The Singapore Court of Appeal (COA) recently dismissed Warner-Lambert’s appeal, upholding the decision of the High Court, in Warner-Lambert Company LLC v Novartis (Singapore) Pte Ltd. The High Court judge had denied Warner-Lambert leave to amend its patent relating to a method of treating pain by administering Pregabalin. The COA agreed with the High Court that there had been an undue delay by Warner-Lambert in seeking the amendments, and that the amendments, if made, would extend the scope of the protection of the patent (previously reported in ReMarks 4th Quarter 2016).

Although the COA was not required to comment on the validity of Swiss-style second medical use claims, the COA made some interesting observations, which, though not binding, are the first to be made in the Singapore courts in relation to Swiss-style claims.

The Singapore Patents Act does not explicitly provide whether a second/ further medical use of a known substance/ composition is considered to be patentable. To date, s.14(7) of the Act has been interpreted as protecting only the first medical use of known substances. However, following the Act, it has been the practice of the Intellectual Property Office of Singapore (IPOS) to accept claims for a second/further medical use of a known substance/composition in the form of Swiss-style claims.

IPOS’s Examination Guidelines for Patent Applications provide that “…if the substance or composition has already been known to be useful for a medical purpose, then in order to protect a further new medical use of the substance or composition, a second medical use format (Swiss type format) must be used”. 

Whilst the validity of second medical use claims in the UK has been clarified by recent legislation, whereby a purposelimited product claim (i.e. “Substance X for use to treat disease Y”) is now considered the acceptable form of such claims, corresponding legislative changes have not been made in Singapore. Consequently the Swiss type format remains the only acceptable form of second medical use claims in Singapore. In fact, the Examination Guidelines provide that “second or subsequent medical uses of a substance or composition may only be claimed in the form of “Swiss-type” claims”, with an example of a suitable form being: ‘Use of substance X for the manufacture of a medicament to treat disease Y’”.

The COA commented that s.14(7) of the Singapore Patent Act appeared to support the patentability of second and subsequent medical uses of known substances because by “its ordinary meaning, [it] does protect any use, first or subsequent, which is not part of the state of the art”. By virtue of this interpretation, the COA endorsed the position that the patenting of second and subsequent uses of a known substance was enabled, and a purpose-limited product claim in the form of “compound X for use in the treatment of disease Y” may suffice to obtain protection, thereby removing the necessity of Swiss-style claims. The COA further added that while it did not disagree with the validity of Swiss-style claims as currently allowed by IPOS, it believed that if the COA’s interpretation of s.14(7) was given, Swiss-style claims would not be needed.

Although Swiss-style claims remain the current form of protection of second/ further medical uses, the comments of Singapore’s highest court may lead to legislative changes. In fact, soon after the COA’s decision was published, IPOS issued a note stating that it was reviewing the COA’s observations in relation to Swiss-style claims, but the current practice of using Swiss-style claims as provided in the Examination Guidelines for second/ subsequent medical uses remains until further notice.

It therefore remains to be seen whether the law in Singapore will be amended to recognise a similar purpose-limited product claim as in the UK. In the meantime, applicants should seek the advice of a qualified Singapore patent attorney with experience in second medical use claims to ensure that suitable forms of second medical use claims are included in their patent application