EPO opposition activity around GLP-1 patents shows where competitors see patent rights as commercially important enough to challenge.
The data covers GLP-1-related EPO opposition’s record from 2010 to 2026. Opposition filings increased tremendously after 2017, reached their highest point in 2021, and remained active through 2024. Boehringer Ingelheim and Novo Nordisk are the most opposed patents owner, while Generics UK, Sandoz, Teva, Nutricia, and Strawman Ltd appear among the most active opponents respondent.
The pattern suggests that GLP-1 patent competition in Europe (EPO) is not limited to product launches or patent filings. It is also playing out through post-grant challenges, where companies test the strength of patents that may affect market access, formulation choices, product positioning, or future freedom to operate.
For readers tracking the broader GLP-1 innovation landscape, GreyB’s earlier analysis on GLP-1 patents covers patent filing activity, leading companies, and technology focus areas. This article looks specifically at what EPO opposition data reveals about competitive pressure in the GLP-1 space.
What EPO Opposition Activity Actually Signals in GLP-1
EPO oppositions in GLP-1 are not random legal challenges. They represent structured competitive behaviour across three strategic layers:
1. Portfolio Weakening Strategy
Oppositions are concentrated around core blocking patents, suggesting competitors are systematically targeting foundational protection layers rather than isolated inventions.
2. Market Entry Timing Strategy
The surge in opposition filings aligns with commercialization readiness in GLP-1 therapies, indicating that opposition activity increases when market entry windows become economically relevant.
3. Defensive Patent Stress Testing
Repeated challenges against the same assignees suggest competitors are evaluating the robustness of entire patent portfolios rather than single patents.
GLP-1 EPO Opposition Activity Snapshot
| Metric | Data Point |
| Time period analyzed | 2010–2026 |
| Highest opposition filing year | 2021 |
| Opposition filings in 2021 | 108 |
| Most opposed patent owner | Boehringer Ingelheim |
| Boehringer Ingelheim opposition records | 116 |
| Most active opponent | Generics UK Ltd |
| Generics UK opposition records | 83 |
| Most active opponent representative | Elkington and Fife LLP |
| Elkington and Fife LLP records | 100 |
| Most opposed patent | EP3689365 |
| EP3689365 opposition count | 18 |
| Most used opposition citation patent | WO2012080471A1 |
| WO2012080471A1 citation count | 15 |
The opposition activity is concentrated around a few patent owners, opponents, representatives, and patent assets. That concentration is important because EPO oppositions are usually not filed randomly. They often point to patents that competitors believe could influence market entry, product development, or commercial flexibility.
The concentration of opposition activity around a limited number of assignees, opponents, and representative firms indicates a non-random pattern.
This suggests that GLP-1 oppositions are driven by targeted invalidation strategies, where competitors repeatedly challenge high-value patent clusters rather than distributing opposition effort evenly across the landscape.
What GLP-1 EPO Patent Opposition Filing Trends Reveal?
GLP-1 opposition filings were limited in the early part of the dataset. Filings increased from 3 in 2010 to 108 in 2021. Activity declined after 2021 but remained higher than most pre-2017 levels. The 2025 and 2026 figures, 52 and 32 respectively, should be read carefully because recent opposition data can be affected by timing and data cut-off.
The main takeaway is that GLP-1 opposition activity became much more active after 2017. This suggests that more granted GLP-1 patents were seen as important enough to contest as the market and technology space became more commercially relevant.
Which Companies Are Filing the Most GLP-1 EPO Oppositions?
Generics UK Ltd is the most active opponent in the dataset, with 83 opposition records. Sandoz follows with 37, while Teva Pharmaceutical has 33.
This is a strong signal because the top three opponents include major generic or generic-focused pharmaceutical players. Their presence suggests that GLP-1 oppositions are being used to test patent barriers that may affect future product entry or development flexibility.
The most active opponents indicate that GLP-1 patent challenges are closely tied to market-entry pressure and competitive positioning.
Which Law Firms Are Most Active in GLP-1 EPO Opposition Proceedings?
Elkington and Fife Llp is the most active opponent representative, with 100 records. Ter Meer Steinmeister & Partner follows with 54, and Hamm & Wittkopp has 49.
The concentration is notable. The top three representative names together account for 203 records. This suggests that GLP-1 opposition work is not spread evenly across many firms. Instead, a smaller group of representatives appears repeatedly in these proceedings.
For patent owners, this matters because opposition defense is different from patent prosecution. When the same firms appear frequently on the opponent side, patent owners can expect structured validity challenges and repeated use of opposition experience.
Who Are the Most Opposed GLP-1 Patent Owners in Europe?
