Pfizer Canada Inc. v. Apotex Inc.

Pfizer Canada Inc. v. Apotex Inc.
Court (s) Database
Federal Court Decisions
Date
2007-09-27
Neutral citation
2007 FC 971
File numbers
T-1314-05
Decision Content
Date: 20070927
Docket: T-1314-05
Citation: 2007 FC 971
Ottawa, Ontario, September 27, 2007
PRESENT: The Honourable Mr. Justice Mosley
BETWEEN:
PFIZER CANADA INC.
AND PFIZER IRELAND PHARMACEUTICALS
Applicants
and
APOTEX INC.
AND THE MINISTER OF HEALTH
Respondents
REASONS FOR JUDGMENT AND JUDGMENT
[1] The applicants market a drug for the treatment of Erectile Disfunction, or “ED” as it is more discretely referred to in the advertisements, under the brand name VIAGRA. For many years, the “Holy Grail” of impotence therapy was to find an orally administered medication to alleviate the symptoms. The applicants obtained patent protection for the use of the compound sildenafil for this purpose. The respondent Apotex Inc. says that the patent is invalid for several reasons, notably that the use of sildenafil for such use was obvious in light of the state of the art, and that it should therefore be allowed to market its own generic version.
[2] Pfizer Canada Inc., and Pfizer Ireland Pharmaceuticals, hereafter the “applicants” or “Pfizer”, seek an order prohibiting the Minister of Health from issuing a Notice of Compliance to Apotex Inc. in accordance with section 6(1) of the Patented Medicines (Notice of Compliance) Regulations, S.O.R./93-133 for sildenafil, sildenafil citrate, or for any drug which has a connection to the drug known as sildenafil citrate, as described in section 5(1) or section 5(1.1) of the Regulations, until after the expiry of its patent.
[3] For the reasons that follow, I conclude that the applicants have met their burden of proof on the balance of probabilities to establish for the purpose of these proceedings that the patent is valid and that the prohibition order should issue.
THE PATENT AT ISSUE
[4] The applicants obtained Canadian Patent No. 2,163,446 (hereafter the ‘466 Patent) on July 7, 1998 from an application filed in Canada on May 13, 1994 claiming priority from Great Britain Patent Application No. 9311920.4 filed on June 9, 1993. The ‘466 Patent will expire on May 13, 2014.
[5] Two disclaimers have been filed and recorded with respect to the ‘466 Patent, the first on December 11, 2002 (hereafter the “first disclaimer”) and the second on April 29, 2004 (hereafter the “second disclaimer”). The primary effect of the two disclaimers was to limit all Claims to the treatment of ED in men.
[6] Pfizer Ireland Pharmaceuticals owns the ‘466 Patent and is party to these proceedings pursuant to section 6(4) of the Regulations. Pfizer Canada Inc. is a “first person” under the Regulations, and Apotex Inc. is a “second person”. The Minister of Health maintains a register of information submitted under s. 4 of the Regulations, and subject to the Regulations or an order of this Court, may issue an NOC to a “second person”. As is usual in these matters the Minister played no role in these proceedings and all references to the “respondent” herein relate to Apotex.
[7] Pfizer Canada Inc. submitted a patent list pursuant to Section 4(1) of the Regulations in connection with NOCs in its name for 25 mg, 50 mg and 100 mg oral tablets of the drug known as sildenafil or sildenafil citrate (hereafter “sildenafil”). The patent list includes the ‘446 Patent and Canadian Patents Nos. 2, 044,748 and 2,262,268.
[8] Apotex delivered its Notice of Allegation (NOA) on June 16, 2005 to Pfizer Canada Inc. in relation to the ‘466 Patent. In this NOA, Apotex claims to have filed with the Minister of Health a submission for sildenafil citrate tablets for oral administration in strengths of 25, 50 and 100 mg tablets for the treatment of ED in men, arguing that the ‘446 Patent is invalid. I note that Pfizer initially took issue with the manner in which the NOA was delivered, by courier, as not being proper service as prescribed by s. 9 of the Regulations. That objection was abandoned in the course of the proceedings.
[9] The applicants filed their Notice of Application on July 28, 2005 and it was amended on February 5, 2007. By order of the case management Prothonotary dated October 31, 2006 the 24 month statutory stay provided for in s.7(1) (c) of the regulations was extended to October 31 , 2007.
