Pfizer Canada Inc. v. Apotex Inc.

Pfizer Canada Inc. v. Apotex Inc.
Court (s) Database
Federal Court Decisions
Date
2002-11-05
Neutral citation
2002 FCT 1138
File numbers
T-2096-00
Notes
Digest
Decision Content
Date: 20021105
Docket: T-2096-00
Neutral citation: 2002 FCT 1138
Ottawa, Ontario, Tuesday the 5th day of November 2002
PRESENT: The Honourable Madam Justice Dawson
BETWEEN:
PFIZER CANADA INC. and PFIZER INC.
Applicants
- and -
APOTEX INC. and THE MINISTER OF HEALTH
Respondents
REASONS FOR ORDER AND ORDER
DAWSON J.
[1] The applicants seek an order pursuant to section 6(1) of the Patented Medicines (Notice of Compliance) Regulations, SOR/93-133 ("Regulations") prohibiting the respondent Minister of Health ("Minister") from issuing a Notice of Compliance ("NOC") to the respondent Apotex Inc. ("Apotex") in connection with its version of the drug sertraline until after the expiration of Canadian Letters Patent No. 2,029,065 (" '065 Patent ").
1. BACKGROUND
[2] Pfizer Inc. is the owner of the '065 Patent and is joined as a party to this proceeding in accordance with subsection 6(4) of the Regulations. Pfizer Canada Inc. markets and sells sertraline in Canada under the trademark Zoloft. Together Pfizer Inc. and Pfizer Canada Inc. are referred to as "Pfizer" in these reasons.
[3] Apotex is a Canadian manufacturer of generic products.
[4] The Minister of Health neither filed materials on the application nor appeared at the hearing.
[5] Sertraline is not a new drug. On August 31, 1982, Canadian Letters Patent No. 1,130,815 (" '815 Patent ") were issued to Pfizer in relation to the use of sertraline for the treatment of depression. The '065 Patent discloses and claims new uses for sertraline for disorders which are distinct from depression. The patent states:
Sertraline may be used to prevent or alleviate anxiety and the symptoms associated with anxiety-related disorders in patients treated with the drug. It is therefore useful in the treatment and management of anxiety-related disorders such as panic disorder, generalized anxiety disorder, agoraphobia, simple phobias, social phobia, posttraumatic stress disorder, obsessive-compulsive disorder and avoidant personality disorder.
[6] The '815 Patent has expired. Upon its expiration Apotex received a NOC for Apo-Sertraline for the treatment of depression only.
(i) The '065 Patent
[7] The '065 Patent contains 13 claims which may be divided into three sets of claims.
[8] Claims 1 and 2 comprise the first set of claims. Claim 1 is a genus claim covering the use of sertraline to prepare a medicament to treat or prevent anxiety-related disorders. Claim 2 specifically sets out those disorders.
[9] Claims 3 to 10 are the second set of claims and they claim the use of sertraline to treat or prevent individual anxiety-related disorders. For example, claim 3 deals with the use of sertraline where the anxiety-related disorder is panic disorder ("PD"), claim 4 is with respect to generalized anxiety disorders and claim 10 is with respect to obsessive-compulsive disorder ("OCD").
[10] Claims 11, 12 and 13 comprise the third set of claims. Claims 11 and 12 relate to compositions of sertraline in amounts effective to treat anxiety-related disorders. Claim 13 is directed to a commercial package of sertraline sold with instructions on how the drug should be used for treating anxiety-related disorders.
[11] Sertraline is marketed, prescribed and sold in Canada for three indications: depression, PD, and OCD. Sertraline was first approved for depression by its first NOC issued on January 30, 1992. Sertraline was then approved for sale for PD in 1996 and for OCD in 1998.
(ii) The Notice of Allegation
[12] Apotex served its Notice of Allegation ("NOA") so that it might obtain a NOC which would enable it to sell Apo-Sertraline with additional uses in connection with OCD and PD. Apotex alleges that the '065 Patent is invalid on the basis that it does not contain inventive subject matter and does not comply with the Patent Act, R.S.C. 1985, c. P-4. Specifically, the legal and factual basis for the claim of invalidity is described as follows in the Notice of Allegation:
(a) Obviousness
1(a). The '065 Patent claims a priority filing date of November 2, 1989 from United States Patent Application No. 431,000. As of that date each of the claims of the '065 Patent are said to be invalid as being obvious on the basis that as of that priority date it was known that:
(a) sertraline was:
(i) a useful antidepressant drug;
(ii) a serotonin reuptake inhibitor; and
(iii) selective for serotonin inhibition over norepinephrine;
(b) serotonin played a role in anxiety-related disorders; and
(c) anxiety-related disorders:
(i) were treated with the use of antidepressants; and
(ii) were treated with the use of serotonin reuptake inhibitors; particularly those which were selective for serotonin inhibition over norepinephrine.
