Aga Medical Corporation v Occlutech (UK) Limited

The patent with which this case is concerned, EP (UK) No. 0,957,773 (“the Patent”), relates to a medical device for occluding defects in the atrial septum of the heart. An atrial septal defect (“ASD”), sometimes referred to as a “hole in the heart”, is a congenital condition in which there is an abnormal opening in the septum between the left and right atria of the heart.

The Claimant (“AGA”) is an American company and the patentee. The device was invented by Dr Kurt Amplatz, among others, who was then a doctor at the University of Minnesota medical center, and the commercial name of the device is “Amplatzer”. One of the “A’s” in AGA stands for Dr Amplatz.

AGA contends that the Patent is infringed by a number of ASD occluders made by the Defendant (“Occlutech”), which is the English sales company associated with the German Occlutech company that manufactures medical devices. Occlutech responds by contending that the Patent is invalid on a number of grounds, and also counterclaims for a declaration of non-infringement regarding a variant of the devices that are subject to the infringement claim.

There is parallel patent litigation between these parties in a number of jurisdictions. There are ongoing proceedings in the Netherlands, to which further reference will be made below. There are also proceedings before the EPO and, following the trial of the present action, on 17 December 2013, the Opposition Division issued a decision revoking the underlying European Patent, on the grounds, as set out in the reasons issued subsequently, of added matter. That decision is under appeal. Proceedings have also been instituted in Germany but they are stayed pending conclusion of the proceedings before the EPO.

Moreover, this is not the first litigation between these parties in this Court regarding an ASD occluder. On 31 July 2009, Mann J held that an earlier patent covering the Amplatzer was not infringed by the Occlutech devices: Occlutech GmbH v AGA Medical Corp [2009] EWHC 2013 (Ch); (Footnote: ¹) upheld on appeal: [2010] EWCA Civ 702.

The Patent was granted on 8 June 2011 and its priority date is 14 May 1996.

The particulars of infringement identify several different Occlutech devices that are alleged to infringe but it was common ground that for the purposes of the issues in this case there is no material difference between them.

After the conclusion of Occlutech’s evidence at the trial, and just before the hearing resumed for closing submissions, AGA applied to re-open its case and call Dr Amplatz to give evidence. I refused that application for reasons set out in my judgment of 14 October 2013: [2013] EWHC 3180 (Pat). AGA’s application to the Court of Appeal for permission to appeal against that decision was finally dismissed on 11 February 2014.

The septum that separates the two atria of the heart comprises two parts: the septum primum, attached to the left atrium, and the septum secundum, attached to the right atrium. The septum primum is a very thin, curtain like membrane about 1 mm thick, whereas the septum secundum is a different kind of tissue, up to 4 mm thick. During foetal life, an opening between the two septa allows blood to pass from the right to the left atrium. After birth, when the lungs become functional, this ‘door’ largely closes, and during the following months the septum should grow to seal the opening completely. An ASD is a structural defect where there remains one, or occasionally more, holes or openings in the septum. As a result, oxygen-rich blood from the left atrium can mix with oxygen-poor blood from the right atrium, a process referred to as a “shunt”. As explained by one of the experts, there is a wide range of possibilities for the size, shape and positioning of an ASD. As regards size, the hole can vary between 1 mm and a very large opening of 40mm and above. Where there are several smaller holes, that is referred to as a multi-fenestrated defect.

Symptoms of a patient with ASD vary depending on the size of the defect. A small hole may be relatively symptomless and may not require closure. However, larger defects cause difficulty in breathing, palpitations, pulmonary hypertension, right side heart failure and occasionally paradoxical embolism.

A related but distinct defect is a patent foramen ovale or “PFO”. This is a small hole resulting from incomplete fusion of the septum primum and septum secundum. Whereas in an ASD the shunt is primarily from the left to the right atrium, in a PFO it is primarily in the reverse direction.

Since ASD, like PFO, is a condition from birth, many interventions to remedy the defect are performed on young children. As at May 1996, in most cases ASDs were surgically closed. Accordingly, there was keen interest among cardiologists, and in particular paediatric cardiologists, in the development of devices that would enable percutaneous closure of ASDs as an alternative to open heart surgery. Although there were several earlier attempts to produce such devices, the breakthrough in development of an effective and successful device came with the Amplatzer.

The Patent explains at the outset that it relates to intravascular occlusion devices for treating ASDs, and also Patent Ductus Arteriosus (“PDA”) which is not relevant for the purpose of these proceedings.

The aims of the Patent are explained in the specification as follows:

“[0009] When using these devices to occlude an ASD, the pressure and therefore the chance of dislodgment of the device increases with the square of the size of the communication. Consequently, these devices have to have a very large retention skirt. Often times, the position of the ASD dictates the size of the retention skirt. Hence, there is a need for an ASD occluder which may be made with a relatively small retention skirt. Also, the shape of the prior devices (for example squares, triangles, pentagons, hexagons and octagons) require a larger contact area, having corners which extend to the free wall of the atria. Each time the atria contracts (approximately 100,000 times per day), internal wires within the prior art devices are bent creating structural fatigue fractures in approximately 30 percent of all cases. Furthermore, the previous devices require a French 14-16 introducing catheter, making it impossible to treat children affected with congenital defects with these devices.

[0010] Accordingly, it would be advantageous to provide a reliable embolization device which is both easy to deploy through a 6-7 French catheter and which can be accurately placed in a vessel. It would also be desirable to provide a recoverable device for deployment in a vessel in a patient’s body which is both economical and yields consistent, reproducible results.”

In simple terms, the Amplatzer comprises two discs or buttons connected by a thinner and short cylindrical waist, all made out of braided or woven strands of a ‘memory metal’, such as nitinol, which has the property of resuming its shape after being compressed. The device can therefore be elongated to enable insertion into the body and through the septal opening by a narrow catheter. As the catheter is slowly withdrawn, the device returns to its original shape, in effect springing out to produce one disc on each side of the septum. The shape and length of the waist approximates to the hole, while the discs rest in contact with the surrounding surface of the septum. The cavities within the woven metal are filled with polyester fibres which promote the formation of thrombus within the device, thereby enhancing its sealing property. The illustration below is reproduced to assist a general understanding of the device, but does not come from the Patent specification which, as will be explained, may embrace other embodiments.

As to the shape of the discs, as explained in paras [0099] and [0102] of the specification, one or both of the discs is cupped inwardly. This has the effect that the distance between the perimeters of the discs is less than the length of the cylindrical waist of the device. The consequence of this, together with the length of the waist approximating the thickness of the atrial septal wall, is that once deployed contact is created between the perimeter edge of the cupped disc and the atrial septum. Further, because of the cupped nature of the disc, the contact area is smaller than it would be if the disc was flat. This reduced area creates a higher contact pressure. As para [0102] explains, the cup shape “ensures complete contact between the occlusion device and the atrial septum” and also therefore encourages endothelialisation over the device to the perimeter of the disc pressing against the septum.

Further, one of the two discs may be larger than the other or the two may be of equal size. Figure 13 in the specification illustrates the former embodiment, where the proximal disc has a relatively flat configuration whereas the distal disc is cupped towards the proximal disc. In that illustration, the cupped disc is larger than the flat disc which in effect nests within it. Figure 17 illustrates an alternative embodiment where the proximal disc is the mirror image of the distal disc.

The Patent comprises nine claims. Although AGA’s pleading contended that several of the claims are independently valid and infringed, it is common ground that the Court is now only concerned with claim 1. This reads as follows, broken down for convenience into numbered integers (and with cross-references to the drawings omitted):

“A collapsible medical device, comprising

(1)

a plurality of metal strands forming a tubular braided metal fabric having an expanded preset configuration,

(2)

the ends of the strands of the tubular braid being secured in order to prevent the strands from unravelling,

(3)

wherein said medical device is shaped to create an occlusion of an abnormal opening in a cardiac septal wall,

(4)

whereby said expanded preset configuration is deformable to a lesser cross-sectional dimension for delivery through a channel in a patient’s body,

(5)

the woven metal fabric having a memory property such that the medical device tends to return to said expanded preset configuration when unconstrained,

(6)

the expanded preset configuration comprising first and second expanded diameter portions respectively at distal and proximal ends of the device and a reduced diameter portion disposed between the two expanded diameter portions, said reduced diameter portion having a length dimension which approximates a thickness of the septal wall at the abnormal opening,

(7)

wherein at least one of said first and second expanded diameter portions is cupped towards the other of the expanded diameter portions causing, in use, the perimeter edge of the cupped expanded diameter portion to fully engage the sidewall of the septum,

(8)

the collapsible medical device further including an occluding fiber retained within said tubular woven fabric.”

