Legal Lens on the Unified Patent Court | Q2 2025

Preliminary injunctions before the UPC are intended to provide swift and effective legal protection. But how high is the threshold for issuance? Two recent decisions by the UPC Court of Appeal (CoA) – Biolitec v. Lightguide (UPC_CoA_540/2024) of February 24, 2025, and Insulet v. EOFlow (UPC_CoA_768/2024) of April 30, 2025 – provide further guidance on preliminary injunctions before the UPC.

The cases at a glance

In Biolitec v. Lightguide, Biolitec applied for a preliminary injunction against Lightguide group companies to stop the distribution of a medical single-use product. Because the product had been on the market for several years (well before the patent was granted in July 2024), the Court of First Instance (the Local Division Düsseldorf) rejected the application because of a lack of urgency. The CoA affirmed this decision on appeal.

The key point of the CoA’s decision is the interpretation of the “necessity” requirement for interim measures under Rule 211 of the UPC Rules of Procedure (RoP) and Article 62 of the Agreement on a Unified Patent Court (UPCA). The CoA clarified that credible patent infringement alone is not sufficient. Applicants must show why awaiting the main proceedings would be unreasonable and why only immediate judicial action can provide effective legal protection. This may be the case, for example, where a new product threatens to disrupt the status quo of the market or where irreparable harm is imminent following the grant of the patent, such as offering the infringing product at medical trade fairs, loss of tender opportunities, or irreversible price erosion. Because Biolitec failed to substantiate any such risk, it could not show why waiting for the main proceedings would be unreasonable. Thus, the CoA affirmed the rejection of the preliminary injunction.

In Insulet v. EOFlow, Insulet applied for a preliminary injunction to stop distribution of EOFlow’s insulin patch pump system. The Court of First Instance (the Central Division Milan) rejected the request, mainly because of doubts about novelty. On appeal, the CoA reversed, finding infringement and granting interim relief. The CoA clarified that claim interpretation is a matter of law, corrected the Central Division Milan’s flawed interpretation of key claim features, and found the patent claims likely novel. In addition to affirming the principles from Biolitec v. Lightguide, the CoA set requirements regarding risk of repeated infringement and commented on the balancing of customer interests.

Trends at the UPC: Tightening standards in UPC appeals

These recent decisions confirm that the CoA does not follow a uniformly strict or lenient approach to preliminary injunctions but rather assesses each case individually. Applicants must substantiate both the infringement and the necessity of the requested measure – the context, arguments related to market position, competitive dynamics, and even customer interests may be decisive factors.

A look at past CoA decisions on preliminary injunctions shows a balanced picture:

*Includes decisions from the start of the UPC to April 2025.
**Two of the three decisions concern parallel cases.

In most cases, the pivotal points in granting preliminary measures were the likelihood of infringement and the validity of the patent in question. That is, on the specifics of the case rather than on particular standards of urgency. Thus, it appears there is no discernible conclusion that the CoA is applying the standards for preliminary injunctions more strictly than the courts of first instance.

Emerging principles

From the CoA’s recent rulings, the following principles for preliminary injunctions under the UPCA have emerged:

• Summary assessments must result in the UPC finding it more likely than not that the applicant is entitled to initiate the proceedings, that the patent is (or is likely to be) infringed, and more likely than not that the patent is valid. The burden of proof for entitlement, infringement, and all other facts supporting the application lies with the applicant. Conversely, unless the case is decided ex parte (e.g., without hearing the defendant), the burden of proof for invalidity and any facts supporting the defendant’s position rests with the defendant (NanoString v. 10xGenomics, UPC_CoA_335/2023, App_576355/2023).
• Necessity is a material requirement. Clear infringement and a high probability of patent validity alone are not sufficient. Applicants must demonstrate why only interim relief ensures effective protection (Rule 206.2(c) of the RoP; Biolitec v. Lightguide). It may be best to wait for the main proceedings if the conduct in question has persisted for some time (Biolitec v. Lightguide).
• Irreparable harm is not a mandatory condition but can strongly support necessity (Ortovox v. Mammut, UPC_CoA_182/2024). This is particularly true in cases of direct competition and risk of market displacement (Insulet v. EOFlow). Claims of harm must be specific and well-supported in court of first instance proceedings. General assertions of market loss or price erosion are insufficient. New arguments on appeal may be rejected as late-filed (Biolitec v. Lightguide).
• Customer interests can be considered in the overall balancing but do not prevent relief if the product is not indispensable or alternatives exist (Insulet v. EOFlow).
• A cease-and-desist declaration with a contractual penalty is typically required to negate the risk of repeated infringement (Insulet v. EOFlow).

