Pfizer Canada Inc. v. Pharmascience Inc.

Pfizer Canada Inc. v. Pharmascience Inc.
Court (s) Database
Federal Court Decisions
Date
2013-02-04
Neutral citation
2013 FC 120
File numbers
T-556-11
Decision Content
Date: 20130204
Docket: T-556-11
Citation: 2013 FC 120
Toronto, Ontario, February 4, 2013
PRESENT: The Honourable Mr. Justice Hughes
BETWEEN:
PFIZER CANADA INC., AND
WARNER-LAMBERT COMPANY LLC
Applicants
and
PHARMASCIENCE INC. AND
THE MINISTER OF HEALTH
Respondents
REASONS FOR JUDGMENT AND JUDGMENT
[1] This is an application brought under the provisions of the Patented Medicines (Notice of Compliance) Regulations SOR/93-133, as amended (NOC Regulations) to prohibit the Minister of Health from issuing a Notice of Compliance to Pharmascience Inc. in respect of its PMS-Pregabalin capsules of 25 mg, 50 mg, 75 mg, 150 mg, and 300 mg dosage strengths until the expiry of Canadian Letters Patent No. 2,255,652 ('652 patent). The original Notice of Application was filed April 1, 2011, which means that this matter must be determined by April 1, 2013.
[2] For the reasons that follow, I find that the Application is dismissed, with costs.
INDEX
[3] The following is an Index to these Reasons by paragraph numbers:
THE PARTIES
Paras 4 to 8
THE '652 PATENT GENERALLY
Paras 9 to 15
THE EVIDENCE
Paras 16 to 20
ISSUES
Paras 21 to 23
BURDEN
Paras 24 to 27
PERSON SKILLED IN THE ART
Paras 28 to 35
THE '652 PATENT IN DETAIL
a) The Specification
Paras 36 to 58
Paras 36 to 58
CLAIM 3
Paras 59 - 62
CONSTRUCTION OF CLAIM 3 – PAIN
Paras 63 to 82
CLAIMS BROADER THAN THE INVENTION MADE OR DISCLOSED
Paras 83 to 95
SOUND PREDICTION – UTILITY DISCLOSURE
Pharmaceutical Claims
Invention
History of the Jurisprudence
Where does all this leave us?
In the present case:
Paras 96 to 163
Paras 102 to 105
Paras 106 to 111
Paras 112 to 158
Para 159
Paras 160 to 163
UTILITY – SOUND PREDICTION –
CLAIM 3
Pregabalin does not treat all types of pain
The patent fails to disclose any utility of the racemate or any basis for a sound prediction that the racemate would treat all or even some types of pain:
Paras 164 to 185
Paras 168 to 178
Paras 179 to 185
OBVIOUSNESS
Paras 186 to 205
REISSUE APPLICATION
Paras 206 to 215
CONCLUSIONS AND COSTS
Paras 216 to 218
THE PARTIES
[4] The Applicant Pfizer Canada Inc. (Pfizer) is a “first person” as so described in the NOC Regulations. It has listed the '652 patent in accordance with those Regulations. Pfizer has obtained from the Minister of Health a Notice of Compliance to sell tablets containing pregabalin in 25, 50, 75, 150, and 300 mg. strengths, which it does under the brand name LYRICA.
[5] The Applicant Warner-Lambert Company LLC (Warner-Lambert) claims to be the owner of the '652 patent. This claim is not contested in these proceedings.
[6] The Respondent Pharmascience Inc. (Pharmascience) is a “second person” as so described in the NOC Regulations. It seeks to sell a generic version of Pfizer’s LYRICA drug. To do so, it must receive a Notice of Compliance from the Minister of Health. In accordance with the NOC Regulations, Pharmascience has served Pfizer with a Notice of Allegation dated February 11, 2011.
[7] In that Notice of Allegation, Pharmascience alleged that claims 4, 6-12, 14 and 15 of the ‘652 patent would not be infringed, and that the patent is invalid on the grounds of anticipation, obviousness, inutility, lack of sound prediction, ambiguity and claims broader than the invention made or disclosed; all as more particularly set out in the enclosed Detailed Statement.
[8] The Respondent Minister of Health is charged with various duties under the NOC Regulations, including the issuance of a Notice of Compliance to a “second person” such as Pharmascience in appropriate circumstances. The Minister took no active role in these proceedings.
