In Singapore, second and subsequent medical use of a known substance has traditionally been claimed as Swiss-style claims which take the form of “Use of compound X in the manufacture of a medicament for treating disease Y”. Recently, two court cases (Warner-Lambert Company v Novartis (Singapore)  SGHC 106 and Warner-Lambert Company v Novartis (Singapore)  SGCA 45) have shed some light, for the first time in Singapore, on how these claims are to be treated.
- Amendment of a method of treatment claim to a Swiss-style claim in post-grant amendments is not considered added matter.
- However, post-grant amendment of a method of treatment claim to a Swiss-style claim extends the scope of protection of the granted patent.
- Post-grant amendment of a patent must be made without undue delay.
- The Court of Appeals observed that a first medical use claim (such as a purpose-limited product claim, which is considered to be a first medical use claim in Singapore) may also be sufficient to protect second or subsequent use of a known substance. Based on the present practice, second medical use of a known substance is protected by Swiss-style claims. The Singapore patent office has announced that until further notice, the current practice of using Swiss-style claims for second medical use claims continues to apply until the Singapore patent office had sufficient time to review the decision.
I) Warner-Lambert Company v Novartis (Singapore) SGHC 106
Warner-Lambert Company v Novartis (Singapore)  SGHC 106, was the first decision in Singapore relating to Swiss-style medical use claims. In this case, the Singapore High Court was required to consider whether Warner-Lambert should be granted leave to amend its patent to amend method of treatment claims to Swiss-style claims in infringement proceedings brought against Novartis.
The decision led to the clarification of two questions relating to Singapore patent practice: (i) does amendment of method of treatment claims into Swiss-style claims constitute added matter?; and (ii) does such amendment, when made post-grant, extend the scope of the protection of the patent?
With regard to added matter, the Court concluded that the amendment did not result in added matter, as both method of treatment claims (““A method for treating disease Y comprising administering compound X”) and Swiss-style claims (“Use of compound X in the manufacture of a medicament for treating disease Y”) implicitly involved a step of manufacturing a medicament. This was particularly so given that a person skilled in the art would understand that it is necessary for the Swiss-style claim to include a manufacturing step to ensure that the claim does not touch the doctor, and fall afoul of the method of treatment exclusion. The court also concluded that a person skilled in the art would realise that the medicament comprising the therapeutically effective amount of the compound would have to exist, based on the original claims, and would therefore regard the manufacture of the medicament as clearly and unambiguously disclosed as a matter of necessary implication, even if the existing claim is directed at the method of treatment.
Extending the scope of protection
With regard to whether the post-grant amendment of method of treatment claims to Swiss-style claims would extend the scope of the protection of the patent, the Court considered a Swiss-style claim to be a purpose-limited process claim and discussed what would constitute infringement of the granted method of treatment claims and the proposed amended Swiss-style claims. Applying the statutory provisions on infringement as set out in sections 66(1)(b) and (c) of the Singapore Patents Act, the Court determined that:
(i) The defendant will infringe the granted claims (i.e. method of treatment claims) under section 66(1)(b) if he offers or provides treatment of pain in Singapore by administering a therapeutically effective amount of the disclosed compound.
(ii) In contrast, the defendant will infringe the amended claims (i.e. the Swiss-style claims) under section 66(1)(b) if he uses the disclosed compound in a process to manufacture the medicament for treating pain. He will also be infringing the amended Swiss-style claims under section 66(1)(c) if he disposes, uses, or imports a product obtained directly from the manufacturing process.
The Court therefore determined that the granted method of treatment claims and the amended Swiss-style claims target different activities. Specifically, the amended Swiss-style claims covered the making of the compound for administration, while the granted method of treatment claims covered only the act of administration of the compound. The proposed amendments therefore were considered to extend the scope of protection conferred by the Warner-Lambert patent. It was further decided that the use of the compound in the manufacture of a medicament did not fall within the scope of administration of a compound in a treatment. The proposed amendments were therefore disallowed as they extended the scope of the granted patent.
As a related issue, the Court further considered whether there was undue and unreasonable delay by Warner-Lambert in applying for the amendments. The Court concluded that there was an undue and unreasonable delay on Warner-Lambert’s part in requesting the amendments, since Warner-Lambert had been put on “sufficient notice” that its claims may be problematic, had ample opportunity to amend its patent both pre-grant and post-grant, and its inaction in this matter had not been adequately explained. The “sufficient notice” was in the form of the following:
a) The International Preliminary Examination Report (IPER) of the PCT application from which the Singapore patent was nationalized already noted that “claims directed to methods of treatment of the human or animal body by therapy might be found inadmissible in some patent systems”, which led Warner-Lambert to amend the original method of treatment claims in their corresponding European application to Swiss-style claims.
b) Warner-Lambert had already applied to amend some of its Singapore patents pre-grant from method of treatment claims to Swiss-style claims many years prior to commencement of the dispute, from as early as 2005. Thus, Warner-Lambert was aware or ought to have been aware as early as 2005 that the granted claims were not capable of industrial application.
c) Warner-Lambert admitted that it received advice from its legal counsel, around March 2015, that under Singapore law, method of treatment claims are not taken to be capable of industrial application under s16(2). Despite the advice, Warner-Lambert proceeded to file the writ of summons without an application to first amend the patent.
Thus, the request to amend the patent also failed on this ground.
II) Warner-Lambert Company v Novartis (Singapore) SGCA 45
In Warner-Lambert Company v Novartis (Singapore)  SGCA 45, Warner-Lambert appealed the High Court’s decision, contending that i) the judge erred in finding that the amended claims extend the scope of protection of the patent and ii) the judge erred in finding that there was undue delay in bringing the amendment.
However, the decisions in Warner-Lambert Company v Novartis (Singapore)  SGHC 106, was reaffirmed by the Singapore Court of Appeal in Warner-Lambert Company v Novartis (Singapore)  SGCA 45, with the Court of Appeal agreeing with the High Court judge’s decisions.
Necessity of Swiss-style claims
In addition, the Court of Appeal went on to consider the scope of second and subsequent medical use under the Singapore Patents Act. In particular, the Court of Appeal reviewed the ambit of section 14(7) of the Singapore Patents Act, which has traditionally been the basis for claiming the first medical use of a known substance in Singapore. The Court of Appeal stated that the provision should be interpreted to recognise new uses of known substances, whether it be first or subsequent, as long as the new uses do not form part of the state of the art. That is, the Court of Appeal construed section 14(7) as possibly encompassing second and subsequent uses of a known substance. If this is correct, then there would be no need to resort to Swiss-style claims to claim second and subsequent medical uses of a known substance, and a purpose-limited product claim (in the form of “Compound X for use in treating disease Y”) may be sufficient to obtain a patent for a second or subsequent use of a known substance.
It is to be noted that the above were mere observations made by the Court of Appeal, and no decision was made as to whether Swiss-style claims should or should not be used to claim second and subsequent medical use of a known substance. The Intellectual Property Office of Singapore (IPOS) issued a notice on 28 August 2017 that it is currently reviewing the decisions and observations made in Warner-Lambert Company v Novartis (Singapore)  SGCA 4, and until further notice, the current practice of using Swiss-style claims for second and subsequent medical use of a known substance, as provided in the Examination Guidelines for Patent Applications at IPOS will continue to apply.