For many years, patent offices in Europe and the courts have sought to grant and uphold patent protection for inventions which are made through the discovery of the new use of a known drug. Such second medical uses can be valuable and sometimes life-saving. Research into new uses of known compounds can be as expensive as discovery of new molecules. Discovery of new molecules is becoming more and more rare, whereas the range of known drugs and their potential for undiscovered effects has expanded.
There is no question of awarding the inventor of a new use absolute protection for the substance itself. Nor can a patent be granted for a method of treatment using the compound in question.
To circumvent these problems the Enlarged Board of Appeal of the European Patent Office has for many years granted claims for “the use of substance X for the preparation of a medicament (or pharmaceutical composition) for treating indication Y”. These are so-called “Swiss claims” because of their first use in the Swiss patent office. (See Eisai (Second medical indication)  OJ EPO 64.)
A problem with the Swiss form of claim is that it is a process claim targeted at the manufacturer. It is difficult to make a case for contributory infringement, because this would require a downstream infringer, and there is generally no-one downstream of the manufacturer who is using the substance for preparation of a medicament.
When the EPC was amended (renamed the “EPC 2000”), a different form of claim became permitted – simply “compound (or composition or substance) for use in a method of treatment of disease Y.” The EPO has stopped granting claims in the Swiss form after the EPO Enlarged Board of Appeal decision G 2/08, but claims already granted in that form continue to have effect.