VIIV Healthcare Company & Ors v Gilead Sciences, Inc. & Ors

Patent infringement remains an objective inquiry. The doctrine of equivalents does not introduce the defendant’s intention or state of mind as an element of infringement. However, evidence that an allegedly infringing product was designed to achieve the same result as the patented product may be relevant evidence when assessing whether it operates in substantially the same way. Such evidence must have a proper evidential basis. A pleaded case relying on the defendant’s design aims should therefore not be struck out merely because intention is not itself part of the legal test.

The claimants brought a patent action concerning anti-HIV compounds. They alleged that bictegravir infringed a patent protecting dolutegravir under the doctrine of equivalents recognised in [2017] UKSC 48. The defendants applied to strike out part of the pleaded infringement case, which relied on a publication indicating that bictegravir had been developed by reference to dolutegravir and with the aim of maintaining its characteristics.

The issue was whether evidence concerning the alleged infringer’s design aims could be relevant to the objective question whether the allegedly infringing compound operated in substantially the same way as the claimed invention.

1. The strike-out application was dismissed. The claimants were entitled to plead paragraph 3(iv) of their Particulars of Infringement.
2. The relevant infringement inquiry, including the first Actavis question concerning whether the alleged infringement operates in substantially the same way as the claimed invention, is objective. The defendant’s intention, or the state of mind of its employees, is not an element which must be proved.
3. That did not make evidence of design purpose irrelevant. Evidence that the allegedly infringing product was developed from knowledge of the patented product, or with the aim of maintaining its characteristics, could assist an expert or the court in assessing the objective way in which the product operates. It could properly be used in cross-examination to test an expert opinion that the products operated differently.
4. The court distinguished between intention as part of the legal test and intention as evidence bearing on an objective issue. The analogy with Slazenger & Sons v Feltham & Co (1889) 6 RPC 531 could not be taken too far, but supported the basic evidential point. A plea of this kind required some evidential foundation. The claimants had such a foundation in the Lazerwith paper.
5. Questions concerning disclosure and proportionality were left for another day. The court indicated that substantial disclosure might not be necessary, particularly if the defendants admitted that the inferences drawn from the paper fairly described the development of bictegravir.
6. The claimants were awarded the costs of the application. The costs were summarily assessed at £67,000.