How specific must you be for an SPC?
06 June 2017
In a recent judgment (Sandoz v Searle), the UK High Court has upheld a supplementary protection certificate (SPC) for the anti-HIV drug darunavir (Prezista®) based on a European patent whose claims covered the drug within a general formula, but which did not specifically disclose or claim the compound. This is welcome news for SPC applicants and provides much needed clarity on this important question.
Article 3(a) of the European Union SPC regulation requires that one of the criteria for SPC protection is that the product must be "protected by a basic patent in force". However, Court of Justice of the European Union (CJ) decisions in recent years have caused considerable uncertainty as to what is required for the product to be "protected" by the patent.
The only matter on which there appears to be consensus is that it is not sufficient for the product to simply fall within the claims of the basic patent: something more is required, but despite several references the CJ has not as yet made it clear what that "more" is. However, two tests have begun to emerge from the case law: firstly, that the product must be "specified" or "identified" within the wording of the claims (Medeva); secondly, that the product must "embody the inventive advance" of the basic patent (Actavis v Sanofi).
In this case, it was common ground between the parties that darunavir fell within the general formula of claim 1 of the basic patent (this type of claim is often referred to as a "Markush claim"), but the specific compound darunavir was not disclosed or claimed anywhere in the basic patent. In view of this, the claimants Sandoz and Hexal argued the SPC was invalid as darunavir was not "specified" or "identified" in the claims of the patent, and the patent did not "protect" the product according to Article 3(a) of the Regulation. The defendants Searle and Janssen counter-argued that even if Article 3(a) was unclear in some other respects, there was no reasonable interpretation of the Article which would mean the product was not "protected" by the patent.
The judge, Mr Justice Arnold, found in the defendants' favour and ruled the product was "protected" by the basic patent. He applied an earlier CJ decision (Lilly v HGS) in which the court held that it is not necessary for the active ingredient to be identified in the claim by means of a structural formula, and 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. He was also clear that darunavir embodied the inventive advance of the patent.
The judge deemed it irrelevant that the Markush claim covered a large number of compounds in addition to darunavir: while this may have been relevant to the question of validity of the basic patent, the claimants did not challenge validity in this case. He also considered it irrelevant that the specific compound darunavir was not discovered until several years after the patent's priority date or that it was independently developed by a party other than the patent proprietor.
This decision is excellent news for the research-based pharmaceutical industry.
It is very common in the medicinal chemistry field for a general structure-activity relationship to be discovered early in a research cycle, leading to a patent claiming the active compounds in terms of a broad Markush formula, but a specific compound falling within that general formula which works particularly well, and which ends up being the compound which receives regulatory approval, may not be identified until many years later. Confirmation that the broader patent may support an SPC even if the specific compound is not disclosed provides a welcome point of clarity following many years of uncertainty on the requirements for SPC protection.
Full decision of  EWHC 987 (Pat) Sandoz Limited & Hexal AG v G.D. Searle LLC & Janssen Sciences Ireland UC: http://dycip.com/ewhc987