The CoA emphasizes the case-specific and exceptional nature of provisional measures, the protection of the status quo, and the careful balancing of the parties’ conflicting interests.

Comparative perspective: The approach under German case law

As the UPC’s principles regarding the standards for preliminary injunctions emerge, they appear to largely align with established standards in German practice. Given the conceptual overlap, a closer look at the German approach can offer valuable guidance to the still-evolving UPC case law and help gauge the prospects and risks of interim relief before the UPC.

As with the UPC, a key requirement in German case law is the likelihood of infringement. If the facts are clear and the validity of the patent is not contested, the chances of success are good. Conversely, significant doubts about validity or complex factual or legal questions often lead to rejection.

Particularly, German courts consider several important factors, including:

• Whether the patent has survived a prior opposition or nullity challenge
• Recognition of patent validity by competitors or licensees
• Prior infringement rulings on the same patent or similar products.

Ongoing opposition proceedings, newly discovered prior art, or minimal inventive step can raise doubts about a patent’s validity, which reduces the likelihood of a preliminary injunction being granted.

Necessity is also an independent requirement in German law. Interim relief is only granted when main proceedings cannot be reasonably awaited. For example, if:

• The patent will soon expire.
• Irreversible market displacement or price erosion is likely (e.g., in the case of medicinal products and generic market entry).
• The infringement is short-lived or tied to imminent events (e.g., trade fairs).
• Enforcement of the patentee’s rights would otherwise be thwarted.

Takeaways

The CoA’s current case law on preliminary injunctions makes clear that each case is decided on its individual merits. The key criterion remains whether it is unreasonable for the applicant to wait for the main proceedings. Only when this criterion is substantiated and proven will the UPC grant interim relief. The overarching goal is to avoid disproportionate harm on either side. This makes the threshold for preliminary measures high but not insurmountable. A well-prepared, prompt application backed by solid evidence and supported by insights from national practice can significantly improve the chances of success.

The UPC just passed its two-year anniversary and is already entrenching itself into global patent litigation. As global patent enforcement becomes increasingly complex, understanding the procedural and strategic differences between major litigation venues is essential. Two of the most prominent forums – US district courts and the UPC – offer distinct advantages and challenges for patent holders and defendants. While both systems aim to adjudicate patent rights fairly, their procedural frameworks and litigation dynamics differ in ways that shape litigants’ behavior.

In this section, we explore how these systems compare in view of the first two years of UPC decisions, specifically in terms of trial outcomes, procedural hurdles, and opportunities for settlement.

Pre-trial obligations and milestones

One of the distinguishing features of US patent litigation is the early issuance of claim construction orders, often referred to as Markman rulings. Many US district courts schedule Markman hearings early in the case while some issue claim construction decisions before discovery has begun. This early interpretation of patent claims can significantly shape a case’s trajectory, influencing everything from summary judgment motions to settlement discussions. For litigants, understanding how and when a court will construe claims is a critical component of early case strategy and can further influence if the parties decide to settle.

Before a case reaches a jury, plaintiffs typically must navigate two significant procedural hurdles: summary judgment and Patent Trial & Appeal Board (PTAB) proceedings. While these hurdles pose risks, they also create opportunities for settlement. The uncertainty and cost associated with surviving summary judgment or a PTAB challenge often incentivizes early resolution.

Summary judgment is a hallmark of US litigation. Procedurally, it permits a court to resolve cases early if there is no genuine dispute of material fact. Although this can be a difficult standard to satisfy, courts often resolve cases of summary judgment in favor of the accused infringer. According to Lex Machina, about 5% of resolved cases in the last five years ended at the summary judgment stage. Within that 5% of cases, there is a finding of infringement in 18% of cases and invalidity in 71% of cases.

