Validity: inventive step
317 An invention is only a patentable invention for the purposes of a standard patent if the invention, as claimed, involves an inventive step when compared with the prior art base as it existed before the priority date of the claim: s 18(1)(b)(ii) of the Act.
318 Subsections 7(2) and 7(3) of the Act are important in determining when an invention will be taken to involve an inventive step.
319 Subsection 7(2), as applicable to the present case, is as follows:
For the purposes of this Act, an invention is to be taken to involve an inventive step when compared with the prior art base unless the invention would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed in the patent area before the priority date of the relevant claim, whether that knowledge is considered separately or together with the information mentioned in subsection (3).
320 Subsection 7(3), as applicable to the present case, is as follows:
The information for the purposes of subsection (2) is:
(a) any single piece of prior art information; or
(b) a combination of any 2 or more pieces of prior art information;
being information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood, regarded as relevant and, in the case of information mentioned in paragraph (b), combined as mentioned in that paragraph.
321 Apotex contended that the invention claimed in each of the challenged claims does not involve an inventive step. It contended that the question should be approached by adopting a problem-solution approach, where the solution is the invention as claimed. It relied, in part, on certain observations made by Aickin J in The Wellcome Foundation Limited v V.R. Laboratories (Aust.) Proprietary Limited (1981) 148 CLR 262. In that case, the High Court was dealing with the question of whether discovery should be ordered of documents relating to the patentee's research and experiments leading to the invention as claimed. This involved consideration of the admissibility of evidence of a patentee's own research and experimentation for the purpose of demonstrating that, at the relevant time, the invention was obvious. His Honour said (at 286):
… In more recent authorities discovery has been ordered to enable those attacking the patent to search for material which may suggest that all that the inventor actually did was to take a series of routine steps or make a series of routine experiments. It is still correct to say that a valid patent may be obtained for something stumbled upon by accident, remembered from a dream or imported from abroad, if it otherwise satisfies the requirements of the legislation. What is important is that the patent itself should involve an inventive step, whether or not it was consciously taken by the patentee and whether or not it appeared obvious to the patentee himself. …
322 His Honour followed this by stating:
… 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 the steps of the inventor or not.
[Emphasis added]
323 The applicability, in appropriate cases, of a problem-solution approach to determining whether a claimed invention involves an inventive step is supported by a number of authorities. These authorities are discussed in Apotex Pty Ltd (ACN 096 916 148) v Sanofi-Aventis and Others (2009) 82 IPR 416 at [145]-[159]. It is not necessary to repeat that discussion for present purposes save to note that, as Bennett and Middleton JJ cautioned (at [159]), the analysis of whether an invention involves an inventive step is not confined to a problem-solution approach.
324 Apotex accepted that a problem-solution approach might not always be appropriate. It argued, however, that such an approach was appropriate in the present case because a problem is stated on the face of the complete specification: "prior art" aripiprazole is undesirably hygroscopic.
325 Apotex then advanced what it identified as a separate argument: s 18(1)(b)(ii) of the Act effected a change in the law with respect to identifying an inventive step by invoking a comparison between the invention as claimed and the prior art base, which relevantly includes a document that is publicly available, whether in or out of the patent area, and whether or not the information in it is part of the common general knowledge. In developing this argument, Apotex pointed to the same comparison expressed in the opening words of s 7(2) of the Act: "… an invention is to be taken to involve an inventive step when compared with the prior art base …". Apotex submitted that there is now a statutory starting point (the prior art base) and a finishing point (the invention as claimed) which must be compared to identify the step to be assessed for inventiveness in light of the common general knowledge.
326 It is not clear to me how this separate argument sits with the problem-solution calculus of its first argument, which posits the problem and not the prior art base as the starting point for identifying and assessing the step whose inventiveness is in issue. It is not necessary, however, for me to dwell on whether and, if so, how the two arguments can or should be reconciled because I am not persuaded that Apotex's separate argument should be accepted. It has been rejected on at least three prior occasions in first instance decisions of the Court: Sanofi-Aventis Australia Pty Ltd and Others v Apotex Pty Ltd (No 3) (2011) 196 FCR 1 at [229]-[230]; Wake Forest University Health Sciences and Others v Smith & Nephew Pty Ltd (ACN 000 087 507) and Others (No 2) (2011) 92 IPR 496 at [701]-[717]; Apotex Pty Ltd v AstraZeneca AB and Another (No 4) (2013) 100 IPR 285 at [216]-[217]. I am not persuaded that those decisions are plainly wrong. It is appropriate, therefore, that I follow them.
