Pfizer Canada Inc. v. Novopharm Limited

Pfizer Canada Inc. v. Novopharm Limited
Court (s) Database
Federal Court Decisions
Date
2009-06-18
Neutral citation
2009 FC 638
File numbers
T-1566-07
Decision Content
Federal Court
Cour fédérale
Date: 20090618
Docket: T-1566-07
Citation: 2009 FC 638
Ottawa, Ontario, June 18, 2009
PRESENT: The Honourable Mr. Justice Kelen
BETWEEN:
PFIZER CANADA INC.,
PFIZER INC., PFIZER IRELAND PHARMACEUTICALS, AND
PFIZER RESEARCH AND DEVELOPMENT COMPANY N.V./S.A.
Applicants
and
NOVOPHARM LIMITED AND
THE MINISTER OF HEALTH
Respondents
REASONS FOR ORDER AND ORDER
[1] This is an application for an Order under the Patented Medicines (Notice of Compliance) Regulations, SOR/93-1333 (the NOC Regulations), prohibiting the Minister of Health from issuing a Notice of Compliance to Novopharm for a generic version of Viagra until Pfizer’s Canadian Patent 2,163,446 (hereafter the ‘446 Patent) expires in 2014. Novopharm alleges that Pfizer’s patent for Viagra is invalid for obviousness, lack of utility, and insufficiency of disclosure so that the generic version of Viagra should immediately be allowed on the Canadian market.
TABLE OF CONTENTS
Paragraph Number
BACKGROUND………………………………………………………………………………….[2]
ANALYSIS
Burden of Proof………………………………………………………………………….[32]
Patent Claim Construction……………………………………………………………….[37]
ISSUE NO. 1:
Whether the invention of sildenafil for the treatment of ED was
obvious at the time of the priority date…………………………………………………...[47]
ISSUE NO. 2:
Whether the ‘446 Patent meets the utility requirement by demonstrating
or soundly predicting the utility of sildenafil by the Canadian filing date………………..[68]
ISSUE NO. 3:
Whether the disclosure in the ‘446 Patent met the statutory requirement for
disclosure set out in s. 27(3) of the Patent Act as of the ‘446 Patent’s
publication date…………………………………………………………………………..[98]
CONCLUSION………………………………………………………………………………...[149]
BACKGROUND
The ‘446 Patent
[2] The ’446 Patent claims the use of sildenafil citrate in the treatment of impotence, including erectile dysfunction (ED). The applicant Pfizer Ireland Pharmaceuticals, owns the ‘446 Patent, and the applicant Pfizer Canada Inc., markets the drug sildenafil cirtrate in Canada under the trade name VIAGRA.
[3] The applicants obtained the '446 Patent on July 7, 1998, from an application filed in Canada on May 13, 1994 which claimed priority from Great Britain Patent Application No. 9311920.4 filed on June 9, 1993. The '446 Patent will expire on May 13, 2014.
[4] The ‘446 patent claims the use of many compounds in Claims 1 to 7 for the treatment of ED, including sildenafil citrate, the active compound used in the VIAGRA drug. The applicant relies on claims 7, 18, 22 and 23 of the ‘446 Patent. The applicant states that all of these claims, although worded differently, cover the use of sildenafil in the treatment of ED through oral administration. Claims 1 to 7, 18, 22 and 23 of the Patent are attached hereto as “Appendix A”.
[5] Two disclaimers have been filed and recorded with respect to the ‘466 Patent. The primary effect of the two disclaimers was to limit all claims to the treatment of ED in men. The disclaimers are not relevant to this application.
The Parties
[6] The applicant Pfizer Canada Inc. is the Canadian operation of the multinational pharmaceutical company Pfizer Inc., which manufactures VIAGRA. The applicant Pfizer Ireland Pharmaceutical owns the patent, and Pfizer Canada is a licensee under the patent.
