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Bulletins » Clinical trials and prior disclosure – a difficult balancing act for patentees.

The European Patent Office (EPO) has recently ruled that patients in a clinical trial were not members of the public such that the trial did not constitute prior public use of a pharmaceutical formulation (Board of Appeal decision T 0670/20). This decision adds to the growing body of EPO case law surrounding the topic of disclosures relating to clinical trials and provides more legal certainty for patentees with drug formulation patents.


The patent at issue (EP 2140867) concerned a tablet formulation of an anti-blood clot drug edoxaban. Prior to the filing of the patent, phase IIa and IIb clinical trials had already started assessing the safety and effectiveness of edoxaban tablets (as claimed) in the prevention of blood clots following hip replacement surgery. The studies involved the administration of the drug for up to ten days, during which time a proportion of patients were discharged from hospital and were allowed to continue the treatment at home.

The Opposition/Appeal

The patent was opposed with the opponent asserting, inter alia, lack of novelty in view of prior public use. This, owing to the distribution of the tablets to participating patients during the clinical trials.

The opponent argued that the trial participants were to be considered members of the public who were theoretically able to investigate the tablet’s internal structure. Moreover, it was argued that the patients were not bound by any confidentiality agreement and although patients were asked to return any leftover medication, it was unlikely that all patients would comply with this request.

The assessment of novelty critically hinged on whether conduct of the trial amounted to prior public use of the edoxaban formulation of the patent.

The Board of Appeal summarised its findings as follows (see Headnote):

“The clinical trials were carried out in accordance with the EMEA Guidelines for Good Clinical Practice. These guidelines explicitly require adherence to the prescribed protocol and assurance of drug accountability. This set-up of the trials implies that the patients who decided to participate in the trials agreed, following their informed consent, to use the provided medication according to instruction or to return the unused medication. Accordingly, the participating patients who were provided with the tablets under investigation entered into a special relationship with the investigators of the trials and were with regard to the provided tablets not members of the public that could freely dispose over these tablets.

The Board further explained that there was no conflict between a patient’s right to discuss their involvement in a clinical trial with their own doctor, family, or friends and their duty to follow the research protocol and return any unused medication.

Clinical trials and considerations of disclosure

The timing of clinical trials and the filing of patent applications has long been a difficult balancing act.  On the one hand, filing patent applications early prior to the publication of clinical trial protocols or the commencement of trials minimises the risk of novelty-destroying disclosures.  On the other hand, trial results may be beneficial or even essential to include in a patent application to meet the requirements of sufficiency or inventive step.  As noted above, there is a large body of EPO case law pertaining to these issues.

As this recent decision demonstrates, the initiation of a clinical trial prior to the filing of a patent application is not always prejudicial.  There are instances, however, where this has not been the case.

The recent decision cites the 2011 decision T 0007/07, in which the EPO ruled that a clinical trial was novelty-destroying because:

“[in T 0007/07] the sponsor of the trial had effectively lost control over the drugs after these had been handed out to the participants of the trial as members of the public who were not bound to secrecy.”

Given the potential for clinical trials or perhaps more significantly, the publication of clinical trial protocols, to prejudice patent filings, we would urge caution in proceeding with clinical studies without a patent application on file.

If you wish to know more about this topic or would like further advice, please contact Joanna Peak or your usual Boult Wade Tennant LLP advisor.

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