Can you extend an expired patent through trademark law?

At a judgment dated June 19, 2025 the Court of Justice of the European Union (CJEU) has tightened the limits on registering a trademark when there is a suspicion that it is being done in order to prevent a lapsed patent unlawful extension. The case, CeramTec GmbH v. Coorstek Bioceramics LLC (Case C-17/24), provides important insights for companies in Belgium and abroad about the nullity ground of "bad faith" in the trademark law. The central lesson? The applicant's intent at the time of the trademark application is decisive, even if that intent is based on a false premise.

The facts: a pink prosthetic and an expired patent

The German company CeramTec, specializing in ceramic components for hip implants, among others, held a European patent on a specific ceramic composite material. A key ingredient, chromium oxide, not only increased the material's hardness and strength, but also gave the prostheses a distinctive pink color.

This patent expired on Aug. 5, 2011. Just weeks later, on Aug. 23, 2011, CeramTec filed three applications to register the pink color as a Union trademark for its ceramic prosthetic components. These were a color mark, a figurative mark and a three-dimensional mark, all for the specific color pink (Pantone 677C).

When competitor Coorstek, an American manufacturer, marketed prosthetics with a similar pink color, CeramTec initiated infringement proceedings based on its newly acquired trademark rights. Coorstek defended itself by claiming the invalidity of CeramTec's trademarks, arguing that they had been filed in bad faith. According to Coorstek, CeramTec tried to artificially prolong the monopoly on its technical solution, which it had lost due to the expired patent, through trademark rights.

The legal battle: autonomous nullity grounds and applicant's intent

The French Court of Appeal in Paris vindicated Coorstek and declared the marks invalid for bad faith. The court ruled that CeramTec had applied for the trademarks with the unlawful purpose of perpetuating its monopoly on the technical solution (the use of chromium oxide) to keep competitors off the market.

CeramTec appealed in cassation, raising a remarkable argument: after the trademark applications, the company allegedly discovered that the chromium oxide was actually no technical effect had on the strength of the material. Thus, according to CeramTec, there could be no intent to protect a technical solution because, objectively, there was no technical solution that could be protected.

In response, the French Cour de Cassation decided to ask the Court of Justice for a preliminary ruling on the interpretation of the relevant provisions of the Union trademark regulation.

The Court's ruling

In its ruling, the Court of Justice gave clear answers to the questions raised. The main points are:

1. Nullity grounds are autonomous but not mutually exclusive

The Court affirmed that the ground of invalidity due to the existence of a absolute ground for refusal (such as a sign consisting solely of a form necessary to obtain a technical result) and the nullity ground because of bad faith of the applicant, are two autonomous grounds. This means that a court can find bad faith without first having to prove that the mark actually has a technical function. Thus, the grounds are independent of each other, but can apply simultaneously and are not mutually exclusive.

2. The subjective belief of the applicant is crucial

This is the crux of the ruling. The Court states that a trademark applicant's bad faith can be shown based on his own conviction that the sign protects a technical solution, even if that belief turns out to be wrong in retrospect.

In other words, the fact that CeramTec thought That the pink color had a technical function at the time of the application is a strong indication of bad faith. After all, the purpose was to prevent competitors from using that (allegedly) technical solution. This is an intent inconsistent with honest practices in economic life and the essential function of a trademark, which is to indicate the commercial origin of a product.

3. Assessment is done at the time of application

The Court reiterates an established principle: bad faith must be judged on the time of filing the trademark application. Circumstances that do not arise until after submission are in principle irrelevant to changing the applicant's intention at that crucial time.

Thus CeramTec's later discovery that the chromium oxide had no technical effect cannot retroactively "cure" or justify the original (unfair) intent.

What does this ruling mean for your business?

This ruling is a clear warning to companies that try to safeguard their market position through trademark law after the expiration of a patent. It is a perfectly legitimate strategy to build a strong brand after a patent, but this must be done with the right intentions.

Some concrete lessons:

• Be careful about claiming functional features: Do not attempt to register features (shapes, colors, etc.) as trademarks with the underlying purpose of monopolizing a technical function or solution that is no longer protected by a patent.
• Intention counts: Your internal beliefs and the commercial logic behind a trademark application can be used against you in any proceedings. So document well why you want to protect a particular sign as a trademark and make sure it is part of a fair competitive strategy.
• A mistake does not free one from responsibility: The "I didn't know any better" or "I was wrong" argument is unlikely to save you if it can be shown that your original intent was to unfairly restrict competition.

The intellectual property rights offers a range of tools to protect your innovations and commercial identity. However, each right has its own purpose and limits. This ruling aptly illustrates that abusing one right to circumvent the limitations of another is severely punished.