[7] The respondent Novopharm Limited filed an Abbreviated New Drug Submission with Health Canada on December 19, 2006 in respect of Sildenafil Citrate Tablets, 25 mg, 50 mg and 100 mg, for oral administration. The ANDS compared the Novopharm tablets with the applicants’ VIAGRA Sildenafil Citrate Tablets, 25 mg, 50 mg and 100 mg. The Novapharm tablets are indicated for the treatment of ED. Novopharm served its Notice of Allegation, alleging the invalidity of the ‘446 Patent, on Pfizer on July 6, 2007.
[8] The respondent the Minister of Health did not participate in this application, as is normally the case in such proceedings.
How Sildenafil Treats ED
[9] The erectile tissue in the penis consists of two symmetrical compartments above and on either side of the urethra called the corpus cavernosa. They are made up 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 is drained from them through veins. The flow of blood into the penis is controlled by the smooth muscle surrounding the arteries. The penis becomes erect when the penile smooth muscle relaxes and blood flows through the arterial network and into the small blood vessels. When the smooth muscles contract, the blood vessels also contract, preventing blood from flowing in. This causes the penis to become flaccid.
[10] Sildenafil inhibits a chemical in the body known as PDEV, which otherwise stops the blood from flowing into the penis and causing an erection.
[11] Many different cascades of first and second messages, known as “pathways,” were known in 1993 to relax or contract smooth muscle tone in the penis. These included the non-adrenergic non-cholinergic (or NANC) pathway. It is now known, although it was not known in 1993, that sildenafil treats ED by virtue of its effects on the NANC pathway in which the first messenger is nitric oxide (NO), and the second messenger is cGMP, which is regulated by PDEV.
[12] Sildenafil was initially developed by Pfizer in the mid-1980s as one of a number of compounds for the treatment of hypertension and angina, cardiovascular conditions in which smooth muscle cells are implicated. Because sildenafil is a potent and selective cGMP PDE inhibitor, it is able to treat ED in men through the operation of the NO-cGMP pathway.
AFFIDAVIT EVIDENCE
[13] The applicants have provided affidavits from five expert witness, two employees and a law clerk employed by applicant’s counsel:
Experts
1. Dr. Peter Ellis
2. Dr. Gerald B. Brock
3. Dr. George Christ
4. Professor Jeremy Heaton
5. Dr. Sharron Francis
Pfizer Employees
6. Martyn Frank Burslem
7. Madeleine Pesant
Law Clerk
8. Christine Ingham (law clerk at Torys)
[14] The respondent has provided affidavits from three experts, a witness of fact and the author of a prior art reference, and an associate employed by respondent’s counsel:
Experts
1. Iñigo Saenz de Tejada, MD
2. Dr. Donald H. Maurice
3. Dr. Jonathan S. Dordick
Witness of Fact
4. Margaret A. Bush
Associate
5. Bryan Norrie (associate at Oslers)
[15] The applicants have provided reply affidavits from three of their expert witnesses, Dr. Ellis, Dr. Brock, and Dr. Francis. The respondent has provided sur-reply affidavits from two of their expert witnesses, Dr. Maurice and Dr. Dordick, both of whom also offered evidence in chief.
[16] Pfizer has accurately described the background of the key witnesses in a document attached hereto as “Appendix B”.
Evidence of Dr. Peter Ellis regarding his discovery of Sildenafil for the treatment of ED
[17] Dr. Ellis, one of the inventors named in the Canadian Patent ’446, deposed at paragraph 17 of his affidavit:
In overview, the development of sildenafil as a treatment for ED arose out of a project in which a…inhibiter was being sought to treat hypertension. This project later evolved into a search for a drug to treat angina. Later, I determined that sildenafil could successfully treat ED based on observations of erections during Phase 1 testing in the angina project combined with my scientific knowledge.
[18] Dr. Ellis explained the many steps, and missteps, which led to the discovery of sildenafil as a solution for ED. It is clear that the discovery was a long and winding road with many twists, turns and dead ends along the way. At first, the drug was injected into the penis [to stimulate the production of the inhibiter for the treatment of impotence]. The results were disappointing. These tests were conducted on monkeys. Dr. Ellis deposed in paragraph 33:
…this negative result probably would have ended our interest in sildenafil for impotence.