327 The rejection of Apotex's additional argument is, perhaps, of no real consequence in the present case when regard is had to the way in which Apotex developed its first argument. Apotex submitted:
The 141 application forms part of the starting point. Its equivalent - the Japanese unexamined patent publication - is cited in the complete specification of the patent as background to the invention.
The 141 application is, in any event, a document that would be ascertained, understood, and regarded as relevant by the person skilled in the art and would, therefore, be considered: s 7(3) of the Act.
There is no inventive step in removing ethanol from the product of recrystallisation obtained by following the directions of lines 5 to 15 of Example 1 of the 141 application.
328 Apotex submitted that the present case is unusual because "there is no question, as a matter of fact, that the very polymorph that is claimed forms part of the problem, or the starting point: Mr Aoki's Type-I crystals". Apotex continued:
… To the extent that an improved hygroscopicity profile is claimed, it was simply an inherent characteristic of that polymorph. Otsuka may have invented a method of preventing the conversion of type-I to the monohydrate by milling first then drying, but that does not confer novelty on Type-I renamed as Crystals B. Claims 12, 13 and 16 are not confined by questions of purity or industrial scale. …
329 Apotex also submitted:
… There was no barrier to cross in the context of an inventive step analysis of the product, per se.
330 The applicants submitted that a problem-solution approach should not be adopted when determining, in the present case, whether the invention as claimed involves an inventive step. The applicants submitted that:
… there are no words in the legislation which require that there be a problem to be solved before one can have an inventive step. The issue is at large. The question is whether it was obvious to move from the common general knowledge to the claimed invention. The common general knowledge may or may not include a "problem" to be solved. A recognised objective indicium of invention is the circumstance where a problem has been recognised in the common general knowledge as requiring a solution which is satisfied by the claimed invention. That is an example of "longfelt want".
However, an objective indicium of invention can also be the satisfaction of an "unfelt want" as the High Court recognised in Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd (1981) 148 CLR 262 at 287.4. In such a case, part of the inventive step includes the perception that although not recognised by others in the field, a particular product or method could provide a key and distinct therapeutic advantage.
[Footnote omitted]
331 With specific reference to the application of the deeming provision of s 7(2) of the Act, the applicants submitted:
… the "starting point" approach is incompatible with the provisions of the Act and thus incorrect as a matter of principle. Inventive step is to be assessed in accordance with s 7(2). That provision deems an inventive step to be present "unless the invention would have been obvious to a person skilled in the relevant art" in the light of the common general knowledge with any available s 7(3) information. There is no room for any resort to information which is not either part of common general knowledge or available under s 7(3). In particular, there is no room for any resort to information simply because it is referred to in the specification of the patent, whether it be expressed as a "starting point" or problem to be addressed or otherwise.
332 The applicants also pointed to two factual matters. They submitted that Apotex had not proved that either aripiprazole or the hygroscopicity problem associated with conventional anhydrous aripiprazole crystals were part of the common general knowledge before 25 September 2001. I accept that these facts have not been established.
333 I do not find it necessary to resolve the parties' competing positions on the correct framework to be used when considering the question of inventive step in the present case. I will proceed by assuming, but without deciding, that a problem-solution approach is the correct framework to adopt in the present case, in order to evaluate the cogency of Apotex's case on obviousness advanced on that particular basis. Proceeding in that way, the question then arises as to what information is to be taken as comprising the starting point. Undoubtedly, knowledge of the existence of conventional anhydrous aripiprazole crystals and the fact that those crystals can exhibit unacceptably high hygroscopicity would be part of the starting point. However, I doubt that knowledge of the 141 application itself would be part of the starting point simply because, as Apotex contended, it is cited in the complete specification as background to the invention.
