Napp Pharmaceutical Holdings Limited v Dr Reddy's Laboratories (UK) Ltd & Anor

In construing a pharmaceutical product claim, stated proportions ordinarily describe the composition of the finished product, not the quantities introduced during manufacture. The claim’s language and technical context govern; isolated examples do not establish a general linguistic convention. Numerical features are not enlarged merely because they are expressed in multiples of 5. A wider degree of precision may be recognised only where the specification and common general knowledge justify it. The word about may extend a numerical term beyond ordinary rounding, but its scope must remain intelligible. Here, about 10%-wt oleyloleate extended from 9 to 11 per cent, not to 15 per cent.

Napp, proprietor of a European patent for a buprenorphine transdermal patch, alleged that Dr Reddy’s Laboratories and Sandoz threatened to infringe the patent by marketing competing patches. Arnold J held that there would be no infringement and dismissed the claims: [2016] EWHC 1517 (Pat).

Napp appealed, challenging the construction of the patent’s example and claim 1. The central issues were whether the claimed percentages referred to input ingredients or the finished device, and how expressions such as 10%-wt and about 10%-wt should be understood.

The Court of Appeal dismissed the appeal. Floyd LJ gave the reasons, with Gloster and Patten LJJ agreeing.

1. Patent example. The natural reading of paragraph [0100] was that Hille’s Example 1a supplied the manufacturing method, while Hille’s Example 3 supplied the intended formulation. The patent did not state that the formulations of Hille’s Examples 1a and 3 were substantially the same.
2. Input or output composition. Claim 1 was a product claim defining a transdermal delivery device by its constituents. Its percentages therefore referred to the composition of the finished device, not the quantities used at an earlier mixing stage. This was reinforced by the functional importance of the excipients in forming the skin depot. The court distinguished Cephalon Inc v Orchid Europe Ltd [2011] EWHC 1591, because the evidence there concerning particle-size measurement was materially different.
3. Evidence that starting ingredients are sometimes used to identify products in scientific work did not establish a general linguistic convention. Construction remained context-dependent. The skilled person could carry out routine laboratory work to determine the finished composition; the inability to predict it precisely from the starting mix did not alter the claim’s meaning.
4. Numerical features. Applying the approach in Smith & Nephew plc v ConvaTec Technologies Inc [2015] EWCA Civ 607, [2015] RPC 32, the figures for buprenorphine and levulinic acid were expressed to the nearest whole percentage. The fact that the patent used multiples of 5 did not imply nearest-5 precision.
5. About 10 per cent. The word about allowed some additional imprecision beyond ordinary rounding, but the boundaries had to remain intelligible. The references to Hille did not establish that 15 per cent was included. The court applied the caution against meticulous linguistic analysis expressed in Catnic v Hill Smith [1981] F.S.R. 60, [1982] R.P.C. 183. The proper range was 9 to 11 per cent.
6. These constructions were sufficient to dispose of threatened infringement. The evidential grounds did not justify interference, and DRL’s respondent’s notice did not require consideration.

1. Court of Appeal (Civil Division) — appeal dismissed; reasons given in [2016] EWCA Civ 1053.
2. High Court of Justice, Chancery Division, Patents Court — Arnold J held that marketing the respondents’ patches would not infringe and dismissed the claims in [2016] EWHC 1517 (Pat).