M&C Reacts: Evidence Of (Im)Plausibility

• Published date: 26 October 2021
• Subject Matter: Intellectual Property, Patent
• Law Firm: Marks & Clerk
• Author: Mr Gareth Williams

The intertwined concepts of plausibility and post-published evidence in relation to sufficiency and inventive step have become embedded in European patent practice over the years. The concept originates with the 2005 Board of Appeal decision T1329/04, which held that, firstly, for inventive step to be recognised, the patent application must at least make plausible that the problem addressed by the invention is solved; and secondly that post-published data confirming that the problem has been solved can be used in evidence, but if the initial plausibility threshold is not met, then this data should not be taken into account. For a recent example where these concepts are applied, see our article on T2015/20, concerning the treatment of asthma.

However, some case law suggests that the plausibility threshold may not be such a high bar to meet - T0578/06 held that plausibility is only relevant when the particular case supports doubts over whether the claimed invention is solved. In other words, is the solution actually implausible.

Now, in decision T0116/18, the Enlarged Board of Appeal has been asked to rule on this difference in approach. The patent in question, EP 2 484 209 to Sumitomo Chemical Company Ltd, is directed to combination insecticides which are said to be synergistic, with claim 1 referring to a combination of thiamethoxam and one or more compounds represented by a general formula. The patent itself does include experimental data showing synergy, but of only two examples covered by the claims, and against two moth species. During opposition, the opponent submitted data intended to show that a combination within the scope of claim 1 did not show synergy against one of these species or against one closely-related species. The patentee criticised this data, and submitted their own post-published data showing that the combination was indeed synergistic against various species. The patent survived opposition, with the EPO accepting that this data confirmed the presence of synergy, and hence an inventive step.

On appeal, the question of...