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You’ll have to do better than that! An update on plausibility at the EPO

29th Aug 2017

In my article ‘Where’s your supporting data? Plausibility at the EPO’, I discussed the increasing significance of ‘plausibility’ at the European Patent Office (EPO) in the context of both inventive step and sufficiency, and particularly in the field of life sciences. I also discussed how one may meet the plausibility threshold even if data is lacking.

In their recent Decision (T 0488/16), the Board of Appeal (BoA) at the EPO has provided further guidance on the plausibility threshold. In this case, the BoA revoked patent EP1169038 directed to an anticancer compound (dasatinib, sold as Sprycel®). The patent was revoked for a lack of inventive step, the main reason being a lack of data in the application as filed.

The anticancer activity of dasatinib derives from its protein tyrosine kinase (PTK) inhibitor activity. Although the application as filed exemplified a large number of compounds within the scope of the generic formula of claim 1, it did not contain any quantitative results indicating the PTK inhibitor activity of the compounds and it did not provide any details about the particular assays that had been used to test their activity.

In the decision, much discussion hinged on the appearance of the phrase “Compounds described in the following Examples have been tested in one or more of these assays, and have shown activity”. The proprietor argued that this statement was enough to show that dasatinib plausibly solved the technical problem underlying the invention because the European Patent Convention (EPC) does not require experimental proof. This statement, according to the proprietor, was sufficient to meet the low plausibility threshold, which was satisfied in the absence of any substantiated doubt. In addition, the proprietor provided post-filed evidence showing that the technical problem had indeed been solved.

Even though the BoA agreed that it is not always required to include experimental data or results in an application, it is a condition sine qua non that it is shown that the technical problem underlying the invention was at least plausibly solved at the filing date. The BoA was of the view that if, as in the present case, the nature of the invention is such that it relies on a technical effect which is neither self-evident nor predictable or based on a conclusive theoretical concept, at least some technical evidence is required to show that a technical problem has indeed been solved. In the BoA’s view, it was not acceptable to draw up a generic formula, which covers millions of compounds, vaguely indicate an “activity” against PTKs and leave it to the imagination of the skilled reader or to future investigations to establish which compound inhibits which kinase and is therefore suitable to treat the respective diseases associated therewith. The BoA also emphasised that the problem was not the absence of any in vivo data or clinical data, but rather the absence of any verifiable data with regard to the technical effect.

The proprietor argued that according to established BoA decisions (e.g. T 578/06) the burden of proof was on the opponent and that there must be prima facie serious doubts as to the suitability of the claimed invention to solve the technical problem. The BoA did not wish to commit on whether the burden of proof fell on the proprietor or the opponent, but they did say that the opponent had provided technically sound and persuasive arguments as to why the alleged effect had not been made plausible, so if the burden was on the opponent, the opponent discharged their burden. In addition, the BoA commented that in the majority of the decisions cited by the opponent to support their argument, there was sufficient evidence in the application as filed which made it at least plausible that the technical problem was solved, such as: screening examples in combination with common general knowledge (T 716/08); structural similarity to known members of a particular family (T 1336/04); or at least a plausible theoretical concept (T 433/05; T 108/09).

The proprietor had formulated the objective technical problem to be solved, based on the closest prior art, as the provision of an improved PTK inhibitor and considered it solved by the compound dasatinib. However, as the disclosure in the application as filed did not make it plausible that this problem had been solved, and as post-filed evidence could not be used to remedy the deficiency, the BoA reformulated the problem in a much less ambitious way: the provision of a further chemical compound. The BoA held that the mere provision of a chemical compound capable of being synthesised and not showing any technical effect does not require any inventive ingenuity. The structural uniqueness of dasatinib alone could not therefore support an inventive step.

This decision emphasises the importance of including data in the application as filed to make a purported technical effect at least plausible, and the risks if the application does not contain such data. Consequently, one must take great care when deciding when is the right time to file a patent application and what evidence a patent application should contain.

This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.

Andrew Carridge
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Would you like to know more? You can talk to Andrew Carridge who will be able to help. Call +44 (0)1223 360 350


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