Ones to Watch Netherlands 2026: Nerissa Teeuwen

Nerissa Teeuwen belongs to the generation of patent litigators of whom it will one day be said that they grew up with the UPC in their blood. She knows the world of patents as it once was, before the launch of the Unified Patent Court, practically only from the stories of veteran patent lawyers. She only began her career as a lawyer in March 2024. By then, the new European patent court had been taking on cases for almost a year, but was struggling with a case management system that was not quite up to snuff.

“I’ve been involved in UPC litigation since the court opened its doors. I really enjoy this work, particularly because of the many international cross-border aspects,’ says Nerissa Teeuwen. ‘But practicing before the UPC still feels a bit like venturing into uncharted territory. There’s still so much to discover and test out.” Together with the other patent lawyers in Freshfields’ Amsterdam team, Teeuwen jumped straight into the deep end of the UPC in spring 2024 and worked on the first UPC cases. Whilst her more seasoned colleagues drew on substantial prior experience in national litigation, Teeuwen had to learn everything from scratch. Apart from two traineeships as a student at Hyong ROKH Monegier and at Freshfields, she had virtually no prior experience in IP at the time.

Assigned to life sciences cases

“Nerissa is a really good lawyer,” says a competitor. The 29-year-old lawyer has only been practising for two years and eight months, yet she quickly gained experience. One of her first cases was Genentech and F. Hoffmann-La Roche’s dispute with Organon concerning the breast cancer drug Perjeta at the Brussels local division. The Freshfields team filed an application for preserving evidence on behalf of its two clients to determine whether a planned biosimilar from Organon infringed the Perjeta patents. Teeuwen was given the opportunity to plead in the UPC courtroom at a very early stage. The case has since settled.

Teeuwen is involved in other important life sciences cases. These are still rare at the UPC, and Freshfields’ Amsterdam team presumably has more experience in UPC pharma and biotech cases than many other teams in the market. It represented its long-standing client Moderna against Arbutus and Genevant. This case has also settled. The team is currently acting in another mRNA case for Moderna against its arch-rival BioNTech at the local division The Hague. BioNTech’s subsidiary CureVac brought the claim in this case.

Teeuwen is always part of the team. For example, they are defending Vertex and Lonza against a claim brought by Toolgen at the Dutch local division concerning the drug Casgevy. Casgevy is the world’s first gene therapy based on CRISPR-Cas9 gene scissors.

Secondment to Munich

“At high school, I was interested in natural sciences and was considering studying biology. But during a long road trip, I changed my mind and decided to study law instead,” says Teeuwen. She can continue pursuing her interest in biology and other natural sciences at Freshfields. The Amsterdam team led by partner and mentor Rutger Kleemans has traditionally had a strong focus on pharmaceutical and biotech cases on behalf of originators. Novartis and Moderna are key clients of the team. Whilst traditional pharma cases tend to dominate in national courts, Teeuwen primarily advises manufacturers of biotech drugs or therapies at the UPC.

At present, however, Teeuwen is gaining insight into the UPC work of the Munich team, where partner Nina Bayerl is particularly active. The Munich team works closely with the Düsseldorf patent lawyers around partner Wolrad Prinz zu Waldeck und Pyrmont, as well as with the Amsterdam and London teams, on cross-border cases. Freshfields’ patent practice is somewhat smaller than that of Hogan Lovells Cadwalader or Bird & Bird, for example, and they are therefore keen to assist one another across national borders.

The German team is equally active in life sciences and mobile communications cases. Teeuwen is currently in Munich preparing for an oral hearing in a major mobile communications case before the Munich local division. Next Tuesday, the division will hear the case brought by the NPE Ueran Technology against Freshfields’ client Xiaomi concerning standard-essential mobile communications patents.

The time for decisions has not yet come

“Life sciences and IT cases dominate my work,” says Teeuwen. “At the UPC, there are slightly more IT and mobile communications topics.” But at some point lawyer have to specialise further. “If I were ask to choose one over the other, I genuinely enjoy both and it’s honestly too early to say. I would like to gain more experience first,” says Nerissa Teeuwen.

Compared with many of her German and UK colleagues, Teeuwen came to the attention of other market players at an early stage. With this head start, she can look to the future with confidence. However, the rise of AI tools is bringing about significant changes in the world of patents, which many of her colleagues — particularly patent attorneys — view with concern. “At Freshfields we already use our Freshfields Lab intensively. It is an exciting space, even if keeping up with such rapid developments is a constant challenge,” says Nerissa Teeuwen. “AI enhances our work, but I do not believe it will fully replace us as litigators down the line.”

For in-depth analysis on the Dutch patent market, read the JUVE Patent Netherlands ranking 2026.