NAPP and DRL fight over transdermal patches patent.

The claimant and appellant, Napp Pharmaceutical Holdings Ltd ("Napp"), is the proprietor of European patent (UK) No 2 305 194 ("the patent") in respect of an invention of a transdermal patch for use in the treatment of pain. Napp contends that the first defendant and respondent Dr Reddy's Laboratories (UK) Ltd ("DRL") and the second defendant and respondent Sandoz Ltd ("Sandoz") both threaten to infringe the patent by marketing their own transdermal patches. In his judgment dated 28 June 2016 ([2016] EWHC 1517 (Pat)), Arnold J concluded that there would be no infringement by either respondent if this marketing occurred and dismissed the various claims. 

It is common ground that it is only necessary to consider claim 1 of the patent, which is as follows:

"A buprenorphine transdermal delivery device comprising a polymer matrix layer containing buprenorphine or a pharmaceutically acceptable salt thereof, for use in treating pain in humans for a dosing interval of at least 7 days, wherein the transdermal delivery device comprises 10%-wt buprenorphine base, 10 to 15%-wt levulinic acid, about 10 %-wt oleyloleate, 55 to 70%-wt polyacrylate, and 0 to 10%-wt polyvinylpyrrolidone."

The dispute about the interpretation of the patent specification.

Infringement - The de minimis principle in quia timet actions

The de minimis principle has been considered in previous patent authorities (Hoechst v BP [1998], Monsanto v Cargill [2007], Napp v Ratiopharm [2009], Lundbeck v Norpharma [2011]). In the present case Arnold J commented that the court was forced, as a matter of practical reality, to draw a line somewhere and referred to a hypothetical scenario in which only 0.01% of products fall within a claim as “precisely the kind of situation covered by the de minimis principle”. 

Further Reading: Court case, IP Kat.