(a) Inventive step
58 A patentable invention, so far as claimed in any claim, must involve an inventive step when compared with the prior art base at the priority date.
59 The respondents bear the onus of establishing that the claimed invention lacks an inventive step over the prior art.
60 The Court must find an inventive step, unless "the invention would have been obvious to a person skilled in the relevant art" at the priority date. The word "obvious" means "very plain" (Aktiebolaget Hassle v Alphapharm Pty Ltd (2002) 212 CLR 411 at [34] and [85]). A "scintilla of inventiveness" is sufficient; alternatively expressed, "no smallness or simplicity will prevent a patent being good" (Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1997) 137 CLR 228 at 249 per Aickin J).
61 Whether the invention would have been obvious is determined by comparing the claimed invention with the common general knowledge alone, or with that knowledge and s 7(3) information.
62 Given that expert evidence has been filed on this topic in the present case, I should observe the following.
63 First, it is impermissible hindsight for an expert witness to be led to the invention by a series of specific questions framed by a person with knowledge of the claimed invention.
64 Second, inventive step cannot be assessed by resort to information or knowledge of the invention or information about any prior art gained through knowledge of the Patent. That involves a hindsight enquiry after the priority date, contrary to ss 7(2) and 7(3). In AstraZeneca AB v Apotex Pty Ltd (2014) 312 ALR 1, at [202]-[203], the Court said:
[W]hether a claim of a patent is invalid for lack of inventive step is to be determined by comparing the invention, so far as claimed, against the common general knowledge and any s 7(3) information. The question is then whether the invention would have been obvious to the hypothetical person skilled in the art in light of that knowledge considered separately from, or together with, the s 7(3) information. So understood, it is apparent that the relevant provisions of the Act do not expressly or impliedly contemplate that the body of knowledge and information against which the question whether or not an invention, so far as claimed, involves an inventive step is to be determined may be enlarged by reference to the inventor's (or patent applicant's) description in the complete specification of the invention including, in particular, any problem that the invention is explicitly or implicitly directed at solving.
If the problem addressed by a patent specification is itself common general knowledge, or if knowledge of the problem is s 7(3) information, then such knowledge or information will be attributed to the hypothetical person skilled in the art for the purpose of assessing obviousness. But if the problem cannot be attributed to the hypothetical person skilled in the art in either of these ways then it is not permissible to attribute a knowledge of the problem on the basis of the inventor's "starting point" such as might be gleaned from a reading of the complete specification as a whole…
65 Third, and relatedly, as Aickin J observed in Minnesota Mining & Manufacturing Co v Beiersdorf (Australia) Ltd (1980) 144 CLR 253 at 293:
When once an idea … has been published, it is very easy to say after perhaps months of search and study in the Patent Office and the public libraries that the integers into which the patent might be dissected could be found scattered amongst the prior documents by a person who already knew the solution to the problem and therefore knew what to look for and what to discard. But that process does not demonstrate lack of an inventive step. The opening of a safe is easy when the combination has already been provided.
66 Fourth, an egregious form of impermissible hindsight has been the situation where a witness has been shown the patent specification in suit at a stage prior to that witness giving evidence that there was no inventive step involved (PAC Mining Pty Ltd v Esco Corporation (2009) 80 IPR 1).
67 Much of the respondents' arguments on this ground of invalidity made much of what had occurred in the US in relation to a corresponding patent application.
68 The respondents made much of the fact that, in assessing the obviousness of the corresponding US patent application, the US examiner noted significant disclosures in each of the Radebaugh (Tylenol) Patent (EP 0 305 051) and the Clemente Patent.
69 The respondents assert that each of the Radebaugh Patent and Clemente Patent are documents that the skilled addressee could, before the priority date of the relevant claims, be reasonably expected to have ascertained, understood, and regarded as relevant to work in the relevant art in Australia (see s 7(3) as it stood at the relevant date).