Therefore, it would have been obvious to a person skilled in the art to use the compound sertraline for the treatment of anxiety-related disorders.
1(b). As further support for the allegation of obviousness it is said that prior art in the form of an article entitled "The Clinical Utility of Pharmacological Agents that Act at Serotonin Receptors", Journal of Neuropsychiatry, (Summer 1989), Vol. 1, No. 3, 253-262 ("Peroutka article") disclosed that Phase II clinical trials were being conducted on the use of sertraline in the treatment of OCD.
1(c). A further ground of obviousness was asserted with respect to OCD in that it is said that the use of sertraline for the treatment of this disorder would have been obvious to persons skilled in the art given the state of the art as described in the notice of allegation and in light of the disclosures in the Peroutka article.
Apotex cited 96 literature articles as evidencing the state of the art and its assertion with respect to obviousness.
(b) Anticipation
2. Claims 1, 4, 10, 11, 12 and 13 of the ' 065 Patent are said to be invalid on the basis of anticipation. Those claims contain claims to the use of sertraline to prepare a medicament to treat or prevent OCD. The use of sertraline to prepare a medicament to treat or prevent OCD is said to have been disclosed before the priority date of the '065 Patent in the Peroutka article, and in addition claims 11, 12 and 13 of the '065 Patent are said to be anticipated by the disclosure of the '815 Patent.
(c) Insufficient Specification and Double Patenting
3. Claims 1 through 13 of the '065 Patent are said to be invalid on the basis that the specification of the patent does not comply with requirements of section 34 of the Patent Act and further on the basis of double patenting. Specifically it is alleged that the specification in the '065 Patent fails to:
(i) correctly and fully describe the invention and its operation or use;
(ii) set out clearly the method of using the compound sertraline to treat anxiety-related disorders in such full, clear concise and exact terms as to enable any person skilled in the art to use sertraline for the purpose of treating anxiety-related disorders; and
(iii) claim distinctly and in explicit terms the things that the patentee regards as new and in which he claims an exclusive property or privilege.
(d) Insufficient Specification and Ambiguity
4. Claims 11 through 13 of the '065 Patent are said to be invalid as being ambiguous and in contravention of subsection 34(2) of the Patent Act.
2. THE ISSUES
[13] The issue to be decided on this application is whether Apotex' allegation with respect to the validity of the '065 Patent is justified. The burden is on Pfizer to disprove the allegations in the NOA. This, in turn requires consideration of the following:
i) Is the '065 Patent invalid because it was obvious?
ii) Is the '065 Patent invalid because it was anticipated?
iii) Does the '065 Patent fail to provide sufficient specification or does it constitute double patenting?
iv) Is the '065 Patent invalid because of ambiguity?
3. THE EVIDENCE
[14] In addition to the evidence of its Vice-President, Government and Public Affairs, as to the approvals granted to Pfizer to sell sertraline and as to the service of two NOAs upon it, Pfizer relied upon the evidence of three expert witnesses: Doctors Lapierre, Greist and Rasmussen. Apotex relied upon the evidence of three expert witnesses: Doctors Deakin, Peroutka and Richter. Apotex also relied upon the affidavit of a senior secretary working for co-counsel for Apotex which attached copies of the 96 prior art references specified in the NOA.
[15] Each deponent was cross-examined on his or her affidavit.
[16] The evidence of each expert witness is summarized below.
(i) Pfizer's Experts
(a) Dr. Yvon Lapierre.
[17] Dr. Lapierre is a psychiatrist and professor of Psychiatry. He described his areas of expertise to be in psychiatry, psychopharmacology, consulting especially on diagnosis and psychopharmacological treatment of psychiatric disorders. He swore as follows (throughout the review of the evidence the parenthetic comments are my own).