334 Nevertheless, I am prepared to find, perhaps somewhat generously in Apotex's favour, that the person skilled in the art would reasonably be expected to have ascertained the existence of the 141 application. Dr Rowe gave evidence that if, as a pharmaceutical formulation chemist, he was faced with the problem of overcoming the disadvantage that anhydrous aripiprazole crystals are significantly hygroscopic, he would review, as a first step, the physicochemical information relating to aripiprazole. If not provided with that information, he said that, in 2001, he would have requested a literature search to be undertaken on his behalf by a specialised searcher using search terms that he had specified. He referred to the existence of electronic databases that index journal articles and patents relating to pharmaceuticals. There is no evidence, however, of the likely results that would have been obtained by conducting a search of the electronic databases that Dr Rowe identified using appropriate search terms prior to 25 September 2001.
335 Professor Easton gave evidence of carrying out a literature search using SciFinder. SciFinder is an online database of chemistry and other science-related information, containing research papers, information about chemical substances, chemical suppliers, and the like. Professor Easton said that, if carrying out a literature search in September 2001, he would have used SciFinder. In the present case, he searched for references to aripiprazole, its molecular formula, and its CAS registry number through the "substance identifier" feature of SciFinder. A CAS registry number is an identifying number assigned to a compound when it is first included in the SciFinder database. The 141 application was one of the documents he found searching in this manner.
336 Although SciFinder is not a source to which Dr Rowe referred, I am persuaded by Dr Rowe's evidence and Professor Easton's evidence that electronic search tools were available to the person skilled in the art as at 25 September 2001 and that, in all likelihood, resources of that nature would have been used by the person skilled in the art seeking to obtain information with respect to aripiprazole. I am further persuaded by Professor Easton's evidence that, on balance, the person skilled in the art undertaking such a search at that time would have been likely to have found the 141 application.
337 I am also satisfied that if, prior to 25 September 2001, the person skilled in the art had located the 141 application, he or she would have understood it and regarded it to be relevant to aripiprazole.
338 Based on these findings, it does not matter whether, as Apotex contended, the 141 application is taken as part of the starting point. It is certainly prior art information that, by dint of s 7(3) of the Act, is to be taken to be available to the person skilled in the art for the purpose of applying s 7(2) of the Act. However, as I have found above, there is no disclosure in the 141 application that aripiprazole crystals can exhibit unacceptably high hygroscopicity or that suitable heating can or should be undertaken to avoid obtaining crystals with unacceptably high hygroscopicity. In my view, if, before 25 September 2001, the person skilled in the art were to be presented with the 141 application, he or she would be no wiser about the postulated problem of significant hygroscopicity in anhydrous aripiprazole crystals or how to solve that problem.
339 Apotex's submission proceeds on the assumption that the person skilled in the art, on being armed with the 141 application, would be motivated to "remove" ethanol. I have accepted that the person skilled in the art might be motivated to obtain anhydrous aripiprazole crystals in their free base form: see [256] to [257] above. But this would not be to address a problem of significant hygroscopicity. Perhaps more importantly, Apotex's submission proceeds on the basis that the removal of ethanol to obtain anhydrous aripiprazole crystals in their free base form is equivalent to achieving anhydrous aripiprazole crystals having the characteristic low hygroscopicity of Crystals B. I do not accept that to be the case. Once again, Apotex's case proceeds on its central contention, which I have rejected, that a given crystalline form of aripiprazole will have, inevitably, a given hygroscopicity. Moreover, as I have found, I am not persuaded that, by following the directions of lines 5 to 15 of Example 1 of the 141 application prior to 25 September 2001, the person skilled in the art would inevitably have obtained Crystals B when seeking to obtain anhydrous aripiprazole crystals in their free base form: see [277] above. In my view, therefore, the 141 application does not advance Apotex's case on lack of inventive step in any material way.