THE '652 PATENT GENERALLY
[9] Canadian Letters Patent No. 2,255,652 (the '652 patent) was applied for by an application deemed to be filed with the Canadian Patent Office on July 16, 1997. Therefore, that patent is governed by the provisions of the “new” Patent Act, RSC 1985, c. P-4, applicable to patents applied for after October 1, 1989.
[10] The application was filed under the provisions of the Patent Cooperation Treaty (PCT) and claims priority from a first application filed in the United States Patent Office on July 24, 1996. This is the date upon which issues of obviousness and anticipation will be determined.
[11] Under the provisions of the PCT the application for the patent was deemed to be filed in the Canadian Patent Office on July 16, 1997. This is the date from which the term of the patent is to be calculated and upon which the issue of sound prediction is to be considered.
[12] The application was laid open for public inspection under the provisions of the Patent Cooperation Treaty on January 29, 1998. This is the date that is to be used for purposes of construing the patent and its claims.
[13] The '652 patent names Lakhbir Singh of Great Britain as inventor. He filed an affidavit in these proceedings and was cross-examined.
[14] The '652 patent was issued and granted to Warner-Lambert Company of the United States on July 13, 2004. The term of the patent, unless the patent is declared to be invalid in an appropriate action, will expire twenty (20) years from the date that the application was filed in Canada; that is, on July 16, 2017.
[15] It is agreed that only one claim, claim 3, of the '652 patent is at issue in this proceeding. The construction of that claim and the patent will be considered later in these Reasons.
THE EVIDENCE
[16] As is usual in these proceedings, the evidence took the form of affidavits, exhibits to affidavits, transcripts of cross-examination, and exhibits to cross-examination. The Court had no opportunity to see or hear the witnesses or to observe their demeanour.
[17] The Applicants have filed the affidavits, with exhibits, of the following persons:
• Dr. Kenneth E. McCarson: Associate Professor of Pharmacology at the University of Kansas Medical Centre, Kansas City, Kansas. He claims expertise in respect of the formalin test, carrageenin test, and post-surgical model all as reported in the '652 patent. He submitted an affidavit in chief and a reply affidavit, and was cross-examined.
• Dr. Stephen McMahon: Professor of Physiology at King’s College London, and Director of the London Pain Consortium. He claims expertise in the fields of neuroscience, somatosensory neurobiology, and particularly, pain. Dr. McMahon submitted an affidavit in chief and a reply affidavit, and was cross-examined.
• Dr. Roman Jovey: A medical doctor trained as a general practitioner and is the Medical Director at CPM Centres for Pain Management in Mississauga, Ontario, and Physician-Director of the Addictions & Concurrent Disorders Centre at the Credit Valley Hospital in Mississauga. He claims expertise, as a medical doctor, in the areas of chronic pain management and substance abuse. Dr. Jovey filed an affidavit and was cross-examined.
• Dr. Lakhbir Singh: He is the person named as inventor in the '652 patent. Dr. Singh filed an affidavit and was cross-examined.
• Dr. Ann G. Hayes: A pharmacologist acting as an independent pharmaceutical consultant to the pharmaceutical industry, particularly in the area of central nervous system diseases. Her affidavit was filed in reply to the affidavit of Dr. Jamali (which I will note later). She was cross-examined.
• Dianne Zimmerman: A law clerk in the offices of the Applicants’ solicitors. Her affidavit served to place a large number of documents in the record. She was not cross-examined.
[18] Pharmascience raised challenges as to the extent of the expertise as claimed by Drs. McCarson, McMahon, and Jovey. I find that they have extensive expertise sufficient to be of assistance here.
[19] The Respondent Pharmascience filed the affidavits, with exhibits, of the following persons:
• Dr. Alan Cowan: A Professor of Pharmacology and Anaesthesiology at Temple University, Pennsylvania. He claims expertise in the treatment of pain and use of various animal models of pain. He filed an affidavit in chief and a sur-reply affidavit. He was cross-examined.
• Dr. C. Peter Watson: An Assistant Professor of Medicine, Division of Neurology, at the University of Toronto. He is a medical doctor and claims expertise in the treatment and diagnosis of neuropathic pain. Dr. Watson submitted an affidavit and was cross-examined.
• Dr. Fakhreddin Jamali: Professor in the Faculty of Pharmacy and Pharmaceutical Services, University of Alberta. He claims expertise in the field of pharmacokinetics and pharmacodynamics, onset of analgesia and inflammation. He filed an affidavit in chief and another in sur-reply. He was cross-examined.
• Rebecca Hayley: A law clerk in the offices of Pharmascience’s solicitors. Her affidavit served to place certain documents in the record. She was not cross-examined.
