In Apotex Inc. v. Sanofi-Synthelabo Canada Inc., 2008 SCC 61 [PDF], a unanimous Supreme Court of Canada upheld the validity of “selection patents,” those claiming a sub-set of subject matter disclosed in a previous patent (the “genus patent,” often relating to classes of chemical compounds”), based on newly discovered properties or uses.

Sanofi-Synthelabo Canada’s (“Sanofi”) patent 1,336,777 (‘777 patent) claims clopidogrel bisulfate, an anti-coagulant inhibiting platelet aggregation activity in the blood. This compound is encompassed within the scope of Sanofi’s earlier patent 1,194,875 (‘875 patent), which disclosed a genus or class of 250,000 possible different compounds useful in inhibiting platelet aggregation activity in the blood. This class included a “racemic” compound, which consists of equal amounts of left- and right-handed enantiomers (also called stereoisomers or optical isomers), chemically identical compounds differing only in that they are nonsuperimposable structural mirror images of each other generally having different chemical properties in the human body. The two isomers in question were dextro-rotatory isomer and the levo-rotatory isomer.

The clopidogrel bisulfate compound claimed in the ’777 patent, marketed under the trade name “Plavix,” is the salt of the dextro-rotatory isomer of the racemate and has more beneficial properties then the racemate mixture compound or levo-rotatory isomer, being less toxic and having greater platelet aggregation inhibiting activity.

Apotex served a Notice of Allegation under the Patented Medicines (Notice of Compliance) Regulations to Sanofi to obtain a Notice of Compliance to market a generic version of Plavix. The Notice of Allegation claimed Apotex would not infringe the ‘777 patent because it was invalid due to anticipation, obviousness and double patenting. Sanofi responded by initiating proceedings in Federal Court under s. 6(1) of the Regulations seeking an order prohibiting the Minister of Health from issuing the Notice of Compliance to Apotex claiming the generic drug would infringe the ‘777 patent. The Federal Court granted the order of prohibition (2005 FC 390), and the Federal Court of Appeal dismissed Apotex’s appeal (2006 FCA 421).

The Supreme Court accepted three nonexhuastive conditions for selection patents from In re I. G. Farbenindustrie A. G.’s Patents (1930), 47 R.P.C. 289 (Ch. D.):

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.

The second and third conditions relate to concepts of overinclusiveness and underexclusiveness respectively.
ANTICIPATION UNDER SECTION 27(1)

The Court rejected Apotex’s argument selection patents are inherently anticipated. However, the Court also rejected the Trial Judge’s anticipation test, “that the exact invention has already been made and publicly disclosed” as too strict, but found the Judge has applied the anticipation test in line with the accepted principles of Beloit Canada Ltd. v. Valmet OY (1986), 8 C.P.R. (3d) 289 (F.C.A.). Relying on recent English caselaw the Court accepted the separation of two sub-requirements for anticipation, prior disclosure and enablement.

Disclosure means “the prior patent must disclose subject matter which, if performed, would necessarily result in infringement of that patent.” Thus “there is no room for trial and error or experimentation by the skilled person”.

The second requirement is “enablement” which means “which means that the person skilled in the art would have been able to perform the invention,” some trial and error experimentation is permitted here. The Court acknowledged that the separation of disclosure and enablement is a refinement of Beloit, where only enablement was at issue.

Disclosure

Section 27(1) of the Patent Act requires inventions not be “known or used” nor “described” in any patent or any publication more than two years before a patent application is filed. For selection patents the Court found it is the absence of discovery of the special properties, and the non-production of the compounds, that permitted patenting of the selected compounds since the selection patent compounds were only soundly predicted at the time of the genus patent. Since the genus patent has not disclosed the special properties of the selected compounds, the disclosure needed to prove anticipation was absent.

Enablement

The Court stated “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,” and drawing from English jurisprudence, setout a nonexhausive list of factors to be considered:

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.

ANTICIPATION
1. Disclosure

Although one of the 250,000 possible different compounds disclosed in the ‘875 patent was the racemate mixture containing the Plavix dextro-rotatory isomer, the trial court found no disclosure of the beneficial properties associated with the dextro-rotatory isomer of the racemate or its salt. The Court accepted and paraphrased this conclusion as

[n]othing 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.