However, in studies of sildenafil as a treatment for angina, patients in the test study taking the drug orally reported “prolonged and spontaneous erections” (at paragraph 37).
[19] Following these studies on angina patients, Dr. Ellis decided that Pfizer should design a study to administer sildenafil to ED patients. A 25mg oral dose of sildenafil was given three times a day for five days to a group of healthy male volunteers. The resulting erections from the drug were surprising because, as Dr. Ellis explained at paragraph 34:
…This too was surprising because when a drug is administered orally, it is presented to the whole body including the vascular system. Further, we knew that a…inhibiter like sildenafil could lower blood pressure, which was a known cause of impotence. Normally, drug treatments for impotence involved injection of the drug directly into the corpus cavernosum (the sponge-like tissue in the penis) to avoid systemic effects.
[20] In June 1993, Dr. Ellis testified that Pfizer filed a provisional specification for a patent in the United Kingdom, which is the “priority application” for the ‘446 Patent. Following this provisional specification, Pfizer conducted a study (Study 350) wherein a group of 16 impotent men were administered an oral dose of either 25 mg of sildenafil or a placebo three times a day for a period of six days. In the evening of the sixth day, the patients were admitted to a hospital and shown sexually explicit videos and kept in the hospital overnight. They were fitted with a RigiScan transducer, a device that measured the rigidity and duration of their erections and recorded the results on a computer. The patients also kept a diary. After a suitable drug washout period, the patients repeated the test, but with the alternate of the sildenafil or placebo that they had received in the first test. As a result of this study, Pfizer concluded that sildenafil was effective in improving erectile function in men with no known organic cause of impotence.
[21] In February 1994, another study was conducted to investigate whether sildenafil could be given as a single oral dose to induce an erection between one and two hours before the anticipated opportunity for sexual activity.
The UK litigation regarding the Viagra Patent
[22] Undoubtedly a motivation to challenge the validity of the VIAGRA patent is the jurisprudence in England, which struck out the Viagra patent for obviousness: Lilly Icos Ltd. v. Pfizer Ltd., [2001] F.S.R. 16 (E.C.A.).This decision of Mr. Justice Laddie of the Chancery Division, was confirmed on appeal by the U.K. Court of Appeal (Civil Division): Lilly Icos Ltd. v. Pfizer Ltd., [2002] EWCA Civ 1.
Notice of Allegation
[23] In this litigation, material parts of the notice of allegation assert that the ‘446 Patent is invalid for reasons of obviousness, insufficient disclosure, and lack of utility.
Previous litigation before this Court relating to Pfizer’s sildenafil patents
Injunction against CIALIS
[24] In 2003, the applicants filed an urgent motion for an interim injunction restraining Lilly Icos LLC and Eli Lilly Canada Inc. from importing into Canada, distributing and selling a pharmaceutical for the treatment of ED called CIALIS, which according to Pfizer infringed the VIAGRA patent.
[25] I heard the motion on October 28, 2003, and in my order dated November 3, 2003, I denied the motion: Pfizer Ireland Pharmaceuticals v. Lilly Icos LLC, 2003 FC 1278, 126 A.C.W.S. (3d) 856. I found that, notwithstanding the decision Mr. Justice Laddie, upheld by the UK Court of Appeal, that the VIAGRA patent was invalid for obviousness, the decision of the European Patent office to revoke the VIAGRA patent and the U.S. Patent office decision to reexamine the VIAGRA patent, the applicants had raised a serious issue, i.e. whether CIALIS infringed the VIAGRA patent. However, I found that the applicants had failed to establish irreparable harm if CIALIS was allowed in Canada, i.e. harm that could not be appropriately compensated by monetary damages.
[26] In the later disposition of the interlocutory injunction, Mr. Justice Pierre Blais (as he then was) found that the Canadian patent was valid until proven otherwise and that the alleged infringement was a serious issue. Justice Blais held, as I had, that the plaintiffs had not shown irreparable harm. He therefore dismissed the motion for an interlocutory injunction: Pfizer Ireland Pharmaceuticals v. Lilly Icos Inc., 2004 FC 223, 129 A.C.W.S. (3d) 399.
