The European Patent Office predominantly uses the “problem-solution-approach” to assess whether an invention involves an inventive step. But what happens if the closest prior art document is not enabled, or if the results it describes are not reproducibly obtainable, because essential information is missing? And what if the secondary prior art document arguably discloses some of the information missing in the CPAD, but in a quite different context and without essential information that could motivate the skilled person to take it further and use it in the context of the CPAD? These interesting legal questions formed the backdrop to two EP opposition proceedings and multinational patent litigation that we have had the privilege of working on for several years now. Thorsten Bausch discusses more in this excellent Kluwer Patent Blog.