The German Federal Patent Court found the German part of the Eli Lilly patent, EP 1 313 508 B in the first instance to be void. An appeal against this decision has now been filed at the German Federal Court of Justice.

Few patents have led to such a large number of landmark decisions as have resulted from the Eli Lilly patent for pemetrexed. This run is continuing due to the aforementioned appeal which is being lodged at Germany's highest civil court.

After surviving opposition proceedings at the EPO, the validity of the patent in Germany has been challenged, and the first instance decision went in favour of the generic companies. The EPO found that the skilled person would have no motivation to use pemetrexed in combination with vitamin B12 to reduce the toxic effects of pemetrexed. The judges at the German Federal Patent Court saw things differently and concluded that there are ample pointers in the prior art to arrive at the claimed combination. In particular, the skilled person would have known that homocysteine elevation is a sign of folic acid deficiency that can inter alia be caused by a vitamin B12 deficiency. As such, the claims were found to be obvious to the skilled person.

The judges emphasised that the conclusion reached is not in direct contradiction to the EPO decision due to the extensive prior art filed by the parties during the proceedings in Germany. Based on these documents, the first instance decision was reached without the use of expert witnesses.

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