Apotex Inc. v.
copyright 2010 Donald M. Cameron, Bereskin Parr LLP
 The parties have accepted that the Sanofi respondents (“Sanofi”) are the relevant holders of patent 1,194,875 (‘875 patent). This patent disclosed a genus or class of compounds useful in inhibiting platelet aggregation activity in the blood which is important in treating coronary artery, peripheral vascular and cerebral vascular diseases. This genus patent discloses over 250,000 possible different compounds useful for this purpose. One of the compounds is a racemate described as methyl alpha-5 (4,5,6,7-tetrahydro (3, 2-c)-thieno pyridyl) (2-chlorophenyl)-acetate (the “racemate”).
 A racemate is a substance containing equal amounts of two structurally different compounds, called enantiomers or optical isomers. The two isomers, the dextro-rotatory isomer and the levo-rotatory isomer, are mirror images of each other and rotate plane-polarized light in opposite directions.
 The parties have accepted that Sanofi is also the relevant holder of subsequent Canadian patent 1,336,777 (‘777 patent), the patent in suit. It discloses and claims clopidogrel bisulfate, which is marketed by Sanofi under the trade name of Plavix as an anti-coagulant that inhibits platelet aggregation activity in the blood.
 Clopidogrel bisulfate is encompassed within the scope of the claims in the ‘875 patent. Clopidogrel is the dextro-rotatory isomer of the racemate, having beneficial properties over both the racemate and the levo-rotatory isomer. The dextro-rotatory isomer exhibits a platelet aggregation inhibiting activity and is less toxic and better tolerated than the levo-rotatory isomer and racemate. The salts of the dextro-rotatory isomer, such as clopidogrel bisulfate, have a better therapeutic index than the salts of the racemic mixture and in fact, the levo-rotatory isomer exhibits almost no platelet aggregation inhibiting activity, and its toxicity is markedly higher than that of the dextro-rotatory isomer.
III. Selection Patents
 This appeal requires the Court to determine whether selection patents are invalid in principle or on the facts of this case on the grounds of anticipation, obviousness and double patenting.
 The locus classicus describing selection patents is the decision of Maugham J. in In re I. G. Farbenindustrie A. G.’s Patents (1930), 47 R.P.C. 289 (Ch. D.). At p. 321, he explained that in the field of chemical patents (which would of course include pharmaceutical compounds), there are often two “sharply divided classes”. The first class of patents, which he called originating patents, are based on an originating invention, namely, the discovery of a new reaction or a new compound. The second class comprises patents based on a selection of compounds from those described in general terms and claimed in the originating patent. Maugham J. cautioned that the selected compounds cannot have been made before, or the selection patent “would fail for want of novelty”. But if the selected compound is “novel” and “possess[es] a special property of an unexpected character”, the required “inventive” step would be satisfied (p. 321). At p. 322, Maugham J. stated that a selection patent “does not in its nature differ from any other patent”.
 While not exhaustively defining a selection patent, he set out (at pp. 322-23) three conditions that must be satisfied for a selection patent to be valid.
1. There must be a substantial advantage to be secured or disadvantage to be avoided by the use of the selected members.
2. The whole of the selected members (subject to “a few exceptions here and there”) possess the advantage in question.
3. The selection must be in respect of a quality of a special character peculiar to the selected group. If further research revealed a small number of unselected compounds possessing the same advantage, that would not invalidate the selection patent. However, if research showed that a larger number of unselected compounds possessed the same advantage, the quality of the compound claimed in the selection patent would not be of a special character.
 Although much has been written about selection patents since I. G. Farbenindustrie, Maugham J.’s analysis is consistently referred to and is well accepted. I find it is a useful starting point for the analysis to be conducted in this case.
(a) Relevant Legislation
 For purposes of anticipation, it is necessary to have regard to s. 27 of the Act which sets forth the basic conditions necessary for obtaining a patent. The invention must not have been previously known or used nor described in any patent or other publication printed in any country more than two years before the filing of the patent application and must not have been in public use or sale in Canada more than two years prior to the filing of the patent application. Section 27(1) provided:
27. (1) Subject to this section, any inventor or legal representative of an inventor of an invention that was
(a) not known or used by any other person before he invented it,
(b) not described in any patent or in any publication printed in Canada or in any other country more than two years before presentation of the petition hereunder mentioned, and
(c) not in public use or on sale in Canada for more than two years prior to his application in Canada, may, on presentation to the Commissioner of a petition setting out the facts, in this Act termed the filing in the application, and on compliance with all other requirements of this Act, obtain a patent granting to him an exclusive property in the invention.
