi repeats his comments regarding antioxidants in relation to claim 13 and refers to the evidence concerning stabilisers and viscosity modifiers, which he identified as part of a typical topical formulation in Alawi 1 at [68]: Alawi 4 at [48]. As indicated above, Professor Bunt acknowledges that the addition of these excipients was commonly done. He agreed that there was nothing special in the addition of an antioxidant or viscosity modifier to the method of claim 18: T252.32-35.
As to claim 19, Dr Alawi says that a viscosity modifier may assist with spreading the formulation around the body of the cow, and refers to his inclusion of viscosity modifiers in a typical topical formulation in Alawi 1 at [68]: Alawi 4 at [49]. However, Dr Alawi says that he would not usually choose a viscosity modifier, as it could separate or precipitate at lower temperatures (2-8ºC and at frozen stage) and this may lead to a blockage of applicator systems, and it increases the cost of the formulation: Alawi 4 at [49]. Professor Bunt accepts that there is nothing inventive about claim 19: Formulation JER at [97].
As to claim 20, Dr Alawi refers to the discussion in the Specification (page 20, lines 22-23) of formulations containing 2-5% viscosity modifiers, being well within the range in claim 20, but repeats his comments as to the addition of viscosity modifiers adding extra cost: Alawi 4 at [50]. Professor Bunt accept that there is nothing inventive about this claim: Formulation JER at [100].
As to claim 21, Dr Alawi says that this includes a broad range of viscosity modifying agents, and that Xanthan gum (which he had referred to in Alawi 1 at [68]) is a cellulose derivative as described in claim 21: Alawi 4 at [51]. Professor Bunt corrects the latter proposition, saying that Xanthan gum is not a cellulose derivative but a polysaccharide made by bacteria: Bunt 1 at [549]; accepted in Alawi 5 at [154]. However, Professor Bunt accepts that there is nothing inventive about this claim: Formulation JER at [103].
Professor Bunt takes issue with Dr Alawi's approach to the Task on three major issues, concerning (a) whether the PSA would attempt to formulate the product in a non-aqueous system; (b) whether the PSA would have formulated the product with the solvents which are required by claim 1 of the Patent (namely DMA, DMI, DEP and DMP); and (c) whether the PSA would include a third active ingredient (as required by claims 11 and 12). The third issue has fallen away in light of Abbey having abandoned its challenge to the validity of claims 11 and 12. I will deal with the other two issues in that order.
As to whether the PSA would attempt to formulate the product in a non-aqueous system, Professor Bunt disagrees with Dr Alawi's evidence that avoiding water completely in a formulation was the usual or exclusive approach of the skilled formulator as at 23 September 2011: Bunt 1 at [536]. Professor Bunt says that, for example, if one were to prepare a formulation with levamisole (in its salt or base form) and a macrocyclic lactone, the formulator may use an organic solvent to assist in the dissolution of the lactone, such as PEG, but would still likely use water to assist in the dissolution of the levamisole: Bunt 1 at [536]. Professor Bunt notes that Dr Alawi's reference to the "usual approach" is limited to levamisole in its base form, but Professor Bunt does not consider that avoiding the salt form from the outset was the usual approach even for pour-on formulations, and in his view, the skilled formulator would seek to test formulations of both the salt form and base form of levamisole during the formulation process: Bunt 1 at [536]. Professor Bunt says that this may be particularly important if it were identified that the base and salt forms of a drug have different stability characteristics: Bunt 1 at [536]. Professor Bunt considers it unlikely that formulators would restrict themselves to only the non-salt form of levamisole at the start of the formulation process (see Bunt 1 at [235]), because:

[119]

