In a recent case in Warner-Lambert Company LLC v Novartis (Singapore) Pte Ltd [2017] SGCA 45, the Court of Appeal dismissed Warner-Lambert’s appeal to amend its patent under S83(1) of the Patents Act to cure its invalidity by amending non-patentable method of treatment claims into Swiss-style second medical use claims.


In 2015, Warner-Lambert received notification of Novartis’ applications to the Health Sciences Authority (HSA) for product licences for Pregabalin products under Section 12A(3)(a) of the Medicines Act. Warner-Lambert subsequently commenced proceedings against Novartis, seeking, among other relief, a declaration that the Patent would be infringed by Novartis, if it did the acts for which the product licences were sought. Novartis, in its defence and counterclaim, sought to revoke the patent on the ground that it claimed a monopoly over methods of treatment of the human or animal body which are not patentable for lack of industrial applicability in Singapore. Warner-Lambert then applied for leave to amend the patent in August 2015 to cure the invalidity of the patent by amending the method of treatment claims into Swiss-type claims.

The High Court refused the amendment application on the basis that (a) the amendments would extend the protection conferred by the patent and (b) there was an undue and unreasonable delay on the part of Warner-Lambert in seeking the post-grant amendments. A summary of the High Court’s decision may be found here.

It should be noted that at the time of Warner-Lambert’s application in 1997, the Singapore patent system was under a self-assessment system, under which the Intellectual Property Office of Singapore (IPOS) did not conduct an independent search and examination to determine if the claimed invention was patentable. Instead, the burden was on the applicant to ensure that the claims comply with the requirements for patentability under the Act. The self-assessment system has been replaced by a “positive-grant” system on 14 February 2014. Under the new positive grant system, IPOS makes a positive determination on whether a patent application complies with the patentability requirements before an application is granted.

The Court of Appeal Held that there was undue delay in seeking the amendments

The Court of Appeal noted that the power to allow an amendment under Section 83(1) is a discretionary one. The court when exercising this discretion takes into consideration various factors as set out in Smith Kline & French Laboratories Limited v Evans Medical Limited [1989] FSR 561. These factors include, for example, whether the patentee delayed in seeking amendments, and if so, whether there were reasonable grounds for such delay.

The Court of Appeal held that there was undue delay in seeking the amendments for over ten years. The Court of Appeal noted, for example, that Warner-Lambert had earlier received an International Preliminary Examination Report in 1998, indicating that method of treatment claims might be inadmissible in some patent systems. Warner-Lambert had also filed amendments in 1998 in the corresponding European application to amend method of treatment claims to Swiss-style claims, but not in the Singapore case. In addition, Warner-Lambert had applied to amend method of treatment claims in some of its other Singapore applications in 2006, 2007 and 2008. These factors led to the conclusion that Warner-Lambert had actual and/or constructive knowledge that method of treatment claims were not patentable in Singapore, and that the patent was wholly invalid as it contained exclusively method of treatment claims. The failure to act on this knowledge expeditiously amounted to unreasonable delay.

The Court of Appeal ruled that the proposed amendments would extend the scope of protection of the patent

The Court of Appeal found that the patent was obviously invalid as the granted claims were method of treatment claims which are not patentable. The patent therefore failed to meet even the threshold criteria for patentability and conferred no protection whatsoever from the beginning. The application to amend the claims was thus seeking to validate that which was not valid from the beginning. On this basis, the application to amend the claims was refused.

For completeness, the Court of Appeal also agreed with the approach taken by the High Court Judge in finding that the proposed amendments into Swiss-style claims would extend the scope of protection conferred by the patent. In particular, the Court of Appeal agreed that the manufacture of the medicament for the purpose of treating pain, as stated in the proposed amended claims in Swiss-style format, is not an act that falls within the ambit of protection of the granted claims (which are method of treatment claims). In other words, the proposed amendments protect the manufacture, while the granted claims protected the method of treatment.

Validity of Swiss-style claims and purpose limited claims

The Court of Appeal observed, in orbiter, that Section 14(7) of the Patents Act could go further than merely conferring patentability on the first use of a known substance. The Court of Appeal believes that a wider and purposive interpretation may be given to Section 14(7) which would allow the protection of a new use of a known substance (via purpose limited product claims), as long as the new use does not form part of the state of the art.

The Court of Appeal recognises that Swiss-style claims are currently allowable by IPOS for the protection of new uses of known substances and does not disagree with the validity of such claims at this stage. The Court of Appeal, however, commented that Swiss-style claims are merely a novel and perhaps questionable way of getting around what has been perceived to be the meaning of Section 14(7) of merely conferring patentability on the first use of a known substance. The Court of Appeal noted that if the wider interpretation of Section 14(7) is adopted, then Applicants would not need to resort to Swiss-style claims since purpose limited product claim formats would suffice.

Following the Court of Appeal’s decision, IPOS released an update on 28 August 2017 stating that IPOS is currently studying the Court of Appeal’s decision and that, in the meantime, the current practice of using “Swiss-style” claim format for second or subsequent medical uses will continue to apply.

Conclusion and Tips

  1. Applicants should be mindful of the adverse effect of “undue and unreasonable delay” when making post-grant amendments before the Patent Office or the Court.
  2. Applicants should take note that method of treatment claims are not patentable in Singapore and should be amended into their corresponding Swiss-style second medical use format that is currently acceptable at IPOS where possible (e.g. prior to requesting Substantive Examination under the new Act).
  3. Purpose limited product claims are currently not acceptable as second medical use claims at IPOS. However, in applications where a novel product is being claimed, it is recommended to include second medical use claims in both purpose limited product use format (such as the EPC2000 style claims) and Swiss-style format.