Patents - Abbott Diabetes Care Inc. v Dexcom Inc.

Jane Lambert 

Patents Court (Mr Justice Richards) Abbott Diabetes Care Inc and others v Dexcom Inc and others [2023] EWHC 2591 (Ch) (18 Oct 2023)

This was a claim by Abbot Daiabetes Care Inc and others ("Abbott") for infringement of European patent (UK)  2549918B1 for Medical device inserters and processes of inserting and using medical devices and a counterclaim by Dexcom Inc and others ("Dexcom") for revocation of the patent on grounds of added matter, anticipation. insufficiency and obviousness,  According to Mr Justice Richatrds who tried the action and counterclaim on 6 and 7 July 2023, this was the third of a series of UK patent infringement/validity trials concerning continuous glucose monitoring ("CGM") systems.  Abbott indicated that it would apply to amend the patent if the court found it invalid.  By para [208] of his judgment which he handed down on 18 Oct 2023 the judge dismissed the claim and by [209] he dismissed the counterclaim.  In view of his dismissal of the counterclaim, he did not need to order amendments (see Abbott Diabetes Care Inc and Others v Dexcom Inc and Others [2023] EWHC 2591 (Ch) (18 Oct 2023)).

The Invention

At para [52] of his judgment, his lordship said that the patent disclosed and claimed in its broadest claims, an apparatus for inserting medical devices of any kind into the skin of a subject but its focus was on the insertion of on-body glucose or analyte monitoring devices.  Although the claims related to an apparatus for inserting a medical device into the subject's skin there was significant disclosure relating to the nature of the inserted medical device.  The judge described the invention by reference to the above drawing.  It shows an inserter numbered 14 that is to be inserted into the skin.  There is a handle coloured green and a sheath coloured blue.  When the handle is pressed with sufficient force, a component known as a "sheath stop" that is numbered 2726 is released allowing the inserter to enter the skin.

The Patent

EP 2 549 918 B1 had been amended to deal with issues raised by Dexicom in opposition proceedings which were resolved in Abbott's favour.   The claims that are alleged to have been infringed were claims 1 and 7.  The judge set them out broken down into integers in an appendix to his judgment.   

The Alleged Infringement

Abbott complains that Dexicom has infringed its patent by selling a device called a "G7 applicator".  Its components appear in the following diagram:

The purpose of the G7 applicator is to insert a sensor into the patient's skin but it does so by means of a spring-operated mechanism.    It was admitted in cross-examination that the device would not work unless some downward force was applied to the top outer casing of the applicator known as "the shroud" though it was explained that that force was required to keep the device in contact with the patient's skin.   The judge explained the operation of the device between paras [56] and [63] of his judgment by reference to schematics that Dexicom's lawyers had prepared for their description of their product served under para 6.1 of the Part 63 Practice Direction.

The Issues

The learned judge set out the issues that he had to decide at para [3]:

"i) the construction of various claims within the Patent;
ii) whether the G7 Applicator infringes Claim 1 or Claim 7 of the Patent as properly construed, it being common ground that the Conditional Amendments raise no different issues relevant to infringement from those of the unamended claims;
iii) whether the Patent's claims should be declared invalid because of the presence of "added matter";
iv) a squeeze argument as to whether the Patent is anticipated by, or obvious over, three aspects of the prior art namely:
a) US/2009/0124979 A1 ("Raymond")
b) US/2005/0101912 A1 ("Faust")
c) US2010/0049129 A1 ("Yokoi")
v) a squeeze argument as to whether the Patent is insufficient in the "Biogen sense" namely that it teaches a reader to perform the claimed invention to some extent, but not to the full extent of the claims."

Skilled Addressee

His lordship's first task was to identify the skilled addressee.  He reminded himself of Lord Justice Jacob's observation in Rockwater Ltd v Technip France SA and another [2004] RPC 46, [2004] EWCA Civ 381 at para [6]:

"The 'man skilled in the art' is invoked at many critical points of patent law. The claims of a patent must be understood as if read by that notional man—in the hackneyed but convenient phrase the 'court must don the mantle of the skilled man.' Likewise many questions of validity (obviousness, and sufficiency for instance) depend upon trying to view matters as he would see them. He indeed has statutory recognition—Arts 56, 83 and 100 of the EPC expressly refer to 'the person skilled in the art'."

