Selected From A Class To Treat Schizophrenia; A Judge Was Not In Two Minds About It*

Contributed By Kilburn & Strode LLP (

Dr Reddy’s Laboratories sought revocation of European patent (UK) No. 0454436 of Eli Lilly. The patent protected olanzapine, which is a widely prescribed anti-psychotic agent used for the treatment of schizophrenia under the trade mark ZYPREXA®. In the 1970s Lilly was granted a UK patent claiming a wide class of thieno-benzodiazepines having useful central nervous system activity. The class was defined by reference to a general formula and it was calculated that this was wide enough to encompass 1019 compounds. The disclosure contained 100 compounds by name but without giving details of physical properties.

It was agreed that the general formula was wide enough to cover olanzapine, but olanzapine itself was not one of the 100 compounds disclosed. In his wide-ranging review of the law of novelty, Floyd J concluded that:

“a generic disclosure will not normally take away the novelty of a subsequent claim to a member of the class. For example, disclosure of ‘fixing means’ is not a disclosure of a nail.”

“The particular question which arises in this case concerns the effect of a particular kind of disclosure, namely that made by a chemical class formula or ‘Markush’ formula. Such formulae are capable of encompassing many millions of compounds. In theory a person (or more likely a computer) could sit down and create a list of all possible individual compounds covered by the formula…”

“This question is addressed on a regular basis by the EPO in deciding applications for chemical patents under the EPC. They have developed a doctrine that a chemical class disclosure does not necessarily take away the novelty of an individual compound falling within the class.”

Floyd J then went on to consider “selection inventions” (i.e. where a class is disclosed in general terms and the invention selects certain species from that class which have advantages not possessed by the genus) and the famous judgment** from the 1930s which, according to previous judgments of the Court of Appeal, survived the advent of the European Patent

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Convention in UK patent law. This requires “that it is necessary for the patentee to define in clear terms the nature of the characteristic which he alleges to be possessed by the selection for which he claims a monopoly…

“I conclude that

i) In relation to lack of novelty, it is doubtful in the light of the EPO jurisprudence whether a newly discovered effect complying with…[the principles of selection patents]…could overcome a finding that a compound was specifically disclosed in a prior document.

ii) Whether or not that is so, provided there is novelty on conventional grounds, obviousness is to be decided according to ordinary principles.

iii) The existence of an advantage possessed by the selected compound will be relevant to the overall assessment of obviousness, but is not an essential prerequisite.

iv) Compliance with…[the principles of selection patents] is equally not an essential requirement for inventive step to be found.”

The judge also had to deal with insufficiency attacks and commented:

“All these insufficiency attacks are based on the premise that the patent can only be upheld over the disclosure of the [earlier Lilly patent] if it is a valid selection patent…I have felt able to hold that olanzapine is both novel and not obvious as a chemical compound without reliance on selection principles. In those circumstances the insufficiency attack does not arise.”

*Dr Reddy’s Laboratories v Eli Lilly [2009] F.S.R. 5 at [271]; Floyd J
** I.G. Farbenindustrie’s Patent (1930) 47 RPC 289

Copyright (Eli Lilly)

Contributed by Kilburn & Strode (