340 In my view, even adopting Apotex's preferred framework of a problem-solution approach, the invention, as relevantly claimed, is far from obvious. Using that framework, the question would be whether, before 25 September 2001, the person skilled in the art would be directly led as a matter of course to take the steps that result in Crystals B with their characteristic low hygroscopicity, in the expectation that those steps might well produce those crystals: Aktiebolaget Hässle and Another v Alphapharm Pty Limited (2002) 212 CLR 411 at [50]-[53]; Alphapharm Pty Ltd (ACN 002 359 739) v H Lundbeck A/S and Another (2008) 76 IPR 618 at [180]; Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth and Another (2010) 88 IPR 459 at [251]-[252].
341 Apotex's case on lack of inventive step was advanced principally through Dr Rowe's evidence. I turn to consider that evidence.
342 Dr Rowe said that, in his experience, hygroscopicity issues were, in the work of pharmaceutical formulation chemists, addressed in the formulation process by chemical means or physical means, or a combination of both.
343 In his first affidavit, Dr Rowe gave the following evidence with respect to chemical means that would be adopted to address hygroscopicity issues:
53. Addressing hygroscopicity issues by chemical means involves identifying a form (ie, a polymorph, solvate or salt) of the pharmaceutical compound which is not hygroscopic or is less hygroscopic. Different polymorphs, solvates and salts of a pharmaceutical compound commonly have different physicochemical properties, such as different degrees of hygroscopicity …
54. If a non-hygroscopic form of the pharmaceutical compound was identified in preformulation studies, this form, whether it be a particular polymorph, solvate or salt, would normally have been used in the pharmaceutical formulation, subject to its overall suitability (for example, having suitable bioavailability).
55. In my experience as at September 2001, information about polymorphic forms of a pharmaceutical was routinely obtained during the preformulation stages of pharmaceutical development … This information was routinely obtained and available to a formulation chemist working with the pharmaceutical because it was required to develop a pharmaceutical and to satisfy regulatory requirements …
344 Later in his first affidavit, Dr Rowe said that, absent relevant information obtained by search, he would have obtained analytical studies from a sample of aripiprazole to determine its physicochemical properties. In that connection, he gave this evidence:
63. These analytical studies would include studying the existence of polymorphs of aripiprazole. As part of these analyses, I would have attempted to prepare different polymorphs of aripiprazole by:
(a) Heating samples of aripiprazole to determine whether a polymorphic conversion occurred.
(b) Recrystallising samples of aripiprazole from different solvents to determine whether different crystalline forms were recrystallised from different solvents. In September 2001, ethanol would have been the first solvent I would have used, and I would have used both pure ethanol, and aqueous ethanol (ie, ethanol containing water). Other solvents I would have used as at September 2001 after ethanol were acetonitrile, ethyl acetate, butyl acetate, chloroform, dichloromethane and hexane.
(c) Studying the effect of grinding and compression on the polymorphic form of aripiprazole.
345 He also gave this evidence:
65. If the polymorphic studies indicated that aripiprazole was capable of existing in more than one polymorphic form, I would have studied the physicochemical properties, including hygroscopicity, of each polymorph. For example, to study hygroscopicity I would have exposed samples of different polymorphs of aripiprazole to various levels of moisture and temperature to determine how much moisture they take up, and which polymorphs are less hygroscopic and more suitable for development to address the Aripiprazole Scenario. If aripiprazole existed in more than one polymorphic form, I would have expected to identify different polymorphic forms of aripiprazole. I would also have expected that some of the polymorphs would be less hygroscopic than other polymorphs.
346 This evidence suggests that, even with a focus on polymorphs, it would have been necessary for the person skilled in the art, before 25 September 2001, to have engaged in a significant research project to attempt to discover how the hygroscopicity problem with anhydrous aripiprazole crystals might be solved using different polymorphic forms of aripiprazole. It does not suggest an obvious solution to a given problem. Indeed, it bespeaks no more than the speculative possibility of a solution which is presently unknown and, perhaps, unattainable.