70 The respondents have pointed to the following matters described in the Radebaugh Patent, considered alone:
(a) A bilayer tablet (p 5, lines 4-10, example 1), comprising;
(i) an immediate release phase of Acetaminophen [paracetamol] in one layer (see p 5, lines 4-10, example 1);
(ii) a sustained release phase of Acetaminophen in another layer (see p 5, lines 4-10, example 1);
(iii) 50% by weight of the Acetaminophen in the immediate release layer (see example 1);
(iv) 50% by weight of the Acetaminophen in the sustained release layer (see example 1);
(v) a matrix forming polymer in an amount from 0.5 to 10% by weight of the sustained release phase (see p 4, lines 45-47; example 1);
(vi) 600-700mg Acetaminophen per unit dose (see p 7, line 3); and
(vii) a mean plasma concentration of at least 3mcg/ml for at least 1.3 hours longer than a 500mg Acetaminophen containing immediate release formulation (see Table 2a and 2b, e.g. 3.0 and 4.0 hours post dosing).
(b) The disclosed formulation is beneficial because it allows for easy modification of sustained release effect (p 4, lines 557-558) so that the rate of release of Acetaminophen may be easily controlled (see p 2, lines 8-10).
71 The respondents also rely upon the fact that the Radebaugh Patent teaches equivalent amounts of 50/50 in the immediate release and sustained release layers. They further point to the fact that the US examiner concluded that "a prima facie case of obviousness exists where the claimed ranges and prior art ranges do not overlap, but are close enough that one skilled in the art would have expected them to have the same properties".
72 The respondents then pointed to what the US examiner noted concerning the Clemente Patent, which is said to have taught:
(a) an immediate release phase of Acetaminophen [paracetamol] (see p 11, lines 27-28; p 19, line 21 - p 21, line 32);
(b) a sustained release phase of Acetaminophen (see p 11, line 28; p 22, line 1-p 25, line 29);
(c) Acetaminophen concentration of up to 650mg (see p 16, line 30);
(d) matrix forming polymers such as hyroxypropyl cellulose and ethylcellulose (see p 9, lines 16-17); and
(e) an in vitro Acetaminophen dissolution profile comprising (see Table 1, p 15).
• 33-49% dissolved after 15 min;
• 43-64% dissolved after 60 min; and
• 59-89% dissolved after 180 min.
73 The respondents say that the dissolution ranges are "strikingly similar" to those of the Patent, in addition to the other aspects of disclosure.
74 In summary, the respondents then contend that it follows that there is a strong prima facie case of a lack of inventive step. I disagree.
75 There seems to be a real doubt as to whether these documents are part of the relevant prior art information. GSK contends that there is no evidence that either of these documents satisfy the criteria of s 7(3). It challenges the assertion that the Radebaugh Patent and the Clemente Patent "could, before the priority date of the relevant claim, be reasonably expected to have [been] ascertained" by "a person skilled in the relevant art".
76 The respondents relied upon evidence of searches that could have been carried out. But GSK pointed to the fact that Mr Sands' evidence refers to two Derwent World Patent Index searches conducted by an employee patent attorney (Dr Dryza) with unknown technical qualifications. Mr Roberts noted that in the year 2000 and years since, Derwent had been expanding its index to "back-capture" a large volume of records that would not have been searchable at 2000. GSK said that conducting a Derwent Index search for publications dated on or before 19 April 2000 would not ensure that the relevant publications were actually included in the index as at that date.
77 In any event, the first search produced 146 results, one of which was the Radebaugh Patent. The second search included as a search term the word "McNeil", the applicant on the Radebaugh Patent. Given that the Radebaugh Patent or its US equivalent were not part of the common general knowledge according to Dr Marshall, and Dr Marshall also was not aware of the Tylenol Extended Relief product, it is said by GSK that it is doubtful that the relevant person skilled in the art would have included "McNeil" in their search, unless they were guided by hindsight. And even with McNeil included in the search, it produced 106 results. Further, amongst the 106 results were two US Patents from the same family as the Radebaugh Patent, but not the Radebaugh Patent.
78 Further, the Clemente Patent was not found in either search. GSK contends that it is clearly not a s 7(3) document.
79 In my view, on the evidence adduced before me, I cannot say that there is a strong prima facie case that the Radebaugh Patent and the Clemente Patent were s 7(3) documents or part of the common general knowledge prior to the priority date. I am also fortified in my preliminary views by the following.
80 First, the Radebaugh Patent was raised during examination of the European equivalent of the Patent, but the examiner concluded that the Radebaugh Patent related merely to the general state of the art and was not relevant to novelty or inventive step considerations.