 It is with s. 27 in mind that the law of anticipation must be considered. Apotex’s arguments based on anticipation are not that the applications judge erred in his analysis of the law of anticipation or its application to the facts of this case. Rather, Apotex implies that the current understanding of the law sets the bar for proving anticipation too high and that the acceptance of a system of genus and selection patents necessarily, or at least on the facts of this case, involves anticipation and therefore invalidity. I would reject the broader objection. A system of genus and selection patents is acceptable in principle, on the line of authority stemming from I. G. Farbenindustrie. The real question is whether, on the facts of this case, the particular selection patent has been anticipated.
(c) Recent United Kingdom Jurisprudence
 For the reasons that follow, and in light of recent jurisprudence, I am of the respectful opinion that the applications judge overstated the stringency of the test for anticipation that the “exact invention” has already been made and publicly disclosed.
 In the 2005 decision of the House of Lords in Synthon, Lord Hoffmann has brought some further clarity to the law of anticipation as understood since General Tire. His reference at para. 20 to the “unquestionable authority” of Lord Westbury in Hills v. Evans (1862), 31 L.J. Ch. (N.S.) 457, at p. 463, makes it plain that his analysis does not depend on any change on English law flowing from the enactment of the Patents Act 1977 (U.K.), 1977, c. 37, or the U.K.’s adoption of the Convention on the Grant of European Patents, 1065 U.N.T.S. 199 (entered into force October 7, 1977). He distinguishes between two requirements for anticipation that were not theretofore expressly considered separately, prior disclosure and enablement.
 He explains that the requirement of prior disclosure means that the prior patent must disclose subject matter which, if performed, would necessarily result in infringement of that patent, and states, at para. 22:
If I may summarise the effect of these two well-known statements [from General Tire and Hills v. Evans], the matter relied upon as prior art must disclose subject matter which, if performed, would necessarily result in an infringement of the patent. . . . It follows that, whether or not it would be apparent to anyone at the time, whenever subject matter described in the prior disclosure is capable of being performed and is such that, if performed, it must result in the patent being infringed, the disclosure condition is satisfied.
When considering the role of the person skilled in the art in respect of disclosure, the skilled person is “taken to be trying to understand what the author of the description [in the prior patent] meant” (para. 32). At this stage, there is no room for trial and error or experimentation by the skilled person. He is simply reading the prior patent for the purposes of understanding it.
 If the disclosure requirement is satisfied, the second requirement to prove anticipation is “enablement” which means that the person skilled in the art would have been able to perform the invention (para. 26). Lord Hoffmann held that the test for enablement for purposes of anticipation was the same as the test for sufficiency under the relevant United Kingdom legislation. (Enablement for the purposes of sufficiency of the patent specification under the Canadian Patent Act, s. 34(1)(b) of the pre-October 1, 1989 Act, now s. 27(3)(b), is not an issue to be decided in this case and my analysis of enablement is solely related to the test for anticipation. The question of whether enablement for purposes of sufficiency is identical in Canada is better left to another day.)
 Once the subject matter of the invention is disclosed by the prior patent, the person skilled in the art is assumed to be willing to make trial and error experiments to get it to work. While trial and error experimentation is permitted at the enablement stage, it is not at the disclosure stage. For purposes of enablement, the question is no longer what the skilled person would think the disclosure of the prior patent meant, but whether he or she would be able to work the invention.
 The Beloit decision by which the applications judge rightly felt bound dealt with only one aspect of anticipation, that is, whether or not the invention in a patent had been disclosed in a single prior publication or patent. In that decision, Hugessen J.A. held that it had not. He had no need to consider the further point whether or not, had there been such a clear disclosure, the working of the invention was also enabled by that disclosure. That point was not in issue in Beloit. Explicitly separating disclosure and enablement is a refinement of the approach set out in Beloit. It explains the process a person skilled in the art would follow if the original patent anticipated the invention of the subsequent patent. I would adopt this approach.
 Subject to any limitations expressed in the Patent Act, I see no reason why the discussion of anticipation should not apply to other prior art than merely genus patents. Again, subject to limitations in the Patent Act, the discussion of anticipation and obviousness would seem applicable to patents generally.  Two questions now must be answered: (1) what constitutes disclosure at the first stage of the test for anticipation, and (2) how much trial and error or experimentation is permitted at the enablement stage?