Boehringer Ingelheim and Novo Nordisk As are the most opposed patent owners, followed by Nestlé, Nutricia, Novartis, AstraZeneca, Amgen, and others.
Boehringer Ingelheim is the most opposed patent owner in the dataset, with 116 records. Novo Nordisk follows closely with 110.
Together, Boehringer Ingelheim and Novo Nordisk account for a large share of the top opposed-owner activity. This shows that opposition pressure is concentrated around companies whose GLP-1 patent positions are likely seen as commercially relevant by competitors.
Heavy opposition activity around Boehringer Ingelheim and Novo Nordisk suggests that competitors see their GLP-1 patent positions as important enough to challenge repeatedly.
Which GLP-1 Patents Were Opposed the Most?
| Top Opposed Patents | Opposition Count | Assignee |
| EP3689365B1 | 18 | Novo Nordisk As |
| EP2395968B1 | 17 | Boehringer Ingelheim |
| EP3539540B1 | 11 | Boehringer Ingelheim |
| EP2981255B1 | 10 | Boehringer Ingelheim |
| EP2791160B1 | 10 | Modernatx Inc |
| EP3474820B1 | 8 | Novo Nordisk As |
| EP3448416B1 | 8 | Novo Nordisk As |
| EP2340828B1 | 8 | Novartis Ag |
| EP2981271B1 | 8 | Boehringer Ingelheim |
| EP2863895B1 | 7 | Novo Nordisk As |
EP3689365B1, assigned to Novo Nordisk, is the most opposed patent in the dataset, with 18 opposition records. EP2395968B1, assigned to Boehringer Ingelheim, follows with 17.
The key point is not only that these patents were opposed. It is that several patents from the same owners attracted repeated challenge activity. That suggests competitors are not looking at isolated patent documents. They are likely watching broader patent positions around specific GLP-1-related technologies.
Strategic interpretation: The most opposed patents point to patent assets that competitors appear to view as commercially important or potentially restrictive.
Check Your GLP-1 Patents for EPO Opposition Risk
Understand which of your GLP-1 patents are most likely to face opposition in Europe based on prior opposition patterns, competitor behavior, and high-risk citation clusters.
Which Patents Are Used Most Often as Opposition Citations?
| Top Patent Used Opposition Citation | Count of Citation | Assignee |
| WO2012080471A1 | 15 | Novo Nordisk As |
| WO2006097537A2 | 13 | Novo Nordisk As |
| WO2008055940A2 | 9 | Boehringer Ingelheim |
| WO2004018468A2 | 9 | Boehringer Ingelheim |
| WO2007128761A2 | 8 | Boehringer Ingelheim |
| WO2005092877A1 | 8 | Boehringer Ingelheim |
| WO2013139694A1 | 7 | Novo Nordisk As |
| WO2009121945A2 | 7 | Boehringer Ingelheim |
| WO2008116179A1 | 7 | Bristol Myers Squibb |
| WO2003099836A1 | 7 | Bristol Myers Squibb |
| WO2003002136A2 | 7 | Novo Nordisk As |
Novo Nordisk’s WO2012080471A1 and WO2006097537A2 are the most cited references. Followed by multiple Boehringer Ingelheim publications also appears strongly in the citation list. WO2008055940A2 and WO2004018468A2 each have 9 citations. WO2007128761A2 and WO2005092877A1 each have 8.
The most cited patents show which earlier GLP-1 patent publications are being used most often to challenge later patent rights.
This shows that Novo Nordisk and Boehringer Ingelheim are not only frequent targets of opposition. Their earlier patent publications are also being used as prior-art references in opposition proceedings.
What this shows: Novo Nordisk is central to the GLP-1 opposition landscape from both sides. Its patents are being challenged, and its earlier publications are also being used in opposition arguments.
Track Competitor Opposition Strategy in GLP-1 Space
Get visibility into who is challenging whom at the EPO – identify active opponents, heavily targeted patent owners, and prior-art networks shaping GLP-1 patent battles in Europe.
Conclusion
GLP-1 EPO opposition activity is concentrated around a small set of patent owners, challengers, representatives, and patent documents.
Boehringer Ingelheim and Novo Nordisk face the highest opposition pressure among patent owners. Generics UK, Sandoz, and Teva are among the most active challengers. Nestlé and Nutricia show that GLP-1 patent competition is also extending into nutrition-related areas. The most opposed patents, led by EP3689365 and EP2395968, point to assets that competitors appear to view as important enough to challenge directly.
The non-obvious takeaway is that GLP-1 opposition data does more than show legal activity. It shows where competitors believe patent rights may affect commercial movement in Europe.