This was despite the fact that experts had agreed “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.” The key was that the beneficial properties of these isomers and of their salts would not “be known with certitude before conducting the tests designed to identify the respective properties of the isomers and of the salt,” that the more active Plavix dextro-rotatory isomer would be less toxic than the racemate or levo-rotatory isomer. Since the ‘875 patent did not disclosure the “special advantages of the dextro-rotatory isomer,” the ‘777 patent “cannot be said to have been disclosed and therefore it cannot be said to have been anticipated.”
2. Enablement

Despite the failure of the first prong of the anticipation test the Court went on to discuss enablement, correcting the trial court, that some trial and error is permitted. “The genus patent must provide enough information so as to allow the selected invention to be performed without undue burden.” Apotex claimed the methods for separating isomers were well known to persons skilled in the art at the time of the invention and thus the genus patent enabled the selection patent with only routine tests. The Court expanded on the person skilled in the art stating “reasonable skill and knowledge of the art is expected in order to correct omissions in the original patent” and the skilled person may use “common general knowledge to supplement information contained in the patent.” However, “inventive steps are not permitted.” The Court implied the trial judge would have found a lack of enablement due to an undue burden based on factual findings that the identification of the advantageous properties required “extensive investigation over a period of months.”

Obviousness

The Court first stated the accepted obvious test set out in Beloit Canada Ltd. v. Valmet OY (1986), 8 C.P.R. (3d) 289 (F.C.A.), whether the person skilled in the art “would, in the light of the state of the art and of common general knowledge as at the claimed date of invention, have come directly and without difficulty to the solution taught by the patent.”

The trial court concluded the Beloit test “would not accommodate a ‘worth a try’ test by the skilled person.” As five well-known separation techniques had existed to separate isomers, and the isomer properties would need to be identified, the trial judge concluded the Plavix dextro-rotatory isomer would not have been obvious, even if it had been “worth a try” according to experts.

The Court canvassed United States and United Kingdom obviousness jurisprudence, responding to Apotex’s allegation that by excluding the “worth a try” inquiry Canada had improperly raised the obviousness threshold. The Court took particular note of KSR International Co. v. Teleflex Inc., 127 S. Ct. 1727 (2007), where a unanimous US Supreme Court rejected the restrictive approach the Court of Appeals for the Federal Circuit had taken, in part by excluding a “worth a try” inquiry from its Teaching-Suggestion-Motivation (TSM) test. The Court also noted the obvious to try test had been accepted in the United Kingdom for many years. Both these observations led the Court to “re-examine” the restrictive interpretation of Beloit.

The Court began by cautioning against an overly linguistic approach to patent law stating “courts have often tended to treat the word formulation of Beloit as if it were a statutory prescription that limits the obviousness inquiry.” Instead, the Court took a narrow version of the test from English law and stated “I am of the opinion that the ‘obvious to try’ test will work only where it is very plain or . . . more or less self-evident that what is being tested ought to work.” The Court clarified “there must be evidence to convince a judge on a balance of probabilities that it was more or less self-evident to try to obtain the invention. Mere possibility that something might turn up is not enough.”

The Court accepted the updated 4-step obviousness originally presented in Windsurfing International Inc. v. Tabur Marine (Great Britain) Ltd., [1985] R.P.C. 59 (C.A.):

(1) (a) Identify the notional “person skilled in the art”;
(b) Identify the relevant common general knowledge of that person;
(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
(3) Identify what, if any, differences exist between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;
(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

The Court envisioned the “obvious to try” issue will arise at the fourth step and would be more appropriate in fields where detailed experimentation was customary. The “obvious to try” inquiry should be guided by the following non-exhaustive factors:

(1) Is it more or less self-evident that what is being tried ought to work? Are there a finite number of identified predictable solutions known to persons skilled in the art?
(2) What is the extent, nature and amount of effort required to achieve the invention? Are routine trials carried out or is the experimentation prolonged and arduous, such that the trials would not be considered routine?
(3) Is there a motive provided in the prior art to find the solution the patent addresses?

