Following hot behind the interim injunction decisions regarding the same subject matter between AstraZeneca and Glenmark (and covered previously in this newsflash here), on 28 April 2025, the High Court handed down its judgment on validity of the patent EP 1 506 211 (the “Patent”) and the respective supplementary protection certificates SPC/GB13/021 and SPC/GB14/050.

Michael Tappin KC sitting as a Deputy Judge of the High Court found the Patent invalid, and accordingly the SPCs also invalid. Although AstraZeneca can maintain the interim injunction against Glenmark that was granted by the Court of Appeal until the form of order hearing.

Background

Three claimants: Generics (U.K.) Limited, Teva (Teva Pharmaceutical Industries Limited and Teva UK Limited) and Glenmark Pharmaceuticals Europe Limited, each launched invalidity proceedings against AstraZeneca AB for the Patent and subsequently the respective SPCs, given that the Patent had expired on 14 May 2023. These proceedings were heard together at trial in March 2025.

The Patent claimed a compound known as dapaglifozin and its use in the manufacture of a medicament for, inter alia, treating diabetes. AstraZeneca market their diabetes drug dapaglifozin under the brand Forxiga. It has been very successful commercially.

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.

Issues

By the time the parties got to trial the Claimants contended 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 was an SGLT2 inhibitor, a selective SGLT2 inhibitor or useful for treatment of diabetes (“Plausibility”); and

(b) the Patent did not make a technical contribution over a PCT application (WO 01/27128 A1) published on 19 April 2001 (“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 (“Arbitrary Selection”).

The Judge came to his decision on the issues by reference only to claim 2 (to dapagliflozin itself) and claim 15 (in summary, to the use of dapagliflozin in the manufacture of a medicament for treating or delaying the progression or onset of diabetes).

Plausibility

In his judgment, the Judge highlighted key aspects of the case law on plausibility from the Board of Appeal of the European Patent Office (“EPO”) and from the courts of this jurisdiction. As expected, his focus was on cases following the Supreme Court’s decision in Warner-Lambert v Generics [2018] UKSC 56.

The Judge spent some time considering the potential effects of the EPO’s Enlarged Board of Appeal decision in G 2/21 and whether its departure from Warner-Lambert was something for him to consider. In the end, he decided that the task before him was to apply the Warner-Lambert standard. And it would be for a higher court to consider the impact of G 2/21 on the Warner-Lambert line of case law.

In assessing plausibility and the technical effect under consideration, the Judge made use of the three steps set out by Birss LJ at [53] in Akebia v Fibrogen [2021] EWCA Civ 1279 (“Fibrogen CA”).

1) To identify what it is which falls within the scope of the claimed class.

The Judge identified that claim 2 was limited to a single compound – dapagliflozin – while claim 15 was limited to the use of that compound in the manufacture of a medicament for treating or delaying the progression or onset of diabetes.

2) To determine what it means to say that the invention works. In other words what is it for?

In following the previous case law in Fibrogen CA and Sandoz v Bristol-Myers Squibb [2022] EWHC 822 (Pat) (“Apixaban HC”), the Judge concluded that the question to be addressed when considering plausibility of dapagliflozin as being useful to treat diabetes (as well as an experimental tool to lower blood glucose in vivo) related to efficacy. This meant for claim 15, treating diabetes, in the sense of having sufficient efficacy to treat diabetes, and in respect of claim 2, this was either (a) the same as in the case of claim 15 or (b) reducing blood or plasma glucose in vivo with sufficient efficacy to allow it to be used as an experimental tool.

3) Once the first two things are known: to answer the question whether it is possible to make a reasonable prediction the invention will work with substantially everything falling within the scope of the claim.

The Judge posed the question of whether the Patent disclosed enough to make it plausible that dapagliflozin had activity as an SGLT2 inhibitor which was sufficient to have a useful effect on blood / plasma glucose levels in vivo and/or on the diabetes disease state.

In assessing the Patent and some of the papers referenced therein, the Judge felt that the Patent did not disclose enough to make it plausible that dapagliflozin would have an in vivo effect on blood / plasma glucose (such that it could be used as an experimental tool) or would treat diabetes.

Arbitrary Selection

On the case for arbitrary selection, the Judge concluded that the Patent did not make a technical contribution over WO 128. There was nothing in the Patent nor in the evidence before him at trial that indicated that dapagliflozin was anything other than an arbitrary selection from the genus of compounds disclosed by WO 128.

Commercial Success Consideration

In line with the comments made by Meade J in Apixaban HC, the Judge acknowledged the commercial success of dapagliflozin, but that in assessing the validity of the Patent, this was not a consideration. Instead, the focus for assessing validity was in the disclosure and what the skilled person would have done at that point in time. Any later findings that occurred after are not considered.

Take Away Points

Plausibility continues to be a popular issue in pharmaceutical proceedings with generic companies finding success of late. It is clear in assessing the validity of a patent that the UK Courts will need performance data of specific compounds if that compound has been selected from a genus of compounds or is looking to treat a particular ailment. Therefore, it is paramount that when drafting patent applications, key performance data is included. It is not sufficient to rely on general statements on how a molecule may behave. Additionally, it is also evident that the UK Courts will not consider commercial success when carrying out an assessment of validity.

The judgment is available here.