Posted on 9/7/2021

Sufficiency of second medical use claims – when can you say enough is enough?

Does this recent decision lower the threshold for sufficient disclosure of a second medical use claim?

T 2015/20: Aclidinium for treatment of asthma/ ALMIRALL

Sufficiency is a condition for patentability of an invention in Europe and requires that a patent provides enough information to enable a person reading the patent application to work the claimed invention.

Second medical use inventions relate to the use of a substance or composition for treatment or diagnosis of a disease or condition, even if the substance or composition is already known to treat a different disease or condition. For a claim to such an invention to meet the requirements of sufficiency, a patent must not merely state that such a substance or composition might be used, but rather must disclose its suitability for the claimed application.

In a recent decision of the European Patent Office (EPO) Boards of Appeal (T 2015/20), the Board tackled the question of how much data is needed in an application to disclose the suitability of a substance or composition for a use, and to satisfy the condition of sufficiency.


The application in question (EP 15173011.6) claimed a pharmaceutical composition providing a 400 µg metered dose of aclidinium bromide for use by inhalation in the treatment of asthma.

The application was initially refused by the Examining Division of the EPO based on insufficiency of disclosure. The examples in the patent specification related only to the use of the composition to treat chronic obstructive pulmonary disease (COPD), and not asthma. The Examining Division stated that it was common knowledge, in view of the prior art, that these two diseases were different diseases and involved different mechanisms. As such, the Division argued that the results obtained relating to treatment of COPD patients could not render treatment of asthma with the claimed composition plausible.

The Examining Division also raised a product insert which advised that aclidinium bromide should not be used to treat asthma, as clinical trials had not yet been conducted. The Division claimed that it was therefore not credible that the compound would have therapeutic activity in asthma.

The applicant appealed the decision of the Examining Division.

Board of Appeal’s Decision

The Boards of Appeal stated that for an invention to be insufficiently disclosed there must be serious doubts, substantiated by verifiable facts, that the skilled person can perform the invention as claimed. They also noted that a patent could not be sufficient if the invention goes against a prevailing technical opinion and the patent does not provide even a single reproducible example with counters it.

The Board then considered one of the prior art documents raised by the Examining Division, which noted that anticholinergic drugs, such as aclidinium bromide, provide a beneficial effect in the treatment of COPD but do not provide the same effect for asthma, in which cholinergic mechanisms are of less importance. The Board observed, however, that this document in fact supported the application, as it confirmed that asthma is influenced by cholinergic mechanisms, although to a lesser extent than COPD.

The Board also referenced a document which declared that M3 muscarinic receptor antagonists, such as aclidinium bromide, are useful in the treatment of respiratory disorders such as asthma and COPD. Accordingly, the Board claimed that the prior art did not cast doubt on the claims of the invention and that the invention did not go against a prevailing technical opinion.

The Board also concluded that the product insert raised by the Examining Division merely warned that the use of the compound in the treatment of asthma had not been officially authorised, and that this did not cast serious doubts on the claimed invention.

The Board then tackled the question of whether the application rendered the claimed invention technically plausible. In doing so, the Board agreed with reference to previous case, T 609/02, that the claimed therapeutic effect in a second medical use claim is a functional feature of the claim and accordingly, the application must disclose the suitability of the product for the use.

The Board deemed the statement made in the application, which stated that a 400 µg metered dose of aclidinium bromide is particularly useful in the treatment of asthma, to represent a significant technical teaching which did not prima facie lack plausibility. As such, the Board overruled the decision of the Examining Division and considered the invention to be sufficiently disclosed.


In some ways, the decision appears to almost lower the threshold for sufficient disclosure of a second medical use claim. It suggests that to meet the requirements, an application must simply provide enough information to show that a claim is not prima facie implausible, but does not have to necessarily demonstrate that the claim is plausible, in contrast to the Examining Division’s initial opinion.

One point that the decision makes clear, though, is that it is not strictly necessary for inventors and applicants to have gathered specific data showing that a substance or composition has a therapeutic effect in a particular disorder, in order to claim it. It is important, nevertheless, to have at least some kind of evidence which can be used as basis for a compelling argument.

If you have any questions regarding this decision, please get in touch to speak to one of our team.

Wilson Gunn