Posted on 21/6/2023

Do clinical trials constitute prior public use of a pharmaceutical formulation?

A recent decision has provided greater legal certainty for those looking to apply to patent a pharmaceutical formulation. 

The European Patent Office (EPO) has recently decided that patients involved in a clinical trial for a pharmaceutical formulation were not members of the public so the trial did not constitute prior public use of the pharmaceutical formulation (Board of Appeal decision T 0670/20).

This decision adds to existing case law relating to the topic of disclosures in clinical trials, and provides greater legal certainty for patentees with pharmaceutical formulation patents or those looking to apply to patent a pharmaceutical formulation.


Owners of pharmaceutical formulation patents are often in a difficult position if they have conducted clinical trials before the priority date of their patent (i.e., before the date of filing a first patent application for their pharmaceutical formulation technology).  The patent owner is often faced with the assertion that their patent lacks novelty because the pharmaceutical formulation was used in a clinical trial, and is therefore publicly available, before the patent’s priority date.

T 0670/20

The patent at issue (EP 2140867) concerned a tablet formulation of an anti-blood clot drug, Edoxaban.  Before filing the patent, phase IIa and IIb clinical trials were carried out to assess the safety and effectiveness of the drug in the prevention of blood clots following hip replacement surgery.  The drug was to be taken over the course of ten days in which time some of the trial participants were discharged from hospital and instructed to continue taking the drug while at home up to the end of the ten-day period.

The Opposition and Appeal

The patent was opposed with the Opponent asserting that the claimed pharmaceutical composition lacked novelty because the drug had been distributed during the clinical trial and the trial participants were members of the public who, theoretically, could investigate the internal structure of the tablet, therefore, establishing the pharmaceutical formulation.

The Opponent further argued that the trial participants were not bound by any confidentiality agreement.

As such, the EPO Board of Appeal needed to decide whether carrying out the clinical trial constituted prior public use of the claimed pharmaceutical formulation.  If it did, then the patent would be found to lack novelty.

The findings of the Board of Appeal were summarised in the case 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.’

As such, the EPO decided that the clinical trial did not constitute prior public use of the claimed pharmaceutical formulation and, therefore, the clinical trial was not prejudicial to the novelty of the patent.

Considering prior disclosure when it comes to clinical trials

A first consideration is that patent applications should be filed as early as possible, prior to the publication of clinical trial protocols or beginning the clinical trial itself, to minimise the risk of a later-filed patent application being found to lack novelty over disclosures relating to the clinical trial.

A second consideration is that the results from the clinical trial may be advantageous, or even essential, to include in a patent application in order to meet the requirements of inventive step and/or sufficiency.  So, filing a patent application before the clinical trial may put the patentee in a worse position than if they filed the application after the clinical trial.

The timing of filing a patent application and carrying out an associated clinical trial is, therefore, a balancing act.

In its decision (T 0670/20), the EPO referred to previous decision T 7/07, where disclosures relating to a clinical trial were found to render an opposed patent as lacking novelty, and stated that the circumstances surrounding each decision differed.  In T 7/07, the drugs subject to clinical trial were handed out to participants not bound to secrecy and this amounted to the sponsor of the trial losing control of the drugs and, therefore, a decision of lack of novelty for the respective patent.  This was not found to be the case with the more recent decision, T 0670/20.

As demonstrated by the recent EPO decision, starting clinical trials before filing a patent application is not always prejudicial to the application being granted.  However, in view of the potential of publication of information relating to clinical trials once started, we urge caution in beginning clinical trials before a patent application has been filed.

For further information about patents, please get in touch to speak to one of our patent attorneys.

Wilson Gunn