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Napp Pharmaceutical Holdings Limited v (1) Dr Reddy’s Laboratories (UK) Limited (2) Sandoz Limited. UK Patents Court (Arnold J). Case neutral citation number: [2016] EWHC 1517 (Pat)

In a decision that considers both numerical ranges and de minimis patent infringement, the UK Patents Court has held that products (7 day buprenorphine transdermal patches) proposed to be marketed in the UK by Dr Reddy’s and Sandoz would not infringe Napp’s European Patent (UK) Nos. 2 305 194 and 1 731 152. The proceedings were expedited and it is notable that it has taken only just over 4 months from the commencement of proceedings to judgment being handed down.

Only EP194 was considered in any detail, as it was agreed that the second patent did not raise any additional infringement issues. Claim 1, the only claim considered, required the transdermal delivery device to comprise “10 %-wt buprenorphine base, 10 to 15 %-wt levulinic acid, about 10 %-wt oleyloleate, 55 to 70 %-wt polyacrylate, and 0 to 10 %-wt polyvinylpyrolidone.” The first question for the court to resolve was whether these percentages referred to the recipe for the matrix (the “inputs”) or to the composition of the finished product (the “outputs”). Napp argued that it was the figures for the inputs that should be used; the defendants that it was the outputs. The court held that the defendants’ interpretation was the correct one.

The second question for the court was to determine the upper and lower limits of the percentages used in the claim. Napp argued that the buprenorphine and levulinic acid ranges were expressed to the nearest 5%, and so should be interpreted as ≥7.5 to <12.5 %-wt buprenorphine and ≥7.5 to <17.5 %-wt levulinic acid, and that “about 10 %-wt oleyloleate” extended to 15 %-wt. The defendants’ position was that the figures in the claim would be understood to have been expressed to the nearest whole number and so applying the conventional rounding approach would lead to ranges of ≥9.5 to <10.5 %-wt buprenorphine, ≥9.5 to <15.5 %-wt levulinic acid, and ≥9.5 to <10.5 %-wt oleyloleate. The critical question the court had to ask itself in order to determine this issue was what the skilled person (who reads the claim with the benefit of his common general knowledge) would understand the author of the patent to have been using the words or numerals appearing in the claim to mean. The judge concluded that the buprenorphine and levulinic acid percentages should be construed as the defendants had contended, that is, by using the conventional nearest whole number rounding approach. To use Napp’s approach would be to deny reasonable certainty for third parties. The judge felt that “about 10 %-wt oleyloleate” would be understood to be referring to a slightly broader range but that it should not extend beyond ≥9.0 to <11.0 %-wt.

On the basis of the court’s interpretation of these percentages in the claim, the court held that neither of the defendants’ products would infringe the patents.

However, the judge went on to consider the position that would apply if Napp’s approach to the percentages were used (in case his decision on this issue was overturned on appeal). Napp contended that due to manufacturing variability some of the defendants’ products would fall within the claim, even if most of them did not most of the time, and that this was sufficient for a finding of infringement. The defendants argued that only a very small amount of their products that would be imported into the UK would fall within the scope of the claim and that the application of the de minimis principle – that the law should not concern itself with trivial matters – meant that this was not a sufficient risk to amount to infringement.

This led to a complex statistical analysis and argument as to what level of statistical probability and certainty should be applied to determine whether any infringements that might occur in the future were indeed de minimis. There was no clear legal authority on the application of the de minimis principle to patent disputes. The judge in this case concluded that the de minimis principle did apply to patent infringement and that although no quantitative limit of general applicability to patent infringement could be stated, on the facts of this case, he held that, for the purpose of testing regime proposed to be applied by Dr Reddy’s to batches of product manufactured abroad (to see if they could be imported into the UK), if it were assessed with a 50% level of confidence that no more than 1 in 10,000 patches in a batch infringed the patent, then the de minimis principle would apply. So far as Sandoz’s product was concerned, the likelihood of a patch infringing the patent was so low that the de minimis principle clearly applied.

The end result was that neither Sandoz’s nor Dr Reddy’s product fell within the claim and there was accordingly no threat by either defendant to infringe the patents.

As a post script, it should be noted that, although the court found that the patents were not infringed, the court nevertheless granted an interim injunction against the defendants pending the outcome of any appeal. Although Napp’s prospects of success on appeal were relatively weak, the overriding task of the first instance court was to arrange matters so that the Court of Appeal was best able to provide justice as between the parties following the appeal. That favoured an injunction but only until 16 August 2016. Any extension of that injunction would be for the Court of Appeal to decide.

A copy of the judgment can be read here.

Headnote: Graham Burnett-Hall, Marks & Clerk Solicitors