21 August 2020
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The four thousand or so European patents that are opposed every year represent only about 3% of all granted patents. And only a tiny fraction of this tiny minority have several oppositions filed against them. So, what’s special about this group of patents and what can it tell us about trends in innovation.

If a particularly large number of oppositions is filed against a patent this usually means that at least one of the following is true: the core invention’s commercial value is particularly high, the protection given by the patent is particularly broad, the field of technology is particularly crowded, or the patent proprietor’s competitors particularly aggressive. In some opposition cases all of these criteria seem to be met.

For the past few years patents protecting the platform CRISPR/Cas technology have been some of the most opposed in Europe. 2019 was no exception – three patents in the table all relate to CRISPR/Cas – and this seems set to continue for years to come.

Therapeutic treatments are the subject of many of the most opposed patents. Many of these patents protect the new application of known therapeutics, for example in new combinations or new dosing regimes - or in specific patient populations, reflecting innovation trends in personalised medicine.

A quick scan through the titles of the most opposed patents for 2019 tells us that almost all of these large and complex opposition cases are for life science or chemistry technologies, the only exceptions are cases highlighted in green in the table. This in contrast with the landscape for numbers of application filings, where the top applicants are in the telecommunications, computing and electrical fields. These differences reflect the contrasting patent strategies of innovative companies in life sciences compared with engineering. Consistently, the most opposed patents at the EPO are in the life sciences - for our detailed report on EPO Opposition Trends in the Life Sciences click here.

Mewburn Ellis has a wealth of experience in oppositions before the European Patent Office, read here for more.

This article is based on information as it appeared on the EPO Register on 10 January 2021 and from bulk data sets extracted on this date. It is an updated version of an earlier article based on older data. The table only includes patents for which the 9-month deadline for filing an opposition expired in 2019.

The Most Opposed European Patents of 2019

The Most Opposed European Patents of 2019 addendum table2308212 (3)

Oppositions Report 2019 Front CoverSpecial Report
Oppositions Trends in the Life Sciences Sector

We published this report to help tackle the key questions our clients ask regularly. In spring 2019, we undertook 350 hours of research, analysing more than 5,000 opposition cases filed at the European Patent Office over the last ten years, studying the timelines for hundreds of oppositions both before and after the EPO’s opposition streamlining initiative.


Download The Report






Katherine is a Partner and Patent Attorney at Mewburn Ellis. She specialises in EPO oppositions and appeals, particularly defending patents in complex opposition cases involving very large numbers of opponents. Katherine advises on European prosecution strategies for many important patent families, particularly divisional strategies for opposed patents. Her prosecution work includes advising on securing grant for the high-profile family of cases protecting CRISPR/Cas platform technology invented by Jennifer Doudna and Emmanuelle Charpentier.

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