Summary

This was a significant and well reported patent case which was determined in the Intellectual Property List within the High Court last autumn.   

The technical aspects of the case required significant expert input from the panel involved.  The cross-examinations performed by leading Counsel for the parties were lengthy and complicated.  This led to confusion over what evidence was given when the transcripts were re-visited on subsequent trial days. The case shows how consideration should be given to experts who are being cross-examined so not to overload them with questions and information on the stand.

Learning points for experts

• Experts owe a duty to the court whilst been cross-examined.

• Giving expert evidence can be a tiring process and this is something to bear in mind and express concern as necessary.

• If as an expert you believe you have given incorrect answers in cross-examination, then you should have the opportunity to correct it, but you should not abuse this opportunity and give 'replacement answers'.

• When working with an instructing party, be clear what you can recall from memory and what you can report on with reference to sources (e.g. textbooks).

Learning points for instructing parties

• Don’t leave the Judge to disseminate lever arch files full of scientific materials.

• Aim to address matters succinctly and use the right approach to expert’s written evidence.  This will avoid the need to remedy unclear points in cross-examination.

• Use the time for cross-examination wisely so not to cause the expert to become over tired and lose concentration.

• Consider the timetable for the day at trial. When are the breaks likely to take place?

• Legal teams should carefully observe their witnesses and speak up at trial if they detect that an expert witness is becoming tired during cross-examination.

• When preparing an expert’s report consider what the expert can accurately recall from memory.  Will extracts of the report cause suspicion if not backed up with references? Such references can be to textbooks for example.

The case

The parties to the litigation were two pharmaceutical giants, Pfizer (Claimant) and GSK (Defendant). 

The parties were in dispute over the validity of a number of patents which described a strategy for vaccinating against Respiratory Syncytial Virus (RSV).  Pfizer as Claimant claimed that GSK’s patents were invalid.  GSK counterclaimed against Pfizer for patent infringement.  This type of scenario is common in patent litigation. 

RSV is known to be particularly problematic to children, the elderly and those at increased risk during the winter months.  Every year there is an annual epidemic owing to RSV been one of the most infectious human viruses.  The symptoms normally present in upper respiratory tract infection which can be mild to moderate and similar to those of a cold.  Within children this can progress to bronchiolitis and pneumonia requiring hospitalisation.  Within elderly patients, data has shown significant mortality rates owing to the severity of the disease.

The case was of paramount importance to both as at the time of trial (summer 2023) whilst both parties were relatively close in obtaining approval for their vaccines, there was no RSV vaccine in place in the UK.  It was paramount to both sides that they had the most skilled legal teams and knowledgeable experts on board to take the dispute to high court trial.  The experts involved had decades of combined experience to educate the court on the precise vaccine technology at the relevant date.

A strong understanding of how vaccines worked was crucial and these parts spanned many paragraphs.  Several well-known vaccines for ‘MMR’ and ‘Hepatitis B’ were brought into the equation for illustration.  A useful summary was provided at para 120 –

“The goal of all vaccines against infectious disease is to expose the individual to the antigen(s) of a pathogen in a safe way, in order to elicit the development of specific and long-lived adaptive responses, so that the vaccinated individual will be protected in the future when they encounter the real pathogen.”

Central issue

The patents to be determined are precisely set out in the judgment.  They would have formed the key documents to be frequently referred to by all within the trial bundles. 

The standard approach in patent litigation when addressing patentability and validity arguments is to understand how a skilled person / team would have understood concepts of the patent at a relevant date.  In this case, the required approach was to consider the ‘skilled team’. 

The Judge was keen to hear the expert’s evidence on the following central issues:

(a) the makeup of the Skilled Team

(b) communication and collaboration between the members of the Team and

(c) what was their collective CGK (Common General Knowledge).

These areas formed the majority of dispute between the parties creating a ‘significant battleground’ (an expression used by the judge) at trial.

