Generics, Teva & Glenmark v AstraZeneca

Hearing dates: 10–14 and 19–20 March 2025

Approved Judgment

I direct that no official shorthand note shall be taken of this judgment and that copies of the version as handed down may be treated as authentic.

This judgment was handed down at 2.00 pm on 28 April 2025 by circulation to the parties' representatives by email and release to The National Archives

The Deputy Judge:

In these proceedings the Claimants each seek declarations that supplementary protection certificates SPC/GB13/021 and SPC/GB14/050 (“the SPCs”) are invalid and orders for their revocation, as well as a declaration that European Patent (UK) No. 1506211 (“the Patent”), which was the basic patent on which the SPCs were granted, was invalid. The only ground of invalidity of the SPCs which remains live is that the Patent was invalid.

The Patent was originally in the name of Bristol-Myers Squibb Co. (“BMS”) but was assigned to the Defendant (“AZ”) in 2014. The Patent claimed a priority date of 20 May 2002 and expired on 14 May 2023. It claimed a compound known as dapagliflozin and its use in the manufacture of a medicament for, inter alia, treating diabetes.

Dapagliflozin is an inhibitor of the sodium-dependent glucose co-transporter protein SGLT2. SGLT2 is responsible for the re-uptake of glucose in the proximal tubule of the kidney back into the bloodstream. SGLT2 inhibitors are understood to reduce blood glucose levels by preventing glucose reabsorption into the blood, thereby facilitating excretion into the urine.

Dapagliflozin was first authorised for marketing in the UK for the treatment of type II diabetes as monotherapy on 14 November 2012 and, in combination with metformin, on 21 January 2014. SPC/GB13/021 relates to dapagliflozin and (with its associated paediatric extension) is due to expire on 13 May 2028. SPC/GB14/050 relates to a combination of dapagliflozin and metformin and is due to expire on 14 May 2028. Dapagliflozin has been very successful commercially; hence the Claimants' interest in invalidating the SPCs.

The Claimants contend that the Patent was invalid for lack of inventive step and/or insufficiency. In summary they plead that:

(a) the Patent did not make it plausible that dapagliflozin is an SGLT2 inhibitor, a selective SGLT2 inhibitor or useful for treatment of diabetes; and

(b) the Patent did not make a technical contribution over a BMS PCT application published on 19 April 2001, namely WO 01/27128 A1 (“WO 128”), but rather merely made an arbitrary selection of dapagliflozin from the class of compounds disclosed in WO 128 without disclosing any advantage for dapagliflozin compared to that class.

Originally the Claimants contended that it was in any event obvious (in the conventional sense) to arrive at dapagliflozin as an SGLT2 inhibitor from the disclosure of WO 128, but that allegation was not pursued in their closing submissions.

At trial, Mr Mitcheson KC conducted the oral advocacy for the Claimants and Ms Lane KC did likewise for AZ. Given that all the issues in this case were closely related, it was entirely understandable that the parties decided, after due consideration, not to allocate any part of the oral advocacy to junior counsel. I am grateful to all counsel and to all the firms of solicitors involved for their work in preparing the evidence and submissions.

THE LAW

This case raises once again the question of the nature and extent of the disclosure which is required in order for a patent for a chemical compound to satisfy the twin statutory requirements of inventive step and sufficient disclosure. As has often been emphasised, the fundamental principles underlying the requirements of inventive step and sufficient disclosure are that patents are granted for technical contributions to the art (or, to put it another way, for technical solutions to problems) and that the claimed monopoly must be justified by such a technical contribution. The task facing tribunals has been to work out how those principles apply, in the context of the twin statutory requirements, to patents for chemical compounds which are said to have a particular utility.

I shall address the case law under two heads, reflecting the way in which the parties presented it (and using the headings which they adopted), though the two strands of case law and the principles which they reflect are in fact interwoven.

Plausibility

The Warner-Lambert line of cases

The case law of the Boards of Appeal of the European Patent Office (“EPO”) and of the courts of this jurisdiction has been reviewed in a number of judgments of the Court of Appeal (most recently in the judgment of Arnold LJ in Sandoz v Bristol-Myers Squibb [2023] EWCA Civ 472 (“ Apixaban CA”)) and by the Supreme Court in Warner-Lambert v Generics [2018] UKSC 56. It is not necessary to traverse all that ground again, particularly as it is common ground that I am bound by the judgments in those cases to apply the standard set out by the majority in Warner-Lambert. It is, however, worth highlighting certain aspects of the authorities.

The starting point in the relevant line of authorities is generally regarded as being T 939/92 AgrEvo / Triazoles. In that case the application claimed a class of compounds defined by a Markush formula, and asserted that the claimed compounds had herbicidal activity. The Board emphasised (at paragraph 2.4.2) the general legal principle that a patent monopoly should be justified by the technical contribution to the art, and held that this principle applied to the requirement of inventive step (Article 56 EPC) as much as it did to the requirement of sufficient disclosure (Article 83 EPC). It observed (at paragraph 2.5) that if claimed compounds did not have a technically useful property, then the “problem” solved by their provision would be the minimalist one of merely providing further compounds, which was not inventive. That is because “structural originality [has] no intrinsic value or significance for the assessment of inventive step as long as it [does] not manifest itself in a valuable property in the widest sense, an effect or an increase in the potency of an effect” (see paragraph 2.5.1). The Board said (at paragraph 2.5.3) that in light of the general legal principle, in order for a selection of compounds to be patentable, it “must not be arbitrary but must be justified by a hitherto unknown technical effect which is caused by those structural features which distinguish the claimed compounds” from other compounds. It went on to say (at paragraph 2.6) that a technical problem could only be accepted as having been solved if it would be credible that substantially all the compounds claimed possessed the relevant technical effect.

In T 609/02 Salk Institute / AP-1 complex the claim was in Swiss form (i.e. to the use of a compound for the manufacture of a medicament for a particular therapeutic application). At paragraphs 8–10, the Board explained the policy reasons for requiring an application for such a patent to disclose sufficient information to make it at least plausible that the compound would be effective to treat the relevant disease, and provided guidance as to the nature and extent of the information that would be required for that purpose. The whole passage is worth recalling (citations omitted, emphasis added in paragraph 9):

“8. …Sufficiency of disclosure must be satisfied at the effective date of the patent, ie on the basis of the information in the patent application together with the common general knowledge then available to the skilled person. Acknowledging sufficiency of disclosure on the basis of relevant technical information produced only after this date would lead to granting a patent for a technical teaching which was achieved, and, thus, for an invention which was made, at a date later than the effective date of the patent. The general principle that the extent of monopoly conferred by a patent should correspond to, and be justified by, the technical contribution to the art, has to be kept in mind…

9. Where a therapeutic application is claimed … in the form of the use of a substance or composition for the manufacture of a medicament for a defined therapeutic application, attaining the claimed therapeutic effect is a functional technical feature of the claim…. As a consequence, under Article 83 EPC, unless this is already known to the skilled person at the priority date, the application must disclose the suitability of the product to be manufactured for the claimed therapeutic application. It is a well-known fact that proving the suitability of a given compound as an active ingredient in a pharmaceutical composition might require years and very high developmental costs which will only be borne by the industry if it has some form of protective rights. Nonetheless, variously formulated claims to pharmaceutical products have been granted under the EPC, all through the years. The patent system takes account of the intrinsic difficulties for...