[10] On May 24, 2007 the respondent filed a Notice of Motion returnable on May 28th, the opening date of the hearing, seeking dismissal of the application pursuant to paragraph 6(5)(a) of the Regulations on the ground that the Claims in Issue were not eligible for inclusion in the patent list as they were neither claims to a medicine, nor claims to the use of a medicine within the meaning of the regulations. At the outset of the hearing, I advised counsel that I would hear argument and deal with that question as one of the issues to be dealt with on the prohibition application. As discussed below, I find no merit in the respondent’s submissions on this issue and dismiss the motion as part of the disposition of these proceedings.
[11] Before addressing the issues, it will be helpful to briefly describe penile physiology and how sildenafil works to alleviate ED.
HOW SILDENAFIL WORKS
[12] The erectile process involves smooth muscle tissue in the penis. The penis contains two symmetrical compartments above and on either side of the urethra each of which is called a
corpus cavernosum. They consist of small blood vessels or passages surrounded by smooth muscle which can contract or relax as with any form of muscle. Blood is supplied to the corpora cavernosa by a network of arteries and it is drained from them through veins. When flaccid, the flow of blood into the corpora is restrained by contraction of the smooth muscle surrounding the arterial network. The penis becomes erect when the penile smooth muscle relaxes and blood flows through the arterial network and into the small blood vessels or sinusoids. The resulting swelling squeezes the veins thus reducing their drainage capacity.
[13] Full erection is achieved when the pressure in the corpora cavernosa equals the pressure of the blood leaving the heart. Detumescence results when the smooth muscles contract, the arteries are again restricted and pressure on the veins relaxed allowing for the outflow of blood. Abnormal vascular responsiveness is the underlying cause of impotence in the majority of sufferers and the most common cause is the failure to retain blood within the sinusoids.
[14] Penile smooth muscle is “told what to do” by a complex biochemical system involving chemical messengers operating on communication systems called pathways in the evidence. The term is used to describe a chain of related events in a signal transmission extending from the source of the signal to a cell and continuing within the cell through the various steps that are triggered to change the cell. The NO-cGMP pathway in particular plays a central role in the mechanism of penile erection and defects in this pathway can lead to impotence and underlie certain diseases that cause ED.
[15] In the NO-CGMP pathway, a “first messenger” (nitric oxide) relays a message to the inside of the smooth muscle cells, activating receptors to stimulate the production of a “second messenger” (cGMP or cyclic3c,5c,-guanosine monophosphate). Nitric oxide (NO) is produced or released from two sources: endothelium cells in the lining of the smooth muscle and nerves in the smooth muscle known as non-adrenergic non-cholinergic or NANC nerves. Accordingly, this route is referred to as the NANC pathway. NO is produced by a reaction from a chemical called L-arginine catalyzed by the enzyme nitric oxide synthase. This was often referred to in the evidence as the “front end” of the process.
[16] The production of cGMP sets off a chain of events that leads to relaxation of the smooth muscle in the penis. This allows more blood to enter causing an increase in pressure which restricts blood outflow, the resulting effect being an erection. In brief, production of cGMP contributes to tumescence and its removal leads to detumescence. Another chemical agent which relaxes smooth muscle is cyclic adenosine monophosphate or cAMP, produced by other material in response to different chemical messengers.
[17] The physiological effects of cGMP and cAMP may be reduced by PDE (phosphodiesterases) enzymes, which break down (hydrolyze) cGMP and cAMP by binding to the molecules. By June 1993, it was known that there were five PDEs and that some of them could be inhibited or blocked by other chemicals called PDE inhibitors. By inhibiting a PDE, one can stop the degradation of cGMP or cAMP. Inhibiters are selective in that they preferentially hydrolyze a particular enzyme, for example PDE5 is a selective cGMP PDE in that it prefers to hydrolyze cGMP over other enzymes. PDE4 is specific to cAMP only. The others are non-specific but PDE3 is more effective with cAMP.
[18] Sildenafil was initially developed by Pfizer in the mid-1980s as one of a number of compounds which could be employed in the treatment of hypertension and angina, cardiovascular conditions in which smooth muscle cells are implicated. Due to PDE5’s functional importance in the process of penile erection, and the fact that sildenafil is a potent and selective cGMP PDE inhibitor, sildenafil is able to treat ED in men through the operation of the NO-cGMP pathway.
