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Court of Appeal provides clarification “about” numerical values

3 January 2017

The use of numerical ranges and values to accurately describe the amount of ingredients present in a composition or formulation is a widely used approach in patent specifications, especially in the field of pharmaceuticals and formulation chemistry.  Patentees need to clearly define the limits of various active ingredients, excipients and the like in order to effectively protect the working embodiments of their inventions.

The true scope of numerical ranges and values provided in a claim is open to interpretation in the same way as any other features of a claim.  However, over the years, various decisions have been issued by both the EPO and the UK Courts which provide some clarity for third parties as to how far numerical values can be stretched.

In a recent decision ([2016] EWCA Civ 1053), the Court of Appeal upheld the findings of the High Court as to how numerical values ought to be interpreted.

The patent in question was directed towards a transdermal patch for providing pain relief that contained buprenorphine.  Whether or not the defendants’ (Dr Reddy’s Laboratories AND Sandoz Limited) activities infringed the patent depended, inter alia,  on whether or not the term “about 10{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c}” could be construed as encompassing concentrations of up to 15{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c}.

In the initial decision, the term “about 10{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c}” was considered to cover values in the range 9{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c} to 11{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c} and hence, the patent was not infringed.  The patentee (Napp Pharmaceutical Holdings Limited) appealed and made various arguments as to why a broader interpretation was reasonable.  However, Lord Justice Floyd was unconvinced:

A patent specification is not intended to be a puzzle game in which the skilled person must come up with his own theory as to what degree of precision was intended by the patentee.  If the patentee had wished to claim, for example, 7.5-12.5{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c}-wt buprenorphine, he was free to do so by making it express in the claim, or stating in the specification that the figures are expressed to the nearest 5{e27634494e39db391c4a3c1babcce9c96667e0da0c02f00a98e80c871bbff07c}…  The figures he chose may have been the very outer limits of what he considered would work.  I therefore entirely agree with the [High Court] judge that the figures … are expressed to the nearest whole number.”

This case serves as a useful reminder that numerical values should be clearly defined in the claims and that clear guidance on how such ranges are to be interpreted should be present in the description.  This is especially true when qualifying ranges or numerical values with terms such as “about“.


Bruce Dean
Life Sciences & Chemistry

If you require further information on anything covered in this briefing, please contact Bruce Dean or your usual contact at the firm.

This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.

© Withers & Rogers LLP, January 2017