Date: 19980211
Docket: T-1722-95
| IN THE MATTER of an Application for an Order of Prohibition pursuant to s. 55.2(4) of the Patent Act and s. 6 of the Patented Medicines (Notice of Compliance) Regulations |
BETWEEN:
ABBOTT LABORATORIES, LIMITED
and
ABBOTT LABORATORIES
Applicants
- and -
| NU-PHARM INC. |
and
THE MINISTER OF HEALTH CANADA
Respondents
REASONS FOR ORDER
LUTFY J.:
[1] The applicants Abbott Laboratories, Limited and Abbott Laboratories seek an order prohibiting the Minister of National Health and Welfare from issuing a Notice of Compliance to the respondent Nu-Pharm Inc. concerning the drug known as divalproex sodium, until after the expiration of Canadian letters patent 1,136,151 on November 23, 1999. This compound is sold by Abbott in Canada under the trade mark "Epival", in tablets of 125 mg, 250 mg and 500 mg, for the treatment of epileptic seizures. The order is sought pursuant to section 6 of the Patented Medicines (Notice of Compliance) Regulations1.
[2] On July 5, 1995, the respondent Nu-Pharm forwarded to Abbott the following Notice of Allegation concerning its intention to seek regulatory approval for divalproex sodium on the basis that its process does not infringe the 3151 patent:
| Re: Divalproex Sodium Tablets |
| This is a Notice of Allegation pursuant to Section 5(3)(b) of the Patented Medicines (Notice of Compliance) Regulations. |
| With respect to patent 1136151, we allege that 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 us of tablets containing divalproex sodium. |
| The legal and factual basis for the aforesaid allegation is as follows: |
| This patent has claims for divalproex sodium when prepared by processes claimed. We have available to us divalproex sodium made by a process that does not fall within the scope of the claims of patent 1136151. Until expiry of patent 1136151 we will use only this noninfringing material. |
Apotex Inc. has agreed to supply Nu-Pharm with divalproex sodium. The process relied upon by Nu-Pharm in its Notice of Allegation is the one used by its supplier Apotex to manufacture divalproex sodium. In their representations, the parties spoke interchangeably of the Apotex process and the Nu-Pharm process. Throughout these reasons, this process will be referred to as the Nu-Pharm process.
The two processes
[3] Claim 1(a) of the 3151 patent sets out a process for preparing divalproex sodium comprising dissolving substantially equimolar quantities of valproic acid and sodium valproate in acetone at about 50o C and recovering the product. Claim 16 is for divalproex sodium whenever prepared by the process of claim 1 or by an obvious chemical equivalent. In an example described in the Detailed Description of the Invention in the 3151 patent, 166 g. of sodium valproex (a solid) and 144 g. of valproic acid (a liquid) are dissolved in 1,000 ml. of acetone at about 50o C. The new compound is said to be a stable, white, crystalline powder which melts at 98o-100oC.
[4] The Nu-Pharm process to make divalproex sodium comprises taking 4.65 kg of valproic acid, heating to 120oC and slowly adding 5.25 kg of sodium valproate with a temperature being maintained at 120oC. The resulting liquid is then allowed to cool and the solid mixture recovered in 100% yield.
[5] Claims 1 and 16 of the 3151 patent, with the example by way of illustration only, and the Nu-Pharm process may be compared as follows:
The 3151 Patent Process
Claim 1: A process for preparing divalproex sodium comprising: (a) dissolving substantially equimolar quantities of valproic acid and sodium valproate in acetone at about 50oC and recovering the product; or (b) forming said valproic acid in situ by adding sodium hydroxide at half molecular equivalent to valproic acid contained in said acetone and recovering the product.
Example 1. In 1000 ml. of acetone at about 50oC is dissolved 166 g. of sodium valproate and 144 g. of valproic acid. The solution is cooled at about 0oC, filtered and the crystalline precipitate is washed with pre-cooled acetone at about 0oC.
Claim 16: Divalproex sodium whenever prepared by the process of claim 1 or by an obvious chemical equivalent.
The Nu-Pharm Process
1- Place 4,65 kg of valproic acid in a stainless steel pot.
2- Place the pot on a hotplate and begin heating while blending.
