Barbara Mooij, a patent litigator at Brinkhof, has become one of the Netherlands’ leading voices in pharmaceutical patent disputes. Her career transitioned from cosmetic science to law after early immersion in both fields. She earned her degree in cosmetic science at the University of the Arts London before joining Unilever’s research and development department. That experience later shaped her legal work, where she now specializes in the intersection of scientific and legal arguments.
At Brinkhof, Mooij has built a reputation for handling high-stakes pharmaceutical litigation. The firm focuses on patent disputes, and her expertise has positioned her at the center of cases involving major drugs. Last week, she played a defining role in a victory for Halozyme. The District Court of The Hague ruled in favor of Halozyme against MSD in a dispute over the subcutaneous version of Keytruda, a cancer treatment that generated sales of approximately €25.8 billion for MSD in 2024. The court upheld Halozyme’s European patent and issued a cross-border injunction covering eight countries, prohibiting MSD from marketing Keytruda. The judgment is not final, as MSD can appeal.
This case demonstrates Mooij’s ability to manage complex, cross-border litigation. The dispute spans jurisdictions including the Netherlands, Germany, the UK, and the US. “The Halozyme case has all the aspects a lawyer could want in a case. International cooperation with the client and law firms in other countries, complex technology, and legally interesting issues,” she says. Her client roster includes Novo Nordisk, Sandoz, Celltrion, and Synthon, with cases involving drugs like semaglutide, rivaroxaban, and trastuzumab.
Her scientific background provides a distinct advantage in patent litigation. Before law school, Mooij worked in Unilever’s R&D program, contributing to product development. That hands-on experience in innovation now informs her legal practice, where she connects technical details with legal arguments. Her parents—one a lawyer and the other a patent attorney—further strengthened her early interest in intellectual property law.
Related Post: Halozyme wins patent case over Keytruda
Mooij’s career progression has been supported by mentors at Brinkhof, including partners Mark van Gardingen, Daan de Lange, and Koen Bijvank. She joined the firm in 2019 after completing a law clinic incubator program. Since then, she has become a key figure in Brinkhof’s life sciences practice, managing some of the most significant pharmaceutical disputes in the Dutch market.
Why Big Pharma Still Avoids the UPC
Together with its German partner firm Vossius, it is heavily involved in the UPC through a joint venture, Vossius & Brinkhof UPC Litigators. However, among the many UPC cases handled by both firms, there are only a few pharmaceutical cases. The pharma giants are still reluctant to have their crown jewel patents for blockbuster active ingredients such as rivaroxaban, semaglutide or pembrolizumab heard before the UPC. As a result, Mooij’s focus has remained primarily in national courts, where disputes over drugs like Keytruda, semaglutide, and Xarelto are typically resolved.
Beyond litigation, Mooij is active in education and professional networks. She lectures on patent law at Leiden University and plans to expand her academic role. She also engages with the international Chips Network, which supports women in technology, law, and policy. This combination of legal practice and mentorship establishes her as both a leading practitioner and an influential voice in the field.
Key Cases: Semaglutide, Rivaroxaban, and Beyond
The Halozyme case represents Mooij’s most prominent victory to date. In the semaglutide litigation, she advised Novo Nordisk against Ceban’s biosimilar, Wegovy, where Dutch courts are evaluating whether Ceban’s manufacturing process avoids Novo’s patent claims. The dispute centers on chemical structure equivalency rather than functional similarity.
Related Post: Brazil’s Courts Speed Up Patent Disputes
Her work on rivaroxaban, Bayer’s anticoagulant, followed a different path. Representing Sandoz in nullity proceedings, Mooij challenged the validity of Bayer’s European patent for Xarelto by arguing prior art revealed a crystal form identical to Bayer’s claimed structure. The Dutch Patent Office rejected Sandoz’s arguments, but Mooij is now appealing.
In Celltrion’s disputes over trastuzumab/Herceptin, she countered Roche’s claims that Celltrion’s biosimilar, Herzuma, lacked sufficient clinical comparability.
Brinkhof’s UPC strategy has involved preliminary discussions for potential cases, though Mooij’s direct involvement in these remains limited. The firm’s joint venture with Vossius, Vossius & Brinkhof UPC Litigators, participates in UPC litigation, but major pharmaceutical companies remain reluctant to submit their most valuable patents to this new system. Consequently, Mooij is less frequently involved in UPC cases than younger litigators with a broader technical background. She is currently working behind the scenes on new UPC cases.
Rising Star in Patent Litigation
The 2026 JUVE Patent rankings named Mooij among the top three rising stars in Dutch patent litigation, alongside colleagues from Allen & Overy and Bird & Bird. This recognition reflects her ability to merge scientific and legal arguments—a skill developed during her Unilever placement, where she drafted regulatory submissions for new products. Her current cases demonstrate this dual expertise: in the valsartan/Entresto invalidity dispute, she challenged Novartis’s patent on grounds of obvious-type combinations, requiring both chemical knowledge and legal precedent analysis.