From a statement prepared by both parties on the skilled addressee's common general knowledge ("CGK"), the judge concluded at para [12] that the patent as amended was addressed "primarily to persons having expertise in the fields of mechanical engineering and having some expertise as a product designer." That mechanical engineer would be working within a larger team in the field of medical device design and development which would have expertise across various disciplines such as manufacturing and production engineers, biologists and chemists, clinicians and medics, regulatory and quality departments and electronics and software engineers. Claims 1 and 7 of the patent indicate that the skilled team would be involved in the design and development of an inserter for a medical device.  As regards claim 7, the skilled team would be looking specifically at the design and development of an inserter for an analyte sensor.  He held that the skilled team would be led by a project leader with overall responsibility for developing the CGM system as a whole. The project leader would have specific CGM experience including at least 3 to 5 years working on CGM systems and would be familiar with all relevant aspects of CGM system design.


The judge adopted the following definition of CGK from the claimants' written closing submissions:

"…the CGK consists of information that is generally known to the Skilled Team at the Priority Date and is generally regarded as a good basis for further action by the bulk of those engaged in the relevant field. The CGK includes information that the Skilled Team would know existed and would know where to find as a matter of course, even if they could not quote that information off-hand. It also includes information that would be acquired by the Skilled Team as a matter of routine."

As I mentioned above, the parties prepared a joint statement of the agreed CGK which his lordship discussed between para [14] and [30].  However, there were disputes on the team's mindset which he addressed between paras [31] and [50].  These concerned the likely focus of the skilled team as at the priority date, the relevance of infusion set design to the design of inserters for CGM and CGK and thinking with respect to sensor and electronics/transmitter design.

Issue (i) Construction of Claims 1 and 7

Mr Justice Ruchards said in para [67] that determining the questions of construction was a necessary step in determining the question of infringement and also the prior art based challenges.

In the next paragraph,  the judge directed himself that "as a general matter, the Court's task is to construe the claims objectively through the eyes of the skilled person and using their common general knowledge." He set out to apply the following principles applicable to the construction of claims in patents that were expounded by the Court of Appeal in Saab Seaeye Limited v Atlas Elektronik GmbH and another [2017] EWCA Civ 2175:

"[18]. There was no dispute about the principles which apply to the construction of patent claims. Both parties relied, as did the judge, on the summary in this court's judgment in Virgin Atlantic v Premium Aircraft [2010] RPC 8 at [5]:
'(i) The first overarching principle is that contained in Article 69 of the European Patent Convention.
(ii) Article 69 says that the extent of protection is determined by the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.
(iii) It follows that the claims are to be construed purposively – the inventor's purpose being ascertained from the description and drawings.
(iv) It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.
(v) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.
(vi) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Article 69 itself. It is the terms of the claims which delineate the patentee's territory.
(vii) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.
(viii) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.
(ix) It further follows that there is no general 'doctrine of equivalents.'
(x) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.
(xi) Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge."

Sub-paragraph (ix) must now be read in the light of the Supreme Court's judgment in Actavis v Lilly [2017] UKSC 48, which explains that, at least when considering the scope of protection, there is now a second question, to be asked after the patent claim has been interpreted, which is designed to take account of equivalents…."

His lordship noted that the question of equivalents did not arise in this case and that the above principles continued to apply with the following qualifications which he mentioned at para [69] of his judgment: 

"i) The Protocol to Article 69 of the European Patent Convention referred to in the quotation above requires that the extent of protection confirmed by a European patent is to be interpreted in a manner 'which combines a fair protection for the patentee with a reasonable degree of certainty for third parties'.
ii) Where a patentee has used general language in a claim, but has described the invention by reference to a specific embodiment, it is not normally legitimate to write limitations into the claim corresponding to details of the specific embodiment if the patentee has chosen not to do so. That would amount to rewriting the claims rather than construing them. (See [41] of the judgment of Floyd J (as he then was) in Nokia v IPCom [2009] EWHC 3842 (Pat).) That said, the colour taken from the specification of a patent can sometimes narrow the acontextual meaning which the claim would bear out when read alone (a process described by Lord Hoffmann in his speech in Kirin Amgen and others v Hoescht [2004] UKHL 46 as being analogous to a recognition that in particular contexts, "the City" can mean the City of London specifically).
iii) The construction of a patent claim is a matter solely for the Court. Expert evidence as to the meaning of language is not admissible except where a term is a "term of art". That said, expert evidence can shed some light on the meaning of a claim: for example expert evidence might establish that it is only if a particular construction of a claim is adopted, that general technical statements made in the body of the patent about what the invention achieves will hold good. That can serve as a guide as to the true construction of the claim (see [10] of the judgment of Floyd J, as he then was, in Qualcomm v Nokia [2008] EWHC 329) (Pat) (3 March 2008)."

