Merck & Company, Inc. v Pharmaforte Singapore Pte Ltd

• Jurisdiction: Singapore
• Judgment Date: 22 December 1999
• Date: 22 December 1999
• Docket Number: Suit No 413 of 1999
• Court: High Court (Singapore)

Merck & Co Inc

Plaintiff

and

Pharmaforte Singapore Pte Ltd

Defendant

[1999] SGHC 323

Lai Kew Chai J

Suit No 413 of 1999

High Court

Patents and Inventions–Industrial application–Whether utility necessary for invention to be capable of industrial application–Patents and Inventions–Infringement–Burden of proof–Alleged infringer importing and selling product–Whether alleged infringer having to prove products not made using patentee's process–Whether new product obtained–Whether substantial likelihood existing that product made naturally by patented process–Construction of claim–Approach to meaning of particular words in claim–Whether strict compliance with language of process claim intending to be essential requirement of invention–Whether process for making alleged infringer's product containing variants outside scope of patentee's claim–Section 68 (1) Patents Act (Cap 221, 1995 Rev Ed)–Patents and Inventions–Inventive step–Test of obviousness for chemical products–Chemical anticipated in prior art–Whether chemical product of sufficient inventiveness–Patents and Inventions–Novelty–Patentee engaging in research and deriving compound of higher degree of purity than could be derived using conventional processes–Whether higher degree of purity rendering compound novel–Disclosures within patentee's prior patents showing prior art enabling skilled addressee to produce compound of higher purity–Whether claim anticipated–Significance of role of utility to doctrine of novelty

The plaintiff was the registered proprietor of a Singapore patent (“the patent”). The patent comprised claims for a process of lactonisation (“the process claim”), and a product, Lovastatin, with a dimeric impurity of 0.2% or less (“the product claims”). This level of purity in its product was attained as a result of the plaintiff embarking on a research project to improve the purity levels which, when obtained using conventional processes, could be no lower than 0.4%. The patent derived from a European patent which claimed priority from a US patent application. The defendant was an importer and distributor of pharmaceutical products including Apo-Lovastatin, which also possessed dimeric impurity levels of less than 0.2%. Evidence and expert testimony given by the defendant showed that there were differences in various aspects of their respective processes in terms of temperature, the role of materials used in the purification process, water addition, and the use of a “strong acid catalyst” - factors described in the process claim.

The plaintiff alleged that the defendant had infringed its product claims and process claim in the patent, by, inter alia, importing, selling, offering for sale, etc the product Apo-Lovastatin, which the plaintiff also claimed was manufactured by a process that infringed its patent claimed over lactonisation. With reference to the process claim, the plaintiff purported to invoke s 68 (1) of the Patents Act (Cap 221, 1985 Rev Ed) to shift the burden to the defendant to show that Apo-Lovastatin was not made by the patented process.

The defendant filed a defence and counterclaim, challenging the plaintiff's product claims as invalid for lack of novelty and inventive step and arguing that the process used to produce Apo-Lovastatin was different from that specified in the plaintiff's process claim. The defendant relied on two prior patents filed by the plaintiff in Canada: the purification processes therein allowed the defendant in experiments to reduce the dimer to levels below 0.2%.

Held, dismissing the claim and allowing the counterclaim:

(1) The crux of the invalidity claim was the question whether the substance of the product claim, which was claimed to be the 0.2% (or less) level of dimeric impurity in the finished Lovastatin, was part of the state of the art as at the priority date.It was a settled principle of patent law that only differences in the kind of compound were patentable, whereas differences in the degree of purity of the compound were not. The disclosures within the plaintiff's Canadian patents confirmed that a skilled addressee would be so instructed by the prior art as to enable the manufacture and production of Lovastatin with a dimer of 0.2% or less. The prior art disclosures in this case contained “clear and unmistakable direction to do what the patentee claims to have invented” in the product claims so as to invalidate the patent for lack of novelty: at [18], [21], [32] and [33].

(2) A useful prescriptive test, within a novelty inquiry, was an assessment of the utility of the patented product. The question was whether subsequent inventors would be obstructed from future dealings with the subject. The product claims would effectively prevent any manufacturer from selling Lovastatin where the dimer was 0.2% or less even if manufactured by a different process. The reduction of the level of dimeric impurity in Lovastatin to 0.2% did not result in a better therapeutic effect of the drug. An invention could not be considered “useful” if it only differed from an earlier invention by an ingredient (in this case 0.1% purity) which did neither harm nor good: at [23].

(3) Anticipation only arose if it disclosed to a notional instructed reader essential integers to the invention as claimed. The disclosure had to be “enabling”, ie sufficient so as to enable the skilled addressee to put the invention into practice: at [31].

(4) For an invention to qualify for inventive step, it had to not be obvious. With chemical products, “obviousness” had to be assessed with reference to the state of chemical knowledge existing at the date of the patent which consisted of the chemical literature available and general chemical knowledge. One was looking for a “spark of imagination” beyond that which might be attributable to a man skilled in the art. If various techniques and processes were available which the man skilled in the art thought were worth trying out to yield beneficial results, or if the same could be said to be “lying in the road” for the research worker to use, the case for “obviousness” in the inventive idea was that much stronger. The only distinction between the prior art and the compound claimed in the patent in suit was the level of dimeric impurity in the compound. It was manifestly clear from the teachings of the patentee's earlier Canadian patents that numerous techniques were available to reduce the dimeric impurity present in the Lovastatin compound referred to in the product claims. The product claims should be invalidated and the patent revoked for lack of inventive step: at [40] to [43].

(5) A patent specification should be given a purposive construction rather than a purely literal one. The question was 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. If the issue was whether a variant was nevertheless within its language as properly interpreted, the court should ask itself three questions: (a) did the variant have a material effect upon the way the invention worked? If yes, the variant was outside the claim. If no, (b) would the fact that the variant had no material effect been obvious at the date of publication of the patent to a reader skilled in the art? If no, the variant was outside the claim. If yes, (c) would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant was outside the claim. If no, the patentee was intending the word or phrase to have not a literal but a figurative meaning denoting a class of things which included the variant and the literal meaning (“the Improver Corp test”). In adopting a purposive construction, a court was not entitled to rewrite or amend the patent claim under the guise of construction: at [52] to [54].

(6) Section 68 (1) could not be invoked to shift the burden in this case for two reasons. First, a new product had not been obtained owing to the invalidity and revocation of the product claims. Second, given the numerous purification techniques that were available and part of the prior art, it would be extravagant to proclaim that a “substantial likelihood” existed that Apo-Lovastatin was naturally made from the patentee's process, as set out in the process claim: at [57].

(7) The construction of the process claim had to be conducted through the eyes of the skilled addressee to decide whether strict compliance with a particular descriptive word or phrase was intended so that any variant would fall outside the claim. A subjective approach was adopted in the construction of claims, particularly the meaning of particular words. The court was required to examine the specification to ascertain if the inventor had used his own dictionary as to the meanings of words and phrases used in the claims. In this case, there was a lack of similarity between the plaintiff's and defendant's processes. The evidence showed that the answer to the third step in the Improver Corp test had to be in the affirmative; the defendant's process contained variants which fell outside the scope of the plaintiff's process claim. The plaintiff's action for infringement of the process claim failed: at [59], [60], [65] to [70].

[Observation: It would be controversial to resurrect the doctrine of utility as bearing upon whether an invention was capable of industrial application, under the patent law of Singapore. The plain words of s 16 (1) of the Patents Act, which provided that an invention...