The UK Court of Appeal has recently referred a question relating to Article 3(a) of the SPC Regulation (469/2009) to the European Court of Justice (the CJEU) in the case of Sandoz Limited v Searle.

Article 3 sets out the conditions for obtaining an SPC, with Article 3(a) specifying that:

“the product must be protected by a basic patent in force.”

In more detail, Sandoz Limited and Hexal AG (the Appellants) wish to clear the way for production of a generic version of the drug darunavir. Darunavir is an anti-retroviral drug used for the treatment of HIV and AIDS and is the subject of an SPC (SPC/GB07/038) which expires on the 23 February 2019. The proprietor of the SPC is G.D. Searle and darunavir is marketed under the trade mark “Prezist®” by the exclusive licensee Janssen Sciences Ireland. Sandoz alleged that the SPC was invalid as darunavir was not protected by a basic patent in force. Searle contended that the product described in the SPC was protected by the European Patent (UK) No 0 810 209 (the patent).

During the proceedings Sandoz argued that darunavir was not protected by the patent for several reasons, including that the patent specification did not specifically refer to darunavir. The specification did provide two Markush formula which covered somewhere between 7 x 10135 and 1 x 10377 compounds. According to expert evidence the patent specifically disclosed around 100 compounds, but darunavir was not one of them, however, it fell within the scope of claims 1, 2, 5, 10 and 11. In a decision dated 3 May 2017 Arnold J decided that darunavir was protected by the patent and so the SPC was valid. Sandoz appealed the decision.

On appeal Sandoz focussed on the agreement that for Article 3(a) to be satisfied it must be shown that “the skilled team would recognise the product as forming a part of the subject matter of the patent by reference to a careful reading of the patent based on the common general knowledge at the priority date”. Sandoz submitted that this was not the case for darunavir, due to the large number of compounds covered by the claims and the unusual structure of the substituents that formed darunavir. Sandoz also argued that the use of the “inventive advance test” originally applied by Arnold J in Actavis Group PTC EHF v Sanofi [2014] RPC 20 (Sanofi) was not appropriate when applied to Markush-type claims and was not in line with the CJEU’s jurisprudence that “something more” than infringement was required and that the inventive advance test did not add anything to an infringement test.

In response Searle contended that the test should be whether the Markush formula encompassed the product in question. Furthermore, Searle argued that the test proposed by Sandoz would discriminate against the phase of medical research in which the structure-activity relationship has been discovered but the specific compound which was to be administered to humans had not yet been singled out.

In his Judgement Lord Justice Floyd referred to the requirement set out in C-493/12 Eli Lilly & Co Ltd v Human Genome Sciences Inc [2014] RPC 21 (Eli Lilly), in which the CJEU specified that claims could relate to an active ingredient “implicitly but necessarily and specifically” indicating that functional claims could satisfy Article 3(a) as well as stating that the active ingredient for which an SPC is sought should be “immediately evident from the claims of the basic patent”.

He then identified that two different tests may be appropriate depending on the objective of the requirement of Article 3(a). On one hand, if the objective is to ensure that the product is an embodiment of the inventive effort or advance contributed by the patentee (as suggested in Sanofi), the appropriate test would be asking whether it is clear that the product is claimed as such. On the other hand, if the objective of the requirement is to ensure that the patent demonstrates that the proprietor has in fact come close to an actual realisation of the product, then asking whether the product is one which is sufficiently identified would be the appropriate test.

Lord Justice Floyd went on to clarify that the test should not be purely an infringement test as combinations which are not specified in the claims which could infringe the patent may not be subject to a SPC.

Lord Justice Floyd went on to state that a better test would be that applied by Arnold J at first instance i.e. whether the product that is the subject of the SPC embodies the inventive advance of the basic patent. Lord Justice Floyd believed that this test would be satisfied by a valid Markush claim, with every compound encompassed delivering the core inventive advance, thus considering darunavir to be protected by the patent.

Also, if it is established that the active ingredient constituted the core inventive advance of the patent, a further test should be “whether the skilled person, considering the claims of the patent on the one hand and the structure of the product in question on the other, would immediately recognise that the active ingredient in question as one of those specified by the formula”.

Despite this opinion, due to the unclear jurisprudence of the CJEU, Lord Justice Floyd was uncertain whether this was the correct test and submitted the question detailed below:

“Where the sole active ingredient the subject of a supplementary protection certificate issued under [the SPC Regulation] 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 Article 3(a) of the SPC Regulation 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?”

The detailed nature of the question is most likely intended to clarify what the correct test to apply is and particularly for Markush-type claims.

It is clear from Lord Justice Floyd’s closing statements that he believes that in the case of Markush type claims, all compounds included in the formula satisfy the “inventive advance test”. The question then should be whether the substituent in question would be immediately recognised by the skilled person. Whether Lord Justice Floyd’s interpretation is correct shall hopefully be clarified by the CJEU.