To the extent that Professor Bunt's choice of levamisole in a salt form would have involved consulting the Merck Index (see Bunt 1 at [165] - [174]), I read that evidence as indicating what the PSA would do as a matter of course, and that the relevant information in the Merck Index was thus part of the CGK at the time. It is common ground that the sources which would be consulted by those involved in the development of a new anthelmintic product would include the Merck Index: Team JER at [7(f)]; and see Formulation JER at [14] (Alawi). The Merck Index thus falls within the kind of literature which is included in the CGK, even though the PSA may not have instant recall of the relevant contents: see Gilead Sciences Pty Ltd v Idenix Pharmaceuticals LLC [2016] FCA 169; (2016) 117 IPR 252 at [216] (Jagot J).
Professor Bunt disagrees with the opinion expressed by Dr Alawi in Alawi 4 at [40] that levamisole hydrochloride is used in oral formulations, while levamisole phosphate is used in injections, and that neither of these forms of levamisole would be used in a pour-on formulation. Professor Bunt says that Dr Alawi is over-generalising in respect of which forms of administration can use the salt of levamisole: Bunt 1 at [544]. For example, Professor Bunt says that injections benefit from the salt forms as they are less of an irritant, and there are also potential advantages of using the base form in a pour-on (for example, in moving across the skin faster due to lipophilicity). However, each form works for oral formulations: Bunt 1 at [544]. Further, in Professor Bunt's experience, a skilled formulator would not rule out using a salt form of levamisole in formulating a topical composition, without first attempting to formulate it based on the relevant active ingredients in the composition: Bunt 1 at [544]. Professor Bunt would consider also using the base form when undertaking that Task: Formulation JER at [64] and [67]. Contrary to Abbey's submission, I do not regard Professor Bunt's evidence as betraying that levamisole base was the only real candidate for topical applications (Abbey's closing written submissions at [115]).
Professor Bunt says that he would begin testing levamisole's solubility in water across different pH values, and would prioritise using the salt form of levamisole in these tests (for example, levamisole hydrochloride or levamisole phosphate) as salts are the most water-soluble form of a compound: Bunt 1 at [177]. In addition, Professor Bunt says that levamisole is soluble in propylene glycol, the properties of which are similar to those of PEGs: Bunt 1 at [178]. I discuss Professor Bunt's evidence concerning PEG further below. Professor Bunt says that, after testing the actives individually in both water and PEG, he would then combine the macrocyclic lactone and levamisole, and would attempt to prepare an acceptable formulation using as much water as possible by adding small quantities of PEG at a time until both active ingredients were dissolved: Bunt 1 at [181]. Based on the solubility data in the Merck Index, he considers it reasonably likely that he would be able to develop an aqueous formulation of levamisole and a macrocyclic lactone (for example ivermectin or abamectin) with a sufficient amount of PEG to solubilise both active ingredients: Bunt 1 at [181]. Professor Bunt notes that PEGs are water miscible and thus cannot be used to formulate a rainfast topical formulation alone, without the addition of other excipients: Bunt 1 at [182]. Professor Bunt says that solvents that are not water miscible are preferred for topical formulations as they do not mix with water and are less likely to be washed away by rainwater, however, where water miscible solvents (such as PEG) are shown to be the most effective at dissolving the active ingredients, other components such as thickening agents are typically added to the formulation to achieve rainfastness: Bunt 1 at [182]. Professor Bunt says that water also has the advantage of being a safe, effective, easy to register, and commercially desirable solvent, so he would prioritise an aqueous solution where at all possible, and using an aqueous solution also maximises the range of viscosity modifiers that he can use: Bunt 1 at [182].
In his oral evidence, Professor Bunt rejected the broad proposition that the skilled formulator would not give any serious consideration to an aqueous system, given the instability of the macrocyclic lactone in the aqueous solution (as discussed in the Team JER) and the trouble and time involved in trying to overcome that problem: T163.28-39. Professor Bunt explained that it is always good practice to confirm information concerning solubility and stability from the Merck Index and other resources for oneself and not rely on those resources, as sometimes they can be wrong or not report the true situation, and one might be surprised that something that the information might say should not work, can be achieved, and thus it is worthwhile keeping an open mind from the beginning: T163.33-39. I do not regard that aspect of the evidence as undermining the Merck Index's position as being within the kind of literature included in the CGK. Professor Bunt accepted that the results of using a "fully aqueous system" would be "disappointing": T163.41-45. However, Professor Bunt rejected the proposition that the simplest way to proceed would be to forget about using an aqueous solvent and simply choose an organic solvent, saying that it would still be worthwhile exploring the use of an amount of water, and not a purely organic solvent early on in the process: T164.27-35. Professor Bunt said that he would test compositions with an amount of water present rather than simply adopting an organic solvent, and although he might move on from systems that have a degree of water in them very quickly, until he had done the work he would not know: T164.37-42. I accept that evidence.
Dr Alawi replied to Professor Bunt's affidavit evidence by saying that he understood, as at September 2011, that the inclusion of the water required to solubilise a levamisole salt in this type of formulation is contraindicated because of the absolute need to protect macrocyclic lactones from low pH conditions: Alawi 5 at [10]. Based on his experience, which he claims was common among formulators with experience in these types of organic solvent formulations (as at September 2011), Dr Alawi says that it was well known that the base form of levamisole was effectively the only form that could be used in pour-on formulations: Alawi 5 at [10]. Hence, Dr Alawi expressed the opinion that Professor Bunt's inclusion of water (and the use of levamisole salts in substitution for levamisole base) in this type of formulation "could only be described as unusual and a waste of time": Alawi 5 at [10]. Dr Alawi says that, unlike water, the use of an organic solvent avoids the need to consider the pH of the formulation and its impact on the active ingredients, and that this choice would give rise to expected stability and efficacy issues: Alawi 5 at [10]. Dr Alawi says that an experienced formulator would have expected water to fail as the carrier for a combination of a macrocyclic lactone and levamisole, because he knew as at 23 September 2011 of the large difference between the pH of these two classes of actives, causing it to be very difficult to have a stable product where water was the carrier: Alawi 5 at [47].
The difficulty confronting Dr Alawi in that responsive evidence was exposed in his oral evidence, dealing with Example 8 and Table 12 in the 040 Patent (pages 18-19), which showed that the twelve formulations combining abamectin and levamisole that included water that Dr Alawi tested had product instability (as Dr Alawi had acknowledged in Alawi 5 at [82]). The 040 Patent was filed on 13 December 2006, and the invention was expressly related to a pour-on formulation (page 2, line 9). Dr Alawi accepted that his evidence, that it was unusual and a waste of time to use a salt form of levamisole and water, was based on the trial formulations using an aqueous system which he had performed for the 040 Patent: T158.1-10. Dr Alawi said that prior to 2011 there is no way that he would again use water as a carrier for a pour-on formulation because of his own personal experience (and that of his colleagues in the business) in undertaking the research program for the 040 Patent: T158.12-23. Importantly, Dr Alawi accepted that he is unable to put himself in the position of someone who had not conducted that research program, and volunteered that someone who had not conducted those trials would say: "Okay. Let's try the water.", and "let's try the levamisole ... hydrochloride format": T158.25-34. Dr Alawi accepted that such a person would try levamisole hydrochloride: T158.33-36. Dr Alawi accepted that it was the months-long work in trialling all the formulations set out in Example 8 of the 040 Patent that enabled him to identify the further advantage of adopting a non-aqueous approach: T160.8-14. Dr Alawi said that based on his experience, he would entirely exclude water from the pour-on formulations, that experience being the trialled formulations set out in Example 8 of the 040 Patent, and four or five other products that went to the market and others that were tried internally: T165.7-17. It follows that Dr Alawi's approach is based on specialised knowledge from his own research, which has not been shown to be part of the CGK known to the PSA.
A further difficulty confronting Dr Alawi arises from the trialled formulations for the 154 Patent, being a patent for a combination of macrocyclic lactone and levamisole able to be administered as a pour-on product (although the preferred embodiments were for an injectable composition) and with a filing date in June 2011, only about three months before the Priority Date. It took over forty attempts to formulate the composition which was the subject of the 154 Patent because of the pH issues arising from using water (T171.19-24). Table 1 in the 154 Patent specification (page 7) shows thirteen trialled formulations, with water being used in eleven of those formulations: T171.43-46. Only the first two formulations set out in Table 1 were non-aqueous: T172.19-22. Dr Alawi explained that he tried aqueous solvent systems and used both the hydrochloride salt form of levamisole and the phosphate salt form in the different formulations as part of the trial and error process in order to build up information: T172.34-173.3. Dr Alawi accepted that the nature of such a trial and error process is that sometimes one hits a dead end and has to retrace one's steps: T174.1-5. The fact that Dr Alawi tried both aqueous and non-aqueous solvent systems as recently as June 2011 contradicts his evidence that it was unusual and a waste of time to include water and use levamisole salts in this type of formulation. As I have indicated, although the preferred embodiments were for an injectable composition, the specification says that it can be administered via other methods such as orally or as a pour-on: 154 Patent, page 3, lines 21-23. Dr Alawi accepted that the contents of the specifications naming him as an inventor or co-inventor were true to the best of his knowledge: T152.11-23.
The 600 Patent filed on 5 October 2009, and naming Dr Alawi as sole inventor, used water as a co-solvent in a combination macrocyclic lactone and levamisole formulation for an oral drench. Dr Alawi explained that the castor oil, used as the carrier in that formulation, protected the macrocyclic lactone (being abamectin) and enabled him to use water and the salt form of levamisole: T176.17-177.9. The 600 Patent, however, is confined to administration via an oral drench. The specification for the 600 Patent states that it should be appreciated by those skilled in the art that producing a formulation of this nature is particularly challenging (page 8, lines 19-20). Professor Bunt agrees that there are significant additional challenges in the preparation of stable products containing two or more active ingredients in relation to solubility, stability, solvent compatibility, pH and interactions between the active ingredients: Bunt 1 at [108]-[119].
The evidence concerning Dr Alawi's work in trialling formulations for the 040 Patent and the 154 Patent establishes two propositions which are fatal to Abbey's case in relation to the alleged obviousness of the requirement in the Patent of a non-aqueous solvent system. First, the expert evidence given by Dr Alawi is based on Dr Alawi's specialised private knowledge acquired from his own research work, which was not part of the CGK. Second, the notion that using water and levamisole in its salt form was unusual and a waste of time for a pour-on product is inconsistent with what Dr Alawi actually did in trialling formulations for the 040 Patent and the 154 Patent, noting in particular that the filing date of the 154 Patent was only about three months before the Priority Date.
For completeness, I set out my findings on several other issues which arose on the question of whether the skilled formulator would use a non-aqueous solvent system. First, there is a dispute between the experts as to whether the Eclipse Pour-On product contained water. Professor Bunt expressed the opinion that it was reasonably likely that it did contain water: Bunt 1 at [190(b)] and [192]. Dr Alawi disagreed, and referred to a more recent Australian label (which appears to have been post-dated 23 September 2011) for the product which showed that the other solvent (apart from NMP) is DGME rather than water: Alawi 5 at [89]-[91]. I infer from the subsequent Australian label to which Dr Alawi refers that it is more likely than not that the product did not contain water as at 23 September 2011, and thus I prefer Dr Alawi's evidence on the point. However, there is no real significance in this dispute giving the findings which I have already made on the question of an aqueous or non-aqueous system. Further, in my view the PSA as at 23 September 2011 would not have known that the Eclipse Pour-On product used a non-aqueous solvent system.
Second, Dr Alawi says that, in addition to stability and efficacy issues, an aqueous pour-on formulation would likely run off the back of an animal after application, would not be rainfast and would wash off the animal more quickly, thus preventing the actives from being absorbed through the skin of the animal at the appropriate dose: Alawi 5 at [31]. However, Dr Alawi acknowledges that viscosity modifiers could be used to alter the viscosity of the formulation, and says that the use of viscosity modifiers would not have been a surprising thing for a veterinary formulator to consider in September 2011, although he expresses a preference not to use them: Alawi 5 at [32]. In my view, it cannot be concluded that the PSA would have excluded an aqueous solvent system for this reason.
Third, Dr Alawi says that pour-on formulations sold in Australia and New Zealand as at September 2011 were almost exclusively non-aqueous formulations that included organic solvents: Alawi 5 at [30]. That is consistent with the agreement of all three experts in the Team JER, to which I have referred above, that non-aqueous solvent systems were the "predominant choice" and "dominated the market" for anthelmintic products used for cattle in Australia as at September 2011. However, that does not mean that the PSA would exclude the use of water if asked to formulate a new product, as Dr Alawi's own trials for the 040 Patent and the 154 Patent demonstrate.