ISSUES
[19] Apotex does not dispute that their proposed tablets of sildenafil citrate would be infringing if the patent is valid in the sense that issuance of the prohibition order is justified. Validity in the context of these proceedings is limited to the scope of the regulations. The issues raised by Apotex’s NOA and addressed at the hearing of this application can be stated as follows:
1. Burden of proof;
2. Validity of the disclaimers relating to the ‘466 Patent;
3. Validity of the patent on the basis of one or more of the following:
a) obviousness;
b) anticipation;
c) the relevant claims being broader then the invention made or disclosed; and
d) a failure to meet the requirements of the legislation;
[20] This case turns in particular on the issue of obviousness.
CLAIM CONSTRUCTION
[21] As is frequently stated, the first task of the Court, before considering whether or not a patent is valid or infringed, is to construe the patent. Claim construction is a matter of law and the claim language must be read in an informed and purposive way. The key to purposive construction is the identification by the Court, with the assistance of the skilled reader, of the particular words or phrases in the claims that describe what the inventor considered to be the “essential” elements of the invention: Whirlpool Corp. v. Camco Inc., 2000 SCC 67, [2000] 2 S.C.R. 1067 at para. 45 [Whirlpool].
[22] In addition, it is important to recall that patent specifications are not addressed to specialists or the public generally; they are addressed to skilled individuals sufficiently versed in the art to which the patent relates to enable them on a technical level to appreciate the nature and description of the invention: Whirlpool, above at para. 53. Furthermore, the words chosen by the patentee are to be read in the sense the inventor is presumed to have intended. Though expert evidence is admissible to determine what the common knowledge was at the time of the patent and with respect to the meaning of the words used in the claims, the role of the expert is not to interpret the patent claims but to put the application or trial judge in the position of being able to do so in a knowledgeable way: Whirlpool, above at para. 57. Claims must also be read in context. The question is therefore what, at the date the patent was issued, would a person skilled in the art at issue
have understood from a reading of the claims, together with any definitional assistance from the rest of the specification: Whirlpool, above at para. 54.
[23] In this regard, as soon as the disclaimers were filed and recorded they were made part of the Patent, and the only existing Claims became those amended by virtue of the disclaimers: Roche Palo Alto LLC v. Apotex Inc., [2005] O.J. No. 1390 (Sup.Ct.)(QL) at para. 47 citing Canadian Celanese Ltd. v. B.V.D. Co., [1939] 2 D.L.R. 289 (P.C.). Therefore, so long as the disclaimers were validly filed, as I have found in the present case and discuss in the next section of these reasons, the claims must be interpreted as disclaimed.
[24] The ‘466 Patent relates to the use of a series of pyrazolo[4,3-d] pyrimidin-7-ones compounds and their pharmaceutically acceptable salts for the treatment of ED. Sildenafil is one such compound and has the formula 5-[2-ethoxy-5-(4-methyl-1-piperazinylsulphonyl)phenyl]-1-methyl-3-n-propyl-1,6-dihydro-7Hpyrazolo[4,3-d]pyrimidin-7-one].
[25] The applicants are relying on Claim 7 of the ‘446 Patent; Claims 8, 10, 18, and 22 to the extent that they relate to Claim 7; and Claim 23 to the extent that it relates to Claims 10 and 11 (hereafter the “Claims in Issue”). Claim 7 is limited to sildenafil and its salts. Claims 8, 10, 18, 22 and 23 are each defined with alternative dependencies, one of which is Claim 7.
[26] Each of the Claims in Issue is specific to the treatment of ED with sildenafil, or more specifically its salt, sildenafil citrate, which is the active ingredient in Apotex’ proposed products. These claims originally read as follows:
7. The use according to claim 4 wherein the compound of formula (I) is 5-[2-ethoxy-5-(4-methyl-1-piperazinylsulphonyl)-phenyl]-1-methyl-3-n-propyl-1,6-dihydro-7Hpyrazolo[4,3-d]pyrimidin-7-one] or a pharmaceutically acceptable salt thereof.
8. The use according to any one of claims 1 to 7 wherein the said male animal is man.
10. A pharmaceutical composition for the curative or prophylactic treatment of erectile dysfunction in a male animal, including man, comprising a compound of formula (I) according to any one of claims 1 to 7, or a pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable diluent or carrier.