Occlutech raised a wide range of challenges to the Patent, even after some narrowing of the bases of challenge from those set out in the pleadings.

The primary grounds of invalidity asserted were:

Accordingly, a striking feature of this case as regards both the novelty and obviousness challenges is that they are not based on independent prior art but on disclosure by the patentee itself.

As mentioned above, a single ground of alleged anticipation is relied on: the clinical procedures carried out by Slovak doctors in the Bratislava Children’s University Hospital. This arose as follows. Dr Amplatz had a long-standing friend at the hospital, Dr Augustin Formanek. Through Dr Formanek, he was put in touch with Professor Jozef Masura, who was, and still is, a paediatric cardiologist at the hospital. In September 1995, Dr Amplatz travelled to Bratislava with a number of devices in sealed, sterilised pouches and also a loose device for demonstration. He then oversaw the catheterised insertion of the devices administered by Slovak doctors at the Hospital, closing ASDs in three children in the course of one afternoon. Apart from Dr Amplatz, three doctors were involved in the procedures (as well as an anaesthetist and a nurse): Prof Masura, Dr Formanek, and Dr Pavel Gavora.

These procedures were successful and about a year later a further 27 patients (including two adults) underwent ASD closure with the Amplatzer. However, those subsequent procedures all took place after the priority date and using a consignment sent to Bratislava in late August 1996. Prof Masura, in conjunction with the other doctors involved (but not Dr Amplatz (Footnote: ²)), published an account of the interventions in the medical journal, Catheterization and Cardiovascular Diagnosis, in 1997 (“the Masura article”).

It is important to note that development of what became the Amplatzer went through several stages. In particular, a prototype was produced in which the two discs were flat. That was the form of device that is the subject of Dr Gu’s presentation describing tests on animals. That prototype was subsequently modified to produce a version with one or both discs cupped, which is the subject of the Patent. In consequence, two issues are raised by the allegation of anticipation:

Direct evidence for AGA pertaining to these issues was given by Mr Franck Gougeon, who was executive vice-president of AGA when the Amplatzer was developed. He initially held a one third shareholding in the company and the “G” in AGA stands for his name. Mr Gougeon gave his evidence by video-link from Minnesota. Evidence for Occlutech was given by Prof Masura by video-link from Bratislava through an interpreter (who was in court) and by Dr Gavora, who came to London from Slovakia to testify, also with the assistance of an interpreter. I found that all three witnesses were honest and doing their best to recall what happened some 18 years beforehand. In addition, AGA put in witness statements from a number of the lawyers who had attended a hearing of the patent proceedings before the Dutch court as regards the response given by Dr Gavora to a question from the judge hearing that case. Those statements were not challenged.

Mr Gougeon’s involvement in these events was limited. He was not involved in making the arrangements for the Bratislava procedures: that was done by Dr Amplatz directly. Mr Gougeon packed the pre-sealed devices to be taken by Dr Amplatz to Bratislava in a box and he recalled that there were between five and ten devices but could not remember the exact number. Dr Amplatz showed him the loose device which he kept separate. Mr Gougeon was sure that the loose device had flat discs and he believed that all the devices taken in September 1995 were the same as those which had been used in the animal studies, which also had flat discs. However, he agreed in cross-examination that if not all those devices had the same shape, that would not be something that he would remember or even have noticed.

Mr Gougeon was involved in sending the further devices to Prof Masura in August 1996. It was common ground that all those devices had cupped discs. Mr Gougeon accepted that if any modification had been made to the devices as between those used in September 1995 and the subsequent shipment in August 1996, someone would have told Prof Masura about the change. However, Mr Gougeon said that he was not aware of what communications may have taken place between Dr Amplatz and Prof Masura between September 1995 and August 1996.

Prof Masura was understandably proud that his hospital and department in Bratislava had been chosen by the American inventor to be the first place in the world where implants would be carried out with what he recognised was a revolutionary new device. He was clear in his recollection that not all of the three devices implanted had the same shape. Two of the devices had discs of different sized diameters whereas in the third device the two discs were of equal size. He said that in two of the three devices the inner surface of the discs was cupped. He said that, as best he could recall, in the loose sample brought by Dr Amplatz for demonstration, the discs were flat. In the Masura article, which describes the device and gives data from all 30 procedures (i.e. the three in September 1995 along with the 27 carried out a year later), there is no mention of the shape of the discs and it was put to Prof Masura that for him the shape was therefore not important. Prof Masura responded that it was not so important, but it was still significant: he had never seen the device before September 1995 and so he examined the devices brought by Dr Amplatz closely at the time.

Altogether, I found Prof Masura to be a very clear witness. He had no particular reason to seek to help Occlutech. I have given careful consideration to whether his memory may be misleading him, and whether he might be confusing the shape of the devices that he implanted after August 1996 with the three that he had implanted a year before. However, he said that the occasion when he carried out the first implants in September 1995, in the knowledge that these were the first clinical trials in the world of the new device, was perhaps the most memorable day of his career. Having had the opportunity to observe the way he responded to full cross-examination on this issue by Mr Meade QC, I found his evidence convincing.

Dr Gavora’s evidence was that in all three of the devices implanted in Bratislava, one of the discs was cupped. He had in his oral evidence to correct what he said in his first witness statement regarding the date of the later implants (i.e. after the first three patients in September 1995); and prior to giving evidence he also corrected, by a further witness statement, his assertion that all three children were foster children, and stated that the parents of one were involved in giving their consent. However, in acknowledging these mistakes, Dr Gavora said those matters were much less important to him than the detailed form of the medical device itself, in which he took a close interest.

The position regarding the statement made by Dr Gavora to the Dutch court was somewhat confused. The court’s provisional judgment given on 26 September 2012, says (at para 4.31) that Dr Gavora “eventually stated at the hearing that the inside of the discs was flat (after claiming in his statements filed by Occlutech that the discs were “cupped towards the other”).” However, it appears that Dr Gavora did not formally give oral evidence in the Dutch proceedings but was present in court while evidence was being given by Dr Gu. The Dutch judge thereupon addressed a question (in English) to Dr Gavora regarding the shape of the devices. There is no transcript of this exchange. The lawyers present relate that when asked by the judge whether the inside of the discs was cupped or flat, Dr Gavora responded that it was flat, making a hand gesture to that effect. In giving evidence in the present case, Dr Gavora explained that he was asked two questions by the Dutch judge: first, whether the first three implanted devices were the same as the 27 implanted later, to which he responded that the only change of which they were informed was that in the later consignment one disc would be broader than the other; and secondly, whether the shape of the device to which Dr Gu referred would be evident when it was on the table, to which Dr Gavora responded to the effect that the device when on the table could be seen to have discs that were flat.

Dr Gavora said in his evidence in this trial that he did not mean by his answer to the Dutch judge’s question that the three devices used for the September 1995 implants had flat discs. As I have stated above, I found Dr Gavora to be an honest witness and AGA very properly does not seek to question his good faith. Dr Gavora has no particular link to Occlutech; he left the Bratislava Children’s Hospital in 2009 and has had no contact with Prof Masura for several years. I do not think that the issue before me is advanced by consideration of what Dr Gavora meant by the response which he gave, in different proceedings, in what is not his main language.

AGA unsurprisingly sought to make much of the discrepancy as between Dr Gavora and Prof Masura regarding the number of cupped devices, and the fact that Dr Gavora said that all three of the initially implanted devices were the same. Mr Meade submitted that this showed that Dr Gavora was confusing the initial devices with the later consignment. I reject that suggestion. It does not matter for present purposes whether only two or all three of the devices implanted in September 1995 had a cupped disc. If it is necessary to decide, I would hold that the evidence of Prof Masura is to be preferred. The fact that Prof Masura recalled specifically that there were two different shapes is, in my view, the sort of detail that makes it likely that his account represents the better recollection. What is significant, in my judgment, is that both Prof Masura and Dr Gavora distinctly recalled that when they saw the devices for the first time in September 1995, one feature that they noticed was cupped discs; and that both said that AGA never informed them prior to the despatch of the later consignment that a change had been made to introduce cupped discs. That evidence is to be placed alongside Mr Gougeon’s acknowledgment that if such a change was going to be made, he would expect AGA to have informed the clinicians accordingly.

