Paris court invalidates crucial claim of Bayer’s sorafenib patent

For years, Bayer has fought a fierce pan-European battle over its cancer drug Nexavar. The dispute concerns Bayer’s patent EP 2 305 255, which expired in December 2022. The patent protects the compound of a tosylate (a type of salt) of the active ingredient sorafenib. This forms the basis of Bayer’s drug Nexavar, which treats various types of cancer, including kidney, liver cell and thyroid cancer.

In July 2021, after the expiration of a related SPC, Bayer first launched an interim action against Teva at the Judicial Court Paris, followed by an action on the merits against multiple generics manufacturers a few weeks later. The originator based its actions on claim 12 of its EP 255. However, the French court dismissed the interim action against Teva, reasoning that claim 12 lacked inventive step. The Court of Appeal upheld this decision in May 2022.

Subsequently, in June 2022, Bayer requested that the French patent office INPI limit this claim to tosylate sorafenib for its use in the treatment of cancer by oral administration. Further proceedings were suspended until the INPI accepted this request in mid-December 2022.

Infringement case resumes

Meanwhile Bayer had launched infringement proceedings against several generics manufacturers including Biogaran, Zentiva, Sandoz, and Viatris. Recently the Judicial Court Paris handed down judgments in the disputes against Biogaran, Viatris, and Zentiva.

The Paris court ruled that claim 12 was invalid due to added matter (case IDs: RG 21/09781, RG 21/09963 and RG 21/09961). The panel, consisting of presiding judge Irène Benac and judges Anne Boutron and Malik Chapuis, found that claim 12 was not included in the application as filed. They stated that substantial amendments had been made to the patent description to allow the patent to be granted.

Proceedings between Bayer and Sandoz have meanwhile ended throughout Europe.

The dispute also played out in several other European countries. In Germany, the Federal Court of Justice largely upheld EP 255 at the end of 2023, thus overturning a first-instance decision of the Federal Patent Court. In the UK, the High Court declared the patent invalid in October 2021.