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England and Wales Court of Appeal (Civil Division) Decisions |
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You are here: BAILII >> Databases >> England and Wales Court of Appeal (Civil Division) Decisions >> Hospira (UK) Ltd v [2015] EWCA Civ 57 (06 February 2015) URL: http://www.bailii.org/ew/cases/EWCA/Civ/2015/57.html Cite as: [2015] EWCA Civ 57 |
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ON APPEAL FROM THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
THE HON MR JUSTICE BIRSS
Strand, London, WC2A 2LL |
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B e f o r e :
LORD JUSTICE KITCHIN
and
LORD JUSTICE FLOYD
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HOSPIRA (UK) LIMITED | Claimant/Respondent | |
- and - | ||
GENENTECH, INC. |
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WordWave International Limited
A Merrill Communications Company
165 Fleet Street, London EC4A 2DY
Tel No: 020 7404 1400, Fax No: 020 7831 8838
Official Shorthand Writers to the Court)
Defendant/Appellant
Mr Richard Meade QC, Mr Tom Mitcheson QC and Mr Jeremy Heald (instructed by Taylor Wessing LLP) for the Respondent
Hearing dates: 13 & 14 January 2015
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Crown Copyright ©
Lord Justice Floyd:
Introduction
Background and the judgment of Birss J
i) The effect which a drug has on a patient is normally dependent on the concentration of the drug in the serum at the site of action, normally measured in micrograms per millilitre (µg/ml).
ii) Pharmacokineticists attempt to model the absorption, distribution, metabolism and excretion of the drug, and by this means to calculate the concentration of a drug at a site of action at given times after its administration.
iii) The serum half-life of a drug is the time for the serum concentration to drop to one half (from its initial level after a dose).
iv) An initial higher dose, called a loading dose, was a well known way of reducing the time to reach a steady state concentration.
v) Doses are either expressed in absolute terms (in milligrams, mg) or as an amount per kilogram of body weight (mg/kg). It is a standard assumption that the patient weighs 70 kg: so one type of measurement can be converted into the other. A dose of 7.14 mg/kg is treated by convention as the same thing as an absolute dose of 500 mg.
"Even if the whole of it [i.e. the Figure 2 reasoning] was rejected, the pharmacokinetics expert would still be prepared to support 500mg three weekly and it would have been wholly obvious to try to use somewhat lower doses on the three weekly schedule if the schedule was efficacious."
"Genentech … were also submitting that Dr Earhart's analysis based on figure 2 was not sound (as I accepted)".
i) There was no evidence that the claimed 8 + 6 q3w range would be inventive once the skilled team had decided to conduct a trial using three weekly dosing based on the first part of Dr Earhart's reasoning.
ii) Based on that reasoning a number of regimens were all obvious including the claimed regimen.
iii) The Figure 2 reasoning was only concerned with investigating what dose below 500 mg would be feasible: even if the whole of it was rejected it would remain obvious to try the somewhat lower doses in the claim.
iv) There was no basis in the specification to support the idea that it was inventive to select the particular claimed dosage regimen;
"111. In the end it seems to me that it is important to be clear about the nature of the exercise being carried out. The proposal is to consider running a small trial of a new dosing schedule for an existing drug. The skilled team is being asked to make what Dr Earhart called a go/no go decision. Such decisions are made by real teams. Both Dr Earhart and Prof Boddy had experience of making go/no go decisions about clinical trials but Dr Earhart had more of that experience than Prof Boddy.
112. Dr Earhart's approach seeks to estimate what will happen using the information to hand from the FDA label. Weighing up and balancing the risks and uncertainties associated with such an estimate is the task of the pharmacokinetics expert. It is not simply a matter of mathematics. In carrying out the task they bring their experience to bear.
113. I found Dr Earhart's approach to be compelling and I find that it reflects what a skilled pharmacokinetics expert would do. Therefore I am satisfied that a pharmacokinetics expert would advise the clinician that there was no reason on pharmacokinetic grounds not to conduct a study of three weekly dosing. Choosing 8 mg/kg for the initial dose and 6 mg/kg for the three weekly maintenance dose would be obvious."
The law
"An invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which formed part of the state of the art…".
The arguments on the appeal
i) the half-life after the administration of a single dose was the same as that derived from the FDA label which related to a repeated 500 mg dose;
ii) the half life remained the same throughout the 21 day period of administration.
New points
Discussion
"On the basis of the assumptions and calculations set out above, a single dose of 500 mg will result in a serum concentration of trastuzumab well above the targeted level of 20µg/ml for at least three weeks. In this simulation, the day-21 serum trastuzumab concentration would be 48µg/ml. As a working hypothesis, based on the data in the FDA label alone, a dose of 500 mg every three weeks should provide serum levels that are higher than the target level."
"There is no doubt about the mathematics. Based on this calculation the trough serum concentration would be 48µg/ml on day 21. In other words after three weeks, at the time the next dose would be due on a three weekly schedule, a 500mg dose of trastuzumab would produce more than double the target trough serum concentration."
"The expectation would be that the target serum trough concentration would be exceeded probably by a substantial margin and so one would be entitled to expect that the drug would be efficacious."
"It is recognised in oncology that there is variability in the clinical situation and so small changes of dose are not thought to have any effect on clinical outcomes of efficacy and toxicity."
"A group of patients treated at, say, 95 would behave exactly, in terms of the things we look for, as a group of patients treated at 100 or 105. So I guess what I am trying to do is let the court walk in on what I consider a meaningful degree of uncertainty. I would say that if we are 20% off in the regimen that we eventually select, we have a problem. What I am doing is selecting the lower margin of that regimen and I know that if I am wrong on that lower margin, it is not going to have a huge effect on the eventual decisions that are made clinically."
i) Dr Earhart's analysis was not performed at steady state, that is to say after repeated 500 mg doses, but on a single dose. In terms of the figure I have reproduced in paragraph 12 above, Dr Earhart's analysis was carried out on the first downward trough of the rising saw-tooth. This is in all likelihood the lowest trough in the entire span of administration of the drug. Dr Earhart was therefore applying, as Mr Meade put it, the most demanding test he could have set himself.
ii) The Figure 1 analysis also included no loading dose. The effect of the loading dose is to accelerate the arrival of a steady state. Thus any concern you might have that lowering the dose below 7.14 mg/kg might bring you closer to the target trough level would be alleviated by the fact that the skilled pharmacokineticist would know that he could include a loading dose. Dr Earhart pointed out more than once that the fact that he did not model the loading dose was "a safety factor" inherent in his Figure 1. The judge accepted his evidence about this at [103].
iii) The target trough serum concentration of 20 µg/ml is itself a cautious estimate. The literature also supported the use of 10 µg/ml. I would describe this as a minor point, given that the experts agreed that they would probably work to 20 µg/ml, but it is entitled to some weight as indicating that the figure of 20 µg/ml would not be regarded as an irreducible minimum. The judge recognised that taking the 20 µg/ml figure was a cautious approach.
Lord Justice Kitchin
Lord Justice Elias