Turning then to the question whether the PSA would have formulated the new product with at least one of the four solvents required by claim 1 of the Patent, I note at the outset that Virbac adduced evidence from one of its solicitors, Mr Roger Liu, who undertook searches of safety data sheet databases and veterinary product databases in Australia and New Zealand. Mr Liu was unable to find any product at the Priority Date that contained DMI or the phthalates, namely DEP or DMP: Liu 1 at [37] and [43]. Mr Liu identified only one product that contained DMA, being the Eclipse E Injection product: Liu 1 at [37]. It is common ground that DMA, DEP and DMP were required by law to be disclosed on product labels and safety data sheets throughout Australia as at 23 September 2011 (T22.31-23.7 on 10.9.25). Mr Liu's searches of the public veterinary product databases in Australia and New Zealand failed to identify any product with the solvents in claim 1: Liu 1 at [44]-[54]. Mr Liu found 143 products on the Australian veterinary product database containing NMP: Liu 1 at [49]. Mr Liu's searches also show that DGME was frequently used. However, I accept Abbey's submission that databases reflecting the contents of labels and safety data sheets do not necessarily determine the CGK.
Taking each of the four solvents in claim 1 individually, the first is DMA. Professor Bunt says that, while he was aware of DMA as at 23 September 2011, he had not used it in any formulation before or since that date, and disagrees that DMA was included in typical topical formulations at that date: Bunt 1 at [156]. Professor Bunt did not keep DMA in his stock of accessible and commonly used solvents (which Professor Bunt terms his "library": Bunt 1 at [79]) at any stage, including before 23 September 2011, nor had he considered using DMA as a solvent in formulating a veterinary product before that date: Bunt 1 at [156(a)]. Professor Bunt is not aware of any other formulators in the field using DMA as a solvent in veterinary formulations before 23 September 2011, including through his work at the National Poisons Centre, his formulation work, his review of the relevant national registers for veterinary products and his review of his students' work in his teaching roles: Bunt 1 at [156(a)]. Professor Bunt says that DMA would have been an unlikely choice of solvent in a topical product (in particular, one in a non-aqueous system), for reasons that include that: (a) it is an irritant to the skin of livestock, being a characteristic that is mentioned in the Merck Index; (b) given its known property of being water-miscible and quite fluid, Professor Bunt understood at 23 September 2011 that DMA would likely cause the formulation to run off an animal, particularly in wet conditions on a farm; (c) DMA has several drawbacks that make it unsuitable for animal health products, such as having a distinct unpleasant odour that animals (or farmers) may find repellent, being linked to reproductive and developmental toxicity, and from a manufacturing standpoint, its flammability presents a hazard during bulk storage and product manufacture: Bunt 1 at [156(a)]. Further, Professor Bunt says that an additional reason why DMA would be an unlikely candidate to use in formulating a topical cattle anthelmintic product as at 23 September 2011, was because of the difficulty in obtaining regulatory approval of a veterinary product containing a compound that had not previously been used in other veterinary products, such regulatory approval being a long and complicated process as the environmental regulations around agricultural products are very strict: Bunt 1 at [156(c)].
I accept Professor Bunt's evidence in relation to DMA causing skin irritation (see T221.16-222.16), and DMA's unpleasant odour (see T223.3-21). While the postulated difficulties concerning regulatory approval would probably turn out to be relatively insignificant given its presence in the Eclipse E Injection Product, Professor Bunt was not aware that DMA was used as the solvent in the Eclipse E Injection Product, as shown in the EE Injection Data Sheet. Professor Bunt accepted that the possibility of run-off could be met by the addition of a viscosity modifier (T222.39-223.1), and also accepted that the problem of flammability could be met by appropriate warnings (T225.9-29). Professor Bunt also accepted that the link to reproductive and developmental toxicity was not well known in this field as at 23 September 2011 (T225.3-7). Ultimately, however, the cogency or otherwise of the PSA's reasons for not choosing a particular path is not necessarily determinative of whether in fact the PSA would have chosen that path.
Dr Alawi did not use DMA (or for that matter DMI) in the trials leading to the 040 Patent (T158.42-159.4), the 154 Patent (T173.5-8) or the 789 Patent (T179.13-20). Dr Alawi's explanation for not using DMA in his trials for the 040 Patent was that he thought that there was no innovation in trialling solvents which were on the market (T158.42-159.9). That evidence is difficult to reconcile with the fact that he used DMA in the Bomatak AT product which was not commercially released (T159.16-24), and Dr Alawi does not identify any other pour-on product before 23 September 2011 which used DMA.
In Alawi 2 at [36], Dr Alawi said that DMA was, as at 23 September 2011, "a common excipient used in veterinary drug formulations (including injectables, but also pour-ons and orals)". However, Dr Alawi's oral evidence indicates that his affidavit evidence in that regard is overstated: T200.28-202.25. Dr Alawi was able to point to the Eclipse E Injection product as containing DMA (as revealed by the EE Injection Data Sheet) (as too did Dr Agnew: T114.1-33). Dr Alawi referred also to the Bomatak AT product, which he formulated in 2008, being a non-aqueous pour-on product using DMA as the main solvent. However, that product was not released because of commercial issues arising from arrangements between Bomac and Ancare (T159.21-24 and 162.5-18), and there is nothing in the evidence to indicate that the research work for that product was part of the CGK as at 23 September 2011, which in any event seems inherently unlikely. That was the only pour-on cattle product using DMA which Dr Alawi was able to identify. Dr Alawi referred also to patents (for example the 041 Patent) as referring to the use of DMA. Dr Alawi said that not all solvents are required to be disclosed on safety data sheets, and many companies do not disclose them voluntarily so as not to give competitors their formulation: Alawi 5 at [65]. I note that, while that comment makes a valid point in relation to DMI, it is common ground that DMA had to be disclosed on product labels and safety data sheets throughout Australia as at 23 September 2011. However, Dr Alawi was able to identify only one product on the market as at 23 September 2011 for which DMA was used as a solvent, being the Eclipse E Injection product. While Professor Bunt agreed that DMA (and also DMI) was referred to in the literature on veterinary anti-parasitic drugs (as shown by the textbook page dated 1993, annexed to Bunt 1, at CB 113, p 3731, table 6), he did not agree that DMA (or DMI) was typically used in commercial products (T211.1-10, as clarified at T241.15-39). The evidence did not establish that the literature on the point was assimilated into the CGK as at 23 September 2011.
I find that the PSA would not have selected DMA as a matter of routine as one of the solvents to be included in trial formulations in responding to the hypothetical Task.
The next solvent referred to in claim 1 of the Patent is DMI. Professor Bunt disagrees that DMI was included in typical topical formulations at 23 September 2011, and I accept his evidence in that regard. While he was generally aware of DMI at that date, he did not keep it in his "library" and had not used it at that date (or subsequently): Bunt 1 at [156(b)]. Professor Bunt has not considered using DMI as a solvent in formulating a veterinary product and is not aware of others in the field using DMI for veterinary formulations: Bunt 1 at [156(b)]. Professor Bunt is aware that DMI is used in cosmetic products for humans, but cannot recall ever seeing it used in a veterinary product (either before or after 23 September 2011), including through his work at the National Poisons Centre, his formulation work, his review of the relevant national registers for veterinary products and his review of his students' work in his teaching roles: Bunt 1 at [156(b)]. Professor Bunt regards DMI as an unlikely candidate for use in a topical cattle anthelmintic, for reasons including the risk of "run off" due to its relatively low viscosity and the potential for the formulation to leak onto the farmers administering the product and thus expose them to the active ingredients and the associated health hazards: Bunt 1 at [156(b)]. Professor Bunt says that an additional reason why DMI would be an unlikely candidate to use in formulating a topical cattle anthelmintic product at 23 September 2011 was because of the difficulty in obtaining regulatory approval of a veterinary product containing a compound that had not previously been used in other veterinary products, such regulatory approval being a long and complicated process, as the environmental regulations around agricultural products are very strict: Bunt 1 at [156(c)].
I accept Professor Bunt's evidence that a reason for rejecting DMI for the Task was the potential difficulty in getting regulatory approval, and that another reason for rejecting DMI was its cost. I also accept Professor Bunt's evidence that the fact that DMI had been used in products for humans (such as in cosmetics) and was thus regarded as being safe for humans, did not mean that there could be no serious objection to its registration, in that safety for humans does not in itself indicate safety for animals: T213.6-214.41. As Professor Bunt explained, there were similar compounds available which had already been used in livestock, rather than resorting to DMI: T214.37-41. Professor Bunt accepted that the problem with viscosity could be met by the routine method of using a viscosity modifier: T212.1-12. He also accepted that the problem of leakage onto farmers could be met by farmers taking proper precautions: T219.42-220.11.
Dr Alawi had not used DMI in any of the prior products discussed in his affidavits, saying that he was happy with the other solvents that he used, and DMI was more expensive than those other solvents: T190.42-191.3. Dr Alawi said that he included DMI in his list of potential solvents as a back-up in case he failed in finding a co-solvent: T191.7-8, T196.40-46. Nor did Dr Alawi try DMI in any of his prior research work which was referred to in the patents naming him as an inventor or co-inventor, but he knew that it had been used in a patent (being the 041 Patent): T191.10-21, T198.32-41. Dr Alawi was not aware of the use of DMI in any commercially released veterinary product before September 2011: T191.24-31. Dr Alawi knew that DMI was used as a solvent in Virbac's Cydectin Platinum product, but that product was not launched until late 2020: T193.4-40. In my view, the most plausible explanation for Dr Alawi including DMI in his list of solvents (in Alawi 2 at [14] and Alawi 4 at [32]) was that his awareness of the ingredients of Cydectin Platinum led to him including DMI in his list of potential solvents, contrary to his denial of that proposition (T197.19-24), although that process of thought has probably eroded in his memory. That impression is strengthened by the manner in which Dr Alawi dealt with the proposition in his oral evidence, which was both hesitant and evasive (T196.19-46).
Whether or not Dr Alawi would have included DMI in his own list of potential solvents, I do not think that the PSA would have done so. If Dr Alawi would have done so, I do not regard Dr Alawi as reflecting the position of the non-inventive PSA.
As to the phthalates, namely DEP and DMP, Dr Alawi said in oral evidence that he had not used those solvents in his work for the 040 Patent, being a pour-on product, but listed them in his response to the Task as a back-up just in case other solvents did not do the job: T205.1-13. Neither Dr Alawi nor Dr Agnew identified any veterinary products which used a phthalate, let alone any pour-on products, nor did Mr Liu's searches reveal any. Professor Bunt said that it has never been his preference to consider a phthalate when there are other materials that can function just as well as a solvent: T232.47-233.1. I regard Dr Alawi's evidence that he personally would have included DEP and DMP as another example of Dr Alawi's approach not reflecting the PSA, whereas I do regard the PSA's approach as reflected in the approach taken by Professor Bunt.
For completeness, I note that Professor Bunt said in his affidavit that it was widely known in the field as at 23 September 2011 that DEP and the phthalate family in general were undesirable in veterinary formulations by reason of their endocrine-disruptive side effects and other toxicity concerns: Bunt 1 at [240]. That evidence, however, was based on a journal article to which Professor Bunt was taken in his oral evidence (at T227-234), and Professor Bunt accepted that the problem was not widely known in the field at the time (see T239.43-240.9). Accordingly, I do not regard that aspect of Professor Bunt's evidence as pointing away from the potential use of DEP or DMP by the PSA at the relevant time.
In relation to DGME, which is a glycol ether and thus falls within the solvents referred to in claim 3 and 4 of the Patent, Dr Alawi had identified DGME as one of the potential solvents that he would use. Professor Bunt has no experience of using it and was not aware of others in the field using it as at 23 September 2011, and would therefore have been reluctant to use it in his formulation process: Bunt 1 at [241(d)]. Professor Bunt is now aware that it is used in the field of anthelmintics for cattle (T226.43-46), but the relevant time is 23 September 2011 rather than the present. Dr Alawi wrongly claimed that the Eclipse Pour-On Data Sheet identified DGME as a solvent in addition to NMP (Formulation JER at [28]; and see T243.1-244.4), although he acknowledged in that evidence that NMP would be of particular interest because it was cheaper than DGME. I do not think that the PSA would have selected DGME as a potential solvent as a matter of routine. In any event, claim 3 also requires the selection of DMI, and claim 4 requires the selection of at least one of the four solvents referred to in claim 1.
Accordingly, I conclude on the basis of Professor Bunt's evidence that the PSA would not have chosen any of the four solvents required by claim 1. That conclusion is reinforced by Professor Bunt's evidence as to the solvents that he would have chosen in response to the Task, to which I now turn, and which I also accept.
Professor Bunt's evidence is that the solvents that he would have tested in response to the Task, in order of preference, were:

[121]

As I have indicated above, Professor Bunt says that he would begin testing levamisole's solubility in water across different pH values, prioritising using the salt form of levamisole in those tests, as salts are the most water soluble form of a compound: Bunt 1 at [177]. Professor Bunt says that levamisole is soluble in propylene glycol, which has similar properties to those of PEGs: Bunt 1 at [178]. Professor Bunt says that PEG and propylene glycol were also two of his preferred solvents in his "library" as at 23 September 2011, and since ivermectin is also soluble in polyethylene glycols and propylene glycols, PEG would be a promising candidate for a combination product containing levamisole and ivermectin: Bunt 1 at [178]. Professor Bunt says that members of the same chemical family, such as the macrocyclic lactone family, often share similar chemical properties, and that if one member of the family is soluble in a particular vehicle, he would expect the other members of the family to be likely to share this characteristic: Bunt 1 at [178]. As such, Professor Bunt expects that a PEG (and propylene glycol) is likely to be an effective solvent for a combination of levamisole and any of the macrocyclic lactones which he identified in his evidence: Bunt 1 at [178]. Dr Alawi said that such a formulation would be very unlikely to work because it would not be stable and an experienced formulator with knowledge of the physicochemical properties of these active ingredients would have understood that (Alawi 5 at [81]). I regard Dr Alawi's evidence as the result of his own research and development work beyond what had been assimilated in the CGK.
Professor Bunt says that he would only use NMP as a last resort, as it was known to cause irritation to the skin and hide of animals: Bunt 1 at [157], T225.31-45. However, Professor Bunt accepted that NMP is very commonly used in veterinary products, and that the industry accepted the downside of skin irritation and used the product anyway: T226.1-7. Professor Bunt also accepted that one way of dealing with that problem would be to dilute the NMP with a co-solvent: T226.11-14. I accept Professor Bunt's evidence as reflecting the approach of the PSA. In addition, Dr Agnew described NMP as a standard choice of solvent for topical pour-on formulations at the time of launch of the Eclipse Pour-On product, in which NMP was used: Agnew 2 at [32].
The upshot of the findings which I have made is that I do not regard it as obvious that the PSA would adopt a non-aqueous solvent system, nor would the PSA select any of the four solvents required by claim 1, namely DMA, DMI, DEP and DMP. I do not regard Dr Alawi's approach as reflecting that which would be undertaken by the PSA. Accordingly, Abbey's attack on the validity of claim 1 of the Patent (and the claims which are dependent on claim 1) for lack of inventiveness based on CGK alone fails.
Turning to the independent claims of the Patent other than claim 1 (and apart from claims 17 and 22, the validity of which is no longer challenged), claim 16 requires the dissolving of at least one of either the levamisole active ingredient or the macrocyclic lactone active ingredient by at least one solvent selected from DMI, DMA, DEP and DMP. As I do not regard the selection of any of those four solvents as obvious, I find that this claim is inventive.
Claim 19 does not require the use of DMI, DMA, DEP or DMP, but merely the use of one or more organic solvents together with a viscosity modifier. Professor Bunt's choice of potential solvents included a number of organic solvents, and there is nothing inventive about the use of organic solvents in this kind of formulation. The addition of viscosity modifiers was also common practice within the industry as at 23 September 2011: Bunt 1 at [91(a)] and [531]; Alawi 1 at [68(e)]. Accordingly, there is nothing inventive about claim 19, as Professor Bunt accepted: Formulation JER at [97]. It is therefore invalid.
Claim 20 is dependent on claim 19, and stipulates that the viscosity modifier be added at a rate of less than 10% (w/v). It is common ground between Professor Bunt and Dr Alawi that there is nothing inventive about that concentration of the viscosity modifier: Formulation JER at [39], [99]-[100]. Similarly, there is nothing inventive about the type of viscosity modifier claimed in claim 21: Formulation JER at [39], [102]-[103]. Accordingly, claims 20 and 21 are also invalid.
In addition, Abbey relies on three pieces of prior art information, namely the Eclipse Pour-On Data Sheet, the EE Injection Data Sheet and the EE Injection Label. It is common ground that each of them was reasonably to be expected to be ascertained, understood and regarded as relevant by the PSA and thus falls within the kind of information mentioned in subs 7(3) of the Act.
As to the Eclipse Pour-On Data Sheet, Dr Alawi says that this would have given him a greater level of confidence in NMP as a solvent, but he still would have proceeded with testing the solvents which he identified in Alawi 2 at [14] in order to determine which achieved the best levels of solubility and then stability from his initial stability tests: Alawi 2 at [31]. Professor Bunt states that the document confirms that NMP was successfully used as the solvent for the two active ingredients, and as NMP was his last resort he would not need to go outside his preferred shortlist of solvents from his "library": Bunt 1 at [193]. Professor Bunt accepts that the document would guide the formulator in making decisions about solvents: Formulation JER at [29].
As to the EE Injection Data Sheet, Dr Alawi says that DMA was, at 23 September 2011, a common excipient used in veterinary drug formulations (including injectables, pour-ons and orals): Alawi 2 at [36]. As I have indicated above, that was challenged in his oral evidence and shown to be overstated. Dr Alawi says that while this is an injection product, and he is tasked with developing a pour-on, in view of the formulation disclosed in this document, he would expect that he could formulate a pour-on product containing eprinomectin and levamisole base using DMA as the solvent or as a co-solvent with good stability, because it is a lipophilic solvent that would solubilise both eprinomectin and levamisole base, both of which are lipophilic: Alawi 2 at [37]. Dr Alawi refers to the potential risk of skin irritation when using a topical formulation containing DMA, but says that the combination product containing this solvent that he developed in 2008 (namely the Bomatak AT pour-on) showed, through screening animal trials, that skin irritation was not an issue: Formulation JER at [31]. Dr Alawi refers to the declared presence of an antioxidant, primarily indicating the need to protect the eprinomectin (which was well known to him and other skilled formulators as at 23 September 2011, to be sensitive to oxidative breakdown), with a secondary benefit of this ingredient being its potential role in reducing the possible effect of DMA on the active ingredient: Formulation JER at [31]. Professor Bunt considers it likely that the ingredients in the EE Injection Data Sheet are formulated in a water solvent (Bunt 1 at [199]-[205]) and I regard that as a reasonable opinion for the reasons given by Professor Bunt. Dr Alawi agreed that the product "may" include water (Alawi 5 at [95]), but in fact Dr Alawi knows that it does contain water (T106.44-107.13). Professor Bunt accepts that the document would guide the formulator in making decisions about solvents: Formulation JER at [32].
As to the EE Injection Label, Dr Alawi repeats the comments which he made in relation to the EE Injection Data Sheet, noting that he was tasked with developing a pour-on rather than an injection product: Alawi 2 at [41]. Dr Alawi says that the information is of limited value for a pour-on formulation: Formulation JER at [34]. Professor Bunt also repeats his comments on the EE Injection Data Sheet, noting that there is only 5% DMA in the composition which he says reflects concerns that DMA is an irritant (Bunt 1 at [211] and [215]), and accepts that the document would guide the formulator in making decisions about solvents: Formulation JER at [35].
These three documents do not indicate that the development of an anthelmintic combination formulation for cattle should only use a non-aqueous system. They do not affect my finding that the insistence on a non-aqueous system in claim 1 of the Patent involves an inventive step. Nor do any of the three documents refer to or identify, for the purposes of a pour-on (as distinct from an injectable) formulation, any of the solvents specifically nominated in the Patent. The reference to DMA being used in an injectable product does not affect my finding expressed above that the PSA would not have selected DMA as a solvent as a matter of routine in undertaking the Task, which was concerned with a pour-on formulation.
Accordingly, the three prior art documents do not affect my findings as to the inventiveness of the challenged claims.
The 242 Patent is no longer relied on by Abbey as prior art information (see Further Amended Particulars of Invalidity dated 20 May 2025). However, Professor Bunt describes the 242 Patent as describing efforts to combine anthelmintics from four classes, including a macrocyclic lactone and levamisole hydrochloride, and says that the example formulations confirm that it is possible (and a promising option) to combine both levamisole and a macrocyclic lactone in an aqueous formulation (at least in the presence of two additional active ingredients): Bunt 1 at [221]-[223]. Further, Professor Bunt says that the 242 Patent suggests to him that benzyl alcohol and tetraglycol are promising solvents: Bunt 1 at [224]-[225]. However, Professor Bunt accepts that the 242 Patent is primarily directed towards the oral and injectable forms of administration, rather than topical formulations: Formulation JER at [38]. Professor Bunt also said that the patentee of the 242 Patent might have been trying to partly precipitate the macrocyclic lactone out of solution in order to protect it (T119.13-34), which would give rise to the practical problem of farmers having to agitate or shake the mixture before using it (T121.9-26). I do not regard the 242 Patent as having a material bearing on the issue of inventiveness.

