Smith & Nephew plc v Convatec Technologies Inc, 14 December 2012, Case No. A3/2012/1456, Neutral Citation Number:  EWCA Civ 1638
HHJ Birss QC held Convatec’s patent claiming a way of making moist wound dressings containing ionic silver in a light stable form to be sufficient and inventive. Smith & Nephew appealed the finding of inventive step over Kriedl, a US patent published in 1946, which disclosed a method for making silver halide preparations with an excess of halide to bring about light stability. The appeal was dismissed.
The key issue which had been before Judge Birss was whether it was obvious to apply the teaching of Kreidl to new materials such as Aquacel, a gel forming fibre, which formed part of the common general knowledge by the priority date. The Judge had held that the skilled person would consider whether to test Aquacel in Kreidl’s conditions but would have no certainty that the test would work due to the existence of alternative explanations for Kreidl’s results (namely adsorption, which was the theory set out in Kriedl or physical shielding, a theory suggested by Convatec’s expert).
It would not be obvious to the skilled person which theory was right; nor would it be obvious to press on and simply try Kreidl’s method on Aquacel. To run the test and see if the Kreidl conditions worked for Aquacel when the skilled person knew that the simpler explanation for Kreidl’s results (physical shielding) was one which would lead to certain failure and the other explanation (adsorption) by no means guaranteed success, was not the act of an unimaginative and uninventive person. Thus, the claim was valid over Kreidl.
On appeal, Smith & Nephew suggested that the Judge had fallen into error by requiring the skilled team to have a guarantee or certainty of success or, at the very least, too high an expectation of success before they would carry out a simple and straightforward test to see if the teaching of Kreidl would work on Aquacel. The Court of Appeal rejected this submission. The Judge had not asked “would it have been obvious to the skilled person which theory was right?” but rather “was it obvious to carry out Kreidl’s method on Aquacel?”. In the circumstances, where the skilled team would not carry out any test without first thinking about its technical basis, the Judge had asked the right question.
The Court of Appeal further rejected Smith & Nephew’s submission that the Judge had fallen into error in treating the physical shielding theory put forward by Convatec’s expert as having equal or possibly greater force than the adsorption theory set out in Kriedl itself. The Court found that Kreidl was an old publication, yet the theory of adsorption propounded therein had gained no foothold in the common general knowledge over the intervening years. After hearing the evidence, Judge Birss had concluded that the skilled person would consider that the alternative theory of physical shielding may well in fact be the simpler explanation for the results in Kriedl. He was entitled to form this view on the evidence before him.
You can read the judgment (in English) here.
Head note: Gina Lodge and Graham Burnett-Hall