[20] The Applicant challenges the expertise as claimed by Dr.Watson to the extent that he is a medical doctor and not expert in animal models. I reject that challenge as I will find that the patent is directed to persons skilled in the art including medical doctors experienced in the treatment of pain such as Dr Watson.
ISSUES
[21] The principal issue for determination by the Court is whether or not to grant an Order prohibiting the Minister from granting a Notice of Compliance to Pharmascience for its generic pregabalin tablets until the expiry of the '652 patent. The basis for doing so is whether the various allegations raised by Pharmascience as to invalidity of the '652 patent, are justified. Those allegations, though many were raised in the Notice of Allegation, have been reduced in the written and oral arguments made by Pharmascience, to the following:
• Claims Broader than the Invention Made or Disclosed
• Sound Prediction
• Actual Inutility
• Obviousness
[22] It must be noted that while Pharmascience raised the issues of anticipation and ambiguity in its Notice of Allegation these issues were not pursued in its written argument submitted to the Court. The Notice of Allegation did raise the point that Pfizer had applied to reissue the ‘652 patent so as to include a number of very specific claims but ultimately abandoned that application. This point was not included in Pharmascience’s written argument but was addressed in its oral argument. Pharmascience raised a question of sufficiency in Dr Cowan’s affidavit (paragraphs 105-107) however sufficiency was not raised in the Notice of Allegation.
[23] In order to address the active issues, the Court must address the following issues first:
• Burden
• Person Skilled in the Art
• Claim Construction
BURDEN
[24] The main issue is whether Pharmascience’s allegations as to invalidity of the ‘652 patent are justified. Infringement is not an issue.
[25] There have been many decisions addressing the question of burden when the issue in NOC proceedings is that of patent validity. I refer for instance to Pfizer Canada Inc v Apotex Inc, 2007 FC 26 at paras 9 and 12, and 2007 FCA 195, leave to appeal to Supreme Court refused; Pfizer Canada Inc v Canada (Minister of Health), 2012 FC 767 at para 42, affirmed in the result 2012 FCA 308.
[26] To put the matter briefly, the Patent Act, subsection 43(2) affords a patent a presumption of validity. In NOC proceedings the “second person” must lead some evidence to rebut that presumption. Once such evidence has been led the Court must determine the issue of validity on the usual civil burden of proof having regard to all the relevant evidence.
[27] In this case Pharmascience has led evidence as to validity as has Pfizer. The matter will be considered on the usual civil burden which rests upon Pharmascience.
PERSON SKILLED IN THE ART
[28] The person skilled in the art, or as sometimes described, the person of ordinary skill in the art (POSITA) is the notional person, which may include a team of persons, through whose eyes a patent is to be construed, the prior art is to be considered. This notional person may be pertinent to other issues that arise in respect of a patent under consideration by the Court.
[29] In the present case the parties are agreed, to a certain extent, as to the qualifications as to the person skilled in the art. They are agreed that such a person includes a scientist with advanced education and experience in pharmaceuticals used in the treatment of pain. Pharmascience urges that such a person should be in addition should be a physician who treats patients suffering from pain.
[30] Assistance can be derived from the wording of the ‘652 patent. The opening paragraph states:
The present invention is the use of analogs of glutamic acid and gamma-aminobutyric acid (GABA) in pain therapy, as the compounds exhibit analgesic/antihyperalgesic action. Advantages of the use of the compounds includes the finding that repeated use does not lead to tolerance nor is there a cross-tolerance between morphine and the compounds.
[31] The ‘652 patent acknowledges, at page 1, lines 9 to 15 that the compounds themselves are known and have been previously used to treat certain disorders of the central nervous system.
[32] Much of the description of the patent deals with tests administered to rats in order to determine or predict the ability of the compounds to alleviate pain.
[33] I note that the named inventor, Dr. Singh, in cross-examination in reply to questions 79 to 82 said that he was not a chemist but that his contribution was as a pharmacologist.
[34] I am satisfied that a person skilled in the art is a team including a scientist such as a pharmacologist with experience in animal modeling with compounds of interest and a physician with experience in the selection and use of compounds likely or believed to be likely to be effective in the alleviation of pain.
[35] I am able, in varying degrees, to receive assistance from all the expert witnesses whose evidence has been provided in these proceedings.
THE '652 PATENT IN DETAIL
a) The Specification
[36] The specification or descriptive portion of the patent begins at page 1 with a general statement of the invention; namely, the use of certain compounds in pain therapy, because they exhibit certain action. The advantage is stated to be that they do not lead to tolerance or cross-tolerance with morphine.