3- While continuing to blend, monitor the temperature. Continue until the temperature reaches 120oC.
4- As soon as the temperature reaches 120oC, increase blender speed to form a vortex and gradually add 5,35 kg of sodium valproate while continuing to blend.
5- As temperature will drop upon addition of the sodium valproate, continue to heat and continue blending until temperature again reaches 120oC.
6- When the temperature reaches 120oC, turn off the hotplate and turn off and remove the blender.
7- Pour the liquid onto stainless steel trays and place in rack.
8- The next morning remove the hardened material from the stainless steel trays using a stainless steel scraper if needed. Transfer the material to drums lined with PE bags.
Abbott's case
[6] In Abbott's submission, Nu-Pharm's process is within the scope of claim 1 and, in any event, the obvious chemical equivalent of the 3151 patent. In both processes: (a) the same reactants valproic acid and sodium valproate are used to make the compound divalproex sodium; (b) these same reactants are used in exactly the same proportions; (c) the chemical reaction in combining the same reactants is identical; and (d) the end product is the same. For Abbott, divalproex sodium is formed upon contact of the valproic acid with the sodium valproate and, accordingly, the use of the acetone solvent is not an essential feature of the 3151 patent. The acetone is used as a medium for the reaction to be carried out at mild temperatures. It would be expected that acetone would not be used in an industrial environment where the scales of production would require an unacceptable quantity of the solvent. For Abbott, it would have been obvious that a liquid such as valproic acid could, at a higher process temperature, serve the twofold function of reactant and solvent.
[7] The applicants' material includes the evidence of three experts. Their affidavits focus on Abbott's submission that the reference to acetone in claim 1 of the 3151 patent is not an essential feature. In the view of one of these experts, the chemical interaction of sodium valproate and valproic acid is exactly the same regardless of the use of an organic solvent such as acetone. More precisely, because the valproic acid is itself a liquid, "... it is quite an obvious alternative to use the liquid of valproic acid as a reaction medium by mixing the two reactants together and maintaining the temperate above the melting point of the product and, when completed, letting the product solidify".
[8] This view, while expressed in somewhat different terms, is shared by Abbott's other two experts. For the Abbott affiants, the omission of the acetone was a trivial variation, one which in the period between 1979 until now would have been viewed as obvious and logical in manufacturing the valproex sodium on a large scale.
Nu-Pharm's case
[9] The main difference between the two processes is that acetone is not used in Nu-Pharm's. This results in the processes being carried out at different temperatures. Nu-Pharm acknowledges its use and blending of the same components valproic acid and sodium valproate in precisely the same proportions set out in the 3151 patent. However, Nu-Pharm supports its allegation of non-infringement with three principal arguments which raise questions of mixed fact and law. In the first place, Nu-Pharm characterizes the use of acetone as an essential feature of claim 1(a). Secondly, Nu-Pharm describes as superficial Abbott's submission that the chemical reaction is identical when the two processes use the same reactants in exactly the same proportions and result in the same product. For Nu-Pharm, there is no evidence as to "what is happening" during the dissolution process. Finally, Nu-Pharm relies heavily on the processes disclosed in two other Abbott patents for making divalproex sodium to establish that it was not part of the existing knowledge, at the time of the 3151 patent, that the compound in issue could be manufactured without the use of acetone.
[10] It is also suggested by Nu-Pharm that the absence of acetone obviates the need to "recover" the divalproex sodium from the solvent as is required in the 3151 patent process. Nu-Pharm also relies on the differences relating to cost, efficiency, safety and the environment which flow from its non-use of acetone. These may be relevant in an industrial environment. In my view, however, the differences in the recovery and the other differences are not substantive and cannot form the basis of distinguishing Nu-Pharm's process as an obvious chemical equivalent of the 3151 patent.
[11] The more important issue, in my view, is whether Nu-Pharm's process, in simply mixing the valproic acid and the sodium valproate to form the compound divalproex sodium without the use of the acetone solvent, is one which would have been obvious to a person skilled in the art at the time of the 3151 patent invention.