As for Mr Gougeon, although he was also an honest witness, I think his evidence demonstrated that, as one would expect, he had much less reason to focus on the detailed shape of the device than the doctors who used them in carrying out the clinical procedures.

There was also evidence regarding the moulds used to make the devices. Mr Gougeon said that commercial moulds for production of cupped devices were only made after AGA moved to its new premises in November 1995. However, he accepted that the devices used in the trials conducted at the University of Minnesota Hospital, which went through several prototypes, might have involved changes to the moulds used there. But Mr Gougeon explained that although he would have seen those moulds, he was not involved in the development process or the animal studies that were conducted by Dr Amplatz, with the assistance of colleagues including Dr Gu. Accordingly, since only a small number of devices were taken by Dr Amplatz to Bratislava in September 1995, for the purpose of clinical trials prior to the start of commercial production of the Amplatzer, the position regarding commercial moulds takes the matter no further. There was no evidence regarding the previous moulds used in the development process.

Accordingly, I find that at least some of the three devices implanted in children in Bratislava in September 1995 had a disc that was cupped on the inside.

Of the two other doctors involved in the Bratislava 1995 procedures, Dr Formanek died in 1996. Dr Amplatz is fortunately very much alive and would have been an obvious and very relevant witness for AGA to call. In answer to a question from the Court, Mr Gougeon, who was his son-in-law, said that Dr Amplatz is in good health and he could suggest no reason why Dr Amplatz was not giving evidence. At the conclusion of all the evidence on 11 October, before the Court adjourned for the parties to prepare their closing submissions, I asked Mr Meade to address in his closing whether this might be an appropriate case for the Court to draw an adverse inference from the failure of AGA to call Dr Amplatz to give evidence. When the trial resumed on 14 October, AGA applied to re-open its case and call Dr Amplatz. As stated above, I refused that application for reasons set out in a separate judgment delivered at the time. But in the light of that application, I think it would be inappropriate to draw any inference from the lack of testimony from Dr Amplatz. My conclusion as to the shape of the devices implanted in September 1995 is therefore reached solely on the basis of the evidence which was before the Court.

It is well established that a disclosure will only form part of the state of the art if it was made available to the public; and that for this purpose, it must have been made available to at least one person who was free in law and equity to use it: Terrell on the Law of Patents (17^th edn, 2011), para 11-14. Accordingly, it is necessary to consider whether the disclosure to the Slovak doctors placed them under an obligation of confidence. Although this disclosure was made on behalf of an American company to Slovak doctors in Bratislava, both sides were content to argue the case on the basis that the relevant principles were those of English law. Neither side sought to present evidence of any foreign law of confidence.

The basis on which a duty of confidence arises in English law was expressed by Lord Goff as follows, in his speech in the Spycatcher case, A-G v Guardian Newspapers (No 2) [1990] 1 AC 109 at 281:

“I start with the broad general principle (which I do not intend in any way to be definitive) that a duty of confidence arises when confidential information comes to the knowledge of a person … in circumstances where he has notice, or is held to have agreed, that the information is confidential, with the effect that it would be just in all the circumstances that he should be precluded from disclosing the information to others.”

This approach was cited with approval by Lord Nicholls in Campbell v Mirror Group Newspapers [2004] UKHL 22, [2004] 2 AC 457, where he stated at [14]:

“Now the law imposes a 'duty of confidence' whenever a person receives information he knows or ought to know is fairly and reasonably to be regarded as confidential.”

See also per Lord Hoffmann at [48], stating that Lord Goff’s statement of principle is now firmly established.

It is also helpful to set out the oft-cited explication by Megarry J in Coco v AN Clark (Engineers) Ltd [1969] RPC 41 at 47-48, of the circumstances in which an obligation of confidentiality would be imposed:

“It seems to me that if the circumstances are such that any reasonable man standing in the shoes of the recipient of the information would have realised that upon reasonable grounds the information was being given to him in confidence, then this should suffice to impose upon him the equitable obligation of confidence. In particular, where information of commercial or industrial value is given on a business-like basis and with some avowed common object in mind, such as a joint venture or the manufacture of articles by one party for the other, I would regard the recipient as carrying a heavy burden if he seeks to repel a contention that he was bound by an obligation of confidence”

Here, the devices implanted in September 1995 were provided to the Bratislava Children’s Hospital without charge. There is no suggestion that Prof Masura, Dr Gavora or any of the other medical personnel involved were under an express obligation of confidence. They were not asked to sign any form of confidentiality or non-disclosure undertaking by AGA or Dr Amplatz. Accordingly, the question is whether they were under a duty of confidence in equity. In that regard, AGA submitted that such a duty arose from the circumstances of this being a clinical trial of new medical devices.

In my judgment, there is no presumption of confidentiality simply because this was a clinical trial. Everything depends on the facts. The various cases referred to in Terrell at para 11-16 are simply illustrations of the application of the general principle to particular facts. See also the extensive discussion in Gurry on Breach of Confidence (2^nd edn, 2012), chap 7.

Here, both Prof Masura and Dr Gavora were emphatic that they were never given any indication or impression that the details of the devices they used in September 1995 were to be kept confidential. Dr Amplatz obviously discussed the new device and implantation procedure with them when he came to Bratislava but he said nothing about confidentiality. Prof Masura spoke subsequently about the device in briefing sessions he gave to other doctors in the Bratislava Children’s Hospital. It also emerged in his oral evidence that he discussed the new device and the success of the clinical trials in a presentation he made to a wider medical audience at a paediatric congress in Slovakia in November 1995.

For AGA, Mr Meade emphasised that Prof Masura could not recall whether in speaking at this congress he mentioned that the discs in the occluder were cupped. However, that is beside the point. The disclosure relied on by Occlutech is not disclosure to other doctors by Prof Masura, but the disclosure to Prof Masura himself (and to Dr Gavora). Either the devices were given to those doctors by Dr Amplatz in September 1995 in circumstances giving rise to an obligation of confidence or they were not. It cannot tenably be held that the circumstances were such that Prof Masura and Dr Gavora were free to talk about all aspects of the occluders except only for the fact that they were cupped, and that this aspect alone was subject to an equitable duty of confidence.

The wider disclosure by Prof Masura is accordingly relevant to the question of whether he was under an equitable duty of confidence. If he were, his presentation at the congress would have breached it. Since I consider that he would never have wished to betray a confidence placed in him by Dr Amplatz, I think it demonstrates that he did not perceive himself to be subject to a duty of confidence.

Dr Gavora explained why he did not regard the nature of the device they implanted in September 1995 as confidential, in answer to a question from Mr Meade suggesting that it would have been wrong to speak to a competitor developing atrial septal occluders about this:

“It would be wrong when Dr. Amplatz will tell us that this is wrong, but Dr. Amplatz did not tell us anything about confidentiality. He came like the best friend of Dr. Formanek, who has passed [away] since 1996. … We were talking with him and during all these talks, there was no word about confidentiality. He came like a professor of radiology. He did not come like a businessman and he did not talk not one word about this. So at that time in Slovakia, 1995, we did not think that even something like this could be, really [sic], and we never signed any document. Maybe Masura signed something. You should again ask him,”

As I have already observed, there is no suggestion that Prof Masura ever signed any confidentiality undertaking.

In my judgment, it is not surprising that Prof Masura and Dr Gavora did not regard the nature of the devices they were brought by Dr Amplatz for implantation as confidential. Prof Masura was not embarking on a commercial venture with AGA or Dr Amplatz. The disclosure to him was not, to adopt the language of Megarry J in Coco v Clark, “on a business-like basis and with some avowed common [commercial] object in mind”. Since the device was, in Prof Masura’s words, “revolutionary” and fulfilled a long-sought objective to create a device that would effectively occlude ASDs in children and avoid the need for open heart surgery, and since these trials were a major event for Prof Masura and his medical team, it was only natural that he would wish to speak about it, and the successful trials he conducted, to a wider medical audience.

Moreover, Prof Masura said that, as one would expect, Dr Amplatz’ visit and the procedures carried out that day in September 1995 had been preceded by exchanges by letter and fax to prepare for the trials. I consider that it was reasonable for Prof Masura to assume that if the details of the clinical trials, and the device used, were to be kept confidential, he would have been told something to that effect by Dr Amplatz before they took place even if he was not asked to give any formal undertaking. Applying Lord Nicholls’ formulation, I do not consider, in all the circumstances, that just because this was the first clinical trial, Prof Masura ought to have known that it was fairly and reasonably to be regarded as confidential.