The present invention is the use of analogs of glutamic acid and gamma-aminobutyric acid (GABA) in pain therapy, as the compounds exhibit analgesic/antihyperalgesic action. Advantages of the use of the compounds includes the finding that repeated use does not lead to tolerance nor is there a cross-tolerance between morphine and the compounds.
[37] The next paragraph at page 1 acknowledges that these are known compounds previously used to treat certain central nervous system disorders; a number of patents disclosing the compounds and such uses are cited; the WP 93/23383 patent should be noted as it is referred to by some of the expert witnesses:
The compounds of the invention are known agents useful in antiseizure therapy for central nervous system disorders such as epilepsy, Huntington’s chorea, cerebral ischemia, Parkinson’s disease, tardive dyskinesia, and spasticity. It has also been suggested that the compounds can be used as antidepressants, anxiolytics, and antipsychotics. See WO 92/09560 (United States Serial Number 618,692 filed November 27, 1990) and WP 93/23383 (United States Serial Number 886,080 filed May 20, 1992).
[38] There follows at page 1 a summary of the invention; namely, the use of a certain compound in the treatment of pain “especially for chronic pain”, including “but not limited to” a long list of particular types of pain, including a type of “acute” pain:
SUMMARY OF THE INVENTION
The instant invention is a method of using a compound of Formula I below in the treatment of pain, especially for treatment of chronic pain disorders. Such disorders include, but are not limited to, inflammatory pain, postoperative pain, osteoarthritis pain associated with metastatic cancer, trigeminal neuralgia, acute herpetic and postherpetic neuralgia, diabetic neuropathy, causalgia, brachial plexus avulsion, occipital neuralgia, reflex sympathetic dystrophy, fibromyalgia, gout, phantom limb pain, burn pain, and other forms of neuralgic, neuropathic, and idiopathic pain syndromes.
[39] At the top of page 2, the compound is described by a general formula called Formula I, which is later claimed in claim 1; a set of preferred compounds are set out, which are claimed in claim 2, and more preferred compounds – two of them – are set out; these two compounds are claimed in claim 3, which is the claim at issue.
[40] I digress at this point to deal with the concept of racemates, as the above description deals with diastereomers and enantiomers. A brief discussion of racemates and enantiomers can be found in the affidavits of Dr. Hayes and the reply affidavit of Dr. Jamali. I repeat what I wrote in Janssen-Ortho Inc v Novopharm Limited, 2006 FC 1234 (aff’d 2007 FCA 217) at paragraphs 28 to 31:
28 Molecular compounds although often written out as a series of letters, number and symbols or depicted on a flat sheet of paper, do not exist that way in reality. They are three dimensional structures. Some compounds only assume one three dimensional shape, others such as those that are racemic, do not.
29 Racemic compounds, also called racemates, exist as comprising the same atoms in the same sequence, but bent at joints called chiral centres so as to assume what has been called left handed (levo) or right handed (dextro) configurations. Levo is sometimes simply depicted as (-) and dextro as (+). The left handed configuration is the mirror image of the right.
30 A racemate is said to contain an equal number of left and right handed configurations of the molecule. This concept is sometimes depicted (+/-) although that is unnecessary when a competent chemist would be able to detect a chiral centre.
31 Knowing that a compound is racemic is to know that, if there is only one chiral centre as there is in this case of Ofloxacin, there is a left hand and a right hand version of the molecule. Each version can be detected optically by a device such as a polarimeter. That device will detect which of the two configurations turns light to the left (levo or -) and which turns light to the right (dextro or +). Depending on the prevailing conditions different researchers may detect the molecules differently.
[41] To this I would add that sometimes, instead of using (+) or (-), or dextro or levo, to identify one or other of the enantiomers, the letters R and S are used.
[42] In the language of the '652 patent, the two compounds that are said to be “more preferred’, the racemate (having equal parts of the S and R enantiomers) is written as “3-aminomethyl-5-methyl-hexanoic acid” and the enantiomer of interest is the “S” enantiomer, which is written as “(S)-3-(aminomethyl)-5-methylhexanoic acid”. This “S” enantiomer is also identified in the patent as “CI-1008 (S)”. In the evidence and argument in this case, and in general scientific parlance, the S enantiomer is referred to as pregabalin. Thus, the two “more preferred” compounds, as set out in the description and in claim 3, can more easily be referred to as pregabalin and its racemate.