18. The use of a compound of formula (I) according to any one of claims 1 to 7, or a pharmaceutically acceptable salt thereof, for the curative or prophylactic treatment of erectile dysfunction in man.
22. The use according to any one of claims 1 to 9 wherein the medicament is adapted for oral treatment.
23. A pharmaceutical composition according to claim 10 or 11 which is adapted for oral treatment.
[27] The first disclaimer disclaimed use in animals, thereby limiting Claim 1 to ED in men and female sexual dysfunction (FSD), and Claim 10 to ED in man. By virtue of dependency, Claims 7 and 22 were thus limited to men and women, and Claim 23 to man. The original Claim 8 and Claim 18 were restricted to the treatment of ED in man. The first disclaimer did not affect their scope, although the reference to “male animal” was removed from Claim 8. The second disclaimer disclaimed the use of the compounds for female sexual dysfunction and thus limited Claim 1 to ED in man. Claims 7 and 22, which depend on Claim 1, were therefore also limited to ED in man. Neither disclaimer affected the scope or wording of Claim 18. The second disclaimer did not affect the scope of Claims 8, 10, 22 and 23 to the extent that they are at issue in this application. The effect of the two disclaimers was to limit all Claims to treatment of ED in man.
[28] Counsel raised two claim construction issues that need to be addressed. The first issue is the meaning of the phrase “curative or prophylactic” the question being whether these words are meant to apply to the treatment of ED as a symptom, or are meant to apply to the underlying condition causing the ED. The applicants assert the former while the respondent asserts the latter.
Curative or prophylactic
[29] With the assistance of the advice of the experts, reading the claims in a purposive way, and having determined from the evidence what the inventors had in mind when they spoke of a “curative or prophylactic” treatment of ED, I find that the words “curative” and “prophylactic” relate to providing a remedy for the symptoms of ED as opposed to the underlying illness or condition.
[30] There are various causes of ED. The object of the invention was not to treat those causes but the symptomatic effects. The term erectile dysfunction or ED was coined by researchers and clinicians in the field of treating impotence in an effort to remove the stigma associated with the condition.
[31] With respect to the respondent’s argument, as was noted by the Supreme Court of Canada in Apotex Inc. v. Wellcome Foundation Limited, 2002 SCC 77, [2002] 4 S.C.R. 153 at para. 88 [Wellcome Foundation]: “[w]hile the appellants' argument has some linguistic attraction, it puts too much weight on a supposed "bright line" distinction between treatment and prophylaxis.” I believe the same can be said in the present case with respect to both terms. I have no doubt that the inventors had in mind a remedy for the symptom or condition that is ED when they wrote the patent.
For the manufacture of a medicament
[32] The second issue is how the phrase “for the manufacture of a medicament” within claim 1, affects the Claims in Issue and my determination of what comprises the essential elements of the invention. In this regard the respondent’s argument distinguishes between the phrase ‘use of sildenafil “for the manufacture of a medicament”’ and what is meant by a “claim for the use of the medicine” found in the Regulations. Section 2 of the Regulations defines the latter as “a claim for the use of the medicine for the diagnosis, treatment, mitigation or prevention of a disease, disorder or abnormal physical state, or the symptoms thereof”. The respondent suggests that a claim “for the manufacture of a medicament” is distinguishable in meaning because it implies that it is the medicament and not the sildenafil itself that is intended for curative and prophylactic purposes.
[33] Taking a purposive approach to interpretation of the phrase, I do not see a practical difference. The concepts of medicament and medicine are closely related and often interchangeable. As defined by the Canadian Oxford Dictionary, “medicament” is “a substance used for medical treatment”; the comparable meaning of “medicine” is “any drug or preparation used for the preparation or treatment of disease, esp. one taken by mouth”. A review of Stedman’s and Dorland’s medical dictionaries supports this interpretation.
[34] In referring to either a medicament or medicine employing sildenafil as the active ingredient, it is the sildenafil that would give the medicament or medicine its curative or prophylactic properties. I am satisfied that the word medicament was meant to be understood in this sense by the inventors, and the claims will be construed without drawing the distinction asserted by the respondent.
[35] Taking into consideration the two disclaimers and with the aid of the expert evidence, to my mind the essential elements of the Claims in Issue can be described as follows: the use of sildenafil (or a salt thereof) in the form of an oral medicine for the treatment of erectile dysfunction in man.
