Hindsight In Expert Evidence ' A Warning From The High Court

• Published date: 18 December 2020
• Subject Matter: Intellectual Property, Patent
• Law Firm: J A Kemp LLP
• Author: Mr Callum Docherty

The UK High Court recently found a patent for a breathing tube to be valid and infringed on the basis of expert evidence submitted by the parties. The judge clearly preferred the evidence of one expert over the other and this was decisive for the case result.

The case concerned Fisher & Paykel Healthcare Limited's EP(UK) patent for expiratory limbs of breathing circuits. Fisher & Paykel ('F&P') sued Flexicare Medical Limited and Flexicare (Group) Limited (together 'Flexicare') for infringement. Flexicare admitted their products fell within the claims of the patent, but argued the patent was invalid and counterclaimed for revocation.

As part of their case, Flexicare submitted an expert report from Dr Dixon. Mr Justice Meade found there to be significant problems with Dr Dixon's report. The judge noted that there has been an heightened focus in recent years on the way in which expert evidence is prepared, and especially the sequence in which experts are shown documents. Ideally, experts should first be asked about the common general knowledge (CGK), then shown the prior art, and only then shown the patent in suit (following MedImmune). The courts recognise that this may be difficult in practice, as the expert may already be aware of the invention in the patent, for example from a patentee's commercial embodiment of it. Mr Justice Meade considered that in such cases, the expert must identify in their report how they knew about the invention and when, and to reflect carefully on how this might influence them. This was where Dr Dixon's evidence fell short of the judge's expectations.

Dr Dixon did acknowledge that he had seen the patent before, but said he only remembered this when shown the patent after he saw the prior art. In fact, Dr Dixon's exposure to the patent was considerably more extensive, something that had to be drawn out from him in cross-examination. He had long experience with F&P's products and knew the relevant features of them pertinent to this case. He even had his own patent application identifying solutions to problems that, he had to accept, could only have been a reference to F&P's products. Mr Justice Meade found that Dr Dixon's mere reference in his report to having...