[12] Nu-Pharm presented two affiants. Bernard Sherman, the president of Apotex Inc., introduced his company's manufacturing instructions for the production of the divalproex sodium which Apotex had agreed to supply to Nu-Pharm. Nu-Pharm's second affiant and sole expert opined on the principal difference between the two processes. He acknowledges that in the 3151 process the two components, the valproic acid and the sodium valproate, are dissolved in the acetone. He describes the Nu-Pharm process as mixing the two components together at a temperature sufficient for them to form a liquid mixture. In characterizing these two processes as "totally different", Nu-Pharm's affiant states:
| 13. In the 3151 process, the solvent functions by providing a medium in which the components of the mixture, the neutral compound valproic acid, the sodium cation and the valproate anion, are dissolved and dispersed. [...] |
| 14. The Apotex process functions by forming a liquid state comprising the components held in a close association. [...] |
| 15. The functioning of the processes during the crystallizations that are required to isolate the solid divalproex sodium is different. |
| 16. In the 3151 process, the molecules and ions must move together and associate to form the solid structure, squeezing out the solvent molecules in this process. |
| 17. In the Apotex process, the molecules and ions are already associated, and there is no solvent to squeeze out. All that is required is that the molecules and ions simply arrange themselves in the manner appropriate to the solid state. |
After dealing with the recovery step and the differences relating to cost, efficiency, safety and the environment, Nu-Pharm's affiant concludes that "... it would not have been obvious in 1979 from the teachings of 3151 or from standard chemical knowledge, that the [Nu-Pharm] process involving mixing the two components at 120o C would have resulted in a useful product."
[13] There is no evidence, in my view, from which to conclude that the functional difference in the Nu-Pharm process where "there is no solvent to squeeze out" is one which is significant in drawing a chemical distinction between the two processes. Also, during cross-examination, when asked to explain why the Nu-Pharm process involved mixing the two components at a temperature of 120oC, the answers of Nu-Pharm's expert affiant varied from uncertainty to the less equivocal assertion that "a good part of the divalproex sodium [had to be kept] in liquid form until ready to be poured onto trays".2 This last statement at least is consistent with those of Mr. Sherman of Apotex who acknowledged that the requirement to blend the valproic acid and sodium valproate at 120OC was an arbitrary decision to assure that the process be carried out at a temperature above the 100o melting point of the divalproex sodium, a threshold which was noted in the 3151 patent disclosures.
[14] Nu-Pharm also relies on two other Abbott patents, the applications for which were filed shortly after the one for the 3151 patent. One of these two other patents was issued prior to the 3151 patent.
The two other Abbott patents for divalproex sodium
[15] The application for 3151 patent was filed on July 28, 1980. Some two months later, on September 17, 1980, Abbott filed two other applications for Canadian letters patent which were eventually issued under no. 1,135,272 entitled "Manufacture of Sodium Hydrogen Divalproate" and no. 1,144,558 entitled "Process for Making Sodium Hydrogen Divalproate". It is common ground that all three patents are with respect to the same compound divalproex sodium. All three patents were granted to Abbott Laboratories. The inventor of the 3151 patent was a Canadian and not employed by Abbott. The inventors of the 3272 patent and the 3558 patent were Abbott employees in the United States.
[16] There is no evidence concerning the actual dates on which the inventors made their inventions. All three patents claim priority dates in 1979 on the basis of U.S. patents. The 3151 priority date is some two months earlier than the identical priority dates of the other two patents. It was the 3272 patent which was the first to issue on November 9, 1982. The 3151 patent issued two weeks later on November 23, 1982. The 3558 patent was issued on April 12, 1983.
[17] Several of the paragraphs of these three patents for making divalproex sodium are identical or substantially so.
