The question of whether evidence filed after the priority date of a patent application (so-called "post-published evidence") can be taken into account in the determination of inventive step has been a hot topic in Europe for several years. A recent referral to the Enlarged Board of Appeal, the EPO's highest judicial authority, seeks answers to the following questions:

  • Must post-published evidence be disregarded if an inventive step is acknowledged on the basis of a technical effect and the proof of the effect rests exclusively on such post-published evidence?
  • If the answer to the first question is yes, can the post-published evidence nevertheless be taken into consideration if the skilled person at the filing date of the patent application would have considered the effect plausible or, at least, not implausible?

Following the referral to the Enlarged Board of Appeal, which we reacted to here, the EPO has now announced that it will stay, with immediate effect, "all examination and opposition proceedings before the EPO in which the decision depends entirely on the outcome of the referral". The stay will be lifted as soon as possible after the Enlarged Board of Appeal has issued its decision.

If the EPO decides that proceedings are to be stayed, the EPO will inform the parties, withdraw any communications setting time limits requiring a reaction, and set no further time limits until the stay is lifted.

According to the EPO's notice, this decision will affect patent applications and patents in which the assessment of inventive step is exclusively based on evidence, such as experimental data, which was not publicly available before the filing date of the application and which was filed after that date.

What this means for applicants, patent owners and opponents is, so far, unclear. Consideration of plausibility and post-published data is relatively common at the EPO, particularly in cases in the chemical and life sciences. It is not yet clear in how many of these cases the assessment of inventive step can be said to rest exclusively on post-published evidence. How broadly the EPO applies this stay will become apparent in the coming weeks and months as they start to notify the affected parties.

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