Bayer’s uphill fight re sorafenib tosylate

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Case No. S2021_006 | Hearing of 4 April 2022

Zentiva logo

Bayer HealthCare is seeking preliminary injunctive relief against Sorafenib Zentiva of Helvepharm, the Swiss branch of Zentiva. Bayer’s product is Nexavar® (see Compendium and Bayer’s Nexavar website for more information); the active ingredient (AI) is sorafenib, a kinase inhibitor inter alia for the treatment of primary kidney and liver cancer.

Bayer logo

The basic patent on sorafenib is EP 1 140 840 B1 which lapsed on 11 January 2020. An SPC had been in force until 28 March 2021; C01140840/01. The present litigation is about alleged infringement (and validity) of EP 2 305 255 B1 (see EPO Register), specifically claiming the tosylate salt of sorafenib. EP 255 will only lapse on 3 December 2022.

As patent protection is fading out, Bayer’s turnover generated with Nexavar® fell sharply in 2021:

Nexavar® package

Patent practitioners might recall Nexavar® and/or sorafenib tosylate for the first compulsory license that had been issued in India already back in 2012, which has been confirmed through all instances.

Lately, EP 255 was held to be invalid both in Germany (Federal Patent Court, judgment of 29 September 2021 in cases 3 Ni 12/20 and 3 Ni 13/21) and the U.K. (judgment of 8 October 2021 in case [2021] EWHC 2690 (Pat); the Court of Appeal decided on 1 April 2022 to hear the appeal).

Helvepharm logo

From the announcement of the hearing, it had been known that Helvepharm asserts invalidity of EP 255 in view of unallowable amendments, lack of novelty over WO 00/42012 A1 and obviousness in view of Lyons et al. (the acronym BAY 43-9006 refers to sorafenib as such, i.e. the free base; not sorafenib tosylate).

In the hearing, it became clear that the judge-rapporteur‘s expert opinion held that the claimed subject-matter was obvious, in line with the judgments in Germany and the U.K.

Plaintiff urged the court to independently assess the matter, in particular in view of the many expert declarations on file in the present proceedings which the foreign courts had not at hand. Plaintiff emphasized that the skilled person had not been in a position at the priority date to reliably determine the dissolution rate of sorafenib tosylate; the experimental setup previously known in the art had not been suitable. Further, a tosylate had not been a promising candidate for a weak base such sorafenib in any event.

However, the inventors had a moment of genius:

Die Erfinder hatten einen genialen Moment.

With its concluding remarks of the first pleadings, Bayer essentially held that if ever a salt form of a pharmaceutical compound was patentable, then sorafenib tosylate is it.

Expenses for the assistance of a patent attorney were orally indicated (and detailled to some extent) as kCHF 52, but no evidence was handed over.

After a break, the President gave the floor to Zentiva‘s counsel, indicating that the judges had a lively discussion during the break, and that they are now eagerly awaiting Zentiva‘s pleadings:

Die Diskussionen im Spruchkörper in der Pause waren heftig! Wir sind gespannt auf Ihre Ausführungen.

Defendant focused its pleadings on non-obviousness only.

In defendant‘s view, Lyons does not teach that the free base has been used in the clinical trials. Lyons is just silent about this (in my understanding, contrary to what had been held in the judge-rapporteur‘s expert opinion). In any event, the first step would be a salt screening in order to assess the bioavailability of sorafenib — and tosylate would have been included in such a salt screening, essentially as outlined in Bastin. A salt screening involves not only the assessment of solubility, but also the dissolution rate. The skilled person would not have disregarded the tosylate in view of its low solubility. Further, defendant argued that it had well been possible for the skilled person to determine the dissolution rate, actually with reference to an experimental setup that had been known in the art and which is similar to the one used by plaintiff.

Defendant handed over a cost note for assistance of the patent attorney. Further, defendant objected to plaintiff‘s asserted costs of kCHF 52 as somewhat high for summary proceedings („etwas hoch“), and not evidenced anyway.

An entertaining aspect of the second round of pleadings circled around the (lack of) plaintiff‘s cost note for patent attorney expenses. Plaintiff was seemingly taken by surprise that the expenses were not accepted by defendant, and asked for a break to come up with written evidence of the expenses in the amount as indicated earlier. The judges were noticeably perplexed (instructions for the hearing typically remind the parties that cost notes shall be provided in the first round of pleadings). Still, the President interrupted the proceedings for ten minutes, for the plaintiff to gather the written evidence of expenses, and defendant to prepare the rebuttal to plaintiff‘s pleadings. Worse comes to worst: Plaintiff apparently had a letter in its electronic dockets that set forth the costs incurred, but could not provide any printout. Defendant did not consent to an on-the-spot visual inspection of the electronic file.

The parties did not engage in settlement discussions.



Case No. S2021_006 | Hearing of 4 April 2022

Bayer HealthCare LLC
Helvepharm AG

Panel of Judges:

    • Dr. Mark SCHWEIZER
    • Dr. Tobias BREMI
    • Dr. Andreas SCHÖLLHORN


    • Dr. Tobias BREMI

Court Clerk:

    • Dr. Lukas ABEGG

Representative(s) of Plaintiff:

    • Dr. Simon HOLZER (MLL)
    • Dr. Ulrike CIESLA (MLL), assisting in patent matters

Representative(s) of Defendant:




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