The UK Court of Appeal limits the requirements 'sufficiency'

In their decision Generics v Lundbeck¹, the Court of Appeal has reversed a recent extension of the concept of 'sufficiency' by the UK Courts.

The concept of 'sufficiency' requires that every patent must provide enough information so that the technical content of its claims can be repeated by third parties.  If a patent is not sufficient, it is not valid.

  The minimum requirement for sufficiency is that a patent must describe at least one way to carry out its claimed invention.  However, for a patent claiming a class of embodiments, sufficiency requires the patent to allow the invention to be performed across the whole range of the claimed class of embodiments².  As a result, a patent that has broad claims but has only a narrow description of how to carry out the subject-matter of its claims is at risk of being found insufficient.

  The leading case in the UK Courts to consider sufficiency is the House of Lords 1997 decision in Biogen v Medeva³.  In this case, the patent being litigated defined its product in terms of its method of manufacture (a so-called product-by-process patent).  Considering the patent's novelty and inventive step, the House of Lords found that it would have been obvious to try to make the product of the patent but that there was no obvious way of actually making it.  Therefore, the patent was considered to be novel and inventive.  However, on considering sufficiency, the House of Lords found that the patent had to provide enough information to allow the method of manufacture used to define the patent's product to be repeated across the whole breadth of the method.  From this conclusion, the House of Lords found that an otherwise acceptable patent claiming a product defined by being made by recombinant DNA technology but only illustrating one specific method of recombinant DNA technology was insufficient.

This decision by the House of Lords had been interpreted by some as a green light to extend the concept of sufficiency to invalidate any patent that was perceived to claim more than its technical contribution to its field.  The High Court decision in Generics v Lundbeck† was an example of this trend.  In this case, the High Court considered a patent claiming a pharmaceutical product.  The Court found that, while it would have been obvious to try to make the product, there was no obvious way of actually making the product.  In this respect, the patent was conceptually the same as that considered in Biogen v Medeva.  However, unlike in Biogen v Medeva, the method of manufacture of the product was not included in the patent's claims because the product could be defined by its precise chemical structure.

The High Court then found that the technical contribution of the patent to its field was simply a method of manufacturing its product and not the actual manufacture of a new compound.  The Court concluded that, by claiming its product, the patent was in effect claiming a class of possible methods of manufacturing the product.  However, the patent only provided details of one possible manufacturing method.  Applying Biogen v Medeva, the Court found the patent to be insufficient.

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