DISCLAIMER VALIDITY
[36] Subsection 48(1) of the Act allows for the filing of a disclaimer where, by mistake or inadvertence, a patent specification has been drafted too broadly and provided it is not made with the intent of defrauding or misleading the public: ICN Pharmaceuticals, Inc. v. Canada (Staff of the Patented Medicine Prices Review Board), [1997] 1 F.C. 32, [1996] F.C.J. No. 1065 at para. 70 (C.A.) [ICN Pharm.]. The respondent argues that the requirements of this subsection have not been met in the present case, and that the disclaimed claims are therefore invalid. The applicants assert the contrary.
[37] As was recently noted by the Court in Richards Packaging Inc. v. Canada (Attorney General), 2007 FC 11, [2007] F.C.J. No. 21 at para. 28, the Commissioner and the examiners have no authority under the Act and the Rules to make a decision on the validity of a disclaimer
filed by a patentee; this power belongs to the courts. The fact that the Patent Office has accepted a disclaimer is therefore not determinative of whether the requirements of subsection 48(1) have been met: ICN Pharm., above at para. 70.
[38] I agree with the findings of the Ontario High Court of Justice in Trubenizing Process Corp. v. John Forsyth, Ltd., [1942] O.R. 271-300, 2 C.P.R. 89, rev’d on other grounds [1943] S.C.R. 422, [1943] S.C.J. No. 35, wherein Chevrier J. held that the validity of the disclaimer depends solely upon the state of mind of the patentee at the time he made his specification. Chevrier J. further made it clear that the onus rests on the party who files a disclaimer to justify the need for the disclaimer at the time it was filed by reason of mistake, accident or inadvertence and that there was an absence of intent to defraud or mislead the public. Where the filing party does not discharge this burden, the disclaimer will be held to be invalid and the patent will remain in its original form.
[39] In the present case, little evidence has been presented by either party with respect to this issue. There is, however, the sworn affidavit evidence of Dr. Peter Ellis, listed as co-inventor of the ‘446 Patent. In effect he states that the first disclaimer corrected the use of the term “animal” which was too broad, asserting that when the Patent application had been filed this had been overlooked. The first disclaimer also inserted the word “selective” in Claims 25 and 26 following an United Kingdom Court’s ruling regarding the meaning of the Patent. According to Dr. Ellis, he had thought that the limitation of “selective” had been implied, but felt it was best to defer to the UK Court. With respect to the second disclaimer, Dr. Ellis states that testing had not been done before the filing date to establish utility in women; however he asserts that there was scientific data that indicated that a woman’s clitoris is a homologue of a penis. He asserts that Pfizer now believes that under Canadian law it was a mistake to think that the foregoing would establish an invention of a treatment for sexual disfunction in women.
[40] The respondent argues that a mistake regarding the law is not a mistake for the purposes of section 48. The fact that the applicants discovered the mistake after the filing of the application does not change the fact that on the basis of the state of the law at the time, it would have been a mistake. In this case the mistake was in believing that the correlation between the penis and the clitoris, absent direct test results on the efficacy of sildenafil for FSD, was sufficient to establish an invention under the law. Had the applicants known that this was not sufficient, there is nothing to indicate that at the time of the patent application they would have still filed it with the intention of defrauding or misleading the public.
[41] This evidence, though minimal, is un-refuted. The applicants point out that Dr. Ellis was also cross-examined about the disclaimers and that evidence was consistent with his affidavit.
[42] These issues were given only cursory treatment by the respondent in cross examination, with most of the focus being on the term “selective”. The respondent presented nothing in my estimation that would suggest that there was a “wilful” intent to defraud or mislead the public on the part of the applicants. The fact that Dr. Ellis admitted in cross-examination that his input as to the disclaimers was made in conversations with Pfizer’s counsel (which, in any event, are privileged), and that he neither drafted nor scrutinized it before it was filed, do not suggest that the disclaimers: 1) did not reflect his state of mind; 2) were not filed in good faith; or 3) that there was any willful intent to defraud or mislead the public.
[43] Taking the whole of the evidence into account, on the balance of probabilities standard, I conclude that the applicants have met their burden to demonstrate that this allegation is unsubstantiated.