[136]

This anticipates claims 7, 10 of the patent in suit.

A composition of claim 1 or claim 2 wherein the carrier is present in an amount of from about 63% to about 76% (w/v). (p 50.15 ff)

This anticipates claim 2 of the patent in suit.

A composition according to any of the above claims wherein the carrier is dimethyl isosorbide and a second solvent being dimethylacetamide or diethylene glycol monoethyl ether. (p 73 paras 12 and 13)

This anticipates claim 3 of the patent in suit.

A composition of any of the above claims wherein the carrier includes glyceryl acetates (p 73 para 12, p 40.3, p 40.13), pyrollidones (p 50.23, 50.24), glycol ethers (p 73 para 11 and 12) or glycerol formal (p 73 para 13).

This anticipates claim 4 of the patent in suit.

A composition of any of the above claims which additionally includes antioxidants and/or stabilizers. (p 60.12)

This anticipates claim 13 of the patent in suit.

A composition of any of the above claims wherein the infection or infestation is from parasites commonly encountered by cattle. (p 54.14)

This anticipates claim 15 of the patent in suit.

A composition according to the preceding claim wherein the parasites are nematodes (p 54.8).

This anticipates claim 15 of the patent in suit.

A composition according to any of the above claims wherein the composition is made by mixing the ingredients together to form the composition of the invention. (p 60.2-.4)

This anticipates claims 16, 17, 18 of the patent in suit.

A composition of any of the above claims which additionally includes polyvinyl pyrollidone or polyethylene glycols in a proportion of about 0.25% to about 5% (w/v). (p 50.23-24, p 51.16).

This anticipates claims 19, 20, 21 of the patent in suit.

A method for the treatment or prevention of a parasitic infestation or infection in a cow comprising administering to the cow in need thereof an effective amount of the topical veterinary composition of any of the above claims. (p 80 para 17)

This anticipates claim 15 of the patent in suit.

The method of paragraph 10 wherein the parasite is a nematode. (p 54.8)

This anticipates claim 15 of the patent in suit.

[140]

