Patents Court finds SPC based on a Markush formula valid in Sandoz v Searle

The Patents Court has held that Searle's supplementary protection certificate ("SPC") based on a claim setting out a Markush formula is valid. Arnold J considered the interpretation of Article 3(a) of the SPC Regulation and its application to Markush formulae and concluded that Searle's SPC for the anti-HIV medicine, Prezista®, complied with Article 3(a). This was despite the fact that the claim was very broad, covering a huge number of compounds. In light of the CJEU's judgment in Lilly, Arnold J held that where a patent claim contained a Markush formula that covered a product, this was sufficient for the claim to specify that product for the purpose of Article 3(a) of the SPC Regulation. The judge also indicated that he considered the claimants' arguments better suited to an attack on the basic patent rather than the SPC, but because the claimants had not put the validity of the patent in issue, there was a presumption that the patent was valid.

Business Impact

• This decision is the latest in a line of recent SPC decisions from the Patents Court in which the interpretation of Article 3(a) of the SPC Regulation has been discussed.
• The decision is of interest in clarifying that in the UK an SPC can be validly based on a patent that claims a Markush formula covering a large number of compounds, even though the patent does not individually disclose the relevant compound, or provide any teaching pointing to it.
• Notwithstanding a pending reference currently before the CJEU regarding the interpretation of Article 3(a) (arising from his earlier decision in the case of Teva v Gilead), Arnold J felt the law was sufficiently clear in this case to be able to uphold the SPC on the basis that it complied with Article 3(a).

The Decision

The decision in Sandoz Ltd & anor v G.D. Searle LLC & anor [2017] EWHC 987 (Pat) (link here), concerned the claimants' challenge to the validity of Searle's SPC. This SPC covered an anti-HIV medicinal product which is marketed in Europe as Prezista®, and which contains the protease inhibitor, darunavir, as its active ingredient.

The claimants sought to revoke the SPC in order to clear the way for the marketing of a generic darunavir product. The basic patent had expired in 2013 but the SPC was in force with an expiry date of 23 February 2019. The claimants made no challenge to the validity of the basic patent but sought to revoke the SPC on the basis that it did not comply with Article 3(a) of the SPC Regulation. This was an approach that was an important factor in the court's decision.

The law 

The SPC Regulation enables the proprietor of a patent for a medicinal product to obtain an SPC which extends the duration of the patent with respect to that product so as to compensate the proprietor for the effective loss of patent term caused by the need to obtain a marketing authorisation before the product can be marketed.  Article 3 of the SPC Regulation sets out the conditions for obtaining a certificate.  The relevant part reads as follows:

"A certificate shall be granted if, in the Member State in which the application referred to in Article 7 is submitted and at the date of that application:

(a)  the product is protected by a basic patent in force".

The interpretation of Article 3(a) has been the subject of a number of references to the CJEU from the English courts, the most recent of which arose in the case of Teva UK Ltd v Gilead Sciences Inc [2017] EWHC 13 (Pat) that is currently pending before the CJEU.  In that case, Arnold J found that the test to be applied in order to determine whether a product is "protected" by a basic patent within the meaning of Article 3(a) was unclear and referred a single, broad question to the CJEU asking what the criteria are for deciding this question. In the current case, Arnold J relied on his statements in Teva v Gilead (link here) as to the court's approach to the interpretation of the SPC Regulation and in particular Article 3(a). However, he highlighted the following key points:

• it is not sufficient for a product to be “protected” by a basic patent within the meaning of Article 3(a), that dealings in the product would infringe a claim of the patent applying the Infringing Act Rules;
• it is necessary that the product falls within at least one claim of the patent applying the Extent of Protection Rules;
• it is not clear whether it is sufficient that the product falls within at least one claim of the patent applying the Extent of Protection Rules. According to Arnold J, CJEU case law indicates that this is not sufficient and that something more is required, but it is not clear what more is required.

Arnold J explained that the tests enunciated by the CJEU in the cases of Medeva (Case C-322/10) and Lilly (Case C-493/12) were unclear tests which were difficult to apply.  Arnold J took the opportunity to explain his own suggested approach to the interpretation of Article 3(a) – a two-stage test under which a product is "protected" by the basic patent if:

1. the product falls within the scope of the claim when interpreted in accordance with the Extent of Protection Rules; and
2. the product does so because it contains an active ingredient, or a combination of active ingredients, which embodies the inventive advance (or technical contribution) of the patent.

The basic patent

Even though both sides prepared expert evidence regarding the basic patent, Arnold J commented that it was possible to decide this case without reference to it. Nonetheless, it was accepted that:

• the Markush formulae in the claims of the basic patent covered a large range of compounds, including darunavir.  The claimants' expert estimated that claim 1 covered between 7 x 10¹³⁵ and 1 x 10³⁷⁷ compounds;
• there were approximately 100 compounds specifically disclosed in the patent, but darunavir was not one of them; and
• there was no teaching in the patent to lead the skilled person to darunavir.

Is darunavir a product which is "protected" by the claims of the patent within the meaning of Article 3(a)?

The claimants argued that darunavir was not "protected" by the claims of the patent because darunavir was not specifically identified by name or structure in the claims or in the specification, and because of the lack of any teaching in the patent pointing to darunavir. This was despite the fact that it was agreed that darunavir fell within the Markush formulae of the claims.

For the purposes of determining whether Markush claims complied with Article 3(a), the claimants had proposed a test which required determining whether the skilled person would consider the product to be part of the subject-matter of the patent based on their reading of the specification and their common general knowledge as at the priority date without undue burden or further invention.

However, the claimants accepted that it was not acte clair that this was how Article 3(a) should be interpreted and proposed that the court make a reference to the CJEU.

Arnold J dismissed the claimants' test as unworkable and not in keeping with the "simple and transparent" system that had been envisaged by the European Commission before the SPC Regulation came into force.

Arnold J characterised the claimants' objection to the claims of the patent as one of excessive claim breadth. He explained that such an objection is an objection to the validity of the basic patent, and in so doing, distinguished it from an objection founded in SPC law. He commented that:

"It amounts to saying that the claims are obvious on AgrEvo grounds or insufficient. But as I have already pointed out, the Patent is presumed to be valid unless and until the Claimants put its validity in issue, which they have not done."

Arnold J found the SPC to be valid in light of the CJEU's judgment in Lilly, where the CJEU had held that it is sufficient for the active ingredient to be covered by a functional description provided that the claims “relate, implicitly but necessarily and specifically, to the active ingredient”. From this CJEU judgment, Arnold J drew the following principles:

"It is clear from this that the identification of the active ingredient in the claim by means of a structural formula is permissible, but not essential; that it is not necessary for the claim individually to name or depict the active ingredient; and that it is not necessarily an objection that the claim in question covers a large number of other compounds in addition to the active ingredient in question (since, if that was so, it would have provided a simple answer to the Lilly case)."

Whilst his view remained that the test laid down in Lilly regarding functional descriptions was unclear and difficult to apply, Arnold J considered that where a claim contained a Markush formula that covered a product, this was sufficient for the claim to specify that product. On this basis, darunavir was "protected" by the basic patent, and the SPC complied with Article 3(a).

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