347 Dr Rowe was cross-examined on this evidence insofar as it relates to an investigation of different polymorphs as a chemical means to overcome hygroscopicity issues. He was confronted with evidence given by him in another proceeding in which he said that, in his experience, polymorphs are not considered for their impact on hygroscopicity. To say the very least, that view sits uncomfortably - indeed, discordantly - with Dr Rowe's evidence quoted above. Under cross-examination, Dr Rowe effectively resiled from the thrust of his evidence-in-chief quoted above. He confirmed for the purposes of the present case that, as a general rule, polymorphs are not considered for their impact on hygroscopicity. Indeed, he said that, in his experience, different polymorphs which he had produced "have not shown great differences in hygroscopicity". In the course of seeking to explain why a discussion of polymorphs featured so prominently in his first affidavit, as quoted above, Dr Rowe accepted that his evidence was influenced by an assumption he made or inference he drew that the patent in suit was one concerning polymorphs of aripiprazole. He said that, but for that assumption or inference, the above quoted passages might "have read differently". This explanation does not, however, engage why Dr Rowe was prepared to advance, as matters of fact, seemingly contradictory positions with respect to the utility of considering different polymorphic forms of a given compound in order to overcome a problem of hygroscopicity exhibited by that compound.
348 It then emerged in cross-examination that, if confronted with the problem of hygroscopicity as at September 2001, Dr Rowe's first approach would have been to consider simple physical means, about which he gave the following evidence in his first affidavit:
56. Depending on the nature of the hygroscopicity issues, hygroscopicity was, in my experience as at September 2001, often controlled in manufacture and storage of a pharmaceutical composition. There were a number of techniques routinely used, if appropriate, to physically control hygroscopicity.
57. As at September 2001, there were, in my experience, a variety of physical measures available to control hygroscopicity. For example, the following measures were used:
(a) Manufacturing the pharmaceutical composition in a low humidity environment, ie, an environment in which there is very little or no water vapour present in the air. The absence of water in the environment means that the hygroscopic pharmaceutical compound cannot take up water from the environment.
(b) Selecting excipients to include in the formulation, such as microcrystalline cellulose and mannitol, that tend to prevent moisture being taken up by the pharmaceutical and the pharmaceutical formulation.
(c) Coating the particles of the pharmaceutical to be formulated with a water impermeable coat (microencapsulation).
(d) Coating the pharmaceutical composition (eg, a tablet) with a water impermeable substance to prevent water from permeating into the tablet.
(e) Adding silica gel, for example in a sealed sachet, to the container in which the formulated product is stored.
58. These physical means can alleviate or minimise the hygroscopicity problem. However, they also increase the cost of production and storage (as relevant) of the pharmaceutical composition. In the case of some hygroscopic compounds these physical means cannot be used to control hygroscopicity to the extent necessary to prepare a solid oral dosage form.
349 He accepted that the above means would be one obvious solution to the problem of hygroscopicity. When asked in re-examination why his first approach would be to consider physical means, he said:
… Well, they're, in fact, the simplest way and, certainly, in my experience and, also, I believe, my [colleagues'] experience, most of the problems can be solved by simple physical means. And by that I mean things like low humidity manufacturing areas, the use of oil packaging in the final tablets, the use of certain excipients and silicone dioxide to mop up moisture and so forth. And then once the drug in a dosage form is in a foil pack, the likelihood of water getting through is extremely small. But that would be borne out in stability studies. That's - that's purely from the point of view of ease rather than looking at something else because if you look at a new salt or polymorph, to the TGA that's a new drug substance, and you will have to do more viability studies, stability studies, it's very expensive and time consuming.
350 He accepted that another obvious solution would be to attempt to use a salt form of the compound. He said that this would have been his personal preference as at September 2001 after having first investigated physical means to solve the problem. Tellingly, Dr Rowe accepted that it would not have occurred to him, as a solution to the problem, to "stay within the same polymorph" and to heat it.
351 Professor Easton agreed that the physical means proposed by Dr Rowe could be possible means for controlling hygroscopicity with respect to aripiprazole. He said that, alternatively, he would have considered investigating a liquid formulation for the drug. He said that, if that approach was not successful, he would consider different forms of aripiprazole, being salts, polymorphs, and solvates, with the investigation of salts being his "strong preference". He said that he would not have given high priority to investigating solvates and polymorphs and that approach was not, in his experience, routine in September 2001 or now.
