Last year we reported on the first limb of this litigation, being the unsuccessful application by Gilead for interlocutory injunctive relief to prevent generic versions of the Truvada product from being sold in the Republic of Ireland. Since then generic products have been on the market and the substantive stage of the litigation took place this year during a month long trial in which the cases against our client Mylan and also against Teva Pharmaceuticals were heard together. Judgment issued in October 2019 revoking Gilead’s supplementary protection certificate (“SPC”) for Truvada. Gilead has now obtained a stay of the revocation order pending its appeal which is unlikely to be heard before the end of 2020.
The case is of particular interest to practitioners because it reviews in depth and in the context of a substantial amount of expert evidence, the much considered and very fraught interpretation of Article 3(a) of Regulation EC No 469/2009 concerning the supplementary protection certificate for medicinal products (”the SPC Regulation”). The essential question at issue was whether an SPC is valid where one of its key constituent elements is not mentioned at all on the face of the underlying patent? What may at first blush may seem a quite straightforward question based on standard patent law principles has exercised judicial minds across Europe for many years and this case is the latest in a line of pan European decisions concerning Truvada. It is also the first common law based decision to undertake a rigorous review of the question in the context of expert evidence.
Truvada is a combination drug containing active ingredients tenofovir disoproxil (“TD”) and emtricitabine (“FTC”) sold by Gilead as a prophylactic antiretroviral for the treatment of HIV. First protected by a base patent that claimed TD, Gilead claimed that after expiry of that patent Truvada was protected by an SPC for the combination of TD and FTC. Gilead issued proceedings in jurisdictions across Europe to prevent the sale of generic forms of Truvada, which Gilead claimed was protected by equivalent SPC’s in each country. The defendants claimed that Gilead’s SPC was invalid because the combination that it purported to protect was not covered by the base patent.
In Ireland the relevant SPC is based on Irish Patent No EP 0915894 which essentially claimed TD and which expired on 25 July 2017 and had a priority date of 26 July 1996. The Irish SPC for Truvada is due to expire in 2020.
The Defendants to the Irish invalidity proceedings contended that FTC was neither identified nor specified in the base patent. Gilead alleged that the combination of TD and FTC fell within claim 27 of the base patent on the basis that FTC fell within the meaning of the expression “optionally other therapeutic ingredients. However, the patent provided no guidance as to the interpretation of this term.
The CJEU two-stage test
The key question at issue in the case was what is meant by the “basic patent in force” language in Article 3(a) of the SPC Regulation. On 25 July 2018 the CJEU had delivered judgment in Case C-121/17 Teva UK Ltd v Gilead Sciences Inc. in response to a preliminary reference made by Arnold LJ from equivalent proceedings in the High Court of England & Wales that specifically considered the criteria for deciding whether “the product is protected by a basic patent in force” under Article 3(a). In that judgment the CJEU had established a two-stage test which, firstly, required the national court to look at the invention protected by the base patent and to establish whether the combination of active ingredients fell within it. The second limb of the test required that each of the active ingredients must be specifically identifiable, in the light of all the information disclosed by the patent.
Acknowledging that the interpretation of the patent was a matter for national courts, the CJEU went on to observe that the patent in question in the English proceedings contained no information in relation to the combined effect of TD and FTC thus it did not seem possible that that a person skilled in the art would be able to understand that the combination fell within the invention.
The first limb of the Teva v Gilead test
On 11 October 2019 Justice Denis McDonald delivered judgment in the Irish leg of the Truvada dispute - Gilead Sciences Inc & Ors v Teva B.V. & Ors and Mylan S.A.S & Ors (2017) 6494P. The Irish equivalent SPC for Truvada is due to expire in 2020 and is based on an Irish patent which expired on 25 July 2017, with a priority date of 26 July 1996.
The CJEU test firstly requires the national court to look at the invention and to establish whether the combination of active ingredients falls within it. McDonald J confirmed that it is clear from the CJEU’s judgment that the patent is to be viewed through the eyes of the skilled person on the basis of the common general knowledge and in light of the description and drawings of the invention. In the judge’s opinion the approach of the CJEU was “invention focussed”.
Expert witnesses for the respective parties included two of the most experienced HIV clinicians worldwide and a leading medicinal chemist. The judge accepted evidence that the combination of TD and FTC was not mentioned anywhere in the patent. He found that the patent claimed wide utility to a number of human and animal viruses and was not restricted to HIV drugs. He considered that this evidence supported the conclusion that the scope of the invention focused on prodrugs to enable the bioavailability of compounds in man and animals in relation to a wide range of viruses and not just on the combination of FTC and TD as an HIV treatment. Therefore, he held that Truvada did not fall within the ambit of the invention claimed by the base patent and the Truvada combination product could not be said to be protected by the basic patent in force within the meaning of Article 3(a) of the SPC Regulation.
The second limb of the Teva v Gilead test
The second limb of the CJEU test requires that each of the active ingredients must be specifically identifiable, in the light of all the information disclosed by that patent. In applying the second limb McDonald J found that it was necessary to consider what was in the common general knowledge of the skilled person at the priority date. In the judge’s opinion the person skilled in the art construes the patent with common general knowledge of the art as explained by Lord Hoffman in Kirin-Amgen. In this regard he admitted that he differed from the interpretation of prior art in this context made by Advocate General Hogan in his recent opinion in Joined Cases C650/17 and C-114/18, the Royalty Pharma case.
The priority date for the base patent (July 1996) was very early in terms of the development of anti-HIV treatments. The expert evidence revealed that although there were various early research references to FTC, only one small and early phase 1 clinical study of FTC had been conducted and published on a poster (“the Wang Abstract”) at the World Aids conference by this time and even if experts saw that poster they would only see a reference to a product development number and not to FTC It was significant that both expert clinicians had attended that particular conference and neither had seen it.
Accordingly, the defendants argued that the existence of FTC and/or its combination with TD was not common general knowledge for the skilled person as of July 1996. By contrast, the plaintiff argued that prior art is only significant in respect of the second limb of the test (based on Advocate General Hogan’s approach) and that FTC was identifiable in the prior art, in particular, as a result of the Wang Abstract and in any event was one of only a small number of combination partners for TD at the priority date .
Rejecting Gilead’s contention that HIV was the focus of the patent and also that the Wang Abstract would in the circumstances have been recognised by the skilled person at the priority date, McDonald J held that the second limb of the test was not satisfied. In short, he found that HIV was only one of the viruses covered by the patent and that based on the expert evidence and in particular various concessions made by Gilead’s expert in cross-examination, that a skilled clinician would have understood the patent to cover every form of virus. He also found that the use of “optionally” in “optionally other therapeutic ingredients” was not consistent with the plaintiff’s thesis that the patent claim covered HIV combination therapy at the priority date. Finally, he found that the plaintiff had not in any event proven that FTC was a therapeutic ingredient at that time such that it would have been specifically identifiable by the skilled person in the context of the patent at the relevant date.