[18] Prior to the 3151 patent, each of the valproic acid and the sodium valproate were among products used to treat epileptic convulsions. Each had its disadvantage. As a liquid, the valproic acid was less desirable for preparing an oral dosage form. As a solid, the sodium valproate had poor stability characteristics. This is set out in the identical first three paragraphs of the Detailed Description of the Invention in all three patents:
| In the last decade, 2-propylpentanoic acid and its alkali or earth alkali salts (hereinafter referred to as valproic acid and valproates or valproate salts, respectively) have been introduced in the arsenal of drugs useful for treating epileptic seizures or convulsions. Most commonly used are valproic acid itself or its sodium salt. The former is a liquid and as such is less desirable for preparing an oral dosage form while the latter is a solid that has poor stability characteristics partially due to pronounced hygroscopicity. |
| It has now been found that a highly stable, non-hygroscopic, solid entity can be prepared from valproic acid and its salts, representing a single chemical molecule with well-defined physical characteristics, although a definite structure has not been assigned to this entity. |
| The new compound represents a single crystalline entity consisting of one molecule each of valproic acid diethylacetic acid and a valproate salt, the cation of said salt being sodium or calcium. While it has not been determined for sure whether the new compound represents a solution of the valproic acid in the valproate salt or a complex between the two compounds, the new material has been tentatively assigned the following structure: |
| CH3(CH2) n O .... MO CH 2CH2CH3 ( ' ( ' |
| CHC CCH |
| ' ( '' ( |
| CH3(CH2) n OH .... O CH 2CH2CH3 |
| wherein M represents Na or 1/2 Ca and n is 1 or 2. |
[19] The fourth paragraphs of the Detailed Description of the Invention of the 3272 patent and the 3558 patent set out in identical terms the process in the 3151 patent:
| In previous methods, the above compound was prepared by dissolving one mole each of valproic acid and sodium valproate in 1000 ml. of acetone at about 50oC. After cooling the solution to 0oC. or below, the formed new compound was filtered, washed if desired with pre-cooled acetone, and dried under reduced pressure to remove all traces of acetone. Another method involved a two-component liquid medium which included acetone. In this instance, sodium valproate was formed in situ by adding NaOH at a level of one-half of a molecular equivalent of the valproic acid present, preferably as a solution in an acetone-miscible solvent for said NaOH, e.g., water. The new dimer was then recovered from the liquid phase by evaporating the solvents. |
[20] The next paragraphs of the 3272 patent and the 3558 patent describe in general terms the different process specific to each:
(a) concerning the 3272 patent:
| It has now been found that, against expectations and documented precedents, the above compound can be prepared without use of an organic solvent; i.e., by simply admixing an aqueous solution of sodium hydroxide of at least 10% concentration and valproic acid, said sodium hydroxide being used in an amount corresponding to 48 - 52% of the stoichiometric amount of said valproic acid, and removing the water from the reaction mixture by evaporation. |
(b) concerning the 3558 process:
| The current invention provides a new method for making or purifying Compound I. The new process consists essentially in reacting sodium hydroxide with two molar equivalents of valproic acid in an amount of acetonitrile sufficient to form a clear solution at a temperature of at least 50oC., concentrating that solution to a solids content of 15-25% weight/volume through evaporation of said acetonitrile, cooling said concentrated solution to room temperature, or below, and separating the formed crystalline, pure sodium hydrogen divalproate from said cooled solution. |
[Emphasis added.]
[21] In addition, the last three paragraphs of the Detailed Description of the Invention in the three patents are substantially identical but need not be recited at length for the purposes of this decision.
[22] In summary, the 3272 patent teaches that divalproex sodium can be prepared "without use of an organic solvent; i.e., by simply admixing an aqueous solution of sodium hydroxide of at least 10% concentration and valproic acid". This process is said to have been found "against expectations and documented precedents". Similarly, the 3558 patent sets out "a new method" for making divalproex sodium through a "new process" which substitutes acetonitrile for the acetone solvent used in the 3151 patent.
[23] The 3272 patent and the 3558 patent were made part of this record through Nu-Pharm's cross-examination of Abbott's three affiants. Counsel for Nu-Pharm acknowledges that these two patents were not introduced with the evidence of Nu-Pharm's affiants for tactical reasons. The record is silent as to whether Nu-Pharm's expert affiant was made aware of the other two patents. Nu-Pharm's two affiants were cross-examined in March 1996, prior to the cross-examination of Abbott's affiants in January 1997. As a result, there is no evidence at all from the Nu-Pharm affiants concerning these two patents.
