In an appeal taken by Lundbeck against an earlier decision in which certain claims of Lundbeck's patent, directed to an enantiomer of the antidepressant drug Citalopram, were held invalid, the Court of Appeals reversed, finding that Lundbeck's patent was valid. H. Lundbeck A/S v. Generics (UK) Limited & Ors, et. al., Case Nos. A3/2007/1326, A3/2007/1387 (Eng. Ct. of Appeal, April 10, 2008) (Lord Hoffman, Lady Justice Smith and Lord Justice Jacob).
Citalopram was patented by Lundbeck, but since the original patent expired several years ago, the respondents have been selling the generic form. Upon separating the enantiomers from the racemic mixture of Citalopram, Lundbeck filed an application for a new patent and obtained patent-in-suit EP (UK) 0,347,066 for the (+) enantiomer and have been marketing the resultant drug. The respondents sought revocation of the patent, basing their claims on lack of novelty, obviousness and sufficiency of disclosure for enablement.
As to the issue of sufficiency of disclosure for enablement, the judge in the court of first instance had held that claims 1 and 3 were insufficient on the basis that Lundbeck had discovered one way of resolving the enantiomers and as such should not be entitled to a monopoly for every way of achieving this. In contrast, the Appeals Court held that if the invention is sufficiently enabled, then one method of achieving the invention is enough and that the first instance judge had erred basing his contrary decision solely on Biogen v. Medeva. Biogen dealt with a claim that was defined in terms of a "class" of processes of manufacture, but only one process was described and no general principle was disclosed. The Appeals Court reasoned that such a decision cannot be extended to an ordinary product claim.
With reference to the lack of novelty issue, the claimants argued that the claim in issue not only covered the isolated enantiomer but also the enantiomer as an unresolved moiety of the racemate, and hence was anticipated by Lundbeck's patent for the racemate (Citalopram). This raised a question of claim construction since the claim does not expressly disclaim the unresolved enantiomer or state that the (+) enantiomer was "isolated." However, the Appeals Court concluded that the context would have made it obvious to the person skilled in the art that the patentee was not intending to claim the unresolved moiety of the racemate and that the claim would not be construed as such. Hence, novelty was intact.
Regarding inventive step, both parties were in agreement that one skilled in the art would initially attempt resolving the enantiomers from the final product. However, the claimed method was not directed to resolving the enantiomers from the final product but rather was directed to an indirect route of resolving the enantiomers from an intermediate product. The respondent's expert had suggested that the route pursued by the patentees was an obvious one to try with a high expectation of success. However, since this was rejected by the first-instance judge. The Appeals Court saw no reason to re-assess the evidence and so concluded that the claimed method was not obvious.
Practice Note: As illustrated by this case, English courts differentiate between a non-allowable claim in which the breadth of the claim is not enabled by the description and an allowable claim in which the breadth of the claim is enabled, even though different or alternative techniques may be used. Where novelty is an issue, the English courts tend to take a pragmatic approach to claim construction.
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