 Section 27(1) of the Act requires as a condition for obtaining a patent that the invention was not “known or used” and was not “described” in any patent or any publication more than two years before the patent application was filed. In the context of genus and selection patents, in E. I. Du Pont de Nemours & Co. (Witsiepe’s) Application,  F.S.R. 303 (H.L.), Lord Wilberforce stated, at p. 311:
It is the absence of the discovery of the special advantages, as well as the fact of non-making, that makes it possible for such persons to make an invention related to a member of the class.
The compound made for the selection patent was only soundly predicted at the time of the genus patent. It was not made and its special advantages were not known. It is for those reasons that a patent should not be denied to the inventor who made and discovered the special advantages of the selection compound for the first time.
 In the context of disclosure as explained in Synthon, “the absence of the discovery of the special advantages” to which Lord Wilberforce was referring in Witsiepe’s means that the genus patent does not disclose the special advantages of the invention covered by the selection patent. Where there is no such disclosure, there is no discovery of the special advantages of the selection patent as compared to the genus patent, and the disclosure requirement to prove anticipation fails. At this stage, the person skilled in the art is reading the prior patent to understand whether it discloses the special advantages of the second invention. No trial and error is permitted. If in reading the genus patent the special advantages of the invention of the selection patent are not disclosed, the genus patent does not anticipate the selection patent.
 What amount of trial and error or experimentation is permitted before a prior disclosure will not constitute enabling disclosure? Certainly, if the applications judge finds that an inventive step was required to get to the invention of the second patent, the specification of the first patent will not have provided enabling disclosure. But even if no inventive step is required, the skilled person must still be able to perform or make the invention of the second patent without undue burden.
 Two recent United Kingdom decisions are of assistance. In Halliburton Energy Services Inc. v. Smith International (North Sea) Ltd.,  EWCA Civ 1715 (BAILII), Jacob L.J., a highly experienced patent judge, states at para. 18:
Patents are meant to teach people how to do things. If what is “taught” involves just too much [work] to be reasonable allowing for all the circumstances including the nature of the art, then the patent cannot be regarded as an “enabling disclosure.” . . . The setting of a gigantic project, even if merely routine, will not do.
 Jacob L.J. characterizes the problem at para. 20 as: “[H]ow is one to say when the work involved to perform the invention is too much?” The determination of how much work is too much is inevitably a line-drawing exercise. His answer to the problem is at para. 21:
The answer is that the line is one to be drawn by an exercise of judgment, taking into account all of the relevant factors, one of which is of course the nature of the invention itself and its field of technology. But there are other factors too — for instance, the width of the patent claim or whether it has functional limitations which require too much work to explore.
 A more extensive review of the law of enablement as defined in Synthon is contained in a decision of Kitchin J. in Wobben v. Vestas-Celtic Wind Technology Ltd.,  EWHC 2636 (Pat.) (BAILII), at paras. 196-97. Although Wobben was a case in which the alleged infringer raised as one of its defences insufficiency under the United Kingdom legislation, I think guidance is provided as to what will or will not constitute enablement for purposes of anticipation.
 Drawing from this jurisprudence, I am of the opinion that the following factors should normally be considered. The list is not exhaustive. The factors will apply in accordance with the evidence in each case.
1. Enablement is to be assessed having regard to the prior patent as a whole including the specification and the claims. There is no reason to limit what the skilled person may consider in the prior patent in order to discover how to perform or make the invention of the subsequent patent. The entire prior patent constitutes prior art.
2. The skilled person may use his or her common general knowledge to supplement information contained in the prior patent. Common general knowledge means knowledge generally known by persons skilled in the relevant art at the relevant time.
3. The prior patent must provide enough information to allow the subsequently claimed invention to be performed without undue burden. When considering whether there is undue burden, the nature of the invention must be taken into account. For example, if the invention takes place in a field of technology in which trials and experiments are generally carried out, the threshold for undue burden will tend to be higher than in circumstances in which less effort is normal. If inventive steps are required, the prior art will not be considered as enabling. However, routine trials are acceptable and would not be considered undue burden. But experiments or trials and errors are not to be prolonged even in fields of technology in which trials and experiments are generally carried out. No time limits on exercises of energy can be laid down; however, prolonged or arduous trial and error would not be considered routine.
4. Obvious errors or omissions in the prior patent will not prevent enablement if reasonable skill and knowledge in the art could readily correct the error or find what was omitted.
