Another win for Astellas as Dutch court upholds Xtandi patent

At present, the Dutch courts are busy churning out decisions in patent disputes, especially in pharma cases. Last week, the judges bench at the District Court The Hague, comprised of M. Visser, Hans van Walderveen, and Cornelis Schüller, upheld EP 3 725 778 owned by Astellas Pharma and Medivation Prostate Therapeutics.

The latter is a US company dedicated to developing therapies to treat diseases for which there are limited treatments available. Medivation worked with Astellas to develop enzalutamide. Pfizer acquired the biotechnology company in 2016.

The patent EP 778 protects the formulation of enzalutamide, the active ingredient in Astellas’ drug Xtandi, which is used to treat prostate cancer.

Formulation is inventive

Synthon argued that on the priority date it was obvious for the average skilled person to formulate enzalutamide in amorphous form with a concentration-enhancing polymer in the form of a solid dispersion. Thus, Synthon claimed that the formulation patent is not inventive due to obviousness. Furthermore the company also claimed that the patent is not valid due to added matter.

Astellas argued that EP 778 is inventive because, at the priority date, it was not obvious to the skilled person to choose the claimed formulation. This is because developing a new formulation for enzalutamide required a lengthy trial-and-error process and the skilled person would not expect a new formulation to have bioavailability comparable to the Xtandi capsules and to be physically stable.

Astellas further argued that the matter claimed in EP 778 is directly and unambiguously derivable from the original application so there is no added matter. The court rejected Synthon’s arguments for revocation of these claims based on added matter and lack of inventive step (case ID: : C/091654337 / HA ZA 23-858). JUVE Patent does not yet know whether Synthon will appeal the decision.

Synthon’s further attacks

In a previous opposition filed by eleven opponents, Synthon among them, the Opposition Division of the EPO upheld EP 778 in May 2024. An appeal against this decision is pending before the Technical Boards of Appeal. Synthon has also filed nullity actions against the patent in Italy and Spain.

The basic patent EP 1 893 196 and related national SPCs covering the active ingredient enzalutamide are equally the subject of invalidity actions brought by several parties before the District Court The Hague, as well as in national courts abroad, including the UK and Germany. A decision from the Dutch court in this case is expected within the coming weeks. Last autumn, the UK High Court dismissed a nullity action brought by Accord, Sandoz and Teva against the patent.

Market leaders at the front

Two market-leading firms in the Netherlands are going head to head in these proceedings, namely Brinkhof and Hoyng ROKH Monegier.

For the attack on the basic patent as well as the formulation patent, Synthon relied on teams from Amsterdam IP boutique Brinkhof. Litigators Koen Bijvank and Mark van Gardingen took the lead in filing the nullity claim against EP 788. Associates Berber van der Wansem and Jasmijn de Groot assisted. The latter has now moved in-house to Netflix.

In the parallel proceedings regarding the basic patent EP 196, Amsterdam-based partners Daan de Lange and Alexander de Leuw lead the case for the claimants Sandoz and Accord.

In the UK, the claimants relied on Pinsent Masons. London partner Catherine Drew represented Accord and Sandoz together with Natalie Coan and Josie Miller. Another team around Charlotte Weekes and Ian Turner, including Sian Banks and Regina Damigou, advised Teva.

Proven mixed team for Astellas

Astellas and Medivation relied on a mixed team from Hoyng ROKH Monegier. Amsterdam-based partner Frank Eijsvogels led the case with partner Theo Blomme. Associates Nathalie Rodriguez Arigon and Inez ten Brink assisted.

Patent attorney Jeroen den Hartog of the firm’s Amsterdam office provided technical support. The team recently scored a win for their long-standing client Astellas in the dispute over Betmiga.

In the opposition proceedings, a team from Hoffmann Eitle represented Astellas and Medivation led by patent attorneys Peter Klusmann and Adam Lacy.

Parallel proceedings are pending in Italy and Spain. In Italy, a team from Trevisan & Cuonzo led by Donatella Capelli is representing the patent owners. For the case in Spain, they rely on a team from Clifford Chance, led by Josep Montefusco.

In the UK proceedings over basic patent EP 196, a London-based team from Kirkland & Ellis is taking the lead for the defence.