[18] Each anxiety-related disorder is distinct and each requires its own therapy to be adequately treated. Anxiety disorders are distinct from depression. Some patients suffer from more than one of these disorders at the same time. In light of the overlap between disorders, if a person diagnosed with depression and OCD, or depression and PD, was treated with antidepressants, the practitioner could observe improvement in the OCD or PD symptoms. These observations led to the identification of antidepressants as a possible effective treatment for OCD.
Treatment of OCD
[19] In the late 1980s, different classes of antidepressants, tricyclics, monoamine oxidase inhibitors and selective serotonin reuptake inhibitors ("SSRIs"), were attempted as treatment for OCD, generally without much success.
[20] The most successful drug for first-line treatment of OCD was clomipramine, a tricyclic. While it is a potent serotonin reuptake inhibitor, its primary metabolite is a potent inhibitor of norepinephrine uptake. Clomipramine has been found to be more effective in the treatment of OCD than more potent serotonin reuptake inhibitors. This suggests that its dual action or its inhibition of norepinephrine uptake plays a role in its efficacy.
Treatment of PD
[21] For panic disorder, benzodiazepenes, tricyclics and monoamine oxidase inhibitors were used in the 1980s. The latter two classes of drugs were used in conjunction with or without concomitant benzodiaxepine medication.
SSRIs in the treatment of OCD and PD
[22] In 1989, research identified some SSRIs (fluoxetine and fluvoxamine) as useful for treating OCD, but also mentioned another SSRI (zimelidine) as being ineffective. The use of sertraline for either of these conditions was not mentioned. At the time researchers felt it was unlikely that complex disorders such as OCD and PD would be caused by dysfunction of a single neurotransmitter. Attributing OCD or PD to dysfunction of a single neurotransmitter was considered simplistic in 1989 and still is today.
[23] It was only in the mid to late 1990s that SSRIs became more commonly recognized in the treatment of OCD and PD.
[24] Even today, what causes OCD is not fully understood, and understanding of its treatment, including the use of antiepileptic drugs, continues to evolve. It would be difficult to say that any hypothesis, such as the role of serotonin, is obvious, given the growing support for new explanations of OCD.
[25] Without conducting experiments with sertraline it was not known that sertraline would be effective for treatment of OCD and PD. The most that could be said was that it was worth a try to do a trial with sertraline.
[26] The Peroutka article does not anticipate the '065 Patent because it says nothing about whether sertraline is effective for the treatment of OCD.
(b) Dr. John Greist
[27] Dr. Greist is a psychiatrist and professor of psychiatry. His evidence was as follows.
[28] In 1989 the only published use of sertraline was for the treatment of depression.
Treatment of OCD and PD
[29] In the 1980s clomipramine, which is an SSRI as well as a norepinephrine reuptake inhibitor ("NRI"), was one of the drugs that worked for OCD. By the mid 1980s, some thought that noradrenergic neurotransmission was more likely to be involved in anxiety disorders, and that serotonergic neurotransmission was more likely to be involved in depression.
[30] The leading text on the subject edited by Jenike, et al. published in 1986 contained no emphasis on SSRIs in treating OCD. The focus of treatment of OCD was with behavioural treatments, or clomipramine or lithium. Antidepressants were noted to have been used extensively to treat OCD, but not all medications were found to work.
[31] In 1990, the second edition of the Jenike text on OCD said that a number of carefully controlled trials had demonstrated that some antidepressants are effective in treating OCD while others were ineffective. With respect to sertraline, the authors reported that preliminary data indicates that sertraline is not an effective treatment for OCD. The text also said that pure serotonergic agents may be less effective than drugs with concomitant effects on other systems.
[32] In Dr. Greist's view, because sertraline was known to be one of the most selective SSRIs, it would have been expected to be not as effective for OCD treatment as were less selective drugs.
OCD
[33] In a 1985 article, Insel concluded that the first double-blind trial of the SSRI zimelidine, versus the tricyclic clomipramine, versus placebo, showed that zimelidine was no better than the placebo in the treatment of OCD. The authors wrote they "found no evidence that a selective serotonin uptake inhibitor is more effective than a selective noradenergic uptake inhibitor for decreasing obsessional symptoms." This data led some researchers to hypothesize that SSRIs failed to work in OCD because of their lack of effects on other neurotransmitter systems such as norepinephrine.
[34] In 1989, research into the efficacy of SSRIs was an active area of study. However, there was debate as to whether OCD was more closely related to an anxiety disorder, a mood disorder or neither.
