Dans l’affaire Pfizer Canada Inc. v. Canada (Health), 2008 FCA 108, (March 20, 2008), la Cour d’appel fédérale, dans une affaire d’avis de conformité, réexamine les principes de suffisance de description, “double patenting” et les brevets de sélection. Voici des extraits pertinents, qui sont utiles pour la préparation des examens d’agents de brevets au Canada qui s’en viennent la semaine prochiane:
(A) Disclosure requirement under the Act
 Subsection 27(3) of the Act provides that the specification of an invention (which includes both the disclosure and the claims in the patent) must:
(a) correctly and fully describe the invention and its operation or use as contemplated by the inventor;
(b) set out clearly the various steps in a process, or the method of constructing, making, compounding or using a machine, manufacture or composition of matter, in such full, clear, concise and exact terms as to enable any person skilled in the art or science to which it pertains, or with which it is most closely connected, to make, construct, compound or use it;
(c) in the case of a machine, explain the principle of the machine and the best mode in which the inventor has contemplated the application of that principle; and
(d) in the case of a process, explain the necessary sequence, if any, of the various steps, so as to distinguish the invention from other inventions.
(i) Purpose of subsection 27(3):
 The disclosure requirement under the Act lies at the heart of the whole patent system: see Consolboard Inv. v. MacMillan Bloedel (Saskatchewan) Ltd.,  1 S.C.R. 504 at 517; Pioneer Hi Bred Ltd. v. Canada (Commissioner of Patents),  1 S.C.R. 1623 at paragraph 23. The granting of a patent is akin to a contract between the Crown and the inventor in which the latter receives an exclusive right to exploit his invention for a certain period in exchange for complete disclosure to the public of the invention and the way in which it operates: see Pioneer Hi Bred, supra, at paragraph 23. The description of the invention is therefore the quid pro quo for which the inventor is given a monopoly for a limited term of years on the invention: see Consolboard, supra, at 517. The Supreme Court has referred with approval (for example, in Consolboard, supra, at 517; in Pioneer Hi Bred, supra, at paragraph 23) to the following passage by Harold G. Fox in Canadian Patent Law and Practice, 4th ed. (1969) at p. 163:
The consideration for the grant is double: first, there must be a new and useful invention, and secondly, the inventor must, in return for the grant of a patent, give to the public an adequate description of the invention with sufficiently complete and accurate details as will enable a workman, skilled in the art to which the invention relates, to construct or use that invention when the period of the monopoly has expired. The function of the description contained in the specification is both to enable the construction and use of the devices contained therein after the expiry of the patent, and also to enable others to ascertain with some measure of exactness the boundaries of the exclusive privilege upon which they may not trespass during the exercise of the grant.
(ii) Scope of subsection 27(3):
 In Pioneer Hi Bred, supra, at paragraph 27, the Supreme Court of Canada explained the scope of subsection 27(3) as follows:
The applicant must disclose everything that is essential for the invention to function properly. To be complete, it must meet two conditions: it must describe the invention and define the way it is produced or built (Thorson P. in Minerals Separation North American Corp. v. Noranda Mines Ltd.,  Ex. C.R. 306, at p. 316). The applicant must define the nature of the invention and describe how it is put into operation. A failure to meet the first condition would invalidate the application for ambiguity, while a failure to meet the second invalidates it for insufficiency. The description must be such as to enable a person skilled in the art or the field of the invention to produce it using only the instructions contained in the disclosure (Pigeon J. in Burton Parsons Chemicals Inc. v. Hewlett-Packard (Canada) Ltd.,  1 S.C.R. 555, at p. 563; Monsanto Co. v. Commissioner of Patents,  2 S.C.R. 1108, at p. 1113) and once the monopoly period is over, to use the invention as successfully as the inventor could at the time of his application (Minerals Separation, supra, at p. 316).
 In Hughes and Woodley on Patents, 2nd ed., Volume 1, at 333, the authors describe the requirement that a disclosure be sufficient as follows:
Insufficiency is directed to whether the specification is sufficient to enable a person skilled in the art to understand how the subject matter of the patent is to be made […] An allegation of insufficiency is a technical attack that should not operate to defeat a patent for a meritorious invention; such attack will succeed where a person skilled in the art could not put the invention into practice.
 Subsection 27(3) of the Act does not require that a patentee explain how well his invention works in comparison to other inventions. He is not required to describe in what respect his invention is new or useful, nor is he obliged to “extol the effect or advantage of his discovery, if he describes his invention so as to produce it”: see Consolboard, supra, at 526.
