The Biogen test revisited

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 issue is to which 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 enantiomerof 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 it i.e. a product per se claim. He applied the test set out by Lord Hoffmann in the House of Lords case, Biogen v Medeva, that for “sufficiency” a disclosure should enable the full extent of the claim and not merely a single example of something within the claim.

The Court of Appeal Decision

The Court unanimously upheld Lundbeck’s appeal and found that the product claims were not invalid for insufficiency. A product claim is sufficiently enabled if the specification discloses one way of making it. In the words of Lord Hoffmann: “in an ordinary product claim, the product is the invention. It is sufficiently enabled if the specification and common general knowledge enables the skilled person to make it. One method is enough.” Lord Hoffmann confirmed that the Biogen test applied to a hybrid or “product-by-process” claim such as that considered by the House of Lords in the Biogen case itself. The test could not be extended to an ordinary product claim in which the product is not defined by a class of processes of manufacture or is not simply a member of a large class. An inventor who finds a way to make a new product is entitled to claim the product however made and however used, even if the desirability of making it was known. The Court of Appeal also upheld Kitchin J in holding that the product claims were novel and inventive.


This decision may in practice put an end to the “Biogen Insufficiency” doctrine, and brings the UK patent courts in line with most other patent jurisdictions worldwide as well as the EPO jurisprudence. As to patent validity it may open up a new trend into a more patentee friendly disposition.

Advances in industrial chemical processes have made it economical for pharmaceutical manufacturers to take drugs that were originally marketed in racemic form and market the individual enantiomers, each of which may have unique properties. For some drugs, such as zopiclone, only one enantiomer (eszopiclone) is active; the FDA has allowed such once-generic drugs to be patented and marketed under another name. In other cases, such as ibuprofen, it is not economically feasible to isolate a single enantiomer from a racemic mixture or to synthesize just the active one, and therefore a racemic mixture is marketed, with an essentially doubled recommended dose (see . See for background chemistry: “Patents and enantiomers: Generics v Lundbeck” by Brian Whitehead, Stuart Jackson, and Richard Kempner in Journal of Intellectual Property Law & Practice, 2007, Vol. 2, No. 12, p. 808-810 In Biogen v Medeva [1997] R.P.C. 1, Biogen’s patent for recombinant DNA coding for a polypeptide having hepatitis B virus (HBV) antigen specificity was held by the House of Lords in 1996 to be insufficiently enabled by its specification, not because of any inability for the described invention to deliver all the promised results, but because the same claimed results could be produced by different means which owe nothing to the teaching of the patent or any principle it disclosed.Thanks to Simmons & Simmons (London), Howrey (London)

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