The Biogen test revisited
IPEG: 
When is a product claim in a patent insufficient? That is the core question in the judgement of April 10 by the UK Court of Appeal in Generics (UK) Limited v Lundbeck A/S in an appeal against the High Court Mr Justice Kitchin’s judgement in 2007.
The key issue is the extent of the monopoly given by a product claim in a patent. Kitchin J had extended the application of the Biogen test for patent insufficiency such that the scope of the monopoly for a product claim could be severely reduced. Lundbeck’s successful appeal, therefore, has significant commercial implications for the pharmaceutical industry as a whole.
The Facts
Three generic pharmaceutical manufacturers sought to revoke’s Lundbeck patent EP (UK) 0,347,066 for an anti depressant drug escitalopram (a single enantiomer of citalopram), claiming pharmaceutical compositions containing escitalopram, and a method of preparing escitalopram. Lundbeck’s patent expired several years ago. Citalopram was marketed as a racemic mixture and Lundbeck found a way to isolate the (+) enantiomer, discovered that this was the effective enantiomer and applied for the patent. The claims in issue were for the (+) enantiomer itself and for a pharmaceutical composition containing it.
The First Instance
The Patents Court concluded that, as was generally believed, a single enantiomer[1]of a known chemical compound was not patentable. Interesting to the pharmaceutical industry, increasingly reliant upon life cycle management, is why precisely this should be the case. The High Court found these claims were invalid for insufficiency. Kitchin J reasoned that since the existence of the (+) enantiomer was known as part of the citalopram mixture and isolation of the separate enantiomers was known to be desirable, Lundbeck’s invention lay solely in the discovery of a way to make it. He concluded that this should not entitle Lundbeck to a monopoly of every way of making…