In Carflow Products (UK) Ltd v Linwood Securities (B’ham) Ltd [1996] FSR 447, a case concerning a registered design, it was argued that when the defendant disclosed a prototype of his proposed product to a buyer at Argos with a view to seeing if Argos would be interested in the product, that disclosure was subject to an equitable obligation of confidence. Jacob J rejected that argument. He held that the test was subjective, based on the unspoken views of the parties, rather than objective. The judge found on the evidence that the parties did not think that there was an obligation of confidence, but he proceeded in the alternative to apply an objective test:

“On an objective basis what is the position? What would a bystander say about the meeting [between the designer (Footnote: ³) and the Argos representative], assuming he heard and saw all that went on but could not see into the minds of the parties? He would know that the product was a prototype. He would know, I think it fair to assume, that our law provides a variety of ways in which the design of a product may be protected (unregistered design right, registered design, or even patent for an invention). He would know that the would-be seller is promoting his wares or potential wares. I cannot think that on an objective basis the reasonable man would think an obligation of confidence was being imposed merely because a prototype of what was being offered for sale was shown.”

And after referring to the passage from Megarry J’s judgment in Coco v Clark that I have quoted above, Jacob J continued (at 430):

“But all depends on the circumstance. And where the law provides a variety of methods, optional (in the case of rights which must be registered) or automatic (in the case of copyright and design right) I do not think the reasonable recipient must assume that he is placing himself under an obligation of confidence in respect of matter which could be protected independently.”

I was not addressed on the question of whether the test is subjective or objective, nor was I referred to the Carflow Products case. But if the test is subjective, then as regards an enforceable obligation of confidence the evidence was effectively all one way. If the test is objective, then for the reasons I have set out, I do not consider that the disclosure was confidential. It could reasonably be assumed that patent protection is available for a newly developed and innovative device; and further, that a US doctor undertaking that development would take the appropriate steps to safeguard such patent protection as he or his company desired. Together with the reasons I have already set out, those facts provide a further ground why, objectively, the disclosure by provision of the devices for the clinical trials in Bratislava was not such as to give rise, by itself, to an obligation of confidentiality.

Indeed, I think that the most likely explanation of what occurred is that at the time Dr Amplatz believed that a confidentiality undertaking was unnecessary since his device already benefited from patent protection by reason of an earlier patent filing in the United States on 8 July 1994. That led to a PCT application in July 1995 that claimed priority from that earlier date, and ultimately led to the European Patent of which the UK designation was the subject of the previous action between these parties in this Court. Alternatively, AGA may not have appreciated that the EPC operates a ‘first to file’ regime for priority in contrast to the ‘first to invent’ regime that prevailed at the time in the United States. This would also explain why AGA was content for Dr Gu to make a presentation of the uncupped device in March 1996 at a medical congress, which self-evidently was not confidential, apparently unconcerned that any subsequent patent application for a modified device might as a result face a challenge (as here) on the grounds of obviousness. However, this is speculation and not the basis of my decision.

I note that the Opposition Division of the EPO, in their decision given after the conclusion of the hearing in the present case, held that the disclosure in September 1995 was confidential since that was a clinical trial, which they held gave rise to a prima facie assumption of an obligation of confidentiality that had not been rebutted: decision at pp 30-34. However, as I have explained, as a matter of English law, everything depends on the actual circumstances surrounding the clinical trial, on which I heard detailed evidence. I reach my conclusion, under English law, based on the full evidence given in this Court.

In the light of my conclusion on novelty, the other grounds of challenge to the Patent are academic. Nonetheless, as they were fully argued, it is appropriate to determine them.

The primary evidence as to obviousness was given by the following experts:

Both cardiologists are clearly distinguished specialists, and they gave carefully considered evidence. Where it is necessary to decide as between them, I do so, as will become apparent, on the basis of the persuasiveness of the reasons they gave for their opinions.

As regards the two medical engineers, Mr Wallace was an honest witness but I found him somewhat defensive in his testimony. He had clearly relied on Dr Brecker in coming to a view of the various previous devices. Prof Williams gave very clear evidence but there was a curiosity as regards his opinion as to the desirable shape of the discs, where there was a change in emphasis in his evidence to this court from his expert evidence in the proceedings in the Hague. Although his expert report here clearly derived from his statements to the Dutch court (certain passages were reproduced verbatim), his Dutch evidence included the statement that “ideally contact [with the septum] should be uniform across the whole area of the disc”, which did not appear in his report for these proceedings. Since the Dutch judgment specifically relied on that statement in support of its conclusion that the cupped design in the Patent was not obvious over the Gu presentation, it was put to Prof Williams that he changed his approach following the Dutch judgment to produce a view more favourable to Occlutech’s case. Prof Williams rejected that suggestion and said that he not seen the Dutch judgment before. I of course accept that as true, but I find it difficult to avoid the inference that what he acknowledged was a change of emphasis (albeit he described it as “minor”) was in response to a suggestion that he might express himself differently. However, in the end I have been able to determine the issue of obviousness on the basis of the evidence of the cardiologists and it is not necessary to reach a view on the reliability of this part of Prof Williams’ evidence.

It was common ground that the notional person ‘skilled in the art’ was a team that would include at least a cardiologist and a medical device engineer. The cardiologist would have an interest in structural defects of the heart, and the engineer would be aware of the technical aspects of the design of an implantable device, relying on the cardiologist to explain the purpose and characteristics of the device required. There was a minor dispute as to whether the team would also include a textile engineer with experience in braiding; but it was accepted that if it did not, the team would consult a textile engineer as necessary to deal with manufacturing issues regarding braided fabric. Both Mr Meade and Mr Lykiardopoulos accepted that it is unnecessary to decide this limited dispute.

The law as to the common general knowledge (“CGK”) has received repeated judicial statement and it is unnecessary to rehearse it. For a recent exposition, see the judgment of Arnold J in KCI Licensing Inc v Smith & Nephew [2010] EWHC 1487 (Pat), [2010] FSR 31 at [105]-[115]; approved on appeal, [2010] EWCA Civ 1260, [2011] FSR 8 at [6].

Here, the CGK obviously includes the nature of the atria and septum of the heart and the characteristics and variability of ASDs (and PFOs).

It was also agreed by the two cardiologists that as at May 1996 there was interest in development of a device that could be used for percutaneous closure of the majority of ASDs since none of the various devices that had been produced up to that time was considered adequate.

There was also broad agreement between the experts as to the desirable characteristics of an effective atrial septal occluder. Obviously, a primary requirement is that it is effective in occluding (closing) the defect. The more specific requirements were:

Prof Gewillig considered that a further requirement was that the device achieved fast endothelialisation (i.e. incorporation of the device into the body by cell growth over it), whereas Dr Brecker’s opinion was that speed of endothelialisation was a bonus but not a key consideration. I do not regard this difference as material to the issues in this case: the experts agreed that the device needs to aid endothelialisation.

One of the articles from medical journals adduced in evidence by Dr Brecker also provides a helpful statement of some of the desirable characteristics of the process: (Footnote: ⁴)

“Transcatheter closure of atrial septal defects depends on an adequate rim of septal tissue surrounding the defect, as the device has to cover the defect and bear on an adequate amount of septal tissue for both sufficient occlusion of the defect and firm attachment of the device to the atrial septum. The latter also seems to be important for endothelialisation of the device.”

AGA’s primary submission in opening was that because those other occluders had significant technical issues associated with them, and some had indeed been withdrawn, they did not form part of the CGK because “they would not be considered to be a good basis for further action.” I do not agree: the fact that a device had been withdrawn because it had been found inadequate does not mean that it cannot be CGK. The same applies to devices that were undergoing clinical trials, particularly if those devices were intended to meet a well-recognised need so that the trials would attract the attention of those in the field. Prof Gewillig in his evidence was clear that interventional and paediatric cardiologists, as of May 1996, were well aware of the previously tried devices and followed with interest the progress being made with the development of new devices. And Dr Brecker, who was not a paediatric cardiologist but nonetheless attended meetings of paediatric cardiologists at the hospital where he was doing his specialist training in 1990-1994, said that he was aware at the time of the device introduced by King & Mills, originally described in the 1970s; that he had heard about the devices developed by Rashkind (in about 1975); and he referred to the interest generated by the clamshell devices, involving two opposing umbrella-shapes. Those were first introduced around 1989 and further variations were developed thereafter.