[24] Two of Abbott's affiants were not aware of either the 3272 patent or the 3558 patent when their affidavits were filed in December 1995. The same appears to be true concerning Abbott's third affiant, one of its own employees, but the evidence is somewhat equivocal in his regard. Abbott's counsel acknowledge that they were not aware of these two patents prior to Nu-Pharm's cross-examination of the first of Abbott's three experts. It appears that either as a result of an inadvertent or deliberate omission, and there is no evidence on this point, Abbott did not brief its team of witnesses and counsel concerning the 3272 patent and the 3558 patent.
[25] Abbott sought three expert opinions, including one from its own employee, as to whether the Nu-Pharm process is the obvious chemical equivalent of the 3151 patent. There is no apparent justifiable reason, in my opinion, for Abbott to have done so without informing their experts of the existence of the two other Abbott patents that had been filed within two months of the first and which disclosed different processes to make the very same compound.3
[26] Nu-Pharm urges, with some justification in my view, that Abbott's affidavits must be subjected to the closest of scrutiny in view of its failure to disclose the 3272 patent and the 3558 patent to its affiants. The same can be said, of course, in the assessment of Nu-Pharm's evidence. Neither Nu-Pharm affiant referred to the two patents in their affidavits and both were shielded from questioning on these patents which were introduced through the subsequent cross-examination of Abbott's affiants.
[27] Abbott's counsel argued forcefully that the 3272 patent and the 3558 patent are not evidence before the Court because they were introduced through cross-examination of persons who did not create the documents. This submission would carry more weight if the documents in question were not patents. According to subsection 13(2) of the Patent Act , certified copies of documents deposited in the Patent Office are to be admitted as evidence without further proof. In my view, while the 3151 patent was introduced with the affidavit of an articling student in the law firm of Abbott's counsel and the 3272 patent and the 3558 patent were introduced through cross-examination of Abbott's experts, all three patents are evidence of the same kind in this proceeding.
[28] In its written submissions, Nu-Pharm states that the words of claim 1(a) of the 3151 patent are plain and unambiguous: dissolving the two components "in acetone at about 50o C". Its reliance on the 3272 patent and the 3558 patent is to challenge the credibility of the Abbott's affiants and their assertions that Nu-Pharm's process is the obvious chemical equivalent of the 3151 patent when the existence of the other two patents was not disclosed to them prior to the filing of their affidavits. Nu-Pharm also seeks to use the patents, as part of the contemporary literature, to establish the state of the existing knowledge at the time of the 3151 patent. In this sense, Abbott's argument that the two patents are inadmissible as extrinsic evidence to construe a patent is inapplicable in the circumstances of this proceeding.4
[29] These summary proceedings are not subject to documentary and oral discovery. This is not a license, however, to omit material information in briefing expert witnesses whose opinion evidence the Court is asked to adopt. One wonders also about the value of opinion evidence concerning obvious chemical equivalence where the experts of both parties fail to discover or choose not to mention other processes for the same compounds disclosed in an applicant's patents which are contemporary with the patent in issue. The Court cannot be well served in such circumstances, particularly in a summary proceeding where the expert does not testify before the judge.
Analysis
[30] The "core guidance" of the various decisions of the Court of Appeal concerning the burden of proof in a proceeding under section 6 of the Patented Medicines (Notice of Compliance) Regulations has been summarized in Hoffman-Laroche Ltd. v. Canada (Minister of National Health and Welfare):5
| 2. The initiator of a section 6 proceeding, being the person having the carriage of the litigation, bears "the initial burden of proof" which is a difficult burden because "it must be to disprove some or all of the allegations in the notice of allegation which, if left unchallenged, would have allowed the Minister to issue a notice of compliance". Merck Frosst, [(1994), 55 C.P.R. (3d) 302], per Hugessen J.A., at page 319; |
| 3. This burden, known in a civil case as either the "persuasive burden" or the "legal burden", is the burden of establishing a case to the civil standard of proof. By contrast, the "evidential burden" consists of the burden of putting an issue in play and means that a party has the responsibility to ensure that there is sufficient evidence of the existence or non-existence of a fact or an issue on the record to pass the threshold for that particular fact or issue. Nu-Pharm, [(1996), 69 C.P.R. (3d) 1 (F.C.A.) at page 15]. |
| 4. Where the notice of compliance of a second person alleges non-infringement, the court should start from the proposition that "the allegations of fact in the notice of allegation are true except to the extent that the contrary has been shown by the applicant". Merck Frosst, supra, per Hugessen J.A., at page 319; |
| 5. In determining whether or not the allegations are "justified" "the court must then decide whether, on the basis of such facts as have been assumed or proven, the allegations would give rise in law to the conclusion that the patent would not be infringed by the respondent". Merck Frosst, supra, per Hugessen J.A., at page 319. |
[31] The question in this proceeding is whether Nu-Pharm's allegation that its process does not fall within the scope of the claims, particularly claim 1(a) and claim 16, of patent 3151 is justified. Claim 16 is for any obvious chemical equivalent of Claim 1.6 Nu-Pharm's allegation that its process does not infringe the 3151 patent is assumed to be true except to the extent that the contrary is shown by Abbott.
