The law is not static and it evolves as new decisions are handed down or new legislation comes into force. In a recent article, "The Alps in Mzansi" (without prejudice July 2016 p17), the format for claiming the second medical use of known compounds was explored. It was concluded that claims drafted in the "for use type" format, which are directed toward a second medical use that is "A substance X for use in a method of treatment of Y", are not allowable in South African law. It was further concluded that the second medical use of a known compound should only be claimed in the Swiss-type claim format, viz: "The use of substance X in the manufacture of a medicament for treating Y".
While we are in agreement that the Swiss-type claim format is acceptable in South Africa, we respectfully differ that the second medical use of a known compound should only be claimed in the Swiss-type format for the reasons set out below.
The starting point for any question on South African patent law is the Patents Act. Section 25(11) provides that a method of medical treatment practised on the human or animal body is deemed not to be capable of being used or applied in trade or industry or agriculture, and thus claims to such methods are not allowable. However, s25(12) provides that a substance or composition for use in such methods is exempt from this exclusion. Further, s25(9) states that the fact that a substance or composition forms part of the state of the art immediately before the priority date of the invention is known, will not prevent a patent being granted for the invention, if the use of the substance or composition in any such method does not form part of the state of the art at that date. Therefore, the first and subsequent medical uses of a known compound are patentable.
The Patents Act makes no mention of the Swiss-type claim format. However, prior to any South African court decisions on the correct for- mat for claiming a novel medical use of a known compound, South African practitioners had adopted the use of the Swiss-type claim format for second medical uses, guided by the practice in Europe.
Thereafter came the only South African case on this issue, Elan Transdermal Limited v Ciba Geigy Propriety Limited. In this matter, Judge McArthur based his interpretation of s25(9) of the Patents Act on the interpretation given to the substantially similar s2(6) of the
British Patents Act at the time, and on the decision in the UK case John Wyeth's and Schering's Applications .
According to the decision in the John Wyeth's case, a claim in the Swiss-type format is, in reality, a claim to a method of manufactur-
ing a medicament by using the known substance in its manufacture. Furthermore, provided the novelty requirement is met, there was no objection to patenting an invention directed to second or subsequent uses of a known pharmaceutical claimed using the Swiss-type claim format. Therefore, the John Wyeth case confirmed that the Swiss-type claim format directed to a second or subsequent medical use of a known pharmaceutical is permissible, if the requirement of novelty can be met. Judge MacArthur echoed this ruling in the Elan Transdermal case saying: "Put another way, if the medicament made for the second medical use is novel and is not obvious the claims will be good".
Importantly, both counsel in the Elan Transdermal case accepted that the Swiss-type format was consistent with the provisions of the Patents Act. There was no analysis by the court as to whether the Swiss-type claim format was the appropriate format for a second medical use. It was thus decided that the first medical use of a known substance must be claimed in the "for use type" format, that the second medical use cannot be claimed in this format, and that it is permissible to claim the second medical use of a known substance in the Swiss-type claim format.
European law, which our courts often regard as persuasive, has since evolved and under EPC 2000 (an Act revising the EPC which entered into force in December 2007) it became permissible to utilise the "for use type" format to claim second medical uses of compounds and substances. Under the EPC 2000, Swiss-type claims are allowed but are no longer necessary for claiming second and subsequent medical uses of known substances. The situation changed again in February 2010, when the European Patent Office (EPO) Enlarged Board of Appeals issued a decision (G 2/08) on the acceptability of Swiss-type claims, and decided that in cases where the subject matter of a claim is rendered novel only by a new therapeutic use of a medicament, such claims may no longer have the Swiss-type claim format. Furthermore, in 2014, decision T1780/12 of the EPO Technical Board of Appeal indicated that a claim in the Swiss-type claim format was a purpose-limited process claim and that a claim in the EPC 2000 second medical use format was a purpose-limited product claim. This translates into the two formats giving different scopes of protection with the purpose-limited process claim conferring less protection than a purpose-limited product claim.
Based on the developments in European law over the past decade, and the persuasive value of European patent law on the South African legal system, we are of the opinion that a South African court, when faced with a similar decision in the future, may look favourably on the route taken by the EPC and allow the claim of a second medical use in the "for use type" format.
It is also our view that the correct way to interpret s25(9), as worded, is that it refers to any medical use of a known compound, whether the first use or a second or subsequent use. Thus the "for use type" claim format is appropriate for any invention of a known compound for a medical use.
To conclude, it is our view that in practice it is advisable to include "for use type" claims, together with Swiss-type claims, when claiming further medical uses of a known compound. This will allow a South African court to decide on the correct approach when next faced with the interpretation of such claims. At worst, the set of claims deemed to be invalid can be deleted during any litigation which may occur, a task that is surely easier than trying to persuade a court to allow an amendment from Swiss-type claims to "for use type" claims.
Truluck is an Associate and Mahomed a Candidate Attorney. The article was edited by Alison Dyer, a Consultant at Spoor & Fisher.