[43] I further note that in some of the scientific literature in evidence the R enantiomer is referred to as R-Isobutyl gaba.
[44] To return to the text of the ‘652 patent and commencing at the lower portion of page 2 and continuing to the top portion of page 5 of the '652 patent, six tests conducted using rats are described, together with reference to the drawings attached to the back of the patent. While the description refers to 3-aminomethyl-5-methyl-hexanoic acid (the racemate) as one of the compounds tested it is agreed by Counsel for the parties that what in fact was tested and being reported is a compound which is the R enantiomer and not the racemate.
[45] The first test, Figure 1, compares gabapentin, pregabalin (CI-1008) and the R enantiomer administered to rats in what has been described as a formalin test. The second and third tests, Figures 2 and 3, compares gabapentin and pregabalin administered to rats in what has been described as a carrageenin test; in one pressure is applied to a rat’s paw in the other heat is applied. In the fourth test, Figure 4, morphine, gabapentin and pregabalin are administered to rats before surgery is conducted. The fifth test, Figure 5, is similar but it measures allodynia, a painful response to a mild stimulus such as brushing. The sixth and final test reported, Figure 6 tests only pregabalin administered to rats in respect of thermal hyperalgesia, an increased response to a painful stimulus, and allodynia. It must be noted that no tests in respect of the racemate are reported in the ‘652 patent.
[46] At page 5, a “Detailed Description” of the invention is provided. It reiterates that the invention is a method of using a compound of Formula I as an analgesic in the treatment of pain. A variety of types of pain are listed. This list is not co-extensive with the list at page 1; for instance, the two types of “acute” pain are not listed. The pain is limited to neuropathic pain. A list of such pain is provided; however, it is stated that the pain is “not limited to” the pain as listed. A one sentence paragraph follows which also includes fibromyalgia pain. A paragraph follows stating that currently-marketed analgesics (not named) treat such pain poorly due to insufficient efficacy or limiting side effects. No statement is provided saying that the compounds of the invention are better than existing compounds; nor are test results provided to support a claim of superiority.
DETAILED DESCRIPTION
The instant invention is a method of using a compound of Formula I above as an analgesic in the treatment of pain as listed above. Pain such as inflammatory pain, neuropathic pain, cancer pain, postoperative pain, and idiopathic pain which is pain of unknown origin, for example, phantom limb paid are included especially. Neuropathic pain is caused by injury or infection of peripheral sensory nerves. It includes, but is not limited to pain from peripheral nerve trauma, herpes virus infection, diabetes mellitus, causalgia, plexus avulsion, neuroma, limb amputation, and vasculitis. Neuropathic pain is also caused by nerve damage from chronic alcoholism, human immunodeficiency virus infection, hypothyroidism, uremia, or vitamin deficiencies. Neuropathic pain includes, but is not limited to pain caused by nerve injury such as, for example, the pain diabetics suffer from.
Compounds of Formula I are also useful in the treatment of fibromyalgia pain.
The conditions listed above are known to be poorly treated by currently marketed analgesics such as narcotics or nonsteroidal anti-inflammatory drugs (NSAID) due to insufficient efficacy or limiting side effects.
[47] The remaining portion of page 5, all of page 6 and the first paragraph of page 7 of the '652 patent is directed to chemistry, which is not of interest in respect of the matters at issue here.
[48] The next three paragraphs on page 7 of the '652 patent are directed to the formulation of the compounds into pharmaceutical compositions and to dosages and administration to mammals, including humans.
[49] At the bottom of page 7 and top half of page 8 is a report of a test upon rats injected with formalin, in which the effects of gabapentin, pregabalin and the racemate are measured.
[50] At the lower half of page 8 over to line 11 of page 9, there is a report of a test upon rats injected with carrageenin in which the effects of gabapentin and pregabalin are measured.
[51] At lines 13 and 14 of page 9, it is stated, in respect of these tests:
These data show that gabapentin and CI-1008 (pregabalin) are effective in the treatment of inflammatory pain.
[52] At line 14 to 19 of page 9, there is mention of a Bennett test and a Kim test; but no data, results or conclusions are presented.
[53] At line 20, and following at page 9, there is a description of a Brennan test involving surgery to the hind paw of a rat. Following that description and to the bottom of page 11, the surgical procedures and subsequent tests conducted on the rats are described in detail.
[54] The first two tests set out at page 12 describe administration to the rats, before surgery, of gababentin, pregabalin and morphine; and their reaction to heat and brushing. The third test, described at the bottom of page 12 and over to page 13, reports testing on rats after surgery, who have been administered pregabalin.