The ‘748 Patent
[27] In 2006, the generic Apotex sought a Notice of Compliance to market tablets containing sildenafil, the active ingredient in VIAGRA, and in another Pfizer medicine called Revatio, which treats pulmonary hypertension. Apotex challenged the validity of Pfizer’s ‘748 Patent on the basis of lack of utility and sound prediction, and ambiguity. The ‘748 Patent claimed the use of a broad range of compounds (cGMP PDE inhibitors), including sildenafil, for the treatment of a number of conditions including angina, hypertension, heart failure and atherosclerosis.
[28] Mr. Justice James O’Reilly held that Pfizer had failed to establish that the compounds of the ‘748 Patent, or sildenafil in particular, had been shown or soundly predicted to be potent and selective cGMP PDE inhibitors by the priority date of the patent. He held that the language of the patent was vague, and that the patent did not enable a skilled reader to appreciate the properties in the compounds. Justice O’Reilly concluded that Pfizer had not established that the allegations of invalidity were unjustified and dismissed Pfizer’s application to prohibit the issuance of an NOC. Pfizer Canada Inc. v. Apotex Inc., 2007 FC 26, 306 F.T.R. 254.
The ‘446 Patent
[29] In 2007, Apotex sought to market sildenafil citrate tablets for oral administration in strengths of 25, 50 and 100 mg tablets for the treatment of ED in men – the exact compound and dosage of the VIAGRA drug. Apotex challenged the validity of Pfizer’s ‘446 Patent, the same patent in the case at bar. While the ‘748 Patent considered by Justice O’Reilly claimed the use of a number of cGMP PDE inhibitors in the treatment of a number of heart conditions, the ‘446 Patent claims the use of cGMP PDE inhibitors, including sildenafil, in the treatment of ED. Apotex alleged that the ‘446 Patent was invalid for obviousness, anticipation, and failure to meet the requirements of the legislation.
[30] Mr. Justice Richard Mosley found that the ‘446 Patent was not invalid for obviousness. He held that although there was a significant amount of evidence indicating that cGMP PDE inhibitors should be further explored with regard to the treatment of ED in the months leading up to the Pfizer discovery, the solution was not obvious at the time and was at best speculative. The most that could be said at the priority date is that sildenafil would be “worth a try” as a treatment for impotence. Pfizer Canada v. Apotex Inc., 2007 FC 971, 319 F.T.R. 48 at paragraphs 123-129. Justice Mosley also found that the patent was not invalid for anticipation, overbreadth, or invalid disclaimer. Unlike the case at bar, Apotex did not allege that the ‘446 Patent was invalid for insufficient disclosure or lack of utility.
ISSUES
[31] The issue raised by this prohibition application is whether the respondent Novopharm’s allegations that the ‘446 patent is invalid are unjustified. While Novopharm raised a number of issues in its NOA, the parties argued three main issues in their memoranda of fact and law and in the hearing before me:
a. whether the invention of sildenafil for the treatment of ED was obvious at the time of the priority date;
b. whether the ‘446 patent meets the utility requirement by demonstrating or soundly predicting the utility of sildenafil by the Canadian filing date; and
c. whether the disclosure in the ‘446 Patent met the statutory requirement for disclosure set out in s. 27(3) of the Patent Act as of the ‘446 Patent’s publication date.
ANALYSIS
Burden of proof
[32] In Abbott Laboratories v. Canada (Minister of Health), 2007 FCA 153, 361 N.R. 308, the Federal Court of Appeal dealt with the issue of burden of proof and the presumption of patent validity. At paragraph 9-10, Justice Sharlow stated:
9 It 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...
10 …The presumption [of validity] 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).
[33] While the ultimate legal burden remains on the applicant, the respondent has been described as having an “evidentiary burden” to rebut the presumption of validity. In Pfizer v. Canada Inc. v. Canada (Minister of Health), 2007 FCA 209. 366 N.R. 347, Justice Nadon stated at paragraphs 109-110:
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
[34] These cases were considered by Justice Mosley in Pfizer v. Apotex, 2007 FC 971, supra. Justice Mosley stated at paragraph 48:
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.
