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Cortex - Life Sciences Insights

| 2 minutes read

Clinical trials conducted pre-application can cause enabling disclosure

In a recent webinar titled “Protecting Medical Devices in Europe – Avoiding Common Pitfalls”, Kieran Killough (Partner at HGF) pointed to key considerations when disclosing information about medical devices that could invalidate a related patent application. These considerations are particularly pertinent given the potential issues that may arise from the new EU medical devices regulations being introduced at the moment, which include requirements around the provision of clinical data for medical devices. For further information on this development, please see our recent article on this topic.

This short piece provides an overview of a key case which explores how the conduct of clinical trials can inadvertently constitute an enabling disclosure which could invalidate a patent application.


When it comes to conducting clinical trials as part of a new patent application, it is imperative to exercise caution when doing so in order to avoid potentially invalidating the patent application. Traditionally, the European Patent Office has treated clinical trials as confidential, however, in the 2011 case involving T 0007/07 - 3.3.02 Bayer Pharma Aktiengesellschaft and Hexal AG, the boards of appeal of the EPO ruled that the patent should be revoked as a result of a disclosure involving a clinical trial.

The board’s decision

The case concerned a patent for an oral contraceptive pill and clinical trials took place between December 1996 and July 1998, which was before the priority date of the patent to which the invention related. The participants were told the ingredients in the pill but were never asked to sign a confidentiality agreement. Participants were provided with the drugs to take home as part of the trial but not all unused drugs provided to the participants had been returned once the trial was concluded. As such, the applicants contended that the drugs had become publicly available. The respondents tried to rely on established case law which found that persons involved in clinical trials are implicitly bound by confidentiality. However, the board did not agree with this interpretation and instead considered that “if a single member of the public, who is not under an obligation to maintain secrecy, has the theoretical possibility to access particular information, this information is considered as being available to the public within the meaning of Article 54(2) EPC.”

The board considered that, by handing out the drugs to the participants, the respondents had effectively lost control over them as the participants were not prevented from disposing of the drugs in whichever way they wished. As such, the public availability of the prior use was not restricted to the tablets that were not returned, rather, it included all of the tablets handed out to participants. Consequently, this was considered by the board of appeal to constitute a public disclosure that predated the patent application and, accordingly, the device was considered to lack the necessary element of novelty for it to be registrable as a patent. Accordingly, the patent was revoked.

Key takeaways

Applicants should be cautious not to rely on the assumption that clinical trials shall be treated as confidential by the European courts. When it comes to conducting clinical trials as part of an application to register a medical device as a patent, the advised approach would be to postpone clinical trials until after the patent application has been filed. If this is not possible, either: (a) ensure that all parties and participants in the clinical trial sign confidentiality agreements; or (b) control the use of the product under the trial and ensure that the products are returned to the applicants at the conclusion of the trial


medical devices, clinical trials, eu