[32] In the patent infringement case of Catnic Components Ltd. and another v. Hill & Smith Ltd.,7 Lord Diplock set out the framework within which to determine whether a feature of a patent is essential:
| The question in each case is: whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed, even though it could have no material effect upon the way the invention worked. |
| The question, of course, does not arise where the variant would in fact have a material effect upon the way the invention worked. Nor does it arise unless at the date of publication of the specification it would be obvious to the informed reader that this was so. Where it is not obvious, in the light of then-existing knowledge, the reader is entitled to assume that the patentee thought at the time of the specification that he had good reason for limiting his monopoly so strictly and had intended to do so, even though subsequent work by him or others in the field of the invention might show the limitation to have been unnecessary. [Emphasis added.] |
The highlighted portion of this extract relates directly to one of Nu-Pharm's contentions: that Abbott's assertion of obvious chemical equivalence is based on the "hindsight reconstruction" of its affiants and not on the existing knowledge at the time of the 3151 patent.
[33] Neither party focussed on the relevant time period to be used in the assessment of equivalence. Counsel for both parties presented their positions on the assumption that the 3151 patent preceded the 3272 and 3558 patents. As noted earlier, this is true concerning the priority date and the filing of the applications for the patents. However, the date of publication or issuance of the 3272 patent was the earliest, some two weeks prior to that of the 3151 patent. There was no discussion as to whether Nu-Pharm's process was to be assessed against the existing knowledge as of the priority date of patent 3151, its filing date or its date of issuance.8 Abbott did note, however, that Nu-Pharm's expert stated that mixing the two components at 120oC to obtain the end result was not a process which would "have been obvious in 1979 from the teachings of 3151 or from standard chemical knowledge". Similarly, one Abbott affiant referred to 1979 in stating that the Nu-Pharm process would have been obvious and trivial.
[34] Despite my serious reservations concerning Abbott's failure to disclose the 3272 and 3558 patents, at least to its team of experts, and upon review of all the affidavits and cross-examinations, I have not been able to reach a conclusion other than that Nu-Pharm's allegation is, on a balance of probabilities, not justified. In a proceeding where the affiants of both parties, in the substantive portions of their affidavits, resorted more to bald assertions than relevant factual evidence, I have found Abbott's position, particularly after my review of all the cross-examinations, to be more persuasive.
[35] I accept the testimony of Abbott's expert that a person skilled in the art would have known at the time of the 3151 patent that the use of acetone was a typical laboratory procedure, not intended for large scale production,9 even if this was not stated in the patent. In an industrial setting, the quantity of acetone required would be excessive and the use of such an organic solvent would be avoided.10
[36] Two other statements by Nu-Pharm's affiants are relevant to the issue of obvious chemical equivalence. During cross-examination concerning paragraph 17 of his affidavit, Nu-Pharm's expert acknowledged that the requirement that "the molecules and ions arrange themselves in the manner appropriate to the solid state" was common to both processes.11 He did not add, as might have been expected if the acetone factor rendered the processes chemically different, that the arrangement between the molecules and ions would somehow vary in relationship to the use or absence of this solvent. Also, Mr. Sherman of Apotex linked the blending of the valproic acid and sodium valproate to a temperature of 120o C to the need to avoid the precipitation which would occur below 100oC.12 I interpret this response as reflecting the knowledge communicated in the 3151 patent that divalproex sodium melts at 98o -100oC. These responses reinforce my view, on the basis of the evidence in this proceeding, that the essential features of the 3151 invention are the two reactants and not the organic solvent.