[35] Likewise, in Pfizer, 2007 FC 26, supra, Justice O’Reilly stated at paragraph 12:
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.
[36] To summarize with respect to the burden of proof:
1. Novopharm has the evidentiary burden to present sufficient evidence to give its allegations of invalidity “an air of reality” (Novopharm’s legal burden in this regard has been described in the jurisprudence as “a sufficient factual and legal basis for its allegations of invalidity with “sufficient” evidence on a balance of probabilities.”) Then the burden shifts because the presumption of the patent’s validity has been rebutted or overcome by Novopharm), i.e. that it can rebut the presumption of validity; and
2. Pfizer has the legal burden of proving on the balance of probabilities that Novopharm’s allegations of invalidity are unjustified.
Patent Claim Construction
[37] The first step in a patent matter is to construe the patent claim. Claim construction is antecedent to consideration of both the validity and the infringement issues: Whirlpool Corp. v. Camco Inc. 2000 SCC 67, 9 C.P.R. (4th) 129 at para. 43.
[38] In construing the claims for the purposes of considering the validity of the patent, the court must look primarily to the claims. According to Hughes & Woodley, §26 at p. 311-12, the Court may resort to the specification only in limited circumstances:
In construing a patent, the claims are the starting point. The claims alone define the statutory monopoly and the patentee has a statutory duty to state, in the claims, what the invention is for which protection is sought. In construing the claims, recourse to the rest of the specification is: (1) permissible to assist in understanding the terms used in the claims; (2) unnecessary where the words are plain and unambiguous; and (3) improper to vary the scope or ambit of the claims. This does not mean that claims are never to be construed in light of the rest of the specification but it means that the resort is limited to assisting in comprehending the meaning in which words or expressions contained in the claims are used.
[39] The applicants are relying on Claim 7 which is the claim for the compound sildenafil, and Claims 8, 10, 18 and 22 to the extent they relate to Claim 7. This ‘446 Patent has already been challenged in this Court and the Federal Court of Appeal. This Court and the Federal Court of Appeal construed the relevant patent claim as Claim 7 in the ‘446 patent.
[40] Claim 7 was construed by Justice Mosley in Pfizer v. Apotex, supra, at paragraphs 21 to 35. He concluded, at paragraph 35, as follows:
¶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.
[41] This construction was upheld by the Federal Court of Appeal in Pfizer v. Apotex, 2009 FCA 8 at paragraph 11 per Noel J.A.:
The “solution taught by the patent” that [Justice Mosley] used for this inquiry was consistent with his claim construction, namely “the appreciation that the oral administration of sildenafil, as a potent PDE5 inhibitor, would be useful in the treatment of [ED] in men” (Reasons, para. 57).
[42] The jurisprudence establishes that where a patent has many claims, the Court will construe the relevant claim with respect to the issues. Pfizer submits that in patents such as the one in the case at bar, each claim should be considered separately for the purposes of determining which claim should be construed.
[43] In Laboratoires Servier v. Apotex, 2008 FC 825, 67 C.P.R. (4th) 241, Justice Snider summarized several “guiding posts” for determining demonstrated utility. At paras. 270-1, she found:
[270] …Where a claim is to a class of compounds, lack of utility of one or more of the compounds will invalidate all of the compounds of that particular claim. (Aventis Pharma Inc. v. Apotex Inc., 2006 FCA 64, 46 C.P.R. (4th) 401, at para. 276, leave to appeal to S.C.C. refused, [2006] S.C.C.A. No. 136 (QL), 55 C.P.R. (4th) vi).
[271] Quite simply stated, the question is whether the invention does what the patent promises that it will do.
[Emphasis added]
[44] In C.H. Boehringer Sohn v. Bell-Craig Ltd., [1962] Ex.C.R. 201, 39 C.P.R. 201, Justice Thurlow of the Exchequer Court of Canada found that an individually claimed substance was a separate invention.