Issue (ii): Whether the G7 Applicator infringed Claim 1 or Claim 7 

The judge asked the parties to prepare a "construction schedule" that set out their respective positions on questions of construction of the patent by reference to relevant features of the G7 applicator and the prior art,   Those points were labelled "A" to "J" and after considering the purpose of the patent the judge considered them between para [78] and para [122].   He concluded at [122] that the G7 applicator did not infringe claims 1 or 7 of the patent regardless and would not infringe even if those claims were further amended.

Issue (iii): Whether the Patent's Claims should be declared invalid because of the Presence of "Added Matter"

Dexcom argued that the patent should be revoked under s72 (1) (d) of the Patents Act 1977 because matter was added after the application for the patent had been filed. Under that provision, the court or Comptroller may revoke a patent on the ground that the matter disclosed in the granted patent extends beyond that disclosed in the patent application.  Dexcom contended that Abbott's application involved the use of a "biased retention feature" that interacted with a detent in the housing.  It alleged that claim 1 was extended to include integers involving biased retention features that did not interact with a detent. 

Mr Justice Richards referred to Lord Justice Aldous's judgment in Bonzel v Intervention Ltd (No 3) [1991] RPC 553 on page 574 where he set out the steps to identify added matter:

"(1) To ascertain through the eyes of the skilled addressee what is disclosed, both explicitly and implicitly in the application.
(2) To do the same in respect of the patent as granted.
(3) To compare the two disclosures and decide whether any subject matter relevant to the invention has been added whether by deletion or addition. The comparison is strict in the sense that subject matter will be added unless such matter is clearly and unambiguously disclosed in the application either explicitly or implicitly."

The judge compared Abbott's PCT application and the patent that was granted and noted a difference in language but not in the way the invention worked.  He said at [141]:

"The 'snap' and 'retention features. described at [00254] and [00255] of the PCT Application describe the key aspects of the 'biased retention feature' described in what became Claim 1 of the Patent. The 'retention' aspect is disclosed in [00254] as 'The sheath 3708 is secured to the housing 3702 via retention features 3726, which can be configured, e.g. as a snap'. The 'biasing' element is disclosed at [00255] as 'Sheath 3708 can include retention members 3726, e.g. detent snaps, which are biased into detent 3724 of housing 3702 to create a minimum force that must be overcome in order to advance sharp 324 into the subject's skin'. What ultimately became Claim 1 in the Patent was simply a generalisation of this concept beyond the snaps and detents referred to in particular embodiments. In my judgment, given my conclusion on Point G on the Construction Schedule, the amendment teaches nothing new."

Accordingly, he held that the added matter challenge failed.

Issue (iv):  Whether the Patent was anticipated by, or obvious over Raymond, Faust or Yokoi

Mr Justice Richards noted that all the prior art challenges to the validity of the patent had been squeeze arguments and that Dexcom had indicated that if its G7 applicator was found not to infringe the patent then it would accept in the UK proceedings that the claims of the patent were not invalid in the light of the cited prior art.  Having found that the G7 applicator did not infringe it was not strictly necessary for his lordship to make any finding on the prior art challenges.  He addressed those challenges in case his conclusions on construction had been wrong,

The judge considered Faust between para [151] and [153], Raymond between [154] and [157] and Yokoi between [158] and [166].  He said that if his construction on Point F of the construction schedule had been correct then Claim 1 of the patent had not been anticipated by any of the prior art but if his construction was wrong then all the citations anticipated the claim.  Dexcom did not argue that Claim 7 had been anticipated because none of the prior art related to an inserter for an analyte sensor.

Before considering obviousness, the judge mentioned s.3 of the Patents Act 1977:

"[a]n 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 forms part of the state of the art."

He observed that the burden was on Dexcom to establish obviousness.  He referred to Mr Justice Laddie's judgment in Brugger and another v Medic-Aid Ltd [1996] RPC 635 at 653 for the purpose behind the concept of obviousness:

"A trader must be free to adopt a product, process or design which is the, or one of the, obvious modifications over what has gone before without the need to look over his shoulder to consider whether it is protected by patent. Obviousness is tested against the mental and developmental norm of a notional uninventive person skilled in the art. In doing that the law is protecting not only established businesses which may wish to adopt new products, processes or designs or modify existing ones but also the new entrant who has employed persons skilled in the art to help him get into the market. Each of those categories of trader must be free to adopt what is obvious. Therefore it is legitimate to approach the prior art as if it had been collected and put on the desk of the new entrant at the priority date."

