How much data is needed for biotech applications at the EPO?

About the author

Claire Devine is a trainee patent attorney at Appleyard Lees IP LLP.

As a trainee patent attorney Claire has worked with a range of clients in the biotechnology and pharmaceutical areas, on applications related to a broad range of technologies, including antibodies, industrial biotechnology, gene therapies, RNA therapies, new chemical entities and drug repurposing.

“How much data do I need to file a patent application?” This is a question we get asked by many clients in the biotechnology and pharmaceutical field. In particular, this has been a more pressing concern during the pandemic as many companies had to restrict the number of scientists working in laboratories to allow social distancing. Some projects progressed a little slower than planned, delaying data read- outs. 

Supporting an invention with sufficient data is however critical when applying for a patent at the European Patent Office (EPO), specifically in the biotech field and in the pharmaceutical field. This is particularly important when complying with the requirements for inventive step and sufficiency under European practice. An Examiner will assess whether it is plausible that the invention performs as claimed and whether the technical problem that the invention is said to solve, is actually solved.  The invention must be rendered plausible at the priority date of the application, and in the life sciences field, data is usually required to demonstrate this.

There are a number of legal decisions that illustrate how the EPO makes this assessment. One of the landmark cases relates to the compound Dasatinib (T488/16). In this case, a large number of compounds were claimed by a generic formula and their use in treatment of protein tyrosine kinase (PTK)-associated disorders, including cancer. The application as filed provided many (nearly 600) examples of the different compounds.  However, the application provided no data on the inhibitory activity of the compounds, it merely stated that some of the compounds were tested in one or more assays and that they showed activity.

The Board of Appeal at the EPO found that it was not plausible, at the date of filing, that the claimed compounds had in fact activity in PTK-associated diseases.  Due to this finding, the patentee was not able to rely on post-published data in order to demonstrate the technical effect was plausible at the date of filing.  As a result of this case, the EPO had effectively raised the bar for plausibility.

However, in contrast to the Dasatinib case there are some recent decisions that may indicate that the tides are turning and the bar for plausibility is lowering. This is good news for those seeking patent protection in the biotech or pharmaceutical field.


T184/16- a patentee friendly decision

In this case, the patent claimed a genus of small molecules which the patent stated had inhibitory activity against sodium-glucose linked transporter (SGLT) and so would have use in the treatment of diabetes and related diseases.

The patent was opposed but upheld in amended form. The opponent appealed stating that the medical use claims lacked inventive step and sufficiency.  They argued that there was no biological data in the application and so it was not plausible that the claimed compounds had SGLT inhibitory activity.

However, the Board of Appeal found that it was in fact plausible that the compounds had inhibitory activity despite the lack of biological data.  The Board of Appeal acknowledged that “In the present case, the application as filed does not contain any experimental evidence as regards the disputed plausibility, i.e. the plausibility of the claimed compounds being SGLT2 inhibitors. It is thus necessary to determine whether plausibility can nevertheless be acknowledged in view of the common general knowledge and the prior art.”

The background section of the patent referred to an earlier document, WO01/27128, which disclosed that compounds with an aryl C-glycoside core had been shown to have inhibitory activity against SGLT. The claimed compounds contained the same core aryl C-glycoside core, but different substituent groups. Due to the commonality of the core structure the Board of Appeal found that the therapeutic effect was plausible.

Interestingly, the Board of Appeal also found that these compounds were inventive over the prior art.  The closest prior art document also disclosed compounds with an aryl C-glycoside core. These compounds differed from the claimed compounds in terms of the substituent groups.  In spite of the similarities between the compounds and the arguments that the presence of the same core structure rendered the claimed compounds’ therapeutic effect plausible, the compounds were still found to be inventive. 

This decision appears to have been influenced by the post filed data provided by the patentee. This data demonstrated the claimed compounds had enhanced activity over the compounds of the prior art.  As such, the patentee relied on the technical effect of providing improved SGLT inhibitors which resulted in a finding of inventive step. The decision in this case makes it clear that the assessment carried out for plausibility and for inventive step are distinct from one another:

The criteria for plausibility and obviousness are different. On the one hand, as set out above, for plausibility of a claimed effect to be acknowledged, it is enough if there are no prima facie serious doubts that the effect can be obtained and conversely no a priori reason and indication in the common general knowledge that the effect cannot be obtained. On the other hand, obviousness is decided in the framework of the problem-solution approach, where generally an important consideration is whether the claimed solution is suggested and thus made obvious by the prior art.”

As such, although both the Dasatinib case and the SGLT inhibitor case provided essentially no biological data, the outcomes were in stark contrast.


T2015/20- the bar is lowered

A further case which indicates that the bar for plausibility may have been lowered is T2015/20. In this case, biological data was provided, but for a different indication than that claimed.  

The case relates to the treatment of asthma by “providing a metered nominal dose of aclidinium equivalent to 400 μg (plus/minus 10%) aclidinium bromide for use by inhalation”.  The data in the application only demonstrated aclidinium in the treatment of COPD (chronic obstructive pulmonary disease). The Examining division found that the prior art demonstrated that asthma and COPD were distinct indications and that different mechanisms were involved.  Furthermore, one of the prior art documents, a summary of product characteristics for a bronchodilator, indicated that a similar dose of aclidinium should not be used to treat asthma as clinical studies had not been conducted. Therefore, the application was rejected for lack of sufficiency as it was not plausible that aclidinium would treat asthma. 

However, the Board of Appeal found that the evidence on file did not provide serious doubts that aclidinium could be used to treat asthma.  They found that the prior art confirmed that COPD and asthma were influenced by similar mechanisms and therefore it was plausible that aclidinium could be used in the treatment of asthma.

Since the treatment of asthma was found plausible the patentee was then able to rely on post-published evidence in the assessment of inventive step. This evidence demonstrated that the optimised dose of 400 μg provided greatest improvements in lung function and reduction of required further daily relief medication.  This effect was not taught in the prior art and so the application was found to be inventive.

Therefore, although the data in the application related to a different indication the effect of treating asthma was still found plausible based on the data and the teaching in the prior art as there were no serious doubts that the treatment would be effective. 



The decisions in T184/16 and T2015/20 will come as welcome news to innovators, especially those who are still facing challenges and delays due to Covid-19, because they show that a lower bar has now been set for the assessment of plausibility. In particular T2015/20 states:

“The approaches developed in the jurisprudence of the Boards of Appeal of the EPO for the assessment of sufficiency of disclosure and inventive step specifically take account of the technical contribution actually disclosed in a patent application to avoid patent protection resulting from unreasonable speculation on the basis of propositions that are prima facie implausible.”   

As such this seems to indicate that the bar for plausibility is that the invention is not prima facie implausible.

Both of these cases provide guidance on how to tread the line between sufficiency and inventive step. There is clearly a fine balance to be struck if there is only minimal data available to support a hypothesis of a therapeutic effect of a compound, in particular if prior art is also relied on to support the hypothesis. In formulating arguments in support of the plausible therapeutic effect, one must be careful not to undermine inventive step.

Careful claim drafting is also necessary to ensure that adequate fall-back positions are provided should the broad claim fail to succeed.  For each patent application, the data package and arguments to support a hypothesis must be carefully assessed to develop a robust strategy for filing and prosecution that mitigates against objections for lack of plausibility at the EPO.  Our team can help with this and if you have any queries regarding whether you have enough data for a patent application please contact Claire Devine, Barbara Fleck or your usual attorney at Appleyard Lees.

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