AGA submitted in the alternative that if the previous devices were CGK, “so were their technical shortcomings”. This seems to me the correct view, borne out by the evidence of both the cardiologist experts. Dr Brecker, on whose evidence AGA relied, said in his first report that paediatric cardiologists would share their experience of particular septal occluders with cardiology colleagues through informal discussions as well as more formal presentations. And in his oral evidence he said:

“… I think that the prevailing attitude, if you go to 1996, was that all of the devices had problems. I mean the talk amongst cardiologists were [sic], ‘Did you hear about that device that embolised’.”

That indeed brings out a point made by Prof Gewillig, that the CGK was not confined to what was set out in written papers, which often do not emphasise the problems, but included the subject of discussions that took place between the participants at cardiology conferences and meetings.

Therefore, it seems to me both logical and, indeed, obvious that a cardiologist interested in an ASD occluder would look at a new proposal or patent not only with regard to the desirable objectives but also against the background of the previous devices, since a very relevant issue was how the new device sought to avoid the drawbacks from which those other devices suffered. As Occlutech said in their closing submissions, this is “not an art where there is so much around that a skilled person cannot quickly and relatively easily assimilate the position.”

The submission by AGA that the skilled person would simply dismiss all the previous devices as discredited and worthy of no more attention seems to me divorced from reality. Dr Brecker said in his first report, in the context of the CGK and the experience that a cardiologist would bring to the skilled team:

“The cardiologist might have been able to give input about what was good and bad about the devices that were commercially available but would need the assistance of the engineer to develop an improved device.”

I think that describes succinctly the approach that the notional skilled person would adopt, save only that I think the cardiologist’s knowledge and views would not be restricted to what was commercially available but would extend to devices undergoing trials, about which he would have learnt (and which thus became part of the CGK) not only from published papers but through the informal discussions to which I have referred.

In my view, three particular devices which had been tried or were undergoing trials as at May 1996 require consideration:

Dr Gu’s presentation (the “Gu presentation”) was made to the annual scientific meeting of the Society of Cardiovascular and Interventional Radiology meeting in Seattle on 7 March 1996. An abstract summary was published shortly beforehand. The presentation was entitled: “Transcatheter Closure of Secundum Atrial Septal Defects Using a New Self-expanding Nitinol Prosthesis.” It describes a strong, round, double-button device without hooks, with a short connecting waist, made from Nitinol wire with polyester stuffing (the “Gu device”), that is introduced through a small delivery system. The presentation states that the waist sizes of the device vary to correspond to the sizes of the ASD. A photograph of the Gu device in its expanded state, included in the presentation, is set out below:

The Gu presentation reports the result of testing the device on animals. A hole was surgically punched in the centre of the atrial septum of 9 young swines to create ASDs with a range, when balloon stretched, of 10-18 mm diameter. In one pig there was partial migration into the right atrium at one month follow-up. In the remaining cases, 58.3% closure was achieved after placement, rising to 75% closure after one week and 100% after 3 months. (Footnote: ⁵) Complete endothelialisation occurred between one and three months after placement. The last point is one of the three bullet points set out in the “Conclusions” slide of the Gu presentation:

•

“Permanent closure of moderate to large secundum ASD is feasible using this device

•

Complete endothelialization occurs between 1 and 3 months after placement

•

Accurate determination of ASD location and size, presence of sufficient atrial septal rim, and selection of an appropriate size device are essential to avoid dislodgement”

It was common ground that the critical difference between the Gu device and the subject-matter of the Patent is that both discs in the Gu device are flat.

The correct approach to obviousness has been stated repeatedly in the case law. The principles were recently summarised by Kitchin LJ (with whose judgment Moses and Longmore LJJ agreed) in Regeneron Pharmaceuticals Inc v. Genentech Inc [2013] EWCA Civ 93. Kitchin LJ quoted at [69] the following passage from the judgment of Jacob LJ in Conor Medsystems Inc v Angiotech Pharmaceuticals [2007] EWCA Civ 5 at [45], apparently approved by the House of Lords in that case:

“In the end the question is simply “was the invention obvious?”. This involves taking into account a number of factors, for instance the attributes and cgk of the skilled man, the difference between what is claimed and the prior art, whether there is a motive provided or hinted by the prior art and so on. Some factors are more important than others. Sometimes commercial success can demonstrate that an idea was a good one. In others “obvious to try” may come into the assessment. But such a formula cannot itself necessarily provide the answer. Of particular importance is of course the nature of the invention itself.”

Further, pointing out that Lord Hoffmann in Conor explained that the notion of something being obvious to try is useful only where there is a fair expectation of success, Kitchin LJ quoted from his own judgment in MedImmune Ltd v Novartis Pharmaceuticals Ltd [2012] EWCA Civ 1234:

“90.

One of the matters which it may be appropriate to take into account is whether it was obvious to try a particular route to an improved product or process. There may be no certainty of success but the skilled person might nevertheless assess the prospects of success as being sufficient to warrant a trial. In some circumstances this may be sufficient to render an invention obvious. On the other hand, there are areas of technology such as pharmaceuticals and biotechnology which are heavily dependent on research, and where workers are faced with many possible avenues to explore but have little idea if any one of them will prove fruitful. Nevertheless they do pursue them in the hope that they will find new and useful products. They plainly would not carry out this work if the prospects of success were so low as not to make them worthwhile. But denial of patent protection in all such cases would act as a significant deterrent to research.

91.

For these reasons, the judgments of the courts in England and Wales and of the Boards of Appeal of the EPO often reveal an enquiry by the tribunal into whether it was obvious to pursue a particular approach with a reasonable or fair expectation of success as opposed to a hope to succeed. Whether a route has a reasonable or fair prospect of success will depend upon all the circumstances including an ability rationally to predict a successful outcome, how long the project may take, the extent to which the field is unexplored, the complexity or otherwise of any necessary experiments, whether such experiments can be performed by routine means and whether the skilled person will have to make a series of correct decisions along the way….”

As Laddie J put it succinctly in Pfizer Ltd’s Patent [2001] FSR 16 at [66], the question is: “what would the skilled addressee think and do on the basis of this disclosure?” And in Brugger v. Medic-Aid Ltd [1996] RPC 635 at 661, he observed that if a particular route is an obvious one to take or try, it is not rendered less obvious from a technical standpoint merely because there are a number (and perhaps a large number) of other obvious routes to take.

Accordingly, the key question is whether the development of a device with at least one cupped disc was obvious over the Gu device, in light of the Gu presentation.

Dr Brecker’s view was that the Gu presentation showed that the results with the Gu device were good and that the next step was to try that device in humans. The sole problem disclosed was the migration of the device in one pig, but the abstract indicated that this was due to the waist in that device being substantially smaller than the ASD. The only modification that would be suggested from the Gu presentation would be to address this risk of dislodgment, for which the obvious change would be to reduce the length of the waist or ensure a more intimate fit between the waist and the defect, an aspect emphasised in any event in Dr Gu’s conclusions: see para 71 above. In particular, Dr Brecker did not consider that curving or cupping the discs was an obvious modification. Moreover, since there had been problems with the previous devices, not only would they not be a good starting point for the design of a new device but they were effectively discredited, so the skilled person would not have regard to them in determining what modifications to the Gu device should be made or attempted.

Prof Gewillig, by contrast, considered that the skilled person would realise that while the device in the Gu presentation had great potential, it would require modification. The results there reported were for a very limited number of animal cases in idealised conditions: holes of regular and relatively small size, made artificially in the centre of the septum. A 20 mm ASD would easily stretch up to 30 mm and holes of that size were not included in this trial. Even those results showed that it was important to make the device more stable, and the skilled person would therefore consider various ways to achieve that effectively.

Moreover, Prof Gewillig considered that the use of such a device with flat discs in humans would give rise to a serious risk of clotting, i.e. a thrombus forming between the edge of the disc and the septum that might break away and embolise. He explained this as follows, emphasising the difference in thickness between the septum secundum and the much thinner septum primum and illustrating his answer with a sketch he made in court that is reproduced below:

“The septum in an ASD can be at parts very thin in children and typically the septum primum is membrane. Sometimes you even do not see it very well -- I mean you do not see the edge with echo from outside [i.e., ultrasound imaging]. It is so thin. So let us assume that, okay, we here have a septum secundum and this will be over there; now you get the septum primum and the other side, like this. [Drawing] We know that the filling over here, the filling is there to promote it is Dacron. You use Dacron as a thrombogenic factor, to promote clotting. If you see that with Dacron, you know okay, you cannot get a clot all the way over the device. Now we have here a space with low flow and a clot on the edge. You do not need to be brilliant to understand that, sooner or later, in a significant fraction of the patients, you will have clot over here. Okay, like this it still does not look too bad, but now your patient is going to cough. What does this mean? All of a sudden, a big pressure on this septum. This clot at this moment is mobile. What will happen? It flies away. If you are unlucky, it is straight into your brain. So you do not want to have a thing like that open, asking for a lateral, free, embolisable clot. The way the other devices dealt with this problem, it was one of the ways that they were designed, is to bring the device all the way down to the edge. It is a safety issue. A clot in the heart is both our enemy and our friend. You do not want too much of it, but you need it for the device to work.”