The parties had agreed that it was appropriate to assess obviousness by the structured approach set out in Pozzoli v BDMO SA [2007] RPC 37 at [23] as amplified by the Supreme Court in Actavis Group PTC EHF and others v ICOS Corporation and another [2020] 1 All ER 213, [2019] RPC 9, [2019] Bus LR 1318, (2019) 167 BMLR 1, [2019] UKSC 15:

"i) Identify:
a) the notional "person skilled in the art";
b) the relevant CGK of that person
ii) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it.
iii) Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed.
iv) Viewed without any knowledge of the alleged invention as claimed, determine whether those differences constitute steps which would have been obvious to the person skilled in the art or whether they would have required any degree of invention."

As it is at step 4 that the ultimate conclusion on obviousness emerges, his lordship set out the following principles at para [175]:

"i) It is important for the Court to "don the mantle" of the Skilled Team at the Priority Date. Expert evidence plays an important part in enabling the Court to do this for a number of reasons, including the fact that expert evidence can help the Court to assess what would have been in the mind of the Skilled Team at the Priority Date (see, for example, Panduit Corp v Band-IT Co Ltd [2002] EWCA Civ 465).
ii) Once an invention has been made it is often easy to see, with hindsight, how it was arrived at. However, hindsight is to be avoided. The question is whether it would have been obvious to the Skilled Team to make the invention at the Priority Date (see, for example, British Westinghouse v Braulik (1910) 27 RPC 2009).
iii) The Skilled Team is assumed to read all the prior art properly and, in that sense, with 'interest'. However, that does not mean that the Skilled Team assumes that the prior art will provide it with any assistance in solving the problem confronting it. In some cases, the Skilled Team may conclude that prior art is not a useful starting point for development (see [102] of the judgment of Arnold J as he then was in Jarden Consumer Solutions v SEB SA [2014] EWHC 445 (Pat)). Having read a particular piece of prior art with interest, the way in which the Skilled Team responds to it is a question of fact to be determined in the light of all relevant circumstances. One possibility is that the Skilled Team will say, 'I have read it with interest, but I'm not interested' (see Vernacare Ltd v Environmental Pulp Products Ltd [2012] EWPCC 41)."

Abbott's case was that the invention was not obvious because of the mindset of the skilled team as of the priority date. The judge applied the following propositions of law when evaluating this aspect of its case:

"i) Questions of 'mindset' are of potential relevance when addressing a question of obviousness. That is simply because obviousness has to be considered on the facts of each case and so involves a multi-factorial evaluation. Relevant factors may, therefore, include matters such as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research and the effort involved in pursuing them and expectations of success (see the statement of Kitchin J in Generics (UK) Ltd v H Lundbeck [2007] RPC 32 at [72]).
ii) It can, therefore, be relevant to explore whether there are potential barriers that mean that, although the Skilled Team 'could' have arrived at the claimed invention without inventive effort, it 'would' not in fact have done so. However, care needs to be taken to ensure that the application of a 'would' test is not misleading. For example, the application of a 'would' test does not make it permissible to consider whether it would be worthwhile commercialising an otherwise technically obvious product. Nor does it require it to be shown that the Skilled Team would go ahead and implement a particular invention commercially. In a similar vein, the application of a 'would' test could produce an incorrect outcome if, for example, the prior art reveals a range of obvious possibilities making it statistically unlikely that any particular one of them would be chosen (see [15] and [16] of the judgment of Floyd LJ in Hospira UK Limited v Genentech, Inc [2016] EWCA Civ 780).
iii) Undue focus on whether the Skilled Team 'would' have alighted on a particular claim can also lead to a different type of incorrect outcome. The purpose of the concept of 'obviousness' is to define what is inventive. It follows that, even if the Skilled Team 'would not' alight on a particular claim, because, for example, it is purely arbitrary and non-technical, it does not follow that the claim is protected from an obviousness challenge. In Actavis UK Ltd v Novartis AG [2010] EWCA Civ 82, Jacob LJ illustrates the idea by reference to a hypothetical patentee who claims a patent for a 5¼ inch plate in circumstances where there is no reference in the prior art to a plate having that precise diameter. Even though no skilled person would alight on the idea of a plate with that particular diameter, the alleged invention remains obvious as the 5¼ inch limitation is purely arbitrary and non-technical, solves no problem and does not advance the art at all.
iv) That said, it is not necessarily wrong to ask whether the Skilled Team 'would' have taken a particular step. Analysing that question can shed a light on relevant questions of motivation and, as the Supreme Court makes clear at [70] of Actavis v ICOS 'the absence of a motive to take the allegedly inventive step makes an argument of obviousness more difficult.'
v) The question whether the Skilled Team 'could' have arrived at the claimed invention without inventive effort is a minimum condition that must be satisfied before obviousness case can be established (see the judgment of Slade LJ in Hallen Co. v Brabantia (UK) Ltd. [1991] RPC 195 at page 212)."