(d) Application to the Facts of This Case
i. Disclosure for the Purposes of Anticipation
 The ‘875 genus patent covered over 250,000 possible different compounds. Obviously, every compound was not made or tested. The patent covering those compounds was based on sound prediction. From the specification, it is apparent that 21 examples were made and tested, one of which was the racemate relevant in this case. According to the applications judge, there was no disclosure in the ‘875 patent of the specific beneficial properties associated with the dextro-rotatory isomer of this racemate, nor was there disclosure of any advantages which flow from using the bisulfate salt in combination with the dextro-rotatory isomer (para. 71).
 It was open to Shore J. on the record before him to conclude that a person skilled in the art and reading the ‘875 patent would not be able to come up with the invention of the ‘777 patent. Nothing in the ‘875 patent distinguished this dextro-rotatory isomer as having beneficial properties different from the racemate or the levo-rotatory isomer or from any of the other compounds made and tested and referred to in the ‘875 patent, let alone the compounds based only on sound prediction. At para. 72 of his reasons, he found:
The Court also notes that, although Dr. Klibanov agreed with Apotex’ experts that a skilled person could have ascertained the activity and characteristics of two isomers and of different salts using well-known methods at the time, they did not say that the beneficial properties of these isomers and of their salts — let alone of the dextro-rotatory isomer and of its bisulfate salt — would be known with certitude before conducting the tests designed to identify the respective properties of the isomers and of the salt.
 There was no evidence that the person skilled in the art would know from reading the ‘875 patent that the more active dextro-rotatory isomer would be less toxic than the racemate or levo-rotatory isomer or any of the other compounds made and tested. Indeed, Dr. McClelland’s evidence was that while you “often” get more activity by separating isomers, the answer to the question whether this increased activity was to be found in the levo-rotatory isomer or the dextro-rotatory isomer was unknown. (Affidavit, at para. 42, and cross-examination, at pp. 928-30 and question 322).  Since the ‘875 patent did not disclose the special advantages of the dextro-rotatory isomer and of its bisulfate salt, as compared to the levo-rotatory isomer or the racemate and their salts, or the other compounds made and tested or otherwise referred to in the ‘875 patent, the invention of the ‘777 patent cannot be said to have been disclosed and therefore it cannot be said to have been anticipated.
ii. Enablement for the Purposes of Anticipation
 It is not strictly necessary to discuss enablement since anticipation requires proof of both disclosure and enablement, and disclosure has not been proven. However, for future guidance, I would make the following few observations about enablement on the facts of this case.
 The applications judge was of the opinion that “the skilled reader following the prior art must be able to arrive at the invention claimed in the impugned patent the first time he or she tries and every time thereafter” (para. 65 (emphasis in original)). However, under the test for enablement as described in these reasons, some trial and error is permitted.
 For anticipation, the genus patent must provide enough information so as to allow the selected invention to be performed without undue burden. In this case, the applications judge concluded that the ‘875 patent did not specifically lead to the claimed invention. He noted, on the record before him, that if one were to follow the teachings of the prior art, one would obtain racemates, never their isomers.
 However, Apotex argues that the methods for separating the isomers were well known to persons skilled in the art at the time of the invention. According to Apotex, such a person could eventually obtain the isomer through what amounts to routine tests.
 In determining whether the enablement step for proving anticipation has been met, it is important to note that routine trials are acceptable but inventive steps are not permitted. Also, reasonable skill and knowledge of the art is expected in order to correct omissions in the original patent if a means of determining what is missing can readily be found. The skilled person may use his or her common general knowledge to supplement information contained in the patent.
 Even though Shore J. referred to the excessively stringent anticipation test “in every case”, his findings are relevant to trial and error. He found that the evidence with respect to the methods of separation, including the evidence of the inventor, shows that the identification of clopidogrel, its bisulfate salt and their advantageous properties required extensive investigation over a period of months (paras. 68-70).
 One might infer that, had the applications judge been asked to decide if these investigations constituted an undue burden for the skilled person, he would have held that they did. However, in view of my earlier conclusion on disclosure, it is unnecessary for me to pursue this point further.
(e) Conclusion on Anticipation
 As indicated above, in the context of anticipation, the two-step approach, disclosure and enablement, is a refinement of the approach set out in Beloit and should be adopted.
 In the case at bar, the invention of the ‘777 patent was not disclosed by the ‘875 patent and was therefore not anticipated. The allegation of anticipation has not been justified.
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