[55] The conclusions in respect of these results is set out at page 13:
Gabapentin and S-(+)-3-isoburylgaba did not affect PWL in the thermal hyperalgesia test or tactile allodynia scores in the contralateral paw up to the highest dose tested in any of the experiments. In contrast, morphine (6 mg, s.c.) increased PWL of the contralateral paw in the thermal hyperalgesia test (data not shown).
The results presented here show that incision of the rat plantaris muscle induces thermal hyperalgesia and tactile allodynia lasting at least 3 days. The major findings of the present study are that gabapentin and S-(+)-3-isoburylgaba are equally effective at blocking both nociceptive responses. In contrast, morphine was found to be more effective against thermal hyperalgesia than tactile allodynia. Furthermore, S-(+)-3-isoburylgaba completely blocked induction and maintenance of allodynia and hyperalgesia.
[56] The claims and drawings follow.
[57] There are 16 claims in all. All are directed to a compound for use in treating pain in a mammal. Claim 1 claims the compound in very broad terms. Claim 2 narrows those terms somewhat. Claim 3 restricts the compounds to two; pregabalin and the racemate. Claims 4 to 16, inclusive, all depend upon claim 1, which is the claim directed to a very broad number of compounds, and restrict the pain which the compound is to treat to very specific pain; claim 4 is inflammatory pain, claim 5 is neuropathic pain; claim 6 is cancer pain; claim 7 is postoperative pain; claim 8 is phantom limb pain; claim 9 is burn pain; claim 10 is gout pain; claim 11 is osteoarthritic pain; claim 12 is trigeminal neuralgia pain; claim 13 is acute herpetic and postherpetic pain; claim 14 is causalgia pain; claim 15 is idiopathic pain; claim 16 is fibromyalgia pain.
[58] Claim 3 is the only claim at issue here.
CLAIM 3
[59] Claim 3 is a dependent claim. It depends on claim 1. Claims 1 and 3 read as follows:
1. For use in treating pain, in a mammal, a therapeutically effective amount of a compound of Formula I
Or a pharmaceutically acceptable salt, diastereomer, or enantiomer thereof
Wherein
R1 is a straight or branched alkyl of from 1 to 6 carbon atoms, phenyl, or cycloalkyl of from 3 to 6 carbon atoms;
R2 is hydrogen or methyl; and
R3 is hydrogen, methyl, or carboxyl.
. . .
3. A compound according to claim 1 which is (S)-3-(aminomethyl)-S-
methylhexanoic acid or 3-aminomethyl-5-methyl-hexanoic acid.
[60] Incorporating claim 1 into claim 3, claim 3 reads as follows:
3. For use in treating pain, in a mammal, a therapeutically effective amount of a compound which is (S)-3-(aminomethyl)-5-methylhexanoic acid or 3-aminomethyl-5-methyl-hexanoic acid.
[61] Using the terminology for the compounds as used in the evidence and argument in this case, claim 3 can be simplified to read:
3. For use in treating pain, in a mammal, a therapeutically effective amount of pregabalin or its racemate.
[62] There is no dispute raised that a mammal includes a human (see page 7, line 8 of the patent) and that the claim includes pregabalin or its racemate. The dispute between the parties is what is included in “pain”.
CONSTRUCTION OF CLAIM 3 - PAIN
[63] Claim 3 as set out above is directed to the use of pregabalin or its racemate in a mammal, including humans, in treating pain. Unlike claims 5 to 16, no particular pain or classification of pain is specified. The court has been called upon by the parties to construe claim 3 and, in particular, what is meant by “pain”.
[64] There have been many judicial instructions as to the construction of a claim. To summarize:
• construction must be done before considering the issues of validity and infringement;
• construction is done by the Court alone, as a matter of law;
• the Court is to construe the claim through the eyes of the person skilled in the art to which the patent pertains;
• the Court may obtain the assistance of experts to explain the meaning of particular words and phrases, and as to the state of the art as of the date the claim was published;
• the Court should read the claim in the context of the patent as a whole, including the description and other claims;
• The Court should avoid importing this or that gloss from the description;
• the Court should not restrict the claim to specific examples in the patent;
• the Court should endeavour to interpret the claim in a way that gives effect to the intention of the inventor;
• the Court should endeavour to support a meritorious invention.
