We have previously discussed the European Patent Office (EPO) requirement to amend the Description portion of a patent application to conform with any amended claims. The requirement is most often raised by EPO Examiners in the context of Article 84 EPC (the claims must be clear, concise, and fully supported by the description).

This requirement has been the subject of a lot of discussion, not least because the requirement is strictly applied by some examiners while other examiners seem to almost disregard it as a requirement altogether.

There have also been divergent approaches taken before the Board of Appeal with one line of case law (referred to the Enlarged Board of Appeal Preliminary Opinion as the ‘First Line of Case Law’) supporting requiring description adaptation under Article 84 EPC and another line of case law (referred to the Enlarged Board of Appeal Preliminary Opinion as the ‘Second Line of Case Law’) based around decision T 56/21 which was decided in the opposite way.

The question of whether the Description required amendment and if so, to what extent was therefore referred to the Enlarged Board of Appeal in G 1/25 Enlarged Board opinion with three questions, and the Enlarged Board’s Preliminary Opinion (11 March 2026) has now been released and is available here.

The answers to the three questions are both helpful and unhelpful at the same time.

Question 1 – essentially “is it necessary, in order to comply with the requirements of the EPC, to adapt the description to correspond with amended claims to remove an inconsistency between the amended claims and the description?”

The Enlarged Board stated that there are only two types of inconsistency, those that cause non-compliance with the EPC and those that do not.  Unsurprisingly, the Enlarged Board then answered the question “yes” based on only those inconsistencies which caused a non-compliance required amendment of the description.

Question 2 – essentially “which requirements of the EPC necessitate the adaptation of the Description?” 

As mentioned above, there have been divergent approaches taken before the Board of Appeal.

The Enlarged Board decided that it is the First Line of Case Law which should be followed, which supports requiring description adaptation under Article 84 EPC.

Question 3 – essentially “should different requirements  be applied if the claims were amended during examination or during opposition proceedings?”

Unsurprisingly, the answer was “no” – there was no reason to draw a distinction between examination and opposition proceedings.

The Enlarged Board then set a deadline of 17 April 2026 for any written submissions in response to the EBA opinion. Oral Proceedings in relation to the referral and in light of the Preliminary Opinion are to be held at the EPO on 8 May 2026.

In the Preliminary Opinion, the Enlarged Board effectively ‘toed the EPO line’ in relation to whether amendments were required by deciding that amendments were required to remove inconsistencies which causes non-compliance with the EPC.

There was nothing in the Preliminary Opinion to give guidance on the extent of the amendments required nor the form which those amendments should take to remove the inconsistencies; just that the amendments should do so. It is the practical implementation of the requirement to amend the description which is of great interest to patent attorneys and their clients, as it is the manner in which the requirement is applied by the EPO, and the variation in its application, which causes the most confusion.

Clarity in relation as to how amendments need to be made in the description to satisfy Article 84 EPC will be important, but we suspect that this question will only be more settled after the final Decision is made and then the EPO Guidelines are updated.

There is still more to come!

For more information on this or for any other questions regarding to intellectual property rights, please contact one of our attorneys.