[45] In Merck & Co. v. Apotex, 2006 FC 524, 53 C.P.R. (4th) 1, claims for individually exemplified compounds lisinopril, enalapril and enalaprilat were considered separate inventions despite the fact that all these compounds fell within the class of compounds claimed broadly in another claim of the 340 Patent. In that case, Justice Hughes followed Boehringer in finding that these compounds were separate inventions, stating at paragraph 116:
Were I to approach the matter without jurisprudential constraints, I would readily find that the '340 application is directed to but one invention, a class of compounds, of which individual compounds such as lisinopril are but illustrative. However, Boehringer and Hoechst, supra, oblige me to find otherwise…there was, in the 340 application not only examples but also specific claims to the individual compounds enalapril, enalaprilat and lisinopril, each of which…is a different invention from the class.
[Emphasis added]
[46] This finding was upheld by the Federal Court of Appeal at paragraph 26 of its decision (Merck & Co. v. Apotex (FCA), supra). As the ‘446 Patent specifically claims and describes sildenafil in claim 7, the Federal Court of Appeal’s ruling is applicable here and sildenafil in Claim 7 should be considered separately.
Issue No. 1: Whether the invention of sildenafil for the treatment of ED was obvious at the time of the priority date
Abuse of Process
[47] The applicants submit that re-litigating the validity of the ‘446 Patent for obviousness is an abuse of process given the decision of this Court in Apotex, supra, which was affirmed by the Federal Court of Appeal in 2009 FCA 8. In that case, Mr. Justice Mosley found that Pfizer had sufficiently demonstrated that the allegations against the validity of the ‘446 Patent for obviousness were unjustified.
[48] The applicants submit that Novopharm has, in this case, made substantially the same allegations made by Apotex and has not provided better evidence or argument.
[49] The applicants rely on the Federal Court of Appeal’s decision in Sanofi-Aventis Canada Inc. v. Novopharm, wherein the Court found that the patent-holders were could not “re-litigate a claim” that they had already made. The Court stated at paragraph 50:
… Generics likewise must put forward their full case at the first opportunity. Multiple NOAs issued by the same generic relating to a particular drug and alleging invalidity of a particular patent will generally not be permitted, even if different grounds for establishing invalidity are put forward in each. However, where one generic has made an allegation but has failed to put forward the requisite evidence and argument to illustrate the allegation is justified, it would be unjust to preclude a subsequent generic, who is apprised of better evidence or a more appropriate legal argument, from introducing it…
[50] I will follow the decisions of Justice Mosley and the FCA where those findings are applicable on the facts before me. Novopharm has raised specific arguments in relation to obviousness attempting to distinguish the case at bar from that before Justice Mosley. I do not find this to be an abuse of process, and I will decide these arguments on their merits with reference to Justice Mosley’s decision where appropriate. The allegations of lack of utility and sufficiency raised in this application were not before Justice Mosley and there is no issue of possible abuse of process in relation to these allegations.
The law on obviousness
[51] Until recently, Canadian courts followed the test set out by the Federal Court of Appeal in Beloit Canada Ltd. v. Valmut Oy, (1986) 64 N.R. 287, 8 C.P.R. (3d) 289, to determine whether a patent was obvious. That test focused on whether the protected invention was “obvious to try.” Justice Hugessen set out the Beloit test as follows:
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.
[52] The Supreme Court recently examined in detail the legal test for obviousness in Apotex Inc. v. Sanofi-Synthelabo, 2008 SCC 61, 381 N.R. 125. Justice Rothstein reformulated the test for obviousness at paragraph 66:
¶66 For a finding that an invention was “obvious to try,” 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.
In so formulating the test, the Supreme Court changed semantically the threshold for obviousness. Rather than showing that a person skilled in the art could “come directly and without difficulty to the solution taught by the patent to establish obviousness,” now a person challenging the patent need show that “it was more or less self-evident to try” with more than a mere possibility of success.
