DE - leflunomide and teriflunomide

Leflunomide and teriflunomide, Bundesgerichtshof, Germany, 24 July 2012, Case no. BGH X ZR 126/09

In its decision BGH X ZR 126/09 as of 24 July, 2012, the Bundesgerichtshof nullified a patent that claimed a composition of leflunomide and teriflunomide. Leflunomide is, i.a. used against rheumatoid arthritis, whereas teriflunomide is the active metabolite of leflunomide, that means that within a usual storage period, leflunomide is metabolized to teriflunomide. It One skilled in the art would have come to a formulation comprising leflunomide as only therapeutic agent before the priority date without being inventive. However, the person skilled in the art had no incentive to come to a combination of leflunomide and teriflunomide in the amounts as claimed in the patent.

The Bundesgerichtshof ruled that despite the fact that the claimed combination was novel and inventive, the patent had to be nullified, because the combination of the two components occurred necessarily within usual storage periods from the single agent medicine comprising only leflunomide as active ingredient. Therefore, the only question to decide was if it would have been novel and inventive to the person skilled in the art to come to a single agent leflunomide preparation. The Bundesgerichtshof denied this question and nullified the patent, because the result of the work of the person skilled in the art necessarily revealed the claimed combination of leflunomide and teriflunomide.