[35] The tricyclic clomipramine, which has effects on both serotonergic and noradrenergic reuptake, was the only drug that had been shown to work for OCD in randomized, double-blind placebo-controlled trials.
[36] In the late 1980s, studies found that fluoxetine (Prozac) and fluvoxamine, two SSRIs, demonstrated some efficaciousness with respect to OCD. However, in light of a lack of effectiveness shown with another SSRI, zimelidine, one could not say that every SSRI would be effective for the treatment of OCD.
[37] Dr. Greist and others were therefore brought together to conduct Phase II testing of sertraline, the purpose of which was to determine whether Phase III testing ought to be done to determine if sertraline was efficacious in the treatment of OCD. In 1990, the initial publication from one site of the trial reported that sertraline failed to improve OCD. (However, a correction was published in October of 1990 which revealed errors from incorrect computer entry of the randomization code. The result of the correction was that a stronger usefulness of sertraline was exhibited).
[38] In 1995, Dr. Greist published an article showing that SSRIs were significantly less effective than clomipramine for OCD. (His article did acknowledge that sertraline had been shown to be of substantial benefit for the treatment of OCD.)
PD
[39] In 1989, benzodiazepenes were still the drug of choice for anxiety-related disorders. As with OCD, there were several competing theories to explain PD.
Anticipation
[40] With respect to the Peroutka article, sertraline is not mentioned under the headings OCD or PD. As for its mention of Phase II clinical trials of sertraline, Phase II clinical trials are not studies to determine effectiveness for a particular treatment, but are preliminary guides to possible efficacy and a prelude to Phase III trials where safety and efficacy are investigated. Further, there is no reference to the results of this Phase II clinical trial. It only states that tests are being done.
Obviousness
[41] At the relevant time, it was not substantiated that because antidepressants were effective in OCD, then SSRIs would also be effective. Competing theories implicating different neurotransmitters were being researched. The consensus in November 1989 was that it would be unreasonable to assume that a complex disorder such as OCD could be explained by examining only one neurotransmitter and a more likely explanation would come from the complex interaction of neurotransmitters.
(c) Dr. Steven Rasmussen
[42] Dr. Rasmussen is a psychiatrist and associate professor of psychiatry who specializes in treatment of anxiety-related disorders including OCD. His evidence is summarized as follows.
[43] He conducted a literature search relating to sertraline. The earliest document which stated that sertraline was effective for OCD is dated 1990, and the earliest document which stated sertraline was effective for PD is dated 1998.
[44] None of the results of the Phase II clinical trials referenced in the Peroutka article had been made public by the relevant date. He participated in those trials. The Peroutka article conveys no information about the efficacy of sertraline for OCD other than the fact that it is being tested. Sertraline is not mentioned in those portions of the article entitled "Obsessive-Compulsive Disorder" and "Panic Disorder".
Phase II Clinical Trials
[45] The term "Phase II clinical trials" was understood both in 1989 and now to refer to early controlled clinical studies that are conducted on a small number of humans (50 to 300). The trials are aimed at obtaining a preliminary determination of the efficacy of a drug and are generally the first studies conducted on humans afflicted with the disease or condition the drug is intended to treat. It is generally accepted in medical and regulatory communities that nothing decisive can be said about a drug's efficacy prior to the conclusion of Phase II testing. Until Phase II clinical trials are completed, sufficient information regarding efficacy can not be obtained to support a decision by a drug company to conduct Phase III clinical trials.
[46] Phase I clinical trials involve the same number or fewer patients, who are not afflicted with the condition, and are aimed at establishing the metabolic and pharmacokinetic profile of the drug in humans.
[47] Phase III clinical trials involve several hundred to one thousand patients and are designed to measure the safety and efficacy of the drug so that if confirmed, the safety and efficacy can be extrapolated to the general population.
Obviousness
[48] The theory that SSRIs played a role in OCD and PD was uncertain, unproven and a matter of active debate in 1989. Without experimentation one would not know if sertraline was in fact effective.
OCD
[49] In 1985, the tricyclic antidepressant clomipramine was the only drug to be shown to work in OCD in randomized, double blind placebo controlled tests. This led to a hypothesis that there was a deficit in serotonergic neurotransmission in OCD. In 1985, the first double blind trial of an SSRI in OCD was published, showing that the SSRI zimelidine was no better than a placebo and that clomipramine was better in the treatment of OCD.