Having already identified the skilled addressee and the CGK the judge considered the inventive concept on the basis that his construction of Point G of the construction schedule had been wrong,   On the difference between the inventive concept and the prior art he continued on the assumption that his construction of Point F had been right because that would result in the widest possible difference between the patent and the prior art for making evaluative findings as to obviousness.  He discussed the last step of the Pozzoli analysis between [177] and [188] and found that Claim 7 would have been obvious.   He applied the same analysis to the proposed amendments between [189] and [203] and arrived at the same conclusion. 

Issue (v):  Whether the Patent was insufficient in the "Biogen sense"

In his judgment, his lordship considered this issue before Issue (iv) on whether the patent lacked novelty or an inventive step. This had also been a squeeze argument on construction. By accepting Dexcom's position on Points E, G, H, I and J on the construction schedule the judge no longer needed to consider insufficiency.  However, he made the following finding in case his construction had been wrong.

He set out the following propositions at para [146]:

!i) Section 72 (1) (c) of the Patents Act 1977 provides that a patent can be revoked if "the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art". That reflects a fundamental ingredient of the "patent bargain" namely that a patentee obtains a monopoly for an invention only by laying out in the patent document all the information necessary to equip the uninventive person skilled in the art to perform it by means of an application of CGK.
ii) The simplest kind of insufficiency is where a patent simply fails to inform the skilled person how to perform the invention. For example, explanation may be missing or inadequate or incorrect. Alternatively, the patent may impose an "undue burden" by requiring the skilled person to carry out experiments, trials or investigations in order to discover how actually the invention can be performed. That is not the allegation of insufficiency that is made in this case and so I deal with it no further.
iii) A more subtle kind of insufficiency is known as "claim breadth insufficiency" or "Biogen insufficiency" (named after the judgment of the House of Lords in Biogen v Medeva [1997] RPC 1). That involves situations where a skilled reader is enabled by the patent to perform the claimed invention to some extent but not to the full extent of the claims. There is in the common shorthand, a failure to enable a claim 'across its scope'. In Kymab v Regeneron [2018] UKSC 27, Lord Briggs explained the requirement in the following way:

'The disclosure required of the patentee is such as will, coupled with the common general knowledge existing as at the priority date, be sufficient to enable the skilled person to make substantially all the types or embodiments of products within the scope of the claim. That is what, in the context of a product claim, enablement means.'"

The judge said that he would have rejected Dexcom's assertion of "claim breadth insufficiency" had it been necessary to consider the point. He explained his reasoning at [147]:

"The core of that argument is that the Patent's disclosure focuses on a biased retention feature in the form of a "snap" on the sheath that engages with a detent in the handle but the scope of the claimed monopoly goes further than that. However, I conclude that the aspects in which the claimed monopoly does go further simply involve an application of the CGK described in paragraph 30 above. In short, if I were wrong in my conclusions on Points E, G, H, I and J in the Construction Schedule I would agree with Abbott that, to bridge the gap between the snap and detent features disclosed in the Patent and the relevant features of the G7 Applicator including the Leaf Springs and actuation by means of depressing a button, the Skilled Team would need only to put together an arrangement of standard components with that arrangement being within its CGK."


This is a very careful and well-documented judgment with references to many illuminating authorities that are often overlooked.  Mr Justice Richards has offered useful guidance on claim construction, the last question of the Pozzoli analysis and skilled addressees' mindset when considering obviousness and insufficiency.  Anyone wishing to discuss this case note may call me on 020 7404 5252 during normal business hours or send me a message through my contact form.


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