(iii) Selection patents:
 The law with respect to selection patents was explained by this Court in Pfizer Canada Inc. v. Canada (Minister of Health), 2006 FCA 214, where, at paragraphs 3 to 5, Malone J.A. stated:
 There are two general classes of chemical patents. The first is the ‘originating patent’ where there is an originating invention involving the discovery of a new reaction or a new compound. The second is the ‘selection patent’, which is based on a selection from related compounds derived from the original compound and which have been described in general terms and claimed in the originating patent (see In the Matter of I.G. Farbenindustrie A.G.’s Patents, (1930) 47 R.P.C. 283 at page 321 per Maugham J.).
 While there is little Canadian jurisprudence on the subject of selection patents, its elements are well defined in I.G. Farbenindustrie. Lord Diplock cited this decision with approval in the House of Lords where he stated that the ‘inventive step in a selection patent lies in the discovery that one or more members of a previously known class of products possess some special advantage for a particular purpose which could not be predicted before the discovery was made’ (see Beecham Group Ltd. v. Bristol Laboratories International S.A.  R.P.C. 521 at page 579). All claimed members of the known class must have the advantage and the advantage must not be one that those skilled in the art would expect to find in a large number of the previously disclosed class (i.e. a quality of special character) (see I.G. Farbenindustrie at page 323).
 Selection patents exist to encourage researchers to further use their inventive skills so as to discover new advantages for compounds within the known class. A selection patent can be claimed for a selection from a class of thousands or for a selection of one out of two (see for example I.G. Farbenindustrie at page 323 and E.I. Dupont de Nemours & Co (Witsiepse’s) Application, F.S.R. 303 (H.L) at page 310).
 In Beecham Group, supra, at 579, Lord Diplock stated, in respect of selection patents, that “the quid pro quo for the monopoly granted to the inventor is the public disclosure by him in his specification of the special advantages that the selected members of the class possess” [Emphasis added]. This passage has been cited with approval by the Federal Court on a number of occasions: see Pfizer Canada Inc. v. Canada (Minister of Health), 2006 FC 1471, at paragraph 49; Sanofi-Synthelabo Canada Inc. v. Apotex Inc., 2005 FC 390, at paragraph 56.
 Furthermore, in Patent Law of Canada (Gordon F. Henderson ed., Carswell Legal Publications, 1994), the learned authors write at page 211-212:
When the invention consists of the selection of one or more members of a previously known group, based upon the discovery that the selected members have a previously unknown advantage over the others, the advantage must be disclosed in the specification in order to make full disclosure of the invention. As in other cases, however, what is claimed is not the advantage but the selected members. …
 Subsection 11.12 of the current edition of the Manual of Patent Office Practice has this to say on the topic of selection patents:
A selection from members of a previously known class of substances may be patentable if the substance selected is unobvious and affords a new and useful result. There must be a special advantage arising from the selected substances and any advantage, novel property or use must be fully characterized in the description. The substance should be defined in an explicit manner within the claim.
 The above passages suggest that the disclosure requirement may be a bit more onerous for selection patents. This Court has considered selection patents in only two cases. It did not, however, in either case, suggest that a higher level of disclosure was required: see Pfizer Canada Inc. v. Canada (Minister of Health), 2006 FCA 214; Sanofi-Synthelabo Canada Inc. v. Apotex Inc, 2006 FCA 421.
 While it is true that subsection 27(3) requires that an inventor “correctly and fully describe” his invention, this provision is concerned with ensuring that the patentee provide the information needed by the person skilled in the art to use the invention as successfully as the patentee. The Supreme Court of Canada, in Consolboard, supra, at 526, cited with approval the following passage from R. v. American Optical Company et al (1950), 11 Fox Pat. C. 62 at p. 85:
… It is sufficient if the specification correctly and fully describes the invention and its operation or use as contemplated by the inventor, so that the public, meaning thereby persons skilled in the art, may be able, with only the specification, to use the invention as successfully as the inventor could himself.
 The requirement that the specification of a patent be truthful and not be misleading is not covered by subsection 27(3), but rather by subsection 53(1) of the Act, which reads as follows:
Void in certain cases, or valid only for parts
53. (1) A patent is void if any material allegation in the petition of the applicant in respect of the patent is untrue, or if the specification and drawings contain more or less than is necessary for obtaining the end for which they purport to be made, and the omission or addition is wilfully made for the purpose of misleading.