Two textbooks were also central in the case and therefore relevant to mention here:

1. Fields Virology (“Fields”) (5^th Edition, 2007)” and

2. The Respiratory Syncytial Virus (edited by Patricia Cane (2006) (“Cane”)

The Judge had regard to the lengthy technical background to the patents and the precise detail within the patents themselves.  He commented that “This is a case in which the patents provide an important indication as to the skills and knowledge of the Skilled Team.”

The Experts

Pfizer’s Experts

• Dr J – vaccinology.

• Professor W – structural biology

GSK’s Experts

• Dr T – vaccinology

• Professor A – molecular / structural biology

The judgment incorporates extracts of transcript from the cross-examination of these experts.  The transcripts were incredibly useful when the judge came to prepare his judgment which spanned to 845 paragraphs.  The Judge apologised for the delay in providing the judgment which was partly due to the complexity of the issues which he was left to determine.

Expert's corrections

The Judge explained that it is customary for experts to be given a copy of the transcript following their cross-examination. This allows the expert to correct any misunderstandings or misstatements in the answers given.  One of the experts in the case was due to start their second day of cross-examination but spent some time giving ‘corrections’ to answers given on the first day.  The Judge felt that the ‘corrections’ went far beyond ‘corrections’ in any normal sense of the word.

The Judge went on to say –

“It is important however, that the ability to suggest corrections to the transcript is not abused.  It is inappropriate for a witness to come back the next day and put forward replacement answers which they wish they, perhaps, might have come up with, rather than the evidence they gave in response to clear lines of questioning, which reflected their opinion at the time”.

The parties disagreed over whether the corrections should be accepted and the Judge had to review each of the ‘corrections’ in detail.  GSK argued that the cross-examination had been unfair and that the expert was ‘very tired’.  The Judge reflected on this point but didn’t initially detect this had been the case.  He felt that the legal teams on the day would have had a better opinion on this issue and explained:

“In any event, if a witness does appear to be losing the ability to concentrate, his or her legal team is far more likely to be able to detect those signs than a Judge who is encountering the witness for the first time.  The onus should be on the legal team to speak up, particularly where it is the first time the witness has given expert evidence in a patent case.”    

The Judge continued to analyse the corrections on the second day and had to weigh these alongside submissions from both sides.  The expert herself went on to advise that she may well have been getting tired and losing the ability to concentrate on the intense technical questions.  A further point the judge noted was that the ‘corrections’ were also used as part of an exercise by GSK to misdirect the expert’s evidence.

In view of these matters, the judge reviewed the whole of the transcript with care and detail.

Other criticisms of expert evidence

As identified above, one of the central issues was to look at the Common General Knowledge (CGK) dispute. 

Dr J’s report contained a section on this issue and when questioned during cross-examination, she answered that the content was included from her memory in 2007.  The cross-examination went further due to these been central issues in the case.  This expert went onto explain that an earlier version of her report had references to the two textbooks central in the case (set out above) – “Fields and “Cane”.

The removal of the supporting references was seen as the judge as particularly significant as can be noted from this paragraph:

“Having gone to the trouble of inserting references, I am bound to say it would have been far more helpful if they had been retained in the report as served but Dr J cannot be blamed for this because she did what the solicitors asked of her. The insertion and then the removal of these references gives rise to a suspicion that the possible absence of references against certain propositions might have served to highlight that their status as CGK was questionable.”

This section is included as a reminder to solicitors when removing references and is referenced within ‘Learning Points’ above.

Conclusion

The final decision was a ruling in favour of Pfizer declaring that both of GSK’s patents were invalid.  In addition, even if they had been valid, they would not have been infringed by Pfizer’s vaccine. 

At the time of writing this update (April 2025), there is reference in online news sources that both parties have settled separate RSV patent litigation in a USA court.  It is clear that this UK Court decision will have had some bearing on this latest settlement.

NHS England has now rolled out the first-ever vaccination programme for RSV.  This is reported to have launched in September 2024 aimed at protecting pregnant women and older adults.