*This chart only represents cases granting summary judgment for infringement or noninfringement.
**This chart only represents cases granting summary judgment for invalidity or no invalidity.

After navigating the hurdles of claim construction and summary judgment motions, patent owners who reach trial in US district courts often have a strong chance of success. Jury trials, especially in jurisdictions like the US District Court for the Eastern and Western Districts of Texas, have historically favored patentees. According to Lex Machina, 58% of trials in the past five years resulted in a finding of infringement, and 72% of the trials upheld the validity of the patent. Even so, the path to trial is anything but straightforward. These results can take years; the average time to trial in the US can be 30 months. As these statistics indicate, trial outcomes are favorable for patentees, but the path to trial is long, narrow, and fraught with significant risk.

The PTAB’s influence

Another key risk along the US court path arises at the PTAB. Like European Patent Office (EPO) opposition or nullity proceedings that can run in parallel with UPC proceedings, inter partes review (IPR) proceedings before the PTAB are common and typically run in parallel with US district court litigation. Although EPO opposition proceedings are slower than UPC proceedings, PTAB proceedings are often faster than US district court litigation.

As a threshold matter, the PTAB will decide whether to institute IPR. These institution rates have fluctuated over time, influenced by policy and guidance shifts from the director of the US Patent & Trademark Office (PTO). During periods when the PTAB may be more or less likely to institute review, the litigation strategy of petitioners or patentees may be impacted, leading to more settlement opportunities.

According to Lex Machina, almost 7,000 IPRs have been filed at the PTAB in the last five years, with institution granted in about half of those proceedings. Patent owners have an uphill battle as a mere 8% of instituted proceedings uphold all claims. On the other hand, the petitioner succeeded in about 40% of instituted proceedings, resulting in a final written decision finding at least one challenged claim unpatentable. Further, unlike European proceedings in which claim amendments are common, the PTAB rarely permits amending the claims, with only 9% of completed trials involving a request to amend.

Recently, the PTO director issued interim procedures for discretional denial that separates discretionary denial from a PTAB panel’s determination of whether to institute review. Under this new framework, patent owners may submit a separate briefing to the PTO director on discretionary denial, including Fintiv factors and other equitable considerations. By unifying all discretionary denial decisions under the PTO director, the new framework stands to promote greater certainty and uniformity. This procedural shift may prove to be significant and result in more petitions denied at the institution stage, particularly when parallel litigation is already well underway or will reach trial before any final written decision by the PTAB.

Litigation before the UPC: Uniformity and speed with strategic challenges

After its first two years, the UPC established itself as a central forum for the enforcement and challenge of European patents, with 302 infringement actions and 65 standalone revocation actions through May 2025. The UPC’s goal is to become a competitive venue with the US in obtaining and resolving important global patent battles. But its procedural framework differs significantly from the US system in terms of speed, outcome predictability, and the parties’ ability to shape the proceedings. These differences serve to accentuate and highlight the opportunities provided by the UPC.

In cases before the UPC, parties benefit from an expedited procedure with cross-border effect. The oral hearing typically takes place within 12 months of filing the complaint, and decisions issued by the UPC have uniform effect across all participating member states. Unlike in the US, cases are not decided by a jury but by a panel of legally and technically qualified professional judges.

Unlike the US, the UPC does not provide for a separate early claim construction phase. Instead, claim interpretation is integrated into the written main proceedings, often emerging only in the context of the infringement analysis. The system is highly front-loaded: Parties must disclose their arguments, facts, and evidence comprehensively at an earlier stage. Later additions are permitted only under limited circumstances. Simultaneously, the system allows for counterclaims for revocation and the parallel assertion of technical and legal arguments. This procedural structure means that strategic clarity regarding the scope and reach of the patent arises late in the process, requiring a litigation strategy that is flexible and carefully developed from the outset.

An additional risk lies in the central effect of revocation actions before the UPC: If a patent is declared invalid, it loses its effect in all UPC Member States. This is a significant risk, particularly for strategically important patents. These high procedural demands can promote the prospect of settlement during the proceedings even though, in most cases, the UPC does not provide any decisive preliminary assessments along the way.