 Only two questions are relevant for the purpose of subsection 27(3) of the Act. What is the invention? How does it work?: see Consolboard, supra, at 520. In the case of selection patents, answering the question “What is the invention?” involves disclosing the advantages conferred by the selection. If the patent specification (disclosure and claims) answers these questions, the inventor has held his part of the bargain. In the case at bar, the 546 patent answers each of these questions.
 What is the invention? The invention consists of having identified an enantiomer, and in particular the calcium salt of that enantiomer, that is better at inhibiting the biosynthesis of cholesterol than would be expected, given the common knowledge and prior art at the time of application for the patent.
 How does it work? The 546 patent sets out the methods for producing the compounds covered by the patent.
 I also conclude that the fact that the 546 patent does not provide a justification as to why the calcium salt of atorvastatin is the preferred embodiment of the invention does not render the disclosure insufficient. As I have already indicated, there is no requirement that a patentee explain in the disclosure why and how his invention is useful. When read as a whole, a skilled reader would understand the patent as claiming that the calcium salt of atorvastatin is the compound covered by the 546 patent that demonstrates the most surprising and unexpected inhibition of cholesterol biosynthesis because it has the most preferred physical properties. Pfizer was not required to include in the 546 patent data which supports its statement that the calcium salt of atorvastatin is the preferred embodiment of the invention, nor was it required to explain why the calcium salt was the preferred embodiment.
(E) Conclusion on disclosure under subsection 27(3)
 The applications judge erred in construing the promise of the patent and mischaracterized the disclosure requirement under subsection 27(3) of the Act by asking whether there was sufficient data to substantiate the promise of the patent. Such an examination exceeds the scope of the provision. An attack on a selection patent on the basis that there is no data to support the claimed advantage is certainly relevant for the purposes of validity (most likely to the question of utility), but it is not relevant with respect to disclosure under subsection 27(3) of the Act.
 The patent must disclose the invention and how it is made. The 546 patent does this. It also discloses the advantages that underlie the selection. This, in my view, is the extent of the requirement under subsection 27(3) of the Act, the purpose of which is to allow a person skilled in the art to make full use of the invention without having to display inventive ingenuity.
(i) Double patenting:
 In Pharmascience Inc. v. Sanofi-Aventis Canada Inc., 2006 FCA 229, at paragraphs 67-68, Sharlow J.A. summarized the law on double patenting as follows:
 “Double patenting” refers to certain judge made rules that have been devised to prevent the “evergreening” of patents. Evergreening is the undue extension of the statutory monopoly in a particular patent by means of a series of patents with obvious or uninventive additions (Whirlpool Corp. v. Camco Inc.,  2 S.C.R. 1067, at paragraph 37).
 The jurisprudence has so far identified two categories of double patenting. In the first category, “same invention patenting”, two patents are the same or have an identical or conterminous claim. The second category, “obviousness double patenting”, is somewhat broader. In obviousness double patenting, the claims of the patents are not identical or conterminous, but the later patent has claims that are not patentably distinct from the other patent, or involve no novelty or ingenuity.
 In my opinion, the double patenting allegations are not justified. The 441 patent covers processes, whereas the 546 patent covers compounds. As explained by Hughes & Woodley (at §15, page 172), “[a] previous patent for a product produced by a claimed process does not invalidate a later patent for the product alone for reasons of double patenting” (see: Aventis Pharma Inc. v. Mayune Pharma (Canada) Inc.,  F.C.J. No. 1437 at paragraphs 72-76 (Q.L.)).
 Furthermore, according to Hughes and Woodley (§15, page 172), “[w]here a patent has been found to be a proper selection patent, therefore not obvious, there is no double patenting” (see: Glaxo SmithKline Inc. v. Apotex Inc.,  F.C.J. No. 886 at paragraph 48 (Q.L.)).
 I therefore agree with the following conclusion reached by von Finkenstein J. in Novopharm, above, where he said:
 In same invention double patenting, the claims must be identical or co-terminus. Since the 441 Patent is a process patent, it is obviously not the same as the 546 Patent, which claims a compound. Given that the 546 Patent is a selection from the group of compounds disclosed in the 768 Patent (the Canadian equivalent of the US 893 Patent), the 546 Patent is obviously not identical with the claims of the 768 Patent.
 As far as obviousness double patenting is concerned, the claims or disclosure must exhibit novelty or ingenuity in order for the second patent to be valid. (See Sanofi-Synthelabo Canada Inc., supra at para. 86).
 As the Court found that the 546 Patent was a selection patent, by definition it is novel and unexpected. It thus cannot be invalid on the basis of obviousness double patenting.