[37] The issue of the 3272 patent and the 3558 patent was "put in play"13 by Nu-Pharm to challenge the credibility of Abbott's affiants and their conclusions of equivalence in the context of the available knowledge during the relevant time period. Nu-Pharm fails, in my view, because of the paucity of evidence which results from the way the patents were introduced. Abbott's failure to disclose the patents does not relieve Nu-Pharm's evidential burden on this issue. There is no evidence from Nu-Pharm's witnesses concerning the two patents and none from Abbott's witnesses that assists Nu-Pharm's position.
[38] Claim 1 of the 3272 patent is for a process admixing an aqueous solution of sodium hydroxide and valproic acid. This patent discloses that divalproex sodium can be prepared without the use of an organic solvent such as acetone. There is no evidence comparing the use of sodium hydroxide in the 3272 patent with the use of sodium valproate in claim 1(a) of the 3151 patent and the Nu-Pharm process. There is no conclusive evidence comparing the use of sodium hydroxide in both the 3272 patent and claim 1(b) of the 3151 patent.14
[39] Nu-Pharm's counsel relies extensively on that statement that the process in this 3272 patent was "against expectations and documented precedents". From this, he urges the Court to conclude that it was not known at the time of the 3151 patent that divalproex sodium could be prepared without an organic solvent. Accordingly, as I understand the argument, the Nu-Pharm process cannot be said to be the obvious chemical equivalent of the 3151 patent.15
[40] The initial allure of this argument fades upon a review of the evidence. The phrase "against expectations and documented precedents" in and of itself, particularly in the absence of any Nu-Pharm evidence concerning the 3272 patent and sodium hydroxide, cannot be interpreted to mean that acetone is an essential feature of the 3151 patent nor that the Nu-Pharm process is not the obvious chemical equivalent of the patent in issue. To do so, in the circumstances of this proceeding, would be mere speculation. The same is true concerning the words "the new method" in the 3558 patent. All three patents are presumed to be valid in the absence of evidence to the contrary. There is no evidence that the variants in the 3272 and 3558 patents are not patentable improvements to prepare the same compound. The issuance of other patents does not necessarily exclude the possibility of infringement.16 Accordingly, even in light of the words of the 3272 and 3558 patents relied upon by Nu-Pharm, the evidence in this case supports Abbott's position of obvious chemical equivalence.
[41] For these reasons, the application for the prohibition order will be granted without costs.
Judge
Ottawa, Ontario
February 11, 1998
__________________1 SOR/93-133 (March 12, 1993).
2 Applicants' Record, p. 158 (question 31), p. 161 (question 45), p. 162 (question 48) and p. 165 (question 62).
3 Of interest, the second of Abbott's affiants to be cross-examined noted that he was asked to review patent 3272 and patent 3558 (after their introduction during the cross-examination of Abbott's first affiant), "because they seemed to be relevant to the case at hand". (Application Record, p. 301, l. 10)
4 In this regard, Abbott relied on the decisions in Nekoosa Packaging Corp. v. AMCA International Ltd. (1994), 56 C.P.R. (3d) 470 (F.C.A.) at 480 and Pallmann Maschinenfabrik G.m.b.H. Co. KG v. CAE Machinery Ltd. (1995), 62 C.P.R. (3d) 26 (F.C.T.D.), especially at 43-4.
5 (1996), 70 C.P.R. (3d) 206 (F.C.A.) at 210-11.
6 Other proceedings under section 6 of the Patented Medicines (Notice of Compliance) Regulations concerning the obvious chemical equivalence of processes for medicines include: Eli Lilly and Co. v. Novopharm Ltd. (1995), 60 C.P.R. (3d) 417 (F.C.T.D.) at 432; Bayer AG v. Canada (Minister of National Health and Welfare) (1996), 65 C.P.R. (3d) 203 (F.C.T.D.) at 215; Abbott Laboratories, Ltd. v. Nu-Pharm Inc. (1997), 74 C.P.R. (3d) 498 (F.C.T.D.); Pfizer Canada Inc. v. Apotex Inc., [1997] F.C.J. No. 1087 (QL); and Pfizer Canada Inc.v. Apotex Inc. (February 5, 1998), T-1714-95 (F.C.T.D.).
