EPO Technical Boards of Appeal Decision T0209/22  

Under European Patent Office (EPO) practice a known substance or composition can be claimed for use in a method of treatment. These are so-called “first” medical use claims (Article 54(4) EPC). Furthermore, additional claims can be made to a “second medical use” of a drug for treatment of a different disease or for use at a different dose (Article 54(5) EPC). This is in contrast to the exclusion from patentability of methods of medical treatment themselves.

These provisions for “second medical use” also rely on the claims for use in a method of treatment being interpreted to include the physiological or technical effect of the treatment as being a functional feature of the claim.  

However, the interpretation of this functional feature differs according to EPO practice regarding the novelty of such claim features versus the sufficiency of such claim features.

Accordingly, the Board of Appeal in this case confirmed that there is a different bar for novelty than there is for sufficiency in relation to the therapeutic effect being a feature of the claims for a medical use invention. 

Background of T 0209/22 

The present case (T 0209/22) relates to a European patent (EP2506844B1) with claims to a combination of known drugs for the treatment of asthma and COPD (chronic obstructive pulmonary disease).  

The patent was opposed as being allegedly not novel because of the disclosure of a phase I clinical trial protocol for the claimed drug combination on (NCT00976144). However, the clinical trial summary did not disclose the chemical structure of the drugs but did give their mechanisms of action. Furthermore, the clinical trial was carried out in healthy volunteers.  

The Opponents argued that the clinical trial was prejudicial to the novelty of the claims of the patent because, allegedly, the skilled person could have derived the structure of the drugs by obtaining the study drugs and analysing them.  

However, the fact that the clinical trial was conducted in healthy volunteers rather than patients with asthma or COPD meant that the Board of Appeal considered that this did not disclose the therapeutic use of this drug combination.  

As noted above, under EPO practice the treatment effect in patients is considered a functional feature of a claim. Accordingly, a clinical trial in healthy volunteers could not disclose such a claim feature. Accordingly, disclosure of the clinical trial did not affect the novelty of the claims.  

Notably the Board of Appeal did not answer the question as to whether the claim would have been anticipated if the clinical trial had been carried out in a population of patients with COPD or asthma, rather than what was, effectively, a control population.  


Thus, the claims were found to be novel but they were also opposed on the grounds that they were allegedly not sufficient.  

Whether a claim is judged sufficiently disclosed for the skilled person to work the invention is based on whether it is credible that the technical effect is provided in view of the data in the application as filed and the common general knowledge. In the present patent the data in the patent showed the treatment effect in patients of the claimed drugs administered as monotherapies. The patent also referred to the phase I clinical trial in healthy volunteers that is discussed above. The clinical trial showed that a combination of the drugs was well tolerated. However, the patent did not provide any data showing that the combination of drugs was effective in patients.  

However, in contrast to the finding for novelty the Board of Appeal found that the phase I clinical trial data for the combination in healthy volunteers in combination with the monotherapy data in patients was enough to together establish the credibility of the drug combination having the claimed therapeutic effect.  

Furthermore, post-filed data was made available that supported the existence of the therapeutic effect.  

Therefore, the Board of Appeal did not consider that there was any substantiated doubt regarding the treatment effect of the combination.  

Thus, the bar to sufficiency for a claim to a pharmaceutical effect was surmounted and confirmed as being significantly lower than the bar for novelty.  

Novelty–Sufficiency Squeeze 

Often where there is a difference in the interpretation of the scope of a claim feature there is a squeeze argument to be made. In this case the Opponents had argued that if the clinical trial disclosure did not prejudice the novelty of the patent, then it also followed that the results of the clinical trial could not be sufficient to enable the claimed therapeutic use of the drug combination.  

At paragraph 5.2 of the Board of Appeal Decision the Board of Appeal stated that “for the requirement of sufficiency to be met, the claimed efficacy has to be credible at the effective date of the patent, i.e., on the basis of the information provided in the patent application together with the common general knowledge then available to the skilled person”. 

Thus, for sufficiency it is not essential for a claimed technical effect to be disclosed directly and unambiguously in the application as filed. This contrasts markedly with the provisions for novelty.  

As the Board of Appeal had already found that the phase I clinical trial in healthy volunteers was not a direct and unambiguous disclosure of the therapeutic effect, i.e., it was not prejudicial to novelty, and the Board had already found that the technical effect was not in any substantiated doubt, i.e., therefore was credible, the Board rejected the novelty–sufficiency squeeze argument.  

Inventive Step 

Finally, the patent was opposed on the grounds of lack of inventive step as the Opponent alleged that the skilled person would have taken a direct route from the clinical trial data and common general knowledge, along with separate documents disclosing each of the drugs in the drug combination to yield a reasonable expectation of success that the skilled person could provide a treatment for COPD.  

However, the Board of Appeal stated:  

“While the basis for proceeding with the pharmaceutical developments of a compound is favourable pre-clinical data, this does not necessarily give rise to a well-founded expectation of success, even less in the case of a combination product when neither combination partner has, as yet, progressed to the clinical stage of development”.  

Thus, the prior art disclosures which speculated about each of the drugs separately could only “have provided the person skilled in the art with the hope to succeed, but this does not amount to a reasonable expectation of success.”  

Furthermore, as “neither agent had been established for the treatment of patients, each agent’s efficacy and safety as well as the duration of action was still to be established. Thus, a high level of uncertainty regarding the potential for successful dual therapy with both agents would have been involved”.  

Accordingly, the Board of Appeal found that the claims for the treatment of asthma and COPD had an inventive step.  


Thus the EPO Technical Board of Appeal in this case confirmed that there is a different bar for novelty than there is for sufficiency in relation to the therapeutic effect being a feature of the claims for a medical use invention.  

Furthermore, this decision also confirms that inventive step for a medical use claim must be assessed on a case-by-case basis in the light of what is already known about the physiological effect of the claimed drug or drugs in combination.  

Therefore, this decision confirms that current EPO practice is relatively favourable to the grant of inventions for the use of known compounds in medicine.  

Our articles are for general information only. They should not be considered specific legal advice, which is available upon request. All information in our articles is considered to be accurate at the date of publishing.

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