[50] In 1988, an article noted that further tests would need to be done to determine whether the ability to enhance serotonergic activity is necessary for a drug to have anti-obsessional activity. Thus, the hypothesis that serotonin affected OCD symptoms was only one of several competing theories. The most respected research textbook in 1987 did not mention the use of SSRIs or sertraline in the treatment of anxiety states.
[51] A 1988 study by Zak and others concluded that the association between OCD and serotonin was "weak and sparse despite much speculation on the serotonin hypothesis." (However, in its conclusion the article stated:
[...] numerous studies from widespread centers have suggested that serotonin reuptake inhibitors are more effective than other psychotropic medications in the treatment of OCD, although the response rate does not appear to be as marked as that found in patients with major depressive illness and panic disorder who are treated with agents appropriate for those disorders. However, in view of the absence of alternative treatments and the chronically disabling nature of this illness, there is little doubt that the most promising line of investigation to be pursued is with serotonin reuptake inhibitors that seem to be more selective for OCD.) [underlining added] See: "Potential role of Serotonin Reuptake Inhibitors in the Treatment of Obsessive Compulsive Disorders" J. Clin. Psychiatry 1988: 495: 23-30.
[52] A 1989 study supported the hypothesis that an association between serotonin and OCD was not a complete explanation for the disorder. A 1989 review article suggests that the basis for OCD is complex, that serotonin has been implicated in OCD, but a variety of factors complicate this hypothesis.
[53] Due to sertraline's selectivity, there was considerable doubt among some consultants meeting for the design of the Phase III trial that sertraline would prove effective.
[54] An article published in 1995 showed that SSRIs were significantly less effective than clomipramine in treating OCD (although the article noted that sertraline is of a substantial benefit for the treatment of OCD).
PD
[55] With respect to PD, at the time there were three competing theories regarding neurotransmission dysfunction in PD. The first theory implicated deficits in serotonergic neurotransmission. The second theory implicated deficits in noradrenergic transmission, while the third theory pointed a finger at gamma amino butyric acid.
[56] The noradrenergic theory was supported by two studies by Charney et al. A study by Sheehan et al. in 1988 found there was insufficient evidence that SSRIs exerted their anti-panic effect via the seratonergic system. A 1988 study by den Boer and Westenberg suggested that both the noradergenic and serotonergic systems "exert their influence through a final common pathway" and "that in some patients there is an imbalance between the two systems".
Obviousness
[57] It was not common knowledge in the medical community, as demonstrated by the reports, that in 1989 each and every SSRI would work for the treatment of OCD and PD.
(ii) Apotex' Experts
(a) Dr. William Deakin
[58] Dr. Deakin is a psychiatrist and professor of psychiatry. His evidence was as follows.
Obviousness
[59] Prior to the priority date (November 2, 1989) it was well-known that depression and anxiety co-exist, that many antidepressant drugs were shown in double-blind controlled trials to be effective in such mixed disorders, and that antidepressants were better than benzodiazepine.
[60] Prior to 1989, at least six studies had shown that tricyclic antidepressants were effective in mixed anxiety-depression states and more effective than benzodiaxepine medication for anxiety. _ Antidepressant drugs were known to be preferable in the treatment of patients with prominent anxiety symptoms.
[61] Prior to the priority date, it had become a well-established principle that drugs with prominent actions on serotonin reuptake were effective in the treatment of PD. A practitioner skilled in the art might well have used sertraline to treat a patient with panic attacks, as two other SSRIs, fluoxetine and fluvoxamine perceived to be selective inhibitors of serotonin reuptake, had been proven useful in studies published in 1987 and 1987-1988 respectively.
[62] OCD has the longest history of being associated with serotonin dysfunction, and in a 1984 review a researcher concluded that OCD was sensitive to antidepressants with actions on the serotonin system. By 1988, one study concluded that rational treatment for OCD would either be clomipramine or fluvoxamine (both were viewed as potent inhibitors of serotonin reuptake. However, the metabolite of the former was a noradrenaline reuptake inhibitor. One of the articles referred by the witness stated that "drugs that selectively inhibit the reuptake of serotonin are logical candidates for use with OCD patients." [underlining added]).
[63] Before 1989, two trials showed that the SSRIs fluoxetine and fluvoxamine were effective in OCD, and by November 2, 1989, the concept was firmly abroad that antidepressants with actions on 5HT would be effective in the treatment of OCD. Sertraline could reasonably have been used to treat OCD on those who were not tolerating other 5HT-active drugs.