It was put to Prof Gewillig that the problem he described, of a thrombus forming and embolising, is not referred to in the Gu presentation. His response was as follows:

“A. No, but first of all, it is only nine experiments and apparently what they report is that they only looked at the heart. If you really want to look for thrombus, where would thrombus go to, if it is on the right side, it would fly into your lungs; if it was on the left side, it would fly anywhere in your body. That means you would have to go for a full autopsy of the pig. I did not read any data on full autopsy of the pig.

Q. You have no way of knowing whether they did it or did not do it?

A. No.

Q. Would you assume that they did?

A.

Even if they did, it would be very, very, very difficult to exclude. You see, a clot can fly away and if it obstructs a blood vessel, typically, for instance, in the lungs, it will dissolve within half-an-hour to 12 hours, 24 hours, so it can fade away. The only problem is if that happens to your brain if your brain does not have oxygen for five minutes, it is gone. In your brain, you would know it because there would be a neurological lesion. If it would fly anywhere else, you might miss it.”

I found the evidence of Prof Gewillig in this regard compelling. Although Dr Brecker did not regard the possibility of a blood clot under the disc as a realistic possibility, (he said he had never seen “real evidence that that happens acutely”), Prof Gewellig noted that even in the animal trial with regular holes there was a residual shunt after placement in over 40% of cases, which he said is likely to lead to clotting. Prof Gewellig fully accepted that his drawing was a simplified, schematic illustration as the discs would be closer to the septum, but explained the effect of the relative difference in thickness between the septum primum and secundum, which meant that it would be very difficult to ensure that the discs pressed flat against the surface of both parts of the septum. This led to a real possibility of thrombus formation under at least part of the discs. If the waist of the device was much reduced to approximate to the thickness of the septum primum, then conversely the side at the septum secundum was at risk of splaying out. Either way, movement of the septum caused, for example, by the patient’s cough on a beating heart gave rise to a risk of a clot embolising. Although the risk may be relatively small, the consequences could be devastating. It is appropriate to quote Prof Gewillig again:

“I mean, you may not underestimate the importance of clotting or not clotting. Having a stroke in a patient is disaster. Even if it would occur once in a hundred or once in a thousand, it is too much. Most of those patients that we treat are healthy children. They only are threatened, their health is threatened 30 years later. We cannot afford to introduce a device with even a small risk of clot. You just may not, full stop.”

I accept Prof Gewillig’s evidence and conclude that the skilled addressee would therefore be alert to the risk of a thrombus embolising from beneath the discs and seek to do everything possible to avoid it. Dr Brecker in fact agreed that if thrombus formation was a possibility (which he discounted), one would then have to be very careful to prevent it embolising. And I note that in his first report, when addressing the commercial success of the Amplatzer (which was no longer an issue at trial), Dr Brecker included as one reason:

“the incidence of blood clots with the Amplatzer devices is significantly lower than with other devices. I have never seen any thrombus with the Amplatzer devices;…”

That confirms, in my view, that the possibility of blood clots would be a concern to which the skilled person would be alert when considering any ASD occluder, and thus when assessing the Gu device.

Faced with the desire to modify the Gu device to achieve not only greater stability and also safeguard against the risk of embolisation of a thrombus, I consider that curving down (or cupping) the ends of at least one of the discs so as to achieve greater pressure in pushing the septum against the other disc, was a modification that would appear obvious. Configuring the discs to achieve a backward push onto the septum was an approach suggested by the previous devices. The problem with the previous devices had been not the umbrella shape but the fact that such a design pushed down on only four or five points, whereas with the circular discs of metal braid in the Gu device, cupping would achieve a downward push all the way around.

In short, I accept Prof Gewillig’s evidence that whereas the Gu device would be seen by the skilled addressee as of great interest and as a way of avoiding the shortcomings of the previous devices, he would regard it as requiring further modification to make it appropriate for widespread use in humans; and that what the skilled addressee would think and do would probably be to introduce the concept of curving down to increase the pressure at the perimeter, which as a concept was being used in the ASDOS device and had been attempted long before in the Clamshell. Cupping to achieve a tight seal at the edge also had the advantage of aiding endothelialisation, which was a necessary feature of an ASD occluder. Moreover, such an adaptation of the Gu device was hardly complex: on the contrary, it involved no further research and little expense. I should add that I did not find any sign that Prof Gewillig’s views were vitiated by hindsight.

As will be apparent, I have reached this conclusion on the basis of the primary evidence of the cardiology experts. I found the evidence of the two engineering experts much less relevant in this regard: they both agreed that they would approach the question of whether to make any modification of the Gu device in discussion with a cardiologist. But I note that Mr Wallace said that as an engineer working on a new device, he would wish to know why the prior devices had failed. He rather downplayed the significance of the Gu presentation and the Gu device for making any device for humans, on the basis that this was a small study conducted only in animals. Beyond that, although AGA in its written closing submissions contended that to reduce the risk of dislodgment the obvious change would be to increase the size of the discs (a suggestion put forward by Prof Gewillig), Mr Wallace’s evidence was that bigger discs would be harder to deliver in the small catheter necessary for implementation in children and Dr Brecker also said that he considered bigger discs were harder to deploy.

Mr Wallace’s preferred solution to any risk of movement and to achieve greater contact with the septum would be to shorten the waist and he would not have thought of cupping the discs, whereas Prof Williams thought that cupping was an obvious way to achieve good contact with the septum as this allows for the variability in the septum.

However, the issue for determination is not what is the most likely modification that the skilled addressee might make to the Gu device. As I have observed above, the fact that there may be a number of other obvious modifications does not mean that the modification at issue, i.e. the change between the prior art and the patented device, is not obvious. Shortening the waist may have been one obvious modification, and clearly ensuring a tight fit in the defect is desirable. Whether enlarging the discs was a desirable change is less clear on the evidence. But in my judgment, cupping at least one of the discs to achieve greater contact pressure of the device on the septum, was also an obvious change, and one that would best address the perhaps small but significant risk of a thrombus embolising.

A challenge to validity on the grounds of insufficiency is based on sect. 72(1)(c) of the Patents Act 1977. This 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”.

This provision, and the scope of an insufficiency challenge, was considered by the House of Lords in Kirin Amgen v Hoechst Marion Roussel Ltd [2004] UKHL 46, [2005] RPC 9. After quoting the statutory language, Lord Hoffmann, who gave the leading judgment with which the other four members of the Appellate Committee agreed, explained at [102]-[103]:

“That means that the disclosure must enable the invention to be performed to the full extent of the monopoly claimed: see Biogen Inc v Medeva plc [1997] RPC 1, 48.

Whether the specification is sufficient or not is highly sensitive to the nature of the invention. The first step is to identify the invention and decide what it claims to enable the skilled man to do. Then one can ask whether the specification enables him to do it. For example, in American Home Products Corporation v Novartis Pharmaceuticals UK Ltd [2001] RPC 159 the patentee claimed that the known drug rapamycin and any of its derivatives could be put to a new use. But the claim for such use of all derivatives was not enabled because only some derivatives could be so used and the specification did not enable the skilled man to identify which they were. The answer may well have been different if the claim was to a new process for making rapamycin and its derivatives or if rapamycin and its derivatives had been new products.”

Further, addressing the issue in the case itself, Lord Hoffmann stated, at [126]:

“If the claim says that you must use an acid, and there is nothing in the specification or context to tell you which acid, and the invention will work with some acids but not with others but finding out which ones work will need extensive experiments, then that in my opinion is not merely lack of clarity; it is insufficiency. The lack of clarity does not merely create a fuzzy boundary between that which will work and that which will not. It makes it impossible to work the invention at all until one has found out what ingredient is needed.”

In the end, the only ground of insufficiency pursued by Occlutech related to a question of construction, regarding integer (7) of claim 1: that at least one of the discs should be cupped so that its perimeter edge would, in use, “fully engage the sidewall of the septum”. Occlutech submitted that this meant engagement without any gaps all the way around the perimeter edge, but that this was difficult to achieve and impossible to measure. If something less than that was meant, then the claim is too uncertain and one could not tell what was, and was not, within it.