VALIDITY
Burden of Proof
[44] The issue of burden of proof and presumption of validity was recently dealt with by the Court of Appeal in Abbott Laboratories v. Canada (Minister of Health), 2007 FCA 153, [2007] F.C.J. No. 543 [Abbott Laboratories 2007]. In that case the Court of Appeal found at paragraph 9 that “[i]t is now beyond debate that an applicant for a prohibition order under the NOC Regulations bears the burden of establishing its entitlement to the order” [emphasis added]. With respect to the presumption of validity that emanates from subsection 43(2) of the Act, the Court of Appeal went on to state:
10 … The presumption in subsection 43(2) is weakly worded (Apotex Inc. v. Wellcome Foundation Limited, [2002] 4 S.C.R. 153, per Justice Binnie at paragraph 43). It cannot determine the outcome of prohibition proceedings under the NOC Regulations if, as in this case, the record contains any evidence that, if accepted, is capable of rebutting the presumption (see Rubbermaid (Canada) Ltd. v. Tucker Plastic Products Ltd. (1972), 8 C.P.R. (2d) 6 (F.C.T.D.) at page 14, and Bayer Inc. v. Canada (Minister of National Health and Welfare) (2000), 6 C.P.R. (4th) 285, at paragraph 9).
[emphasis added]
[45] While the legal burden remains on the applicant, the respondent has been described as having an “evidentiary burden” to rebut the presumption of validity: Pfizer Canada Inc. v. Apotex Inc., 2007 FC 26, [2007] F.C.J. No. 36 at para. 10 [Pfizer]; Eli Lilly Canada Inc. v. Apotex Inc., 2007 FC 455, [2007] F.C.J. No. 617 at paragraph 232 [Eli Lilly]. This, however, is a minimal threshold. As was aptly described by the Court in Pfizer:
12 To summarize, Pfizer bears the legal burden of proving on a balance of probabilities that Apotex's allegations of invalidity are unjustified. Apotex merely has an evidentiary burden to put its case "into play" by presenting sufficient evidence to give its allegations of invalidity an air of reality. If it meets that burden, then it has rebutted the presumption of validity. I must then determine whether Pfizer has established that Apotex's allegations of invalidity are unjustified. If Apotex does not meet its evidential burden, then Pfizer can simply rely on the presumption of validity to obtain its prohibition order. [emphasis added]
[46] In oral argument, the applicants pointed to a decision of the Court of Appeal, handed down during the course of the hearing of this matter on May 31, 2007, which, they submit, holds that the respondent must meet the legal standard of proof on a balance of probabilities to rebut the presumption of validity: Pfizer Canada Inc. v. Canada (Minister of Health), 2007 FCA 209, [2007] F.C.J. No. 767 (“Pfizer 2007 FCA 209”).
[47] Paragraphs 109, 110 and 111 of the Pfizer 2007 FCA 209 decision read as follows:
109. Thus, a first person under the Regulations has the overall burden of establishing, on a balance of probabilities, that the allegations of invalidity contained in a second person's NOA are not justified. Although the first person has the initial burden, because of the presumption of the validity of a patent set out in section 45 of the pre-1989 Act, it can meet this burden merely by proving the existence of the patent. The second person then has the burden of adducing evidence of invalidity and of putting the allegations of invalidity contained in its NOA "in play". To do so, the second person must adduce evidence which is not clearly incapable of establishing its allegations of invalidity. Hence, not only must the second person's NOA contain a sufficient factual and legal basis for its allegations, but it must also adduce evidence of invalidity at trial.
110. Once the second person has adduced sufficient evidence, on a balance of probabilities, the first person must, also on a balance of probabilities, disprove
the allegations of invalidity set out in the NOA. As explained by my colleague Sharlow J.A. at paragraph 9 of her Reasons in Bayer, supra:
[9] The operation of the statutory presumption in the face of evidence of invalidity depends upon the strength of the evidence. If the evidence proves, on a balance of probabilities, that the patent is invalid, the presumption is rebutted and is no longer relevant. ...
[citing Bayer Inc. v. Canada (Minister of National Health and Welfare) (2000), 6 C.P.R. (4th) 285]
111. I have not been persuaded that the Judge erred in her understanding of the burden of proof. She correctly referred to the legal principles enunciated by this Court, according to which the overall legal or persuasive burden of proof rests upon the first person, on a balance of probabilities, once the second person has met its evidentiary burden of adducing evidence sufficient to rebut the presumption of validity.