[64] There was therefore nothing inventive in the idea of using sertraline to treat an anxiety-related disorder such as OCD or PD.
Anticipation
[65] The fact that fluoxetine and fluvoxamine had been demonstrated to be efficacious in the treatment of OCD would itself have taught the use of sertraline in the treatment of OCD. The Peroutka article further taught that sertraline, referred to as being in Phase II clinical trials for OCD, would be expected to have anti-OCD activity.
Response to Pfizer Experts
[66] To the extent that Pfizer's experts assert that the SSRI zimelidine was shown to be ineffective in the treatment of anxiety, only one study (Insel) found zimelidine to be less effective than imipramine in OCD. Insel's study of zimelidine versus clomipramine was not placebo-controlled and only five subjects completed the zimelidine arm of the study. The experience with zimelidine had far less salience than the accumulating experience with fluoxetine and fluvoxamine in OCD. Another study found zimelidine to be superior to a noradrenaline uptake inhibitor.
[67] Each of Pfizer's experts fails to distinguish between evidence that serotonin is involved in the causation of OCD, and evidence that drugs which affect serotonin are useful in the treatment of the disorder.
[68] It was clear before 1989 that drugs with a single action on 5HT reuptake were effective in the treatment of PD and that other members of the class would also, with a high probability, be effective. By 1989, it was clear that drugs with the ability to enhance synaptic 5HT concentrations, as well as two of the SSRIs, were probably effective in treating OCD.
[69] With respect to clomipramine, prior to 1989 the weight of the trials was that the noradrenergic agents were ineffective in OCD. There was no protagonist of the theory that actions on noradrenaline were an important therapeutic possibility.
(b) Dr. Stephen J. Peroutka
[70] Dr. Peroutka is a neuropharmacologist and chief medical officer at Collabra Pharma. He is the author of the Peroutka article and swore as follows.
Anticipation
[71] The reference in the 1989 Peroutka article to sertraline undergoing Phase II clinical trials would have been understood to mean that some patients were being administered sertraline for the purpose of determining whether it was effective in treating OCD. Therefore, the article teaches that patients were being administered sertraline for the purpose of treating the condition of OCD. (Nonetheless, on cross-examination Dr. Peroutka admitted that a Phase II clinical trial is a regulatory required study to look for the "first signs of efficacy and safety". Many drugs in development, he said, never get past Phase II trials.)
[72] The Peroutka article gives an exact prior description of the teachings and claims contained in the '065 Patent relating to OCD. His conclusion in this regard is unchanged even if the '065 Patent is interpreted as teaching the efficacy of sertraline for OCD. (In cross-examination he agreed that in 1989 his thinking was that the possibility selective serotonin uptake blockers might be more efficacious in the treatment of OCD was an area of active interest and research. There was room for progress to be made. Dr. Peroutka also admitted that, while the Peroutka article referred to sertraline as being in Phase III clinical trials for treatment of depression and obesity, he did not know if it proved to be effective for that latter condition.)
Obviousness
[73] Given that SSRIs had been shown to be clinically effective in the treatment of OCD and PD by mid-1989, and the fact that sertraline is an SSRI, a person skilled in the art would have predicted or expected that sertraline would be clinically effective in the treatment of OCD and PD. The means of proving the efficacy of sertraline for these conditions would be to conduct clinical trials. The notional skilled person would have conducted such trials. The patent is therefore obvious.
[74] Five cited pieces of prior art support his opinion that a notional person skilled in the art would have known to conduct clinical trials or would have provided direction to that person that clinical trials should be conducted.
(c) Dr. Peggy Richter
[75] Dr. Richter is a psychiatrist and assistant professor of psychiatry. Her evidence was as follows.
Anticipation
[76] Any clinician skilled in the art, having read the Peroutka article, would have known that sertraline worked for OCD. The Peroutka article teaches that sertraline is being administered to patients for the indication or treatment of OCD. With the exception of the dose range which is provided in the '065 Patent, the Peroutka article gives an exact prior description of the patent. However, the dose range for OCD taught by the '065 Patent overlaps with the dose range recommended when sertraline is used in treating depression. Thus, any skilled clinician would automatically have tried sertraline for OCD within the depression dose range, and would likely have observed efficacy.
[77] At the relevant time, SSRIs were regarded by her and others as first-line medications for the treatment of OCD, and were routinely used as soon as they became available on the market.
