Bayer unsuccessful in defending its rivaroxaban patent and maintaining confidentiality over documents.
In a case which exemplifies the complex interplay between intellectual property law, pharmaceutical innovation, and the competition provided by generic suppliers of medicines, the High Court of Ireland recently heard a challenge by Sandoz to the validity of Irish patent EP (IE) 1 845 961 (the Patent) held by Bayer.
The Patent protects the once-daily dosing regimen of rivaroxaban, which is the active pharmaceutical ingredient in the product marketed by Bayer as Xarelto® and treats thromboembolic disorders. Global sales of Xarelto® were estimated to be worth €3.5 billion to Bayer in 2024.
The case represents a significant patent validity challenge in Ireland with generic companies having similarly sought to challenge the validity of the corresponding Patent in other jurisdictions across Europe. Judgment was delivered by Mr Justice Rory Mulcahy on 25 June 2025 ([2025] IEHC 357). However, the judgment was not made public until 23 September 2025 and was published in redacted form on foot of an application brought by Bayer to have certain portions of the judgment redacted and to preserve the confidential nature of 25 documents produced by Bayer on foot of an order for discovery made earlier in the proceedings.
Bayer was ultimately unsuccessful in defending the Patent, which the court held was invalid for lack of inventive step, and Bayer's confidentiality application was also refused by the Court for a lack of evidence, however, the merits judgment has been published in redacted form until the determination of an appeal filed by Bayer.
Merits judgment
The Patent expires on 19 January 2026. Sandoz commenced High Court proceedings in May 2024 and the trial hearing took place over 14 days in April/May 2025 which included detailed cross-examination of four expert witnesses.
The main issue to be decided by the Court at the hearing was whether the Patent was invalid for obviousness. The concept of obviousness in patent law requires that the invention would not have been obvious to a person skilled in the art at the priority date of the patent. This assessment involves considering the state of the art, the common general knowledge of the skilled person/team, and whether the claimed invention represents a sufficient inventive step over what was already known.
Prior art and technical considerations
The case involved thorough consideration of prior art, a significant amount of which came from the 45th Annual Meeting of the American Society of Haematology (ASH) held in San Diego in December 2003.
The judgment includes extensive consideration of agreed common general knowledge between the parties' experts, establishing the baseline understanding that would have been possessed by skilled practitioners in the field at the priority date of the Patent. This analysis is crucial in patent validity challenges as it determines the starting point from which the inventiveness of the claimed subject matter is assessed. Mulcahy J held that whether one applies the four-step Pozzoli test, or the problem-solution approach favoured by the EPO's Technical Board of Appeal the question to be addressed was simply whether once-daily dosing would have been obvious to the skilled team in light of the prior art. Thus, the crucial question for the Court to determine was whether the skilled team would have considered once-daily dosing obvious to try with a reasonable expectation of success.
In finding that the Patent lacked inventive step, the Court ruled that two prior art documents, which set out phase I data from various studies, could be read together due to the fact that one document was expressly referenced in another. One of the documents, ‘Harder’, provided an express suggestion that rivaroxaban might be suitable for a once-daily dosing regimen.
The court determined that "the skilled team would have been motivated to investigate once-daily dosing, and would not have been dissuaded from so doing by the costs and uncertainty of clinical trials" and further that "once-daily dosing was obvious to try and would have considered that it had a reasonable prospect of success ie of being both effective and safe" at [400].
The Court also considered that secondary evidence (published after the priority date of the Patent) was relevant in this case. This evidence consisted of documents relating to the development of once-daily dosing of rivaroxaban by Bayer. The Court concluded that these documents supported Sandoz’s experts’ position that the assay in Harder was the motivation to progress once daily dosing. These secondary documents therefore further undermined Bayer’s experts’ criticisms of the Harder study data.
The tension between transparency in judicial proceedings and the need to protect commercially sensitive information is not uncommon in pharmaceutical patent litigation.
At the trial hearing, "[Bayer] sought an order that information disclosed to [Sandoz] in these proceedings by way of discovery, designated as confidential information pursuant to a confidentiality agreement between the parties, be dealt with in such a way that that information was not released in whole or in part into the public domain or was otherwise caused to lose its character of confidentiality" at [2].
On the second day of the trial, Mulcahy J made an interim order preserving the confidentiality of the documents pending further order, and liberty was granted to Bayer to apply to make the order permanent in respect of some or all of the documents.
Following delivery of the merits judgment to the parties in June, Bayer argued that the documents obtained by Sandoz via discovery relating to the development of once-daily dosing of rivaroxaban, and the relevant portions of the judgment which cited these documents, should be kept confidential given that they related to Bayer’s internal development processes.
Bayer's confidentiality application
Bayer's application consisted of three strands: (i) redacting references to documents in the judgment prior to publication, (ii) redacting references to 19 separate documents in the trial transcript, and (iii) documents designated as confidential under the confidentiality agreement and 'opened' during trial be deemed to retain their confidential status. Of the 1,012 documents produced during discovery, Bayer sought confidentiality orders in relation to 25 documents. The documents contained details of internal Bayer processes and information relating to clinical trials etc.
Ultimately, the Court found that Bayer had "made no effort to identify with any particularity what it is in the confidential trial documents which it claims is worthy of protection" at [91].
The Court concluded that "what Bayer seeks to protect is a small body of documents which reveal, overall, that Bayer's process for developing the Patent was precisely what the experts would expect it to have been and which Bayer has described in some detail elsewhere" at [94].
The Court further found the "documentation cannot be said to meet the definition of trade secrets within the Directive" because "the information about Bayer's internal development process revealed by the documents has become known to those within the circles who normally deal with this type of information" at [95].
Irish confidentiality framework
The approach by the Irish Courts was addressed in the judgment citing Gilchrist v Sunday Newspapers which demands a public administration of justice. The Court "recognised that the circumstances in which there may [be] a departure from the constitutionally mandated obligation that justice be administered in public were not confined to those instances where provision had been made in statute for such a departure" at [80].
The judgment demonstrates that generic assertions of confidentiality are insufficient to meet the evidentiary standards. Ultimately, the Court found that "Bayer has not established that the body of documents contain anything the disclosure of which presents a risk of harm to Bayer, still less that there is a clear need for protection for reasons which are pressing" at [96]. This provides a threshold that a patent holder must demonstrate specific, tangible harm from disclosure rather than relying on wider assertions of commercial sensitivity especially when the underlying patent has been found invalid on grounds of obviousness.
