The EPO’s practice on double patenting has been rather settled over the past decade.  As indicated in the EPO’s Guidelines for Examination, two or more applications of the same effective date filed by the same applicant may proceed to grant if the claims are not identical in scope.

However, the case law on which these guidelines are based made obiter comments that this position is based on the reasoning that an applicant has no legitimate interest in proceedings leading to the grant of a second patent for the same subject-matter if he already possesses one granted patent for that subject-matter.

In an appeal from a decision of the Examining Division on EP 2429542, this point is being challenged and the question has now been referred up to the Enlarged Board of Appeal

The Appellant’s position is that there is one circumstance in which an applicant does have a legitimate interest in having a second EP patent granted to him with identical claims.  This situation is where the second EP application claims priority to an earlier EP patent of the applicant and the claims in each are identical.  In these circumstances the second patent will expire a year later than the first (patent term is calculated from the filing date, not any applicable priority date) and so the Appellant argues that the benefit to the applicant of an additional year of patent protection for the claimed subject matter is sufficient to satisfy the legitimate interest test.

The exact questions referred to the EBA are recited below. 

The implications of this referral are not entirely clear.  At the very least, we should receive a little more certainty on the extent to which EP patent applicants can pursue similar claims in different EP patent applications. This is of course welcome, but this particular circumstance is rather niche and perhaps limited to inventions in the pharmaceutical space where an extra year’s protection at the 20-year point can have enormous value.  However, the wording of question 1 does allow the EBA a chance to take a second look at the practice of double patenting as a whole and this has the potential to reopen the settled practice we have enjoyed over the past decade.