81 Second, the Apotex cross-claim seeking revocation of the Patent was filed on 30 October 2014. The original cross-claim cited six prior art publications. The Clemente Patent was not one of those cited. It would appear that at the time of preparing its cross-claim, Apotex did not consider the Clemente Patent to be sufficiently meritorious to be included in the cross-claim. The Clemente Patent was raised for the first time by Apotex in its amended cross claim on 11 December 2014.
82 I accept, though, that Generic Partners did make reference to the Clemente Patent at an earlier time.
83 Let me now make some comments on the expert evidence that has been relied upon.
84 Apotex has relied upon two reports of Dr Marshall. GSK has relied upon hearsay evidence as to the views of Professor Davies.
85 GSK has made substantial criticisms of the evidence of Dr Marshall.
86 GSK says that the inventive step case to which Dr Marshall's evidence is directed is based on the false premise that it is legitimate to treat knowledge of the Tylenol Extended Relief product and its drawbacks as referred to in the Patent as the "starting point", in circumstances where that knowledge was not information within the common general knowledge of the hypothetical formulator and was not s 7(3) information.
87 Further, it is said that Dr Marshall's evidence is also wrongly based on knowledge of the Radebaugh Patent and the Clemente Patent.
88 GSK says that the respondents' evidence does not establish that the Tylenol Extended Relief product, the Radebaugh Patent or the Clemente Patent satisfy the criteria prescribed by s 7(3). As I say, I am inclined to the view that the respondents have not made out a strong prima facie case that this material satisfies ss 7(2) and (3).
89 But putting to one side the common general knowledge and prior art questions, GSK says that the respondents' evidence is flawed in any event. They say that the respondents' inventive step evidence proceeds by a series of targeted leading questions designed to produce the required conclusion. It is said that such questions of their expert were posed and advanced with full knowledge of the claimed invention. GSK contends that no attempt has been made to heed the warnings of the dangers of hindsight or the leading of expert witnesses in the impermissible fashion that I have discussed earlier.
90 Further, it is said that there is no evidence that Dr Marshall had any practical experience in the formulation of sustained release formulations as at the priority date.
91 There are other criticisms that I do not need to dwell on.
92 Suffice it to say that, in my view and given the significant doubts that the Radebaugh Patent and the Clemente Patent are s 7(3) information, Dr Marshall's evidence has significant difficulties. Moreover, as I have said, the respondents have not established that the Tylenol Extended Relief product was part of the common general knowledge or s 7(3) information prior to the relevant date either.
93 GSK has also relied upon the views of Professor Davies. The evidence of Professor Davies' views was in hearsay form; no report of his was tendered. Such evidence accordingly has diminished weight for that reason alone. But the substance of his views further pointed against the respondents' contentions.
94 Professor Davies had substantial involvement as a formulator before the priority date. In Professor Davies' opinion, the discovery of a relationship or in vitro/in vivo correlation between a specifically defined in vitro profile and an advantageous in vivo profile is, apparently, very interesting and surprising, particularly in circumstances where:
Many formulations do not exhibit an in vitro/in vivo correlation;
Whether a particular formulation may exhibit such a correlation cannot be predicted from the physicochemical properties or formulation under development or the fact that a correlation exists for other formulations; and
The existence of an in vitro/in vivo correlation can only be ascertained by comprehensive dissolution testing.
95 As at April 2000, Professor Davies was not aware of whether an in vitro/in vivo correlation had been developed or established for any formulation of paracetamol. As at 2000, Professor Davies considered that he and other formulators would have had no expectation that an in vitro/in vivo correlation could be demonstrated for a sustained release formulation of paracetamol, let alone one that could be effectively used to predict whether such a formulation would possess the advantageous pharmacokinetic properties identified in the Patent.
96 In substance, his views, if ultimately accepted, further point against the respondents' invalidity case on this ground.
97 In summary, I do not consider that the respondents have made out a strong prima facie case on this ground. Indeed, I consider that their case is quite weak. There is real doubt as to whether the Radebaugh Patent and the Clemente Patent are relevant prior art information. Further, there are significant difficulties in how the evidence of Dr Marshall has been prepared and assimilated. Further, Professor Davies, who is more qualified than Dr Marshall in any event, has valid opposing views. Finally, although the respondents have placed significant reliance on the US Examiner's views and approach, for my context I consider such views and approach to have little probative value, and more befitting of a jury point.