At [82], Emmett J said that subpara (b)(ii)(A) speaks in terms of "a priority date", which directs attention to s 43 of the Act, which relevantly provides that each claim of a complete specification must have a priority date, and the priority date of a claim is the date determined under the regulations. The regulations relevantly provided that the priority date of a claim of a specification was the earliest of the date of filing of the specification, and if the claim is fairly based on matters disclosed in one or more relevant applications, the date of making the relevant application in which the matter was first disclosed.
His Honour then said that there is no mechanism under which "information" can be compared between documents for the purpose of giving that "information" a priority date: Du Pont at [83]. His Honour said that only a claim can have a priority date, and that consideration suggests that the second interpretation is to be preferred: Du Pont at [83]. His Honour said that if the first interpretation were to be adopted, it would be necessary to consider the relevant nexus between the information in a specification as filed, and the information in the relevant priority document, but the Patents Act recognises no such process: Du Pont at [83].
Further, Emmett J said that there must be some relationship between the notional claims and the specification in which the information is said to have been disclosed: Du Pont at [84]. His Honour said that that relationship is provided by the requirement that the notional claim must be a valid claim of the specification in question, and that to be a valid claim, the notional claim must be fairly based on the specification in question: Du Pont at [84].
In Du Pont, the respondent formulated forty-five notional claims which it said were based on the information in the prior document: Du Pont at [91]. His Honour found that in the list of notional claims, the respondent did not identify any information for the purposes of subpara (b)(ii) of the definition of prior art base, given the large number of possible combinations and permutations in the notional claims: Du Pont at [91].
In Danisco A/S v Novozymes A/S (No 2) [2011] FCA 282; (2011) 91 IPR 209 at [178], Bennett J followed Du Pont in saying that a "whole of contents" objection requires that it be possible to draft a notional claim (assuming there is not an actual claim to the relevant subject matter) that is fairly based on the disclosure of the prior specification relied upon. In that case, the postulated need to propound notional claims was not contested (see [292]), and the parties agreed that the question of anticipation was to be determined in accordance with Du Pont (see [293]). Accordingly, the correctness of Du Pont was not raised (see [299]). On appeal, the appellant was held to be bound by the way in which the trial had been conducted: Novozymes A/S v Danisco A/S [2013] FCAFC 6; (2013) 99 IPR 417 at [194]-[197] (Jessup J, with whom Greenwood at [37] and Yates J at [241] agreed). Similarly, the reasoning in Du Pont was followed in Apple Inc v Samsung Electronics Co Ltd [2011] FCA 1164; (2011) 284 ALR 309 at [77] (Bennett J), and in Ranbaxy Laboratories Ltd v AstraZeneca AB [2013] FCA 368; (2013) 101 IPR 11 at [697] (Middleton J).
In DSI Australia (Holdings) Pty Ltd v Garford Pty Ltd [2013] FCA 132; (2013) 100 IPR 19 (DSI Australia) at [230], Yates J noted that a set of notional claims had been formulated in obedience to the requirement referred to by Emmett J in Du Pont. His Honour found that one of the claims in the patent in suit (namely claim 12, but not the other claims) was anticipated by the prior patent application: DSI Australia at [236]-[238]. That conclusion appears to have been reached without reference to the notional claims which had been propounded. His Honour then considered whether the notional claims, if they were to be claims of the prior patent application, would be fairly based on the matter described in the specification of that application, for the purposes of the then s 40(3) of the Act, and held that they were: DSI Australia at [240]-[244]. That is, his Honour found that there was real and reasonably clear disclosure in the body of the specification of the invention that was notionally claimed: DSI Australia [240]. His Honour said that the enquiry as to fair basis is directed to the question of claim width, and a claim may be fairly based where it adds a feature to a combination otherwise described in the specification, and by that addition, limits the described invention to a more restrictive form than that to which the patentee might otherwise be entitled: DSI Australia at [240]. A claim may be fairly based even when all the characteristics by which the invention is defined in the claim are not described in the body of the specification itself, provided those characteristics are truly limiting ones in the sense already described: DSI Australia at [240].
The fact that his Honour dealt with the question of fair basis of the notional claims was, to that extent, consistent with Emmett J's reasoning. Read as a whole, however, I do not read Yates J's reasoning as providing a ringing endorsement of Du Pont, given that the finding that claim 12 was anticipated by the prior patent application was reached without reference to the notional claims. However, the correctness of Du Pont does not appear to have been contested in that case.
In Hanwha Solutions Corp v REC Solar Pte Ltd [2023] FCA 1017; (2023) 180 IPR 315 at [473], Burley J noted that a set of notional claims had been supplied by the respondent. However, in light of concessions by the applicant, it was not necessary to consider whether the notional claims were fairly based on the prior disclosure. I do not regard that decision as providing any support either for or against the reasoning in Du Pont.
Abbey submits, and I accept, that the language of the Act does not require a party to formulate the impugned information into a claim, nor does it require the Court to determine the hypothetical validity of a notional claim within the operation of s 40. As Abbey submits, the words "if the information ... were to be, the subject of a claim" in subpara (b)(ii) make it clear that Parliament did not intend for the impugned information to be, in fact, the subject of a claim for the purpose of a "whole of contents" objection. The statutory language permits the information of the specification to be assessed as if it were a claim, even though not drafted as one. The requirement that the notional claim "would have, a priority date earlier than that of the claim under consideration" reinforces that view, by dealing with circumstances where the information is not formulated as a claim and therefore has no priority date, but hypothetically "would have" a date predating that of the claim under consideration. As Abbey submits, all that is required to appoint a priority date under subpara (b)(ii)(A) is the straightforward exercise of taking the information of the specification as a claim, so that it may be attributed the priority date of the filing of the complete specification (or some earlier date, if established). Abbey submits, and I accept, that to require the drafting of a notional set of claims which would hypothetically be valid imposes a tangential and burdensome enquiry upon the Court and the parties, requiring them to gauge in an artificial validity analysis, with respect to claims devised by a person who may not be the patentee of the prior art.
Further, Abbey submits, and I accept, that the background to the enactment of subpara (b)(ii) indicates that the interpretation adopted in Du Pont was not intended, because it conflicts with the purpose or object that Parliament sought to address when introducing "whole of contents" objections, namely to provide a simpler mechanism for establishing want of novelty. "Whole of contents" anticipation was introduced upon the commencement of the Patents Act in response to Recommendation 14 of the Industrial Property Advisory Committee report_, Patents, Innovation and Competition in Australia_ (29 August 1984), which recommended replacing the prevailing and avowedly unsatisfactory "prior claiming" approach with a simpler method. The report recommended shifting the focus of the enquiry away from specific claims, to focus instead on the whole of the prior art, such that "any disclosure" in the specification could be relied upon for anticipation. Section 7.3 of the report stated the following:

[145]

Accordingly, "whole of contents" objections were designed to implement the recommendation in section 7.3 of the Industrial Property Advisory Committee report. It would be inconsistent with the concern stated in the official response to that report if "whole of contents" objections entailed a complicated mechanism involving the drafting of notional claims, and an enquiry into their validity.
As to the proposition advanced by Emmett J in Du Pont, that the Act provides no mechanism under which information can be compared between documents for the purpose of giving that information a priority date (see [83]), Abbey submits, and I accept, that the Act does provide such a mechanism. That mechanism is the straightforward textual comparison contemplated by the definition of "prior art base"; that is, a comparison between the information in a specification as published, and the priority document. With great respect to Emmett J, the perceived difficulty, that the Act provides no process by which to find the relevant nexus between the information in a specification as filed and the information in the relevant priority document (see [83]), is illusory, because the Act merely requires a comparison. No further process is required to be stipulated by the legislation.
Abbey submits, and I accept, that by holding otherwise and introducing the concept of a notional claim so as to provide a nexus between the priority document and the complete specification as filed, Emmett J introduced unnecessary complexity into the mode of analysis intended by the legislative change, which was not intended by Parliament. As Dr David Brennan contends, Du Pont "has re-routed Australian patent law back towards something resembling prior claiming (which IPAC had rejected 'as unsatisfactory in practice' and 'too narrow') but in an even more obscure form: prior notional claims": Brennan D, Patent Claims: Interpretation, Validity and Infringement (Federation Press, 2025) p 29.
As to the perceived need to show that the notional claims are valid claims under s 40(3), in that under the then legislation they had to be fairly based on the specification in question, Abbey submits, and I accept, that the text of the Act does not require there to be any "relationship" between notional claims (which are not mentioned in the Act at all) and the specification, nor does it require that the notional claim must be a valid claim of the specification in question (contrary to Du Pont at [84]). Abbey submits, and I accept, that for the purposes of attributing a priority date, if any such notional claim were required (contrary to my reasons above), that notional claim is, in effect, a claim whose subject is the whole of the specification, and there is thus no additional requirement to re-formulate that information into notional claims.
Accordingly, with great respect, I regard the reasoning in Du Pont as wrong, and I decline to follow it.
Single judges of the Federal Court are not bound by decisions of previous single judges sitting at first instance. It is often said that a single judge of first instance will usually follow the decision of another judge of first instance of the same jurisdiction as a matter of "judicial comity" unless "convinced" the earlier decision is wrong, or "clearly" or "plainly" wrong. Many of the cases stemming from Burchett J's decision in La Macchia v Minister for Primary Industries and Energy (1992) 110 ALR 201 at 204 were helpfully collected by Wheelahan J in CRS20 v Secretary, Department of Home Affairs [2024] FCA 619 at [256]-[262].
In my view there are two difficulties with such statements. First, the issue whether to follow a previous single judge of first instance on a question of law should not be regarded as one based on "judicial comity". That expression creates the unfortunate (and no doubt unintended) impression that judges should give priority to questions of courtesy and politeness to each other over their duty to apply the law as properly understood. That would wrongly elevate concerns pertaining to internal relations between judges over their fundamental duties to the public. In any event, I do not think that firm but respectful disagreement on questions of law involves a breach of proper standards of judicial etiquette. The question of following a decision of a previous judge should instead be seen as one relating to the rule of law, in that the question concerns the desiderata of the rule of law that the law should generally be consistent and predictable, rather than the question being viewed as one of "judicial comity". However, the desiderata of the rule of law also include that those people who have authority to apply the law in an official capacity do actually apply it in accordance with its tenor. The question whether to depart from a judicial decision made in the same jurisdiction involves a tension between these desiderata, in that maintaining consistency and predictability in decision-making may amount to the perpetuation of an erroneous understanding of the law. The way in which that tension is resolved depends on the particular nature and circumstances of the legal issue in question, and there cannot be an inflexible or rigid approach.
Second, it is neither necessary nor desirable to add vituperative epithets, such as "plainly" or "clearly" wrong. The term "plainly wrong" has been subject to much criticism in the context of intermediate appellate courts departing from decisions of the same intermediate appellate court, and it has been recognised in that context that a more constructive articulation of the principle is whether there is a compelling reason to depart from the earlier decision: Construction, Forestry, Maritime, Mining and Energy Union v Personnel Contracting Pty Ltd [2020] FCAFC 122; (2020) 279 FCR 631 at [126] (Lee J, with whom Allsop CJ and Jagot J agreed); Aristocrat Technologies Australia Pty Ltd v Commissioner of Patents [2025] FCAFC 131 at [114] (Beach, Rofe and Jackman JJ); Pallas v Lendlease Corporation Ltd [2024] NSWCA 83; (2024) 114 NSWLR 81 at [140] (Leeming JA). As Leeming JA observed in the last of those cases, it is generally better to speak to the quality and cogency of the case made out for departure from the earlier decision, rather than the egregiousness of the Court's error. That approach was endorsed by Edelman J in Lendlease Corporation Ltd v Pallas [2025] HCA 19; (2025) 423 ALR 23 at [118]. The same approach strikes me as being appropriate for the question whether a single judge of first instance should depart from an earlier decision of another single judge in the same jurisdiction. For the reasons given above, there are compelling reasons to depart from Du Pont.