[65] I reviewed at length in Merck & Co, Inc v Pharmascience Inc, 2010 FC 510, the development of patent claims from the beginning of the time when patents were first granted for inventions. At first, there were no claims at all. Then, there were generalized statements such as “I claim the invention of X as described herein”. Then, there came the stricter requirements, such as those set out in section 27 of the Patent Act, RSC 1987, c P-4.
[66] The current state of the law has been expressed in the unanimous reasons of the Supreme Court of Canada, written by Justice Binnie, in Free World Trust v Électro-Santé Inc., [2000] 2 SCR 1024, where he described claims as fences, and that the task of the Court is to separate the essential from the inessential. He wrote at paragraph 15:
15 In reality, the "fences" often consist of complex layers of definitions of different elements (or "components" or "features" or "integers") of differing complexity, substitutability and ingenuity. A matrix of descriptive words and phrases defines the monopoly, warns the public and ensnares the infringer. In some instances, the precise elements of the "fence" may be crucial or "essential" to the working of the invention as claimed; in others the inventor may contemplate, and the reader skilled in the art appreciate, that variants could easily be used or substituted without making any material difference to the working of the invention. The interpretative task of the court in claims construction is to separate the one from the other, to distinguish the essential from the inessential, and to give to the "field" framed by the former the legal protection to which the holder of a valid patent is entitled.
[67] At paragraph 33 and following, Justice Binnie considered two approaches to claim construction; the central claim drafting principle, and the peripheral claiming principle. Canadian courts have preferred the latter, which emphasizes the language of the claims as defining not the underlying technical idea, but the legal boundary of the state-conferred monopoly. He wrote at paragraph 33:
33 The Patent Act requires the letters patent granting a patent monopoly to include a specification which sets out a correct and full "disclosure" of the invention, i.e., "correctly and fully describe[s] the invention and its operation or use as contemplated by the inventor" (s. 34(1)(a)). The disclosure is followed by "a claim or claims stating distinctly and in explicit terms the things or combinations that the applicant regards as new and in which he claims an exclusive property or privilege" (s. 34(2)). It is the invention thus claimed to which the patentee receives the "exclusive right, privilege and liberty" of exploitation (s. 44). These provisions, and similar provisions in other jurisdictions, have given rise to two schools of thought. One school holds that the claim embodies a technical idea and claims construction ought to look to substance rather than form to protect the inventive idea underlying the claim language. This is sometimes called the "central claim drafting principle" [page1045] and is associated with the German and Japanese patent systems: T. Takenaka, "Doctrine of Equivalents after Hilton Davis: A Comparative Law Analysis" (1996), 22 Rutgers Computer & Tech. L. J. 479, at pp. 491, 502 and 519. The other school of thought supporting what is sometimes called the "peripheral claiming principle" emphasizes the language of the claims as defining not the underlying technical idea but the legal boundary of the state-conferred monopoly. Traditionally, for reasons of fairness and predictability, Canadian courts have preferred the latter approach.
[68] The conclusions were set out at paragraphs 42 and 43. Discretionary or subjective interpretation is to be kept to a minimum. A claim must be interpreted in an informed and purposive way:
42 The patent system is designed to advance research and development and to encourage broader economic activity. Achievement of these objectives is undermined however if competitors fear to tread in the vicinity of the patent because its scope lacks a reasonable measure of precision and certainty. A patent of uncertain scope becomes "a public nuisance" (R.C.A. Photophone, Ld. v. Gaumont-British Picture Corp. (1936), 53 R.P.C. 167 (Eng. C.A.), at p. 195). Potential competitors are deterred from working in areas that are not in fact covered by the patent even though costly and protracted litigation (which in the case of patent disputes can be very costly and protracted indeed) might confirm that what the competitors propose to do is entirely lawful. Potential investment is lost or otherwise directed. Competition is "chilled". The patent owner is getting more of a monopoly than the public bargained for. There is a high economic cost attached to uncertainty and it is the proper policy of patent law to keep it to a minimum.
43 The patent owner, competitors, potential infringers and the public generally are thus entitled to clear and definite rules as to the extent of the [page1050] monopoly conferred. This in turn requires that the subjective or discretionary element of claims interpretation (e.g., the elusive quest for "the spirit of the invention") be kept to the minimum, consistent with giving "the inventor protection for that which he has actually in good faith invented" (Western Electric Co. v. Baldwin International Radio of Canada, [1934] S.C.R. 570, at p. 574). Predictability is achieved by tying the patentee to its claims; fairness is achieved by interpreting those claims in an informed and purposive way.
