Enzalutamide (Xtandi): when the compound patent holds, the SPC date is the date

What was decided

European Patent (UK) 1 893 196, filed on 29 March 2006, claims enzalutamide, the androgen receptor inhibitor sold as Xtandi for prostate cancer, and supplementary protection certificate SPC/GB13/079 extends it in the UK. Accord, Sandoz and Teva conceded that their generics would infringe if the patent was valid, so everything turned on validity. Their case was that a medicinal chemist would have found the molecule obvious.

Mr Justice Mellor disagreed in a judgment of 8 October 2024, finding the generics’ expert evidence on the main prior art coloured by hindsight; the plausibility and insufficiency points were not pursued on appeal. The Court of Appeal (Lord Justice Arnold, with Lords Justices Snowden and Zacaroli) dismissed the appeal on 23 July 2025, declining to disturb a first-instance obviousness assessment that had weighed the evidence properly. Courts in The Hague and the German Federal Patent Court had already upheld the same patent and SPC.

Timeline

Date	Event
2024	District Court of The Hague and German Federal Patent Court uphold the patent and SPC
8 October 2024	UK High Court upholds the patent and SPC (order 7 November 2024)
23 July 2025	Court of Appeal dismisses the generics’ appeal
29 March 2026	Basic patent reaches the end of its 20-year term; the SPCs continue
2028	SPC expiry (the Dutch SPC runs to 25 June 2028; UK date to be confirmed from the register)

What it means if you are…

A parallel trader. This is the other half of the picture after dapagliflozin and apixaban: here the register date is the real date. When a compound patent survives challenge in three major jurisdictions, the SPC expiry on the register is what you plan around, and no earlier generic source will appear in the UK, the Netherlands or Germany.

A generics or launch planner. Obviousness attacks on a compound patent need more than a chain of reasoning that looks sensible after the event; three courts called it hindsight. The useful question before committing to a challenge is whether the attack is a plausibility point (which has worked in the UK against old compound patents) or an obviousness point against a well-drafted molecule claim (which, on this record, has not).

A wholesaler or buyer. No UK generic enzalutamide until the SPC expires, so no price event to plan for in the near term. Budget on the brand, and on the SPC date.

Status and what to watch

Settled in the UK, the Netherlands and Germany. Watch for the SPC expiry dates country by country and for any paediatric extension, which would add six months in each country where it is granted.