However, I do not think the skilled person would read this integer literally, in the sense of precluding any gap to any degree at any point around the cupped perimeter of the disc. As Dr Brecker said, while the design implies that there is no gap, the skilled person would understand that as the septum is not completely flat, there will be some points of no contact. Thus, I consider that “full engagement” does not equate to perfect engagement with not even minimal gaps, but means that any gaps would be insignificant and unintentional.

Once this integer is so construed, the point about insufficiency falls away. The Patent teaches how that is achieved: through the cup shape combined with the short cylindrical waist that approximates to the thickness of the septum. There is no lack of clarity and the teaching is sufficient to enable the device to be made to the full extent of the claim.

A patent will be liable to revocation if the matter disclosed in the specification of the patent extends beyond that disclosed in application for the patent as filed: sect 72(1)(d) of the Patents Act 1977 and Art. 123(2) EPC. The law in that regard is well established and was not in dispute. The principles were set out and explained by Kitchin J in European Central Bank v Document Security Systems [2007] EWHC 600 (Pat) and his summary was accepted and adopted by the Court of Appeal in the same case:

“96.

The test for added matter was explained by Aldous J in Bonzel v Intervention Ltd [1991] RPC 553 at 574:

“The decision as to whether there was an extension of disclosure must be made on a comparison of the two documents read through the eyes of a skilled addressee. The task of the Court is threefold:

(a)

To ascertain through the eyes of the skilled addressee what is disclosed, both explicitly and implicitly in the application.

(b)

To do the same in respect of the patent as granted.

(c)

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.”

97.

A number of points emerge from this formulation which have a particular bearing on the present case and merit a little elaboration. First, it requires the court to construe both the original application and specification to determine what they disclose. For this purpose the claims form part of the disclosure (s.130(3) of the Act), though clearly not everything which falls within the scope of the claims is necessarily disclosed.

98.

Second, it is the court which must carry out the exercise and it must do so through the eyes of the skilled addressee. Such a person will approach the documents with the benefit of the common general knowledge.

99.

Third, the two disclosures must be compared to see whether any subject matter relevant to the invention has been added. This comparison is a strict one. Subject matter will be added unless it is clearly and unambiguously disclosed in the application as filed.

100.

Fourth, it is appropriate to consider what has been disclosed both expressly and implicitly. Thus the addition of a reference to that which the skilled person would take for granted does not matter: DSM NV’s Patent [2001] RPC 25 at [195]-[202]. On the other hand, it is to be emphasised that this is not an obviousness test. A patentee is not permitted to add matter by amendment which would have been obvious to the skilled person from the application.

101.

Fifth, the issue is whether subject matter relevant to the invention has been added. In case G1/93, Advanced Semiconductor Products, the Enlarged Board of Appeal of the EPO stated (at paragraph [9] of its reasons) that the idea underlying Art. 123(2) is that that an applicant should not be allowed to improve his position by adding subject matter not disclosed in the application as filed, which would give him an unwarranted advantage and could be damaging to the legal security of third parties relying on the content of the original application. At paragraph [16] it explained that whether an added feature which limits the scope of protection is contrary to Art 123(2) must be determined from all the circumstances. If it provides a technical contribution to the subject matter of the claimed invention then it would give an unwarranted advantage to the patentee. If, on the other hand, the feature merely excludes protection for part of the subject matter of the claimed invention as covered by the application as filed, the adding of such a feature cannot reasonably be considered to give any unwarranted advantage to the applicant. Nor does it adversely affect the interests of third parties.

102.

Sixth, it is important to avoid hindsight. Care must be taken to consider the disclosure of the application through the eyes of a skilled person who has not seen the amended specification and consequently does not know what he is looking for. This is particularly important where the subject matter is said to be implicitly disclosed in the original specification.”

It is also helpful to quote the succinct encapsulation of the test by Jacobs J in Richardson-Vicks' Patent [1995] RPC 568 at 576:

“I think the test of added matter is whether a skilled man would, upon looking at the amended specification, learn anything about the invention which he could not learn from the unamended specification.”

As is apparent from the above, in determining a challenge for added matter, the relevant comparison between the application and the granted patent is concerned with what they disclose, not with what the claims actually cover.

There is a particular form of added matter described by the rather opaque expression, ‘intermediate generalisation’ (and for which the expression used in the EPO Guidelines, “generalising isolation”, seems to me rather more helpful). This was described by Pumfrey J in in Palmaz's European Patents (UK) [1999] RPC 47 (upheld on appeal [2000] RPC 631):

“If the specification discloses distinct sub-classes of the overall inventive concept, then it should be possible to amend down to one or other of those sub-classes, whether or not they are presented as inventively distinct in the specification before amendment. The difficulty comes when it is sought to take features which are only disclosed in a particular context and which are not disclosed as having any inventive significance and introduce them into the claim deprived of that context. This is a process sometimes called ‘intermediate generalisation’.”

Therefore, an important consideration is whether the feature in question would be seen by the skilled person as being generally applicable or only of significance in the context in which it was specifically disclosed. As Kitchin LJ said in Nokia v IPCom [2012] EWCA Civ 567 at [59]:

“It follows that it is not permissible to introduce into a claim a feature taken from a specific embodiment unless the skilled person would understand that the other features of the embodiment are not necessary to carry out the claimed invention. Put another way, it must be apparent to the skilled person that the selected feature is generally applicable to the claimed invention absent the other features of that embodiment.”

In the present case, the detailed description in the application for the Patent (‘the Application’) is virtually identical with that in the Patent, (Footnote: ⁶) as are the 27 drawings. Claim 1 of the application, however, is materially different from that in the Patent (set out in para 18 above). It reads:

“A collapsible medical device, comprising a tubular woven metal fabric having a proximal end and a distal end, each end contained by means for securing each end, said tubular woven metal fabric having an expanded preset configuration shaped to create an occlusion of an abnormal opening in a body organ, said expanded preset configuration being deformable to a lesser cross-sectional dimension for delivery through a channel in a patient’s body, the woven metal fabric having a memory property whereby the medical device tends to return to said expanded preset configuration when unconstrained.” [emphasis added]

Various grounds of added matter were alleged by Occlutech, which I address in turn.

At the forefront of its challenge was the argument that claim 1 of the Patent no longer requires the ends of the device to be “contained by means for securing each end”, e.g. by welding or clamping. Instead, in the Patent, the claim requires “the ends of the strands” of the tubular braided metal fabric to be secured, to prevent them from unravelling. (It was accepted that there was no material distinction between “braided” and “woven” in this context). As Occlutech put it: “A disclosure of containing and securing each end of the device is not the same as a disclosure of securing the ends of the strands.” It argued that in the claim of the Patent, the strands may or may not be at the ends of the device, and that therefore it no longer mattered whether the ends of the device itself are contained.

However, Occlutech of course recognised that the comparison cannot be limited to the claims. The teaching in the Application discloses that the starting material for forming the invention is a metal fabric formed of a plurality of wire strands, and illustrates two examples “suitable for use in the method of the invention” at Figures 1A and 1B.

The description proceeds to disclose how the medical device should be formed from the metal fabric. First, a piece of appropriate dimensions has to be cut. However, the application discloses that the wire strands will tend to unravel. To avoid the strands of the braid returning to their unbraided configuration, it is taught that one method is to clamp the braid at two locations before cutting, or to weld the ends of the desired length together; or if a sheet as in Figure 1B is used, to invert the fabric upon itself to form a recess or depression and then clamp it about the recess to form an empty pocket, welding the junctions of the strands together at the periphery before cutting.

AGA pointed out that Figure 1B and the description of how such a sheet may be inverted disclose a device that will be clamped only at one end. Moreover, the risk of the strands unravelling, which is expressly why claim 1 of the Patent requires them to be secured, is expressly disclosed in the Application. AGA submitted that although claim 1 of the Patent no longer requires clamping at both ends of the device, and covers a tubular braid that is closed at only one end (and therefore has strands at only one end), the latter is not disclosed by the Patent. The deletion from the claim of the requirement of clamping at both ends of the device accordingly does not teach anything additional.

Occlutech’s response was to contend that the Application covered a range of medical devices and was not limited, as was the Patent, to ASD (and PDA) occluders. Mr Lykiardopoulos submitted that the disclosure of the flat woven sheet of Figure 1B in the Application applied only to other embodiments of the invention and not to its use as an ASD occluder. The discussion of the invention as an ASD occluder is the preferred embodiment described at pp 27-30 of the Application. Mr Lykiardopoulos argued that in the context of that passage it would be clear to the skilled addressee that only a tubular braid of the Figure 1A type is used.