Obviousness
[78] Sertraline had previously been described as an antidepressant SSRI in the '815 Patent issued on August 31, 1982. It was also known that depression and anxiety disorders commonly existed comorbidly, and both types of conditions benefited from treatment with antidepressants.
[79] Most antidepressants used at the time were tricyclics and monoamine oxidase inhibitors, both of which were known to impact on noradrenergic and serotonergic neurotransmission. In the mid to late 1980s, SSRIs were being investigated in anxiety disorders. Sertraline, being an SSRI, would have been viewed by persons skilled in the art as being potentially useful in the treatment of OCD. With respect to PD, the prior art suggested that sertraline as an SSRI was potentially useful in its treatment.
[80] As of November 2, 1989, it would therefore have been obvious to any competent clinical psychiatrist to use sertraline for the treatment of OCD or PD. (In cross-examination she admitted that not all antidepressants were effective in the treatment of OCD and PD.)
4. ANALYSIS
(i) Preliminary Issues
(a) The Nature of Proceedings under the Regulations and the Burden of Proof
[81] The Regulations ensure that generic manufacturers who apply for a NOC for their version of a patented drug do not obtain a NOC until the relevant patent expires, or until the Court considers the generic's allegation that the patent is expired, invalid or would not be infringed.
[82] In SmithKline Beecham Pharma Inc. v. Apotex Inc. (2001), 14 C.P.R. (4th) 76 (T.D.), Mr. Justice Gibson considered the evidentiary burden in proceedings under the Regulations where an allegation of invalidity is made. At paragraphs 14 and 15 he wrote:
14 Against the foregoing, I conclude that while an "evidential burden" lies on Apotex to put each of the issues raised in its Notice of Allegation "in play", if it is successful in doing so, the "persuasive burden" or "legal burden" then lies with SmithKline. Assuming Apotex to be successful in putting the issue of validity of the '637 Patent "in play", SmithKline is entitled to rely on the presumption of validity of the patent created by subsection 43(2) of the Act.
15 The "persuasive burden" or "legal burden" that lies with SmithKline in the circumstances described in the preceding paragraph is, however, impacted by the nature of the proceeding here before the Court. In Merck Frosst Canada Inc. v. Canada (Minister of National Health and Welfare), [(1994), 55 C.P.R. (3d) 302 (F.C.A.)] Mr. Justice Hugessen, for the Court, wrote at pages 319-20:
As I understand the scheme of the regulations, it is the party moving under s. 6, in this case Merck, which, as the initiator of the proceedings, has the carriage of the litigation and bears the initial burden of proof. That burden, as it seems to me, is a difficult one since it must be to disprove some or all of the allegations in the notice of allegation which, if left unchallenged, would allow the Minister to issue a notice of compliance
. . . . .
In this connection, it may be noted that, while s. 7(2)(b) [of the Regulations] seems to envisage the court making a declaration of invalidity or non-infringement, it is clear to me that such declaration could not be given in the course of the s. 6 proceedings themselves. Those proceedings, after all, are instituted by the patentee and seek a prohibition against the Minister; since they take the form of a summary application for judicial review, it is impossible to conceive of them giving rise to a counterclaim by the respondent seeking such a declaration. Patent invalidity, like patent infringement, cannot be litigated in this kind of proceeding.
Thus, the burden on SmithKline is only to disprove the allegations in the notice of allegation, not to justify declarations of validity and infringement or conversely to negative claims for declarations of invalidity and non-infringement.
[83] Mr. Justice Gibson's decision was affirmed on appeal, 2002 FCA 216, and so I take the above statements to accurately reflect the evidentiary obligations of the parties.
(b) Must Apotex Allege and Lead Evidence that Each Claim of the '065 Patent is Invalid?
[84] Pfizer asserts that for Apotex to succeed in this proceeding, the Court must be satisfied that Apotex' allegation of patent invalidity is justified with respect to each of the 13 claims of the '065 Patent. Pfizer says that Apotex has provided no evidence, for example, that claim 8 of the patent, which claims the use of sertraline to treat post-traumatic stress disorder, is invalid as being obvious. Pfizer also says that Apotex in its NOA does not even attempt to demonstrate that all of the '065 Patent's claims are invalid. Therefore Pfizer argues that because Apotex has not put the issue of the validity of the non-PD and non-OCD claims "in play", Pfizer may rely upon the presumption of validity of the patent created by subsection 43(2) of the Act. Pfizer says that it has therefore disproved the allegation that the patent is invalid so that the application for prohibition should be allowed on this ground alone.