[53] In affirming Justice Mosley’s decision in Pfizer v. Apotex, the Federal Court of Appeal found that although Justice Mosley did not have the benefit of the Sanofi-Synthlabo decision, his reasoning accorded with the test set out by the Supreme Court in that case. The FCA stated at paragraphs 36-37:
36 It is apparent from the above review that the Federal Court Judge throughout his analysis looked for more than possibilities understanding that mere possibilities were not enough, and that the prior art had to show more than that. His appreciation of the matter is summed up and further demonstrated by his concluding remarks (Reasons, para. 125):
Although there was a significant amount of evidence indicating that cGMP PDE inhibitors should be further explored with regards to the treatment of ED in the months leading up to the Pfizer discovery, the evidence does not in my view establish that the solution taught by the patent was obvious at the time. At best there was speculation, which in hindsight proved to be correct, that PDE5 inhibitors might treat impotence. Experiments with zaprinast, a cGMP PDE inhibitor, had been performed but in an effort to understand how the erectile process works, not how to treat ED.
37 In so holding, the Federal Court Judge drew the line precisely where the Supreme Court drew it in Sanofi-Synthelabo when it held that (para. 66) "the mere possibility that something might turn up is not enough".
[54] The respondent submits that it has presented better and different evidence on the issue of obviousness than was before Justice Mosley in the Apotex case. Specifically, the respondent submits that its evidence on the “obvious to try” issue is substantially different from the evidence before Justice Mosley. The respondent states that Apotex’s evidence did not go beyond showing that there was a “mere possibility that the recommendation of the prior art to use cGMP PDE inhibitors to treat ED might work,” and that had the evidence shown that a skilled person would have a “fair expectation of success,” the result would have been different. According to the respondent, its expert evidence in this case demonstrates such a “fair expectation of success.”
[55] The respondent relies on the Federal Court of Appeal’s decision in Pfizer Inc. v. Apotex Inc. in stating that by showing that a skilled person would have had a “fair expectation of success,” it has established obviousness. The Federal Court of Appeal, commenting on the opposite outcome in proceedings in the Chancery Division involving the corresponding UK patent, stated at paragraph 41-45:
41 The assessment made by the Federal Court Judge is different than that made by Mr. Justice Laddie of the Chancery Division and confirmed by the English Court of Appeal in the U.K. case. The Federal Court Judge was aware of these decisions (Reasons, para. 119). However, he was entitled, indeed obliged to draw his own conclusions.
42 Furthermore, a review of Mr. Justice Laddie's decision suggests that the issue of obviousness was determined on the basis of a broader test than that adopted by the Supreme Court in Sanofi-Synthelabo…
43 The reasoning advanced by Mr. Justice Laddie and approved by the English Court of Appeal is that where the motivation to achieve a result is very high, the degree of expected success becomes a minor matter. In such circumstances, the skilled person may feel compelled to pursue experimentation even though the chances of success are not particularly high.
44 This is no doubt the case. However, the degree of motivation cannot transform a possible solution into an obvious one. Motivation is relevant in determining whether the skilled person has good reason to pursue "predictable" solutions or solutions that provide "a fair expectation of success" (see respectively the passages in KSR International Co. v. Teleflex Inc., 127 S. Ct. 1727 (2007) at page 1742 and Angiotech Pharmaceuticals Inc. v. Conor Medsystems Inc., [2008] UKHL 49, at paragraph 42, both of which are referred to with approval in Sanofi-Synthelabo, supra, at paragraphs 57 and 59).
45 In contrast, the test applied by Mr. Justice Laddie appears to be met if the prior art indicates that something may work, and the motivation is such as to make this avenue "worthwhile" to pursue (Pfizer Ltd., supra, para. 107, as quoted at para. 42 above). As such, a solution may be "worthwhile" to pursue even though it is not "obvious to try" or in the words of Rothstein J. even though it is not "more or less self-evident" (Sanofi-Synthelabo, supra, para. 66). In my view, this approach which is based on the possibility that something might work, was expressly rejected by the Supreme Court in Sanofi-Synthelabo, at paragraph 66.
[My emphasis]
[56] Accordingly, the Federal Court of Appeal held on January 16, 2009 that the test for obviousness in England, which Mr. Justice Laddie applied to the Pfizer patent for Viagra, is a different test than the Canadian test for obviousness set out by the Supreme Court of Canada in Sanofi-Synthelabo. In England, the test is if the prior art indicates that something may work and the motivation is such as to make this avenue “worthwhile to pursue”, then such a solution is obvious to the skilled workman in the field. In Canada the possibility that something might work, and the motivation is such that this avenue is “worthwhile to pursue, was rejected as “obvious”. In Canada it is only obvious if the skilled person has good reason to pursue “predictable” solutions that provide a “fair expectation of success”.