[Emphasis added]
[48] When read as a whole, these paragraphs should not be taken as holding that the second person bears a legal burden on the standard of proof of a balance of probability to overcome the presumption of validity. It is clear from the Court of Appeal’s reasons that the legal burden remains with the first person throughout the proceedings and does not shift to the second person. To meet that burden the first person may rely upon the presumption of validity “in the absence of any evidence to the contrary” as set out in subsection 43(2) of the Patent Act R.S.C. 1985, c. P-4 as amended, S.C. 1993, c. 15 [emphasis added]. Should the second person lead any evidence to the contrary, the presumption is spent and the burden remains with the first person to prove validity on the balance of probability standard.
[49] The highlighted words from the subsection indicate that the nature of the burden on the second person is evidential and not persuasive. The difference between the two concepts was discussed by Dickson C.J. (writing in dissent) in the criminal law context in R. v. Schwartz, [1988] 2 S.C.R. 443, [1988] S.C.J. No. 84 as follows:
38 Judges and academics have used a variety of terms to try to capture the distinction between the two types of burdens. The burden of establishing a case has been referred to as the "major burden," the "primary burden," the "legal burden" and the "persuasive burden." The burden of putting an issue in play has been called the "minor burden," the "secondary burden," the "evidential burden," the "burden of going forward," and the "burden of adducing evidence." While any combination of phrases has its advantages and drawbacks, I prefer to use the terms "persuasive burden" to refer to the requirement of proving a case or disproving defences, and "evidential burden" to mean the requirement of putting an issue into play by reference to evidence before the court. The party who has the persuasive burden is required to persuade the trier of fact, to convince the trier of fact that a certain set of facts existed. Failure to persuade means that the party loses. The party with an evidential burden is not required to convince the trier of fact of anything, only to point out evidence which suggests that certain facts existed. The phrase "onus of proof" should be restricted to the persuasive burden, since an issue can be put into play without being proven. The phrases "burden of going forward" and "burden of adducing evidence" should not be used, as they imply that the party is required to produce his or her own evidence on an issue… [Emphasis added].
[50] As was further described by Fish J., again in a criminal case, in R. v. Fontaine, 2004 SCC 27, [2004] 1 S.C.R. 702:
11 An "evidential burden" is not a burden of proof. It determines whether an issue should be left to the trier of fact, while the "persuasive burden" determines how the issue should be decided.
12 These are fundamentally different questions. The first is a matter of law; the second, a question of fact. Accordingly, on a trial before judge and jury, the judge decides whether the evidential burden has been met. In answering that question, the judge does not evaluate the quality, weight or reliability of the evidence. The judge simply decides whether there is evidence upon which a properly instructed jury could reasonably decide the issue.
[underlined emphasis in original, bold emphasis added]
[51] These are principles of general application and are not limited to the domain of criminal law. In this context, what constitutes “any evidence to the contrary” is, as the Court of Appeal put it in paragraph 109 of the Pfizer 2007 FCA 209 decision, evidence which is sufficient to put the allegations of invalidity “in play” and which is not clearly incapable of establishing those allegations. That does not require Apotex to meet the standard of proof on a balance of probabilities but rather, to satisfy the Court that the evidence discloses an air of reality for its allegations of invalidity and that Pfizer must meet its legal burden. To interpret the effects of the presumption otherwise would lead to the absurd result that both parties would bear the burden of establishing the invalidity or validity of the patent at issue on the same standard.
Obviousness
[52] In order to obtain a valid patent inventiveness or inventive ingenuity is required, meaning the subject matter or “invention” claimed must not be obvious. The Court of Appeal in Sanofi-Synthelabo v. Apotex Inc., 2006 FCA 421, [2006] F.C.J. No. 1945 at para. 38 reiterated the test for obviousness as set out in Beloit Canada Ltd. v. Valmet Oy, [1986] F.C.J. No. 87, 8 C.P.R. (3d) 289 at 294 (F.C.A.) [Beloit]:
The test for obviousness is not to ask what competent inventors did or would have done to solve the problem. Inventors are by definition inventive. The classical touchstone for obviousness is the technician skilled in the art but having no scintilla of inventiveness or imagination; a paragon of deduction and dexterity, wholly devoid of intuition; a triumph of the left hemisphere over the right. The question to be asked is whether this mythical creature (the man in the Clapham omnibus of patent law) 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. It is a very difficult test to satisfy.
