T 1994/22 – Polymorphs And Plausibility

When prosecuting inventions pertaining to chemical subject-matter before the European Patent Office (EPO), it is often helpful to demonstrate that the claimed compounds are improved relative to those in the prior art. The most convincing and successful way of doing so is to provide experimental data directly comparing the claimed compounds to those already known. However, using the EPO's preferred problem-solution approach, it is not uncommon for the closest prior art to have been unknown to the applicant at the time of filing. As such, the application as filed may not contain the necessary comparative data needed to demonstrate an improved and unexpected technical effect over the closest prior art.