Although statistical data remains limited, early decisions indicate a favorable trend for patent holders. In decisions up to February 2025, 54% of asserted claims were found valid and infringed. Only 30% of patents were revoked in counterclaims and standalone revocation actions resulted in invalidity findings in just 40% of cases. In this respect, standalone revocation actions have been less favorable for patent challenges in the UPC as compared to IPR challenges in the PTAB. But standalone revocation actions have been more successful in the UPC than counterclaim revocation actions in infringement cases. Thus, parties perceiving an infringement risk in Europe may consider a standalone revocation action in a UPC central division (if the patents have not been opted out of the UPC system), rather than wait and react to an infringement complaint.

Takeaways

• US litigation offers a complex environment where procedural hurdles can be leveraged for negotiation and settlement, with good odds of winning at trial but significant hurdles along a long path that pose a potentially high risk of losing a patent or having its claim scope interpreted narrowly.
• UPC litigation offers streamlined proceedings, cross-border effect, and early decisions that require a technically and legally precise strategy from the outset. A case will turn on the strength of the underlying papers, with a brief oral hearing. Statistics from UPC cases in its first two years indicate that patent owners with such a strategy in place have a better chance to prevail in infringement actions while patent challenges have better odds of prevailing in standalone revocation actions than in counterclaim revocation actions.
• While both forums have strengths and weaknesses, each is tailored to different legal strategies and considerations. In general, the fast timeline of the UPC, with its general procedural favoring of claimants (but overall general disposition toward patent owners), can make the venue desirable for cases with strong technical merits. Parallel US and UPC strategies can also be considered.

The UPC has significantly reshaped European patent litigation by centralizing jurisdiction and offering faster, more efficient proceedings. The Court emphasizes a “front-loaded” process, requiring parties to present comprehensive arguments and evidence early, with strict deadlines particularly challenging for defendants. The UPC has shown a patentee-friendly trend, with lower revocation rates and a higher percentage of infringement findings compared to US courts and greater flexibility in amending claims.

Litigants are encouraged to act swiftly, choose venues strategically, and be well-prepared from the outset to navigate the system successfully.

Read this Law360 article for practical insights, case stats, and tactics to stay ahead in the UPC.

The Court of Justice of the European Union (CJEU) expanded the jurisdiction of EU national courts and the UPC to issue cross-border injunctions and rule on patent infringement in countries outside their jurisdiction, including non-EU states. The CJEU clarified that Article 24(4) of the Brussels I bis Regulation, which grants exclusive jurisdiction for patent validity challenges to the courts of the state where the patent is registered, does not apply to IPR invalidity defenses raised in infringement cases.

This decision allows patent proprietors to sue defendants based in the European Union for infringement in any country, potentially leading to increased forum shopping and parallel proceedings. It also makes the UPC a more attractive venue for global patent litigation due to its less costly and faster decision-making process.

Read this IP Update blog post for an in-depth look at the ruling’s effects across the patent litigation landscape.

This section reflects updated data regarding UPC usage, taken from the UPC’s register as of May 31, 2025.

Note: McDermott collects the data in the Recent Filings section directly from the UPC’s register and is not responsible for the accuracy of the data.

Number of cases on UPC register by type

*The number of counterclaims for revocation cases does not necessarily reflect the UPC’s true case load because the UPC’s Case Management System required several defendants in infringement proceedings to launch their own counterclaim for revocation, even if the substance of the counterclaims was fully identical across the parties. This inflates the number.

Number of cases on UPC register per division

Language of UPC proceedings

First instances of infringement and revocation cases per quarter from 2023 to 2025

*Q2 2025 values reflect data from April and May 2025 and are incomplete.

McDermott welcomes leading IP litigator Frédéric Chevallier in Paris: Frédéric brings extensive experience leading cross-border patent litigation, particularly before several UPC central, local, and regional divisions.

IAM Patent 1000 recognizes McDermott as a recommended firm in the UPC category: IAM Patent 1000 notes that firms listed in this category “have emerged as dominant authorities at the UPC” and have demonstrated “their ability to effectively handle the demanding deadlines of the new pan-European forum.”

Contact a member of our UPC team: Frédéric Chevallier, Hon.-Prof. Dr. Henrik Holzapfel, Chuck Larsen, or Diana Pisani.