352 Nevertheless, he gave the following evidence in his second affidavit:
105. If I had ultimately decided to start investigating solvates and polymorphs as a way to address the problems identified in lines 1-3 of the [patent], I would have first tried to recrystallise from different solvents. That process is simply trial and error, and might or might not result in a different solvate or polymorph.
106. In my experience, recrystallisation is the most common way to investigate whether a new polymorph exists. I am also aware of trying, and have in the past tried, sublimation, pressure, heating and grinding. Sublimation is heating under reduced pressure so that a material converts from solid directly to vapour, then condenses directly to solid, so as to minimise the likelihood of decomposition associated with liquid intermediate phases.
107. I would have tried grinding because I know from my experience with cyclodextrins that it might work. However, from my experience, I would not have expected this approach to have a high likelihood of success because I regularly grind materials to obtain particular particle sizes and do not see polymorphs. … grinding is also used to prepare samples for XRPD analysis and the assumption is that the grinding will not change the crystal form.
108. I would have tried heating only as a last resort after trying recrystallisation from different solvents because heating generally leads only to melting and perhaps decomposition. If and when a solid reforms by condensing the melted liquid, it is common to obtain a solid block or amorphous material, rather than a free-flowing crystalline product.
353 Professor Easton accepted in cross-examination that, if melting and decomposition were concerns on heating, it was possible to test a small sample before proceeding. Notwithstanding that acceptance, Professor Easton's evidence strongly supports the conclusion that the solution to the unacceptable hygroscopicity of anhydrous aripiprazole crystals was far from obvious.
354 Finally, the evidence of Otsuka's own research effort assists in concluding that the solution was far from obvious. The applicants pointed to Mr Aoki's evidence, supported by Otsuka's internal research reports, that it took many years to produce a low hygroscopic form of aripiprazole. The applicants submitted that the "road to a low hygroscopic form of aripiprazole was long and arduous and involved multiple scientists, many years of experimentation, including multiple clinical studies, with failures and a range of problems along the way". I accept that submission.
355 In Hässle at [58], the High Court said:
58 … The tracing of a course of action which was 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 was taken as a matter of course. In [In the Matter of I.G. Farbenindustrie A.G.'s Patents [1930] 47] RPC 289 at 322, Maugham J had said that while "mere verification is not invention", what he likened to the citadel of invention "may be captured either by a brilliant coup-de-main or by a slow and laborious approach by sap and mine according to the rules of the art; the reward is the same."
356 For these reasons, Apotex's contention that the challenged claims do not involve an inventive step does not succeed. Absent the adoption of a problem-solution approach, it follows, even more so, that Apotex's contention cannot succeed. As I have noted, Apotex did not prove that either aripiprazole or the hygroscopicity problem associated with anhydrous aripiprazole crystals were part of the common general knowledge before 25 September 2001.
357 There is a remaining issue to which I should refer concerning the challenge to claim 16. It is to be recalled that claim 16 claims Crystals B with a mean particle size of 50 microns or less. Apotex contended that milling to a size of less than 50 microns was straightforward to the person skilled in the art as at 25 September 2001. Implicit in that contention was that milling to a size of less than 50 microns would not itself provide any missing inventive step. It is not necessary to deal with that contention because I am satisfied that the combination claimed by claim 16, including, as it does, Crystals B, does involve an inventive step.
358 A related argument advanced by Apotex was that there is no working interrelationship between Crystals B and particle size - the crystal form in question is simply made smaller by means well within the common general knowledge. Apotex contended that claim 16 "is not a truly new combination". I do not accept that argument. Dr Rowe's evidence, which Apotex advanced, was that the particle size of the pharmaceutical can influence the rate of dissolution in the body and can therefore impact on bioavailability. He said that particle size may also affect the manufacturing process, in particular, the flow properties of a powder during manufacture, the distribution of the pharmaceutical within a pharmaceutical formulation, and the stability of a pharmaceutical. This evidence removes the foundation for Apotex's contention that the combination claimed in claim 16 of the patent is not a proper combination.