This is an informal case summary prepared for the purposes of facilitating exchange during the 2025 WIPO IP Judges Forum.
Session 2: Pharmaceutical Patents
Federal Court of Justice, Germany [2024]: Case No. BGH X ZR 77/23 – Testosterone Ester
Date of judgment: October 8, 2024
Issuing authority: Federal Court of Justice (Bundesgerichtshof)
Level of the issuing authority: Final Instance
Type of procedure: Judicial (Commercial)
Subject matter: Patents (Inventions)
Plaintiff: R.
Defendant: B.
Keywords: Inventive step, Expectation to succeed, Costs and efforts for research
Basic facts: Citing lack of patentability, the plaintiff challenged the validity of a patent for a composition for intramuscular injection comprising testosterone esters and castor oil in a concentration of 25 to 45% and another co-solvent such as benzyl benzoate. It was known from the prior art to apply the testosterone ester testosterone undecanoate in castor oil for injections in men for the treatment of hypogonadism at intervals of up to twelve weeks.
Based on their general expertise, the skilled person had reason to use another solvent such as benzyl benzoate in addition to castor oil. The skilled person also had reason to examine the effects of adding benzyl benzoate using a dilution series.
The Federal Patent Court ruled that the invention did not involve an inventive step. Even though the percentage of castor oil in approved formulations was 60%, the skilled person would have determined, based on the dilution series, that the viscosity could be significantly reduced with a predominant proportion of benzyl benzoate. This motivated them to conduct corresponding trials on patients. There was a reasonable expectation of success because formulations of other drugs with a proportion of 40% castor oil and 60% benzyl benzoate had already been on the market before the priority date. Due to the pain caused by excessive viscosity, they would have tried to keep this as low as possible.
Held: The Federal Court of Justice, having the power to review findings of fact as well as law, reversed the decision of the Federal Patent Court and dismissed the action for invalidation of the patent in suit, finding it had not been obvious to conduct clinical trials with, among others, a proportion of 40% castor oil and 60% benzyl benzoate.
Relevant holdings in relation to pharmaceutical patents: The criteria for reasonable expectation of success, which give cause to pursue a possible solution despite the uncertainty of the outcome, cannot be defined in general terms. Rather, they depend on the circumstances of each individual case. The decisive factors are, in particular, the field in question, the size of the incentive, the effort required, and any alternatives that may be considered.
The preparations already admitted with testosterone ester and castor oil generally suggested that the parameters chosen there, i.e., a proportion of only 40% benzyl benzoate, should be used. The advantages resulting from the dilution series for lower viscosity with a benzyl benzoate content of 60% may have been an argument in favor of such a mixture. However, this was not sufficient to ensure a reasonable expectation of success, as it could not be reliably assessed without clinical trials.
There was no sufficient incentive for clinical studies, as these would have required long-term trials. The time and financial resources required for this were not in reasonable proportion to the expected success.
The formulation protected by the patent claim was also not obvious because there was reason to examine the solubility and viscosity of the 40/60 mixing ratio as part of a dilution series. It cannot be established that a mixture produced within the scope of such a dilution series with a respective mixing ratio already possesses all the necessary qualities required for a formulation for intramuscular injection.
Relevant legislation: Section 56 of the European Patent Convention (EPC)