7 [1982] R.P.C. 183 (H.L.) at 243.
8 In The Canadian Law and Practice relating to Letters Patent for Inventions , 4th ed. (Toronto: Carswell Company Limited, 1969), Dr. Fox noted that there existed "a conflict of judicial opinion as to the date at which common knowledge is to be taken into account in construing the specification" (at pages 206-7, footnote 325). He also mentioned that English cases may not be relevant on this point, presumably because of different statutory provisions. Some thirty years later, there does not appear to have been a case submitted to this Court which resulted in a binding, authoritative decision where the facts required a distinction between the priority date, the filing date and the issuance date where obvious chemical equivalence is in issue.
In Beecham Canada Ltd. v. Procter & Gamble Co. (1982), 61 C.P.R. (2d) 1 (F.C.A.) at 27, where the validity of the patent was in issue, the Court of Appeal used the actual date of the invention as the relevant period to determine whether the invention was obvious to those skilled in the art.
In AT & T Technologies, Inc., v. Mitel Corp. (1989), 26 C.P.R. (3d) 238 (F.C.T.D.) at 249, Reed J. considered the date as of which a patent is to be construed and concluded that relevant date is that at which the application is filed and not when the patent is issued. In AlliedSignal Inc. v. Du Pont Canada Inc. (1995), 61 C.P.R. (3d) 417 (F.C.A.) at 426, Justice Desjardins, in an obiter dictum in which she relied on the French text ("la date de la délivrance du brevet") of the decision of Pigeon J. in Burton Parsons Chemicals Inc. v. Hewlett-Packard (Canada) Ltd., [1976] 1 S.C.R. 555 at 560, stated that a patent is to be construed at the date it is issued. The English version of Justice Pigeon's decision refers to "the date of the patent" and it is not apparent from the context that he was addressing the issue of priority date, filing date or issuance date.
There are other trial decisions of this Court when the phrases "date of issuance" and "date of publication" are used where it was not necessary to distinguish between the other possible dates: see, for example, Xerox of Canada Ltd. v. IBM Canada Ltd. (1977), 33 C.P.R. (2d) 24 (F.C.T.D.) at 69 and Eli Lilly and Co., supra, note 6 at 439.
9 Applicants' Record, p. 316, ll. 13-18.
10 Applicants' Record, pp. 333-8.
11 Supra, paragraph 12 and Applicants' Record, p. 170, question 78.
12 Applicants' Record, p. 192, question 40.
13 Eli Lilly and Co. v. Nu-Pharm Inc. (1996), 69 C.P.R. (3d) 1 (F.C.A.) at 15. See also Hoffman-Laroche, supra, note 5.
14 The evidence concerning sodium hydroxide is limited. Sodium hydroxide is not a liquid (Applicants' Record, p. 266). Sodium hydroxide is a chemical (Applicants' Record, p. 369). There is some discussion which suggests that the use of sodium hydroxide in claim 1(b) of the 3151 patent is the chemical equivalent of the process in claim 1(a) (Applicants' Record, pp. 306-313). I have not understood this exchange as assisting Nu-Pharm's case. In Nu-Pharm's written submissions and Abbott's oral argument, the parties state that the process in claim 1(b) is not relevant to the proceeding.
15 Concerning the state of the existing knowledge at the relevant time period, neither party focussed on the date of issuance of the 3272 patent some two weeks prior to that of the 3151 patent.
16 Lightning Fastener Company Limited v. Colonial Fastener Company Limited, [1932] Ex. C.R. 89 at 100, rev'd [1933] S.C.R. 363, aff'd [1934] 3 D.L.R. 737 (H.L.); and Airseal Controls Inc. v. M & I Heat Transfer Products Ltd. (1993), 53 C.P.R. (3d) 259 (F.C.T.D.) at 270, aff'd 1997 F.C.J. No. 1337 (QL).