Dr Reddy’s Laboratories (UK) Limited v Eli Lilly & Company Limited, 13 October 2008 [2008] EWHC 2345 (Pat)

This case examines the validity of patents for individual compounds (and their salts) falling within a previously disclosed class of compounds and reviews the old case law on “selection patents”.  

Dr Reddy’s Laboratories sought revocation of Eli Lilly’s patent for olanzapine, used to treat schizophrenia. Different pieces of prior art were cited. In one case, as commonly arises, the prior art disclosed a general chemical formula comprising a large number of possible compounds (a so-called “Markush” formula), included in which was olanzapine. One question was whether the Markush formula constituted disclosure of olanzapine so as to render the patent invalid for lack of novelty.  

The High Court reviewed the EPO case law, which has developed a doctrine that disclosure of a chemical class does not necessarily anticipate an individual compound falling within that class. Following the EPO, the Judge held that a general formula, with multiple substituents chosen from lists of some length, will not normally take away the novelty of a subsequent claim to an individual compound.

The position is complicated by the old English law on selection patents. This relates to cases where an invention is a selection from an existing class. As set out in I G Farbenindustries’ Patent, there were three requirements for a selection patent to be valid. First, the selected members, the subject of the new patent, had to have a substantial advantage over the previous larger class. Secondly, all selected members needed to have that advantage. Thirdly, the selected group needed to have the quality of a “special character” peculiar to it.  

Insofar as the selection law was ever considered to relate to the law of novelty, it is at odds with the EPO approach, which does not require the compounds to have any special advantage for there to be novelty. Moreover, the Court stated that it is doubtful in light of the EPO jurisprudence whether a newly discovered advantage complying with I G Farbenindustries’ Patent principles could overcome a finding that a compound was specifically disclosed in a prior document and therefore lacked novelty. The Court concluded that the selection law did not relate to novelty considerations and was only relevant, but not essential, to obviousness considerations. In the event the Court held the patent valid and infringed.  

Finally, the Court considered an aspect of the law of insufficiency as it relates to a selection patent which does owe its existence to a special advantage disclosed in the specification (according to the old law of selection patents). Following H Lundbeck v Generics (UK) Limited, Eli Lilly sought to argue that the sufficiency requirement would be satisfied even it turned out not to have the claimed advantage after all, as long as the compound could be made. The Judge thought that, in that case, the contribution to the art would be a misrepresentation. Lundbeck v Generics (UK) Limited could be distinguished as it would not be an “ordinary” product claim where the technical contribution was the product itself.