Applying the Obviousness Test to the ‘446 Patent
[57] In Appendix A to the respondent’s memorandum of fact and law, the respondent has set out the findings of fact of Justice Mosley and the relevant “substantially different” evidence before this Court relevant to these findings.
[58] The respondent submits that its evidence – mainly through cross-examination of Pfizer’s experts and the evidence of Novopharm’s experts – establishes the following facts, which are contrary to Justice Mosley’s findings in Apotex:
a. The NANC pathway was generally recognized as the most important pathway to target in treating ED;
b. Very few researchers were working on ED and therefore, it was not true that hundreds of researchers studying ED had failed to realize the importance the NANC pathway;
c. The Murray paper pointed to the potential utility of the cGMP PDE inhibitor zaprinast, not sildenafil however, zaprinast was known to have insufficient selectivity and the fact that zaprinast was not tried does not point to the unobviousness of sildenafil;
d. The focus was not on injections and other therapies prior to sildenafil. Orally administered treatments for ED were known and were considered to be safe and effective; and
e. It was not counterintuitive to use a drug that lowered blood pressure to treat ED. Antihypertensive agents were known to be useful in treating ED
f. Dr. Heaton’s testimony that his reaction to Pfizer’s invention was surprise and skepticism is contradicted by his testimony under cross-examination.
[59] The applicants state that this new evidence is “not new evidence at all” but simply commentary by Novopharm’s experts on Justice Mosley’s findings on obviousness.
My Findings on Obviousness
Prior art did not suggest sildenafil as the invention
[60] In the application at bar I find that the prior art (the Rajfer Paper, the Murray Paper and the Bush Thesis) did not teach sildenafil as a solution for the treatment of ED. Dr. Rajfer did not suggest PDEV inhibitors to treat ED. He suggested direct-acting vascodilators which were NO doners. Dr. Murray suggested PDEV inhibitors could be developed to treat ED, but did not point to sildenafil or call for clinical trials of sildenafil. The Bush Ph.D Thesis did not mention sildenafil or any particular PDEV inhibitor from the ‘‘446 patent. The Court has learned from the evidence that there are billions of PDEV inhibitors, and that the only reason Dr. Ellis, at Pfizer, discovered sildenafil, was by accident in the course of testing sildenafil to treat angina patients in a clinical study. These angina patients unexpectedly experienced erections while being treated with sildenafil to lower their blood pressure.
[61] While Dr. Bush filed an affidavit in the application at bar, which she did not in Pfizer v. Apotex before Justice Mosley, the Court is of the view that her thesis was not widely available at the priority date of this patent and could not be considered part of the prior art at the time the patent application was filed. This Ph.D. thesis was not published; it was only filed in two copies at the universities where Dr. Bush was associated. Nevertheless, the Court has considered the content of the Bush thesis and does not find that its conclusions made it more or less self-evident to try sildenafil.
Other evidence
[62] The Court is also impressed with the evidence produced by Pfizer at this hearing. The experts in the relevant field of science studying pharmaceutical solutions for erectile dysfunction did not have any idea in late 1992, when they attended an international convention on the subject, that PDEV inhibitors, let alone specifically sildenafil, would be effective in treating ED.
[63] The Court is persuaded on the balance of probabilities that persons skilled in the art in 1994, when this patent application was filed, were surprised that Pfizer was claiming an effective oral treatment for ED, and that none of the experts in the field were considering sildenafil as a compound for treating ED (see cross-examination of Dr. de Tejada, Dr. Maurice). Experts in the field were writing after this patent was filed that the treatment of impotence with oral medication was a desired objective for the future. It was the “holy grail” of impotence therapy. When it was finally learned that Pfizer had developed sildenafil for the treatment of impotence, experts wrote that this was a “re