[69] The effect of a purposive construction was set out at paragraph 50, it disciplines the scope of substantive claim construction:
50 I do not suggest that the two-stage approach necessarily ends at a different destination than the one-stage approach, or that the two-stage approach has resulted in abuse. I think we should now recognize, however, that the greater the level of discretion left to courts to peer below the language of the claims in a search for "the spirit of the invention", the less the claims can perform their public notice function, and the greater the resulting level of unwelcome uncertainty and unpredictability. "Purposive construction" does away with the first step of purely literal interpretation but disciplines the scope of "substantive" claims construction in the interest of fairness to both the patentee and the public. In my view its endorsement by the Federal Court of Appeal in O'Hara was correct.
[70] Thus, I will turn to claim 3, and in particular, “pain”, and endeavour to construe “pain” in the context of that claim in an informed and purposive way.
[71] First, I note that claims 4 to 16 are each directed to a specific type of pain. An informed and purposive construction must, therefore, mean that the “pain” of claim 3 must include at least the specific “pains” claimed in claims 4 to 16.
[72] Next, I turn to the description. At page 1, in the SUMMARY OF THE INVENTION, there are a variety of types of pain set out as those which may be treated by the claimed compounds. That variety is greater than those claimed in claims 4 to 16. That variety is somewhat constrained by the initial words “…especially for treatment of chronic pain disorders”, but is subsequently broadened by the words “but are not limited to”, and the inclusion of at least one type of acute pain - “acute herpetic and postherpetic neuralgia” - which particular pain is the subject of claim 13.
[73] ‘Pain” is again discussed under the caption DETAILED DESCRIPTION at page 5 of the patent. The description includes “pain as listed above”, clearly a reference to the description at page 1. A number of types of pain not listed in page 1 are included and some are omitted. The words “but not limited” reappear.
[74] It appears that the patent draughtsman is endeavouring to take advantage of two worlds; narrow and broad. In patent academic circles, this has sometimes been referred to as the “Angora Cat” approach as noted by Lord Justice Jacob in European Central Bank v Document Security Systems Inc, [2008] EWCA Civ 192, where he said, at paragraph 5 of the report:
Professor Mario Franzosi likens a patentee to an Angora cat. When validity is challenged, the patentee says his patent is very small: the cat with its fur smoothed down, cuddly and sleepy. But when the patentee goes on the attack, the fur bristles, the cat is twice the size with teeth bared and eyes ablaze”.
[75] A full description of Professor Franzosi’s recipe respecting parties and Angora cats can be found at:
http://ipkitten.blogspot.com-uk/2010/01/more-on-that-angora-cat.html
[76] The experts are, as expected, divided as to their interpretation of “pain”. I take the answer of Dr. McMahon as given in his cross-examination, found at Volume 4, page 859 of the Record:
…I think again the affidavits all try to explain some or the potential confusion around nomenclature in this field.
[77] The Applicants, at paragraphs 16 to 19 of their Memorandum of Fact and Law, as found in Volume 24 of the Record, concede that there are many forms of pain, acute and chronic, that do not comfortably fit within one category or the other.
[78] Dr. McMahon, at paragraphs 24 and 25 of his first affidavit as found at Volume 3, page 505 of the Record, sets out four different types of pain and concludes:
These different types of classifications necessarily mean that a patient’s pain cannot be given a single label.
[79] Dr. McCarson, at page 82 of his affidavit as found at Volume 1, page 114 of the Record says:
Claim 3 of the Patent would therefore be understood by a person of skill in the art to encompass a broad spectrum of human pain, all of which have features of inflammatory or neuropathic pain or both.
[80] Dr. McMahon argues a somewhat narrower definition at paragraph 58 of his affidavit as found at Volume 3, page 514:
A skilled person would thus have understood that claim 3 of the 652 Patent claims that pregabalin will be useful in treating a wide variety of pain states that have a central sensitization as a feature, and in particular those pain states listed at page 1 of the Patent.
[81] The central sensitization theory or commonality is nowhere set out in the '652 patent. Dr. McCarson, in his cross-examination, at Volume 2, page 270 of the Record; and Dr.Cowan at paragraph 90 of his affidavit, Volume 20, page 6001, in the Record; state that, at least for idiopathic and fibromyalgia pain, no animal model existed in 1996. Dr. McCarson, in his Reply Affidavit, paragraphs 13 and 15, found in the Record at Volume 1, pages 194 and 195, states that the central sensitization theory was, except for a few individuals, widely accepted by 1997.
[82] Given all of the aforesaid, I construe that the meanin