[152]

I note at this point that Professor Bunt refers to spot-on formulations as a subclass of pour-on formulations designed for use in companion animals, and consists of applying a small amount of the formulation (for example 1 ml) to the animal, typically to the back of the neck: Bunt 1 at [273]. In Professor Bunt's experience, the formulation considerations of a spot-on differ because they are applied in a smaller volume and so contain a higher concentration of the active ingredients, which also impacts the solvents that can be used to only those in which the active ingredient(s) are highly soluble, and as spot-ons are used for domestic animals, considerations such as smell and irritation to human skin must also be considered: Bunt 1 at [273]. Professor Bunt says that these considerations are less of an issue for pour-on formulations applied by farmers to livestock: Bunt 1 at [273]. Another difference between spot-ons for companion animals and pour-ons for livestock such as cattle is that formulators are less concerned with viscosity for spot-ons, because a much smaller quantity is applied in a spot-on, and often to a cat or a dog with the type of hair and skin where there is less of a risk of the composition running away than in a cattle product: Bunt 1 at [273].
The specification refers to various embodiments, and states that in some embodiments the compositions and methods comprise at least one of sixteen nominated anthelmintic compounds, among them being levamisole (page 6, lines 6-10). It is also stated that in some embodiments, the topical veterinary composition of the invention may comprise one of a very long list of solvents taking up about fifteen lines of text, among them being DMI and DMA towards the end of the list (page 6, lines 11-26). Other solvents in that list include benzyl alcohol, glycerol formal, dipropylene glycol n-butyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, NMP, diethylene glycol monoethyl ether and triacetin.
Under the heading "Detailed Description", it is stated that the compositions of the invention can be in a variety of forms suitable for different forms of administration including, but not limited to, oral formulations, injectable formulations and topical, dermal or subdermal formulations (page 7, lines 10-12). It is stated that in some embodiments of the invention, the compositions are preferably in a form that is suitable for topical administration, which includes spot-on formulations that are applied to a localised area on an animal, and topical pour-on formulations are also encompassed by the invention (page 7, lines 13-16). It is stated that in one embodiment, the compositions of the invention comprise at least one of avermectin or milbemycin compound, and in another embodiment at least one avermectin or milbemycin compound included in the compositions is abamectin, doramectin, eprinomectin, ivermectin, moxidectin or eight other nominated compounds (page 7, lines 22-26). The specification states that the invention includes at least a number of identified features, one of them being veterinary compositions comprising fipronil (which Professor Bunt identifies as an 1-arylpyrazole compound: Bunt 1 at [289]) in combination with at least one of abamectin, doramectin, eprinomectin, ivermectin, moxidectin or one of eight other nominated compounds, at least one IGR, and at least one anthelmintic compound or pharmaceutically acceptable salts, solvates or hydrates thereof, and a pharmaceutically acceptable carrier or diluent (page 8, lines 11-16).
Under the sub-heading "Definitions", the term "animal" is said to be used to include all mammals, birds and fish and also includes all vertebrate animals, including humans, and animals include (but are not limited to) humans, cats, dogs, cattle, chickens, cows, deer, goats, horses, llamas, pigs, sheep and yaks (page 9, lines 23-25). I note at this point that in Professor Bunt's experience, when developing products a formulator is typically concerned with administration to one animal and sometimes a specific sub-group within that animal (for example, dairy cows), and does not consider it realistic for the 984 Patent to claim it discloses formulations for use in such a broad range of animals: Bunt 1 at [293]. Professor Bunt says, and I accept, 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].
The specification states that the macrocyclic lactone compounds are well known in the art and can be obtained commercially or through known synthesis techniques (page 22, lines 5-6). It is stated that various types of anthelmintic agents (in addition to one or more macrocyclic lactone) may be used in the compositions of the invention (page 23, lines 33-34). As part of a very long list of embodiments, it is stated that the compositions may include an imidazothiazole compound including, but not limited to tetramisole, levamisole and butamisole (page 24, lines 8-9). In one of the preferred embodiments, it is said that the invention provides a composition comprising fipronil in combination with at least one of four compounds including eprinomectin and ivermectin, at least one of seven further compounds, and at least one of five compounds including levamisole, in combination with a pharmaceutically acceptable carrier or diluent (page 36, lines 3-9). Another preferred embodiment refers to fipronil in combination with at least one of eprinomectin, ivermectin, milbemycin oxime or moxidectin, and at least one of levamisole, febantel, pyrantel or praziquantel, with other active ingredients, in combination with a pharmaceutically acceptable carrier or diluent (page 36, lines 10-15).
It is said that the compositions of the invention, which include at least four different active agents in a carrier system that is compatible with each active agent, have been surprisingly discovered to be stable and effective against a broad spectrum of ectoparasites and endoparasites, and that it will be well apparent to one of skill in the art that the combination of multiple active agents in a single composition, without affecting the stability of the active agents during storage or the efficacy of each active upon administration, is extremely difficult and unpredictable (page 36, lines 26-32). It is stated that the four classes of active agents included in the inventive compositions have substantially different structures and consequently have different solubility and stability requirements, presenting a significant problem when including the multiple active agents in a single formulation, particularly in formulations that require the four active agents to be in solution (such as in spot-on or pour-on formulations) (page 36, line 32 - page 37, line 2). Further, it is said that the identification of a suitable carrier system to produce a stable composition comprising four different classes of active agents is challenging and unobvious (page 37, lines 8-9).
The specification then states that it is well known in the art that it is very difficult to formulate macrocyclic lactone active agents together with certain other actives due to different carrier requirements and the susceptibility of macrocyclic lactones to degrade in certain solvents (page 37, lines 10-12). It is stated that avermectins and milbemycins are poorly soluble in water and not compatible with acidic conditions, while some anthelmintic agents such as levamisole are more water soluble and require acidic pH for optimum stability (page 37, lines 12-15). It is stated that, therefore, the combination of four active agents, including a macrocyclic lactone, in a single liquid composition that is both stable for an extended period of time and efficacious against a broad spectrum of ectoparasites and endoparasites represents a significant achievement in the field of veterinary medicine that is not predictable or obvious (page 37, lines 22-25).
It is further stated that in a preferred embodiment of the inventive compositions, the composition will be in the form of a liquid solution or suspension, and the pharmaceutically acceptable carrier may be any suitable carrier or diluent commonly used in the formulation art, including aqueous or organic solvents or mixtures of solvents (page 39, lines 8-11). I note at this point that there is no requirement in the 984 Patent that the solvent system be non-aqueous. A list of organic solvents that can be used in the invention is said to include DMA, DMI and DEP and the full list comprises about fourteen lines of text (page 39, lines 12-27). The other organic solvents in the list include glycol ethers including propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol n-butyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, 2-pyrrolidone including NMP, glycerol formal and triacetin, or a mixture of at least two of these solvents.
The specification states that in some embodiments of the invention, the carrier comprises DMI, which is described as a high purity solvent and carrier which offers a safe, effective delivery enhancement mechanism for active ingredients in personal care products and pharmaceutical formulations (page 40, lines 17-20). It is stated that DMI is sometimes used as an epidermal penetration enhancer, and it may also provide delivery of active agents into the skin while avoiding crystallisation of the active agent which would severely limit the effectiveness of the formulation (page 40, lines 20-24).
In another embodiment of the invention, it is said that the composition can be in paste form, and the paste can contain various products including a viscosity modifier (page 43, lines 27-32). It is stated that in a preferred embodiment of the invention, compositions suitable for topical administration to an animal are provided, and that topical, dermal and subdermal formulations can include emulsions, creams, ointments, gels, pastes, powders, shampoos, pour-on formulations, ready-to-use formulations, spot-on solutions and suspensions (page 45, lines 2-5). Dr Alawi accepted that an emulsion, paste, gel or cream would contain water: T255.1-3, 258.1-14. Plainly enough, these forms do not necessarily comprise a solution in which the ingredients are dissolved: Dr Alawi at T256.21-24.
In another preferred embodiment, it is stated that the compositions of the invention for topical administration will comprise one or more of over ten options, two of them being DMI and NMP (page 46, lines 27-31). The other options are an alcohol including ethanol or isopropanol, propylene glycol, 2-pyrrolidone, NMP, dimethylsulfoxide, glycerol formal, glycerol ethers including diethylene glycol monoethyl ether, diethylene glycol monomethyl ether and the like, or mixtures thereof. In another preferred embodiment, the topical compositions of the invention will comprise glycerol formal, DMI, NMP, diethylene glycol monoethyl ether, or mixtures thereof (page 46, lines 32-34). It is stated that pour-on formulations may be administered to large stock animals such as cattle and sheep (page 47, lines 13-14).
The specification states that typically the formulations of the invention will comprise about 0.01% to about 10% (w/v) of the macrocyclic lactone active agent(s), and more typically, the formulations will contain about 0.01% to about 5% or about 0.01% to about 2% (w/v) of the macrocyclic lactone active agent(s), and preferably the formulations will contain about 0.1% to about 5% or about 0.1% to about 1% (w/v) of the macrocyclic lactone active agent(s) (page 48, lines 12-16). In another embodiment, the formulations will include about 0.01% to about 5% of at least one macrocyclic lactone(s) and about 5% to about 15% (w/v) of at least one anthelmintic active agent(s) (page 48, lines 26-29). In another embodiment, the compositions will include about 0.01% to about 2% (w/v) of at least one of eprinomectin, ivermectin, selamectin, moxidectin or another named macrocyclic lactone, and about 5% to about 15% (w/v) of at least one of over twenty compounds including levamisole (page 49 line 33 to page 50 line 9). In one preferred embodiment, the compositions comprise about 5% to about 15% (w/v) of fipronil, about 0.01% to 2% (w/v) of at least one of eprinomectin, ivermectin, milbemycin oxime or moxidectin, about 5% to about 15% (w/v) of at least one of (S)-methoprene, pyriproxyfen or lufenuron, and about 5% to about 15% of at least one of febantel, levamisole, pyrantel or praziquantel (page 50, lines 10-14). In another preferred embodiment, the compositions of the invention are said to comprise about 8% to about 12% (w/v) of fipronil, about 0.01% to about 1% (w/v) of at least one of eprinomectin, ivermectin, milbemycin oxime or moxidectin; about 8% to about 12% (w/v) of at least one of (S)-methoprene, pyriproxyfen, or lufenuron; and about 8% to about 12% (w/v) at least one of febantel, levamisole, pyrantel, or praziquantel (page 50, lines 14-19).
It is stated that in some embodiments of the invention, an emollient and/or spreading and/or film-forming agent may be added to the topical compositions of the invention, and in some embodiments the emollient and/or spreading and/or film-forming agents include a very long list of items, two of them being polyvinylpyrrolidone and polyethylene glycols (page 50, lines 20-24). I note at this point that those two products were identified in the Specification of the Patent as viscosity enhancers. It is stated that in one embodiment, the emollient is used in a proportion from about 0.1% to about 10%, or about 0.25% to about 5% (w/v) (page 51, lines 15-16).
It is stated that the volume of the topical composition applied is not restricted as long as the amount of the substance administered is shown to be safe and efficacious (page 53, lines 8-9). For spot-on compositions, the volume applied is said to be typically of the order of about 0.1 ml to about 1 ml, or about 0.1 ml to about 5 ml, or about 0.1 ml to about 10 ml, and for larger animals, the volume may be higher including up to 30 ml or higher (page 53, lines 11-15).
It is stated that the compositions and methods of the invention are effective against ectoparasites, and are also effective against endoparasites including (among others) nematodes (page 54, lines 5-8). As noted above, the Specification of the Patent refers to two particular nematodes, namely Cooperia and Ostertagia. It is stated that in one embodiment, the invention provides methods for the treatment and prevention of parasitic infections and infestations of animals (either wild or domesticated), including livestock and companion animals such as cats, dogs, horses, chickens, sheep, goats, pigs, turkeys and cattle, with the aim of ridding these hosts of parasites commonly encountered by such animals (page 54, lines 11-15). In a preferred embodiment, it is said that the invention provides methods and compositions for the treatment or prevention of parasitic infections and infestations in companion animals including cats and dogs, and in a particularly preferred embodiment of the invention, the methods and compositions described are used to prevent or treat parasitic infections or infestations in cats (page 54, lines 16-20).
The compositions of the invention are said to be made by mixing the appropriate amount of the active agents, pharmaceutically acceptable carrier or diluent and optionally a crystallisation inhibitor, antioxidant, preservative, film-former, etc, to form a composition of the invention (page 60, lines 2-4). It is said that various forms (eg, tablets, pastes, pour-on, spot-on, collars, etc) of the composition can be obtained by following the method of making these forms found in general formulation texts known to those in the art, some examples of which are then set out (page 60, lines 5-7). It is said that the inventive formulations may contain other inert ingredients such as antioxidants, preservatives, or pH stabilisers, and among the antioxidants referred to is BHT (page 60, lines 12-16). The antioxidants are generally added to the formulation in amounts of from about 0.01% to about 2.0%, based upon total weight of the formulation, with about 0.05% to about 1.0% being especially preferred (page 60, lines 17-19).
Under the heading "Examples", it is said that the invention is further described by the five non-limiting examples which are then set out, which are said to further illustrate the invention but do not limit its scope (page 63, lines 21-23). Examples 1 to 4 refer only to cats, and deal in turn with the efficacy of the invention against fleas, ticks and endoparasites, and the effect of the eprinomectin dose against endoparasites (pages 63-68). None of the examples refer to levamisole, and examples 1, 3 and 4 do not refer to solvents.
Example 5 deals with the stability of the formulation at 30ºC (pages 68-69). It is said to be surprising that the formulations of the invention having four active ingredients with substantially different physicochemical properties, including solubility and solvent compatibility, could be successfully formulated into a stable composition in one pharmaceutically acceptable carrier system (page 68, line 16 - page 69, line 1). It is stated that the stability of each active in a preferred composition of the invention comprising fipronil, (S)-methoprene, eprinomectin and praziquantel in a carrier comprising glycerol formal and DMI was evaluated at 30ºC using high performance liquid chromatography, and the study demonstrated that each active in the composition was stable in solution for up to twenty-four months at 30ºC in the presence of the other compounds (page 69, lines 1-6). I note that praziquantel was used in the study rather than levamisole. A graph is then set out showing the stability of one of the formulations for periods up to 24 months at 30ºC (page 69).
The invention is further described by numbered paragraphs, which correspond to the twenty claims which are later made.
Paragraph 1 (page 69, line 17 - page 70, line 4) is as follows:

