Achieving success in oppositions at the European Patent Office is critical for any innovation-oriented business seeking commercial advantage and growth. Having advised thousands of clients on their EPO opposition strategies for many years, we are acutely aware that successful oppositions and appeals require not only deep technical expertise and knowledge of the subject matter under scrutiny, but a forensic understanding of the evolving procedural aspects of the EPO process and timeline.

Our 30 plus-strong life sciences team of highly experienced patent attorneys has an enviable track record in patent oppositions and appeals, having successfully defended and attacked hundreds of patents.

We defend more complex opposition cases in the life sciences space than any other UK IP firm and handled three of the top ten most opposed patent cases in 2018.  We have an enormous amount of experience handling multi-party oppositions and are adept at dealing with the complexities of oppositions at the EPO, regardless of the number of opponents. 

Our expertise in life sciences is unrivalled when it comes to opposing patents and our enviable success rate speaks for itself. Only 7.4% of all patents that we have opposed over the last 15 years have been maintained as granted. That's significantly better than the EPO’s 15-year average of 24.6%. Our figures are even more impressive when it comes to appeals, where on average only 2.7% of patents that we have opposed have been maintained as granted, compared to the EPO’s average of 11.9%.

Our success rate is similarly impressive when we look at the proportion of patents that are completely revoked following an opposition handled by us, with 46.1% of all patents that we have opposed over the last 15 years having been revoked. Again, this is significantly better than the EPO average of 37.3%. These figures get even better following an appeal, with 59.3% of patents we’ve opposed having been revoked completely compared to the EPO average of 46.4%.

*Source: Statistics provided by IpQuants AG

Experts in oppositions

Simon Kiddle - Circle

Time is of the essence

"Patentees now have much less time to respond to an opposition. More than ever before, they need to review oppositions early and be prepared to respond within the initial four-month time limit. This means that a very early review of the opposition is required and, in particular, possible claim requests should be considered at an early stage and prompt consideration given to whether expert declarations or additional data are required.

Hearings are being appointed much sooner and there is now very limited time for opponents to review a patentee’s response before a summons is issued. Therefore, for an opponent, a prompt review of the patentee’s response is essential to determine whether or not a response should be fled before issuance of the summons, so that any rebuttal arguments are considered by the Opposition Division when preparing the summons."
Simon Kiddle


Emily Hayes - Circle

Changes in behaviour

"We knew that extensions of time for the patentee’s response had become much less common following the introduction of the streamlining initiative, but wanted to explore whether this was just because the EPO was much less willing to allow these requests or because patentees feel it’s no longer worth asking.

Our analysis showed that it’s both – the EPO and patentees have changed their behaviour.  Not only is the EPO much less likely to allow requests for an extension of time by the patentee, especially for single opponent cases, but patentees are also much less likely to request an extension of time, perhaps feeling that there’s little point in doing so."
Emily Hayes

Kath Green - Circle

Multi-party oppositions

"There is no limit on the number of oppositions that can be fled against any one patent. Filing of a large number of oppositions can signal, for example, that the patent in question covers a particularly valuable technology, that the claims are particularly broad, or that the patentee is active in a particularly crowded or litigious field, or a combination of such factors.

The vast majority of oppositions, however, involve just one opponent. Cases in which there are seven or more opponents are rare."
Katherine Green


Need help with an opposition?

Our opposition specialists work across the whole spectrum of chemical and materials innovation.  We handle everything from compact cost-conscious defences through to multi-party 'win at all costs' proceedings.  We will work with you to understand the real-world commercial context and offer up imaginative and pragmatic strategic advice that achieves the right outcome for your business, at the right cost.

Not sure who to talk to?  Please get in touch and I'll be happy to help. 

Simon Kiddle, Head of Life Sciences


Read our opposition blogs

Learn More

Life Sciences innovation focus

pink pills in packet

Pharmaceutical & Biologics

Patents are a critically important element of protection, alongside Regulatory Protection, for a given drug asset. Our IP experts have extensive experience of drafting and prosecuting such valuable patents to grant for many pharma and life-science clients – from some of the biggest global firms, to the earlier-stage start-ups.  We also have substantial expertise in freedom-to-operate searching and due diligence in this area.

Learn More
precision medicine healthcare dna blue

Nucleic Acids & Molecular Biology

The promise of the human genome project is beginning to be fulfilled. Rapid whole-genome sequencing is now a reality.  These exciting development are underpinned by core platform technologies. Our team have have considerable experience of providing IP protection for core platforms in molecular biology, as well as their innovative applications in research, agriculture and medicine. Many of our experienced patent attorneys have laboratory experience in this area and are supported by talented new recruits with up-to-date practical expertise.

Learn More
Precision Medicine - 1500px x 660px

Diagnostics & Precision Medicine

Our expertise and experience extend across the whole range of precision medicine and diagnostics technologies, from medical devices and wearables, through to biomarker discovery, liquid biopsy, and bioinformatics. Developments in this area are often multidisciplinary, drawing on advances in biology, engineering and computer science, and this is reflected in our team of expert attorneys, drawn from across specialisms, who collaborate to bring together knowledge and experience to develop effective IP strategies for new technologies in this rapidly developing space. 

Learn More
Tractor in a field - Copy (Medium)

Industrial & Agricultural Biotech

Food security and sustainability of resources are concerns that are rarely far from the headlines. While solutions to these challenges must be multi-disciplinary, industrial and agricultural biotechnology has already been used to transform efficiency across a wide variety of industrial process and offers huge potential to do more. Our IP experts have a long history of involvement in this field.  We can offer advice and assistance in obtaining Plant Variety Rights (PVRs) and National Listings in both the UK and Europe.

Learn More


Opposition Trends in the

Life Sciences Sector

Special Report

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



Meet our specialists


Partner, Patent Attorney

Emily Hayes Feb-21

Partner, Patent Attorney


Partner, Patent Attorney

Forward Magazines Overlapping 8

Mewburn Ellis


Mewburn Ellis Forward is a biannual publication that celebrates the best of innovation and exploration. Through its pages we hope to inform and entertain, but also to encourage discussion about the most compelling developments taking place in the scientific and entrepreneurial world. Along the way, we’ll engage with the IP challenges that international organisations face every day.