The UK Court of Appeal has referred to the CJEU the following question regarding the interpretation of the requirement in Article 3(a) of the SPC Regulation for the product to be “protected by a basic patent in force”:
“Where the sole active ingredient, the subject of an SPC is a member of a class of compounds which fall within a Markush definition in a claim of the patent, all of which class members embody the core inventive technical advance of the patent, is it sufficient for the purposes of art.3(a) that the compound would, upon examination of its structure, immediately be recognised as one which falls within the class (and therefore would be protected by the patent as a matter of national patent law) or must the specific substituents necessary to form the active ingredient be amongst those which the skilled person could derive, based on their common general knowledge, from a reading of the patent claims?”
There are now three pending referrals to the CJEU regarding the interpretation of Article 3(a), following the recent referrals from the UK High Court in Teva v Gilead  EWHC 13 (Pat) and from the German Federal Patent Court in the Sitagliptin case (14 W (pat) 12/17).
The SPC in question in the present case relates to a specific compound, darunavir. The claims of the basic patent feature Markush formulae, which encompass a large number of compounds including darunavir. However, none of the claims contain an individualised disclosure of darunavir itself.
There have been a number of CJEU decisions addressing the requirements for complying with Article 3(a), which have stated that it is necessary for the active ingredient to be “specified in the wording of the claims” (Medeva, C-322/10) or “identified in the wording of the claims” (Daiichi Sankyo, C-6/11; University of Queensland, C-630/10). More recently, in the UK, Mr Justice Arnold has suggested in Actavis v Sanofi  EWHC 2545 (Pat) and Teva v Gilead  EWHC 13 (Pat) that a better test would be to consider whether the product embodies the “core inventive advance” (or technical contribution) of the claim.
In the UK High Court decision giving rise to the present appeal (discussed in a previous briefing note here), Arnold J held that darunavir is protected by the basic patent within the meaning of Article 3(a). He made particular reference to the CJEU’s decision in Eli Lilly v HGS (C‑493/12), in which it was held that it is sufficient for the active ingredient to be covered by a functional definition provided that the claims “relate, implicitly but necessarily and specifically, to the active ingredient”.
On appeal, the appellants argued that darunavir is not specified “implicitly, but necessarily and specifically” in the claims because one of its substituents was unusual and did not fall within the common general knowledge of the skilled person at the priority date of the patent.
The Court of Appeal stated that it provisionally agrees with the conclusion reached by Arnold J that darunavir is protected by the patent. However, it held that it is at least arguable in view of Eli Lilly v HGS (C‑493/12) that the appellant is correct that the substituents of a compound must be among those which the skilled person would be able to identify from the claims based on his common general knowledge at the priority date. The Court acknowledged, however, that adoption of this approach would present difficulties to patent offices trying to apply this test.
The Court also noted that the views expressed by the German Federal Patent Court in the Sitagliptin case suggest that a German court could take the view that a Markush formula may, at least in a case like the present, fail to provide protection within the meaning of Article 3(a).
We await the outcome of this reference with interest.