[154]

Professor Bunt refers to claim 1 (which corresponds to paragraph 1 extracted above) as claiming a combination product comprising at least four active ingredients, but not specifying a mode or form of administration, a target animal or parasite, or the specific active ingredients that are to be used within each category, nor specifying any particular solvent or solvents (or whether it is to be in an aqueous or non-aqueous system): Bunt 1 at [373]. Professor Bunt says that the reference to a crystallisation inhibitor suggests to him that the claim may be directed towards solutions, and reflects the difficulty involved in combining four different active ingredients with different solubility properties into a single solution: Bunt 1 at [374]. Professor Bunt says that it is also consistent with his view that the 984 Patent is largely directed at spot-on formulations for cats, as crystallisation inhibitors are more often used in smaller volume formulations rather than the larger volume for pour-ons, as the formulator of a pour-on has much more volume to enable adequate dissolution of the active ingredients with less risk of them precipitating out of solution: Bunt 1 at [374].
Paragraph 7 (corresponding to claim 7) refers to the topical veterinary composition of paragraph 1, wherein the at least one macrocyclic lactone active agent is an avermectin or milbemycin.
Paragraph 8 (corresponding to claim 8) refers to the topical veterinary composition of paragraph 7, wherein the avermectin or milbemycin is one of seven compounds, including ivermectin or moxidectin. As Professor Bunt points out, these paragraphs are dependent on paragraph 1, and thus while the preferred selections from the macrocyclic lactones are disclosed, these must still be in combination with the other three classes of compounds required by paragraph 1: Bunt 1 at [386].
Paragraph 10 refers to the topical veterinary composition of paragraph 1, wherein the at least one anthelmintic active agent is one of sixteen nominated candidates, including levamisole (page 72, lines 21-25).
Paragraph 11 refers to the topical veterinary composition of paragraph 1, wherein the pharmaceutically acceptable carrier is one of a lengthy list of compounds, one of them being a glycol ether (page 72, line 26 - page 73, line 6).
Paragraph 12 refers to the topical veterinary composition of paragraph 1, wherein the pharmaceutically acceptable carrier is one of a list of some twenty-seven options, three of them being glycerol formal, DMI and DMA (page 73, lines 7-15).
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:

[155]

(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.

[156]

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].

[162]

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 [2009] EWCA Civ 1362; [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.

[163]

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.

[165]

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] HCA 8; (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.

Abbey Laboratories Pty Ltd v Virbac

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