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Biogen Wins Injunction Appeal

The Irish Court of Appeal has ruled in favour of Biogen in its appeal regarding the High Court’s decision to refuse Biogen injunctive relief to restrain Neuraxpharm from infringing Biogen’s patent for a drug used in the treatment of multiple sclerosis (MS). The decision delivered in late March 2023 sees Biogen win its appeal for its injunction application to prevent Neuraxpharm from launching a generic medicinal product. Biogen alleges this generic drug would infringe its European patent. We summarise the key findings of the Court of Appeal in Biogen MA Inc & Anor -v- Laboratories Lesvi SL & Anor.[1] and note how it signifies a shift towards granting preliminary injunctions in Ireland in patent cases.

The European Patent (873 patent), which expires in February 2028, covers a medicinal product called Tecfidera, the active ingredient of which is dimethyl fumarate (DMF). Importantly, the parent patent had been revoked by the Opposition Division of the European Patent Office (EPO) and by the Technical Board of Appeal. The 873 patent is a divisional patent of the parent patent. Tecfidera is the only DMF product on the market for the treatment of MS in Ireland. Neuraxpharm sought to launch a generic version of Tecfidera which contains DMF in Ireland on the basis that the 873 patent is invalid, most notably that the 873 patent suffers from the same defects as the parent patent.

Injunction application

Following publication of details of Neuraxpharm’s generic in the Irish health authority’s list of prescribable medicinal products in July 2022, Biogen issued and were granted an ex parte (one side only) interim injunction in August 2022. However, Biogen only became aware of the injunction application after the court made orders granting the interlocutory application. On this basis the application was heard de novo (as a new hearing) by Mr Justice Twomey. In considering whether the injunction should be granted, Mr Justice Twomey applied the interlocutory injunction principles considered by the Supreme Court in Clonmel Healthcare[2]. These principles are examined in detail in our previous article, MSD’s Recent Injunctive Relief – A New Dawn for Patent Litigators in Ireland . The effect of Clonmel Healthcare is that the broader principles laid down in Clonmel Healthcare should be applied in circumstances where the traditional Campus Oil, balance of convenience test when applied is so finely balanced that it favours neither party. Mr Justice Twomey set aside the original order granting injunctive relief. He appeared to be heavily persuaded by arguments that the parent patent was invalid and in respect of the public interest factor concerning saving to the taxpayer in having the generic proceed to market.

On appeal Biogen argued that Mr Justice Twomey had failed to properly apply the Clonmel Healthcare principles. Biogen’s arguments centred around the weight given to the validity of the parent patent which ceased to exist at the time of the proceedings, the parent patent being a different and independent property right. Biogen argued that to overcome the presumption of validity, Neuraxpharm needed to show there was a strong case concerning the invalidity of the 873 patent. It was argued that the decision of the EPO alone that the parent patent was not sufficient to rebut the presumption of validity. Indeed, they were decisions of other European courts expressing a view on the validity of the 873 patent in the context of preliminary injunction applications in those other jurisdictions.

High Court’s argument regarding Biogen’s unlawful monopoly dismissed

The Court of Appeal dismissed Mr Justice Twomey’s finding that Biogen had an unlawful monopoly based on the parent patent, which was ultimately declared invalid. It held that any profit based on the parent patent had no relevance to whether Biogen were entitled to an injunction. Firstly, the fact that the parent patent was revoked did not make the rights it held before revocation invalid. Secondly, the 873 patent is separate from the parent patent. Referring to Astrazeneca AB v Pinewood Laboratories Limited[3], the Court of Appeal noted that each patent stands on its own merits and must be independently assessed. Each divisional patent will have claims that differ to the parent patent. Therefore, the fact that a parent patent has been revoked does not automatically mean that the 873 patent is also invalid and should be revoked.

Case for invalidity of the 873 patent

On the invalidity of the 873 patent, the Court of Appeal held that the threshold test for invalidity in injunctive proceedings is high and there must be successive determinations on the merits invalidating the patent. Decisions regarding interlocutory relief it seems are not sufficient to support this argument by a party the subject of an injunction application. The Court of Appeal held that the EPO decision to grant the 873 patent was not given adequate weight. The Court of Appeal leaned towards the requirement for strong evidence to rebut the presumption of invalidity suggesting that independent technical evidence should be put forward. This would mark a significant change in approach to how these injunction applications have been determined in the past and raises many questions as to what precise evidence would be required and whether a judge, in hearing a preliminary injunction application in the High Court in Ireland, would be expected to make determinations regarding validity based on expert evidence which no doubt would be filed by both parties. This would appear to transcend matters into a hearing on the merits at the preliminary injunction stage, with judges before having only to consider whether there is a serious question to be tried which is a low bar, so it remains to be seen how this new approach is adopted in practice going forward.


This decision further clarifies the principles set out by the Supreme Court in Clonmel Healthcare. To overcome the high presumption of validity threshold pharma companies who launch at risk or fail to clear the path before they launch, who wish to rely on invalidity will need to be armed with evidence of successive substantive proceedings to support their case. It certainly signifies a change in approach to the case law relating to preliminary injunctions in Ireland where there was an assessment of the adequacy of damages which usually went against the patentee given the transparency of the markets concerned on sales and pricing towards one which focuses more on the presumption of validity of the patent in favour of the patentee.

For more information about the impact of this decision, contact a member of our Intellectual Property team.

The content of this article is provided for information purposes only and does not constitute legal or other advice.

[1] [2023] IECA 71

[2] Merck Sharp & Dohme Limited v. Clonmel Healthcare Limited [2022] IESC 11

[3] [2011] IEHC 159 Kelly J

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