I do not accept Occlutech’s submission in that regard. Although the description of the preferred embodiment as an ASD occluder describes the possibility of using a Maypole braider to make the braided mesh, which I understand produces Figure 1A type tubular braid, that is only set out as one way the metal fabric could be made. I do not consider that use of Figure 1B woven sheets is therefore excluded. Occlutech had to submit that although the general disclosure in the Patent as to how the Figure 1B form “is suitable for use in the method of the invention” (para [0019]) and as to the way it can be used (see in particular para [0027]), is identically worded to the equivalent passages in the Application, those passages in the Application relate only to a different invention, i.e. an embodiment for purposes other than an ASD occluder, and so would not be understood as disclosing such use for an ASD occluder. However, the focus of the Application is on occluders for ASDs and PDAs: see the opening paragraph in the Application on the “Field of the Invention”, and then the “Summary of the Invention” (at page 3). In my judgment, while the claim in the application is manifestly of broader scope (“occlusion of an abnormal opening in a body organ” as compared to “occlusion of an abnormal opening in cardiac septal wall”), the disclosure in the Application of the Figure 1B starting material covers the invention generally, and therefore includes ASD occluders. And as Dr Greenhalgh observed, in evidence that was not challenged, a textile engineer would not see any advantage in forming the device by use of a metal braid that was open at both ends as opposed to open at only one end.

As for the need to secure the ends of the strands to prevent them from unravelling, that is clearly disclosed in the Application: see at pages 8 and 10 (lines 27-29).

Accordingly, while deletion or substitution in a patent as compared to the application can constitute added matter, I find that it does not do so in this case.

I note that the Dutch court, in its judgment of 26 September 2012, came to the same conclusion, applying the three stage test of the EPO as set out in T331/87 HOUDAILLE [1991] EPOR 194.

The Application discloses that the cup shape of the disc ensures “complete contact” between the device and the septum: page 29, lines 4-5. Claim 1 of the Patent specifies that “the perimeter edge” of the cupped disc should “fully engage the sidewall of the septum.” Occlutech alleged that this constituted added matter, on the basis that the two concepts are different and the latter was not disclosed by the Application.

I reject that argument, which Mr Lykiardopoulos did not press very vigorously. Given that the disc has a cupped shape, it is obvious that it is particularly the perimeter edge of that disc that will press against the septum. If it fully engages the wall of the septum in that way, I consider that on any sensible view that achieves the complete contact envisaged by the Application. This is not a meaningful distinction in the context of the device described by the Application and does not go beyond what was there disclosed.

This challenge is based on the fact that the cupped feature in claim 1 of the Patent is not mentioned in the claims in the Application. Occlutech contends that it is disclosed in the Application only in a particular context, in conjunction with several other features, and that it has been isolated from those features and generalised, i.e. that it amounts to an impermissible ‘intermediate generalisation’.

First, Occlutech relies on the fact that the teaching in the Application relates to a device that is contained by means of securing at both ends, whereas the cupped device in the claim of the Patent is not so limited. However, for reasons I have given above in rejecting the first ground of alleged added matter, I do not regard the disclosure of the device for use as an ASD occluder in the Application as confined to a device secured at both ends. Further, AGA submits that the skilled person would appreciate that there was no interaction between whether there were loose strands to be contained at one or both ends and the cupping feature. I agree. It is clear from a reading of the specification that the cupping feature is an independent benefit. The requirement to clamp the ends of the braided metal fabric is taught as the means of avoiding fraying at the ends, not of maintaining the cupped shape of one or both discs.

Secondly, Occlutech points to the fact that only two specific forms of cupping are disclosed in the Application: (a) where the proximal disc is flat and the distal disc is cupped and overlaps (i.e. is slightly larger than) the proximal disc; and (b) where the two discs are a mirror image of each other (i.e. both cupped). Embodiment (a) is illustrated in Figures 13-15 and embodiment (b) in Figures 17-18 (Footnote: ⁷) (although the cupping is not evident is Figures 15 and 18): see at para 17 above. However, claim 1 of the Patent merely specifies that “at least one” of the discs should be cupped towards the other. Hence the Patent covers a device with one cupped disc smaller than the flat disc. Occlutech submits that the Patent therefore takes the cupping feature out of the context of the relationship between the sizes of the discs in a way that adds matter.

However, although only those two particular embodiments with cupped discs are described and illustrated, the reason for a cupped feature is disclosed as follows (Application, page 27, lines 3-7):

“The cup shape of the disc, as illustrated in Figures 13, 14, 16 and 17, ensures complete contact between the occlusion device and the atrial septum. As such, a neo endocardium layer of endothelial forms over the occlusion device, thereby reducing the chance of bacterial endocarditis.”

That statement expressly covers both illustrated configurations. I therefore consider that it would be clear to the skilled person considering the Application that the relative disc sizes are not important in this context: the benefit being taught of a cupped feature will apply to other configurations. Accordingly, I find that there is no added matter.

I am fortified in that conclusion by the fact that the Dutch court reached the same conclusion on this point, for essentially the same reason: see at paras 4.17-4.18 of the Dutch judgment.

Finally, Occlutech contends that there is added matter in that the relevant disclosure in the Application is for the use of the device for correcting ASDs (and PFOs), whereas the claim in the Patent refers more generally to “an abnormal opening in a cardiac septal wall.” The latter would therefore cover also ventricular septal defects.

However, the disclosure in the Application includes the claims therein. The device there covered by claim 1 was expressed as designed to “create an occlusion of an abnormal opening in a body organ”. The preferred embodiment taught in the specification at pages 27-28 was for correcting an ASD or PFO but, in my judgment, when that passage is read in conjunction with the claim, the Application discloses the use of the device for the occlusion of any abnormal opening in the heart, not merely in the atrial septum. In any event, there is no additional disclosure in the Patent compared to the Application. It follows that there is no added matter.

I should add that if I were wrong about that, AGA had made a conditional application to amend the Patent to add at the end of claim 1 the words:

“wherein the medical device is for correcting an atrial septal defect or a patent foraman [sic] ovale.”

If I had found for Occlutech on this ground, I would have allowed that amendment. Although Occlutech contended that the wording of such an amended claim 1 was ambiguous, arguing that it is unclear whether “is for” amounted to a limitation, I consider that on any sensible reading that is what the skilled person would have understood the patentee to mean.

If the Patent were valid, Occlutech accepted that its products meet the features of the claim save for the “fully engage” feature. In other words, Occlutech contended that its products do not infringe either because this requirement is unclear so that one cannot show that the Occlutech products satisfy it; or because it is to be interpreted as requiring complete and uninterrupted contact between the perimeter edge of the cupped disc and the septum, and AGA cannot establish that the Occlutech occluders have that feature. This contention therefore goes no further than the points on construction and sufficiency that I have considered at paras 91-93 above. For the reasons there set out, I reject Occlutech’s arguments and find that if the Patent were valid, it would be infringed by the Occlutech products at issue.

In the light of my findings on validity, Occlutech’s counterclaim for a declaration is academic. Nonetheless, I shall address it briefly.

Occlutech seeks a declaration of non-infringement regarding its type of occluders that differ from those that are the subject of AGA’s infringement claim in that they contain no patches of fabric within the hollows of the discs but instead have a coating of polyurethane on the outside of each disc.

It will be recalled that Claim 1 of the Patent specifies as the final integer that the device includes “an occluding fibre retained within the said tubular woven fabric.” This is referred to briefly in the specification at [0104]:

“In order to increase its occluding ability, the device can contain polyester fibers.”

I do not see that Claim 1 can be read as covering occluders with no fabric inside the discs but instead a coating of thin fibre on top of the discs. Accordingly, if the Patent were valid, I would have granted a declaration of non-infringement as regards the relevant Occlutech product or products. As Mr Lykiardopoulos accepted in his closing submissions, the form of wording of such a declaration would require further attention as it has not been appropriately pleaded, although the basis of the counterclaim is clear.

For the reasons set out above, I find the Patent invalid on the grounds of anticipation or, alternatively, obviousness but reject the challenges on the basis of added matter and insufficiency. If I had found the Patent valid, I would have found that Occlutech’s products infringed but would have allowed Occlutech’s counterclaim subject only to appropriate amendment of the wording of the declaration to be granted.