[Emphasis added]
[53] In a recent decision, Novopharm Ltd. v. Janssen-Ortho Inc. 2007 FCA 217, [2007] F.C.J. No. 809 [Novopharm], the Court of Appeal endorsed a list of factors developed by Justice Roger Hughes in the trial decision (2006 FC 1234, [2006] F.C.J. No. 1535) as a helpful framework to guide the factual analysis that must be undertaken in determining obviousness. At paragraph 25 of her reasons for the Court of Appeal, Justice Sharlow set out these factors as follows:
Principal factors
1. The invention
What is in issue is the patent claim as construed by the Court.
2. The hypothetical skilled person referred to in the Beloit quotation
It is necessary to identify the skills possessed by the hypothetical person of ordinary skill in the art.
3. The body of knowledge of the person of ordinary skill in the art
The common knowledge of the hypothetical person of ordinary skill in the art includes what the person may reasonably be expected to know and to be able to find out. The hypothetical skilled person is assumed to be reasonably diligent in keeping up with advances in the field to which the patent relates (Whirlpool at paragraph 74). The presumed knowledge of the hypothetical skilled person undergoes continuous evolution and growth. Not all knowledge is found in print form. On the other hand, not all knowledge that has been written down becomes part of the knowledge that a person of ordinary skill in the art is expected to know or find.
4. The climate in the relevant field at the time the alleged invention was made
The general state of the art includes not only knowledge and information but also attitudes, trends, prejudices and expectations.
5. The motivation in existence at the time [of] the alleged invention to solve a recognized problem
"Motivation" in this context may mean the reason why the claimed inventor made the claimed invention, or it may mean the reason why one might reasonably expect the hypothetical person of ordinary skill in the art to combine elements of the prior art to come up with the claimed invention. If within the relevant field there is a specific problem that everyone in the field is trying to solve (a general motivation), it may be more likely that the solution, once found, required inventive ingenuity. On the other hand, if there is a problem that only the claimed inventor is trying to solve (a unique or personal motivation), and no one else has a reason to address that problem, it may be more likely that the solution required inventive ingenuity. However, if commonplace thought and techniques can come up with a solution, there may be a reduced possibility that the solution required inventive ingenuity.
6. The time and effort involved in the invention
The length of time and expense involved in the invention may be indicators of inventive ingenuity, but they are not determinative because an invention may be the result of a lucky hit, or the uninventive application of routine techniques, however time consuming and expensive they may be. If the decisions made in arriving at the solution are few and commonplace, that may indicate that no inventive ingenuity was required to arrive at the solution. If the points for decision were many and choices abundant, there may be inventiveness in making the proper decisions and choices.
Secondary factors
These factors may be relevant but generally bear less weight because they relate to facts arising after the date of the alleged invention.
7. Commercial success
Was the subject of the invention quickly and anxiously received by relevant consumers? This may reflect a fact that many persons were motivated to fill the commercial market, which may suggest inventive ingenuity. However, it may also reflect things other than inventive ingenuity such as marketing skills, market power and features other than the invention.
8. Meritorious awards
Awards directed to the alleged invention may be recognition that the appropriate community of persons skilled in the art believed that activity to be something of merit. That may or may not say anything about inventive ingenuity.
[54] Justice Sharlow stressed that this is not a list of legal rules to be slavishly followed nor is it an exhaustive list of the relevant factors. In each case, the application or trial judge must determine the appropriate weight to be accorded these factors and that of any other factor that may be presented: Novopharm, para.27. Justice Sharlow agreed with the caution of Justice Hughes that catchphrases, such as “worth a try”, “directly and without difficulty” and “routine testing” are not to be treated as if they are rules of law: Novopharm, para.28.
[55] It is apparent from the evidence that as of the priority date there was a considerable amount of effort invested in research and clinical trials of treatments for male ED in as much as it affects a significant proportion of the male population. In June 1993, there were a number of treatments available for men who were unable to obtain or maintain an erection, notably the self-administration of drugs directly into the corpora cavernosa. This had to be done shortly before intercourse and could result in pain, scarring, or undesired effects such as unduly prolonged erections. Other treatments included prosthetic or suction devices and surgery. None were employed without discomfort, embarrassment and adverse side effects. This was a recognized problem which attracted the attention of leading scientists and clinicians, and public funding for research.
[56] It is not difficult, therefore, to appreciate