[85] In support of this argument Pfizer relies upon:
i) the language of the NOA which claims that the entire patent is invalid and that each claim of the patent is invalid as being obvious;
ii) jurisprudence such as AB Hassle v. Canada (Minister of National Health and Welfare) (2000), 7 C.P.R. (4th) 272 (F.C.A.), to the effect that the detailed statement provided by the generic manufacturer pursuant to paragraph 5(3)(a) of the Regulations must be exhaustive and any deficiency cannot be remedied; and
iii) subsection 6(2) of the Regulations which says that the Court shall make an order of prohibition if it finds that none of the allegations is justified.
[86] In reply, Apotex argues that this interpretation makes a mockery of the Regulations. Apotex points out that on the basis of this argument Pfizer would keep Apotex out of the market for the authorized uses of PD and OCD on the ground that Apotex has not adduced some evidence putting in issue the validity of the patent as it relates to non-authorized uses of sertraline.
[87] Counsel for the parties were unable to cite any authority which has considered this issue.
[88] For the reasons which follow, I have concluded that Apotex is not obliged to put in issue the validity of claims contained in the '065 Patent that are irrelevant to the authorized use of sertraline to treat PD and OCD.
[89] The obligation of the generic manufacturer who seeks a NOC and who compares its drug to another to establish bioequivalence is set out in subsection 5(1) of the Regulations which provides:
5. (1) Where a person files or has filed a submission for a notice of compliance in respect of a drug and compares that drug with, or makes reference to, another drug for the purpose of demonstrating bioequivalence on the basis of pharmaceutical and, where applicable, bioavailability characteristics and that other drug has been marketed in Canada pursuant to a notice of compliance issued to a first person and in respect of which a patent list has been submitted, the person shall, in the submission, with respect to each patent on the register in respect of the other drug,
(a) state that the person accepts that the notice of compliance will not issue until the patent expires; or
(b) allege that
(i) the statement made by the first person pursuant to paragraph 4(2)(c) is false,
(ii) the patent has expired,
(iii) the patent is not valid, or
(iv) no claim for the medicine itself and no claim for the use of the medicine would be infringed by the making, constructing, using or selling by that person of the drug for which the submission for the notice of compliance is filed. [underlining added]
5. (1) Lorsqu'une personne dépose ou a déposé une demande d'avis de conformité pour une drogue et la compare, ou fait référence, à une autre drogue pour en démontrer la bioéquivalence d'après les caractéristiques pharmaceutiques et, le cas échéant, les caractéristiques en matière de biodisponibilité, cette autre drogue ayant été commercialisée au Canada aux termes d'un avis de conformité délivré à la première personne et à l'égard de laquelle une liste de brevets a été soumise, elle doit inclure dans la demande, à l'égard de chaque brevet inscrit au registre qui se rapporte à cette autre drogue :
a) soit une déclaration portant qu'elle accepte que l'avis de conformité ne sera pas délivré avant l'expiration du brevet;
b) soit une allégation portant que, selon le cas :
(i) la déclaration faite par la première personne aux termes de l'alinéa 4(2)c) est fausse,
(ii) le brevet est expiré,
(iii) le brevet n'est pas valide,
(iv) aucune revendication pour le médicament en soi ni aucune revendication pour l'utilisation du médicament ne seraient contrefaites advenant l'utilisation, la fabrication, la construction ou la vente par elle de la drogue faisant l'objet de la demande d'avis de conformité. [Le souligné est de moi.]
[90] The generic's obligation under the Regulations is therefore triggered by the filing of a submission for a NOC in circumstances where a comparison is made between the generic's drug and another drug which has been marketed in Canada pursuant to a NOC.
[91] The evidence of Pfizer's Vice-President, Government and Public Affairs establishes that NOCs have issued to Pfizer with respect to sertraline for the treatment of depression, PD and OCD. Apotex has already received a NOC for the sale of its version of the drug sertraline for the treatment of depression. Sertraline has not been approved for use in Canada for the treatment of any disorders referred to in the '065 Patent other than PD and OCD.
[92] Therefore, ignoring depression, the only comparison which Apotex can make under subsection 5(1) of the Regulations is to Pfizer's sertraline being marketed in Canada for PD and OCD.
[93] Use of Apotex's version of sertraline in connection with PD or OCD will not infringe the