The actual history of the invention is relevant, for example, if the invention was built relatively easily in light of the prior art, taking into account the skill of the inventors, that may support a conclusion of obviousness by suggesting other skilled actors would reach similar results. Conversely, where long difficult searches, including dead-ends, were required, this may support a finding of non-obviousness, particularly where the inventor were more skilled then the ordinary person skilled in the field.

Accepting the lower court’s findings, and filling-in gaps with its own conclusions to integrate the “obvious to try” test, the Court applied its 3 factors. First, the Court found it would not be “self-evident” that the isomer would have different properties from the racemate, that the properties would be beneficial, or that the existence of separating methods would lead a person skilled in the art to apply them. Second, the Court concluded the development of the invention could be described as “prolonged and arduous,” not routine, considering the inventors were already familiar with the genus patent. Third, the Court found no motive present in the prior art or ‘875 patent to pursue the ‘777 subject matter. Fourth, the course of conduct that culminated in the invention involved Sanofi investing resources to develop the racemate compound, only to abandon it for the isomer. The Court concluded in light of the prior art and based on the difficulty and unpredictability in identifying the beneficial properties it was not “more or less self-evident to try to find” the Plavix dextro-rotatory isomer.

Double Patenting

Lastly, the Court addressed the issue of double patenting within the larger issue of selection patent validity, specifically whether selection patents claim the same invention as their respective genus patents. “Evergreening” occurs when a patentee attempts to secure a monopoly over valuable subject matter beyond 20 years by obtaining a second patent for the same invention. While acknowledging evergreening is a legitimate concern, it was “not a justification for an attack on the doctrine of selection patents.” First, “a selection patent may be sought by a party other than the inventor or owner of the original genus patent,” and second:

selection patents encourage improvements by selection. The inventor selects only a bit of the subject matter of the original genus patent because that bit does something better than and different from what was claimed in the genus patent.

The Court agreed with the trial court that the claims in the ‘875 patent were not identical to the ‘777 patent, specifically claim 14 of the ‘875 patent, which claims all derivatives of a general formula as well as the 2 isomers and the racemic mixture, and claim 1 of the ‘777 patent, the dextro-rotatory isomer of the racemate.

This led the Court to a discussion of the doctrine of “sound prediction,” the basis for many genus patents. The doctrine seeks to balance “the public interest in early disclosure of new and useful inventions even before their utility has been fully verified by tests, and the public interest in avoiding cluttering the public domain with useless patents and granting monopoly rights in exchange for misinformation.” Quoting Monsanto Co. v. Commissioner of Patents, [1979] 2 S.C.R. 1108, the Court presented the basis of the sound prediction doctrine:

It cannot mean a certainty since it does not exclude all risk that some of the area covered may prove devoid of utility. It thus appears to me that the test . . . involves just two possible reasons for rejecting claims such as those in issue.
1. There is evidence of lack of utility in respect of some of the area covered; [or]
2. It is not a sound prediction.

The Court reasoned that while the ‘875 patent may be challengeable since the claimed beneficial properties of all members of the genus were inconsistent, “it does not affect the validity of the selection patent.”

The Court noted the difference between “same invention” double patenting, and “obviousness” double patenting. For “same invention” double-patenting the “focus . . . is on the claims of the two patents rather than on the disclosure,” as the claims define the monopoly. While identical language need not be present both patents must “claim the same invention,” leading the court to conclude “[t]he invention defined by claim 14 of the ‘875 patent is not the same as the invention claimed by claim 1 of the ‘777 patent because the former is broader than the latter.”

“Obviousness” double patenting “is a more flexible and less literal test that prohibits the issuance of a second patent with claims that are not ‘patently distinct’ from those of the earlier patent,” for example, the mere dilution of a substance with known medical uses. “A selection patent that claims a compound that is patentably distinct from the genus patent will not be invalid for obviousness double patenting.” As the dextro-rotatory isomer had beneficial properties over both the racemate and the levo-rotatory isomer “the claims in the ‘777 patent reflect a patentably distinct compound from the compounds in the ‘875 patent” and were not invalid based on an “obviousness” double patenting challenge.

Lastly the court referred to a specification requirement for selection patents, “it is necessary that the specification of the selection patent define in clear terms the nature of the characteristic which the patentee alleges to be possessed by the selection for which he claims a monopoly,” which the ‘777 specification satisfied.