The House of Lords has today handed down its opinions in the patent revocation battle between Generics and Lundbeck relating to Lundbeck's patent for the (+) enantiomer of citalopram, a leading anti-depressant drug. The racemic mixture of (+) and (-) enantiomers had been known for many years, as had the desirability of separating the enantiomers, but finding a way to separate them had eluded researchers for a long time. Lundbeck had found a way of doing so, but the patent claimed not only the method it discovered but also the (+) enantiomer, simply as a product.

The question for the House of Lords was whether the claim to the product was supported by the description. Kitchen J at first instance said "no". In a passage many found compelling he said, "The first person to find a way of achieving an obviously desirable goal is not permitted to monopolise every other way of doing so". He based himself largely on the opinion of Lord Hoffmann in Biogen v Medeva. When the case went to the Court of Appeal, Lord Hoffmann himself sat in the court and gave the leading judgment. He distinguished the claim in this case to a single product from the claim in Biogen which was for "a molecule identified partly by the way in which it has been made ('recombinant DNA') and partly by what it does".

It surprised some observers that, even though Lord Hoffmann had sat in the Court of Appeal, leave to appeal to the House of Lords was forthcoming. The House of Lords has now affirmed the views of the Court of Appeal. The European Patent Convention and Patents Act 1977 has two sufficiency requirements. The disclosure must be sufficient to allow a skilled person to carry out the invention and the claims must be supported across their full width. In the case of a claim for a single product all this requires is that the patentee disclose one method of making the product. This was to be contrasted with the Biogen situation where there were molecules within the scope of the claims but no description of how to make them.

Decisions of the European Patent Office Board of Appeals, which the House of Lords rely on consistently for support, require the claims to correspond to the "technical contribution to the art". But as Lord Neuberger points out, in the case of a new, non-obvious product, the technical contribution to the art is the product itself which has become available to the public for the first time, not the method by which it is made. To the obvious surprise of some of the Lordships, it is well-settled law in both the English courts and the boards of the EPO that a particular enantiomer of a chiral compound which has never before been separated is to be regarded as a novel product no matter how well known the compound or how well recognised the desirability of separating the enantiomers.

So was Lundbeck lucky in the way the law applied to its patent? Maybe, or as Lord Neuberger put it, "The role of fortuity in patent law cannot be doubted."