Obviousness: A Paradigm Shift? – Part II

In the first part of this post, I had discussed the standard of obviousness as laid down by KSR and explained the difference between the “obvious to try” and “obviousness” standards, advocating for the most part adherence to the latter. In this part, we shall analyse Angiotech to see for ourselves if there has been a divagation from KSR.

Angiotech Pharmaceuticals Inc v. Conor Medsystems Inc (2008)
Forum: House of Lords, United Kingdom
Defendant-Appellant- Patentee: Angiotech Pharmaceuticals Inc
Plaintiff-Respondent: Conor Medsystems Inc
Decision: Appeal Allowed, Patent valid

Facts of the Case
Angiotech Pharmaceuticals Inc, a Canadian company, and the University of British Columbia are joint proprietors of European patent 0706376 which claims, among other things, a stent coated with taxol for “treating or preventing recurrent stenosis”. Conor Medsystems Inc (Conor), an American competitor, applied in both the United Kingdom and the Netherlands for revocation of the patent on the ground that the claimed invention was obvious. In the United Kingdom, before the court of first instance and the Court of Appeal, the revocation bid succeeded. However, in the Netherlands, before the District Court of The Hague it failed. Angiotech appealed in the House of Lords in the UK saying that the Dutch court was right and that the patent should be declared valid.

In the interim, both the parties reached a settlement and Conor agreed not to oppose the appeal. However, the House of Lords went ahead with the question of validity for it had to be addressed, opposition or no opposition.

Technology Involved in the Patent
Here, I quote from the judgment for the sake of brevity:

“The subject matter of the patent is a stent, a tubular metal scaffold inserted into an artery to keep it open. It is used in connection with angioplasty, one of the great modern advances in the treatment of sclerosis of the coronary arteries. A catheter carrying a balloon is inserted into the arterial system from outside (“percutaneously”), usually at the groin, and manoeuvred through the arteries to the point at which the coronary artery has become constricted or “stenosed”. There the balloon is expanded to push back the artery walls and enlarge the channel. The insertion of a stent will prevent the walls from collapsing when the catheter and balloon are withdrawn.

A serious problem with this form of intervention was that the injury caused to the inner layer of the artery by the insertion of the stent often produced an exaggerated healing response, characterised by the proliferation of smooth muscle cells forming new tissue which once again constricted the arterial channel. This is called restenosis. It affected between a third and a half of patients in whom stents had been inserted and no one knew what to do about it.”

The long and short of it is that the patent’s objective was to treat restenosis and it claimed a stent coated with taxol (a derivative from Pacific Yew tree dissolved in cremophor) to prevent proliferation of new tissue in arteries and also for cancer treatment owing to taxol’s anti-proliferative properties (the claims on cancer treatment were later abandoned for they were broad considering the fact that use of taxol was well-known in cancer literature). Interestingly, this is the bone of contention in this case; according to the supposed defendants Conor, the problem with the patent lay in the ambiguity in its assertion as to the success (not commercial but technological) of the invention. This is explained in detail in the later part of the post.

Prior Art and Issues
Instead of compartmentalizing the prior art and the discussion on the issues of the case, I would like to discuss the issues along with the prior art for it suits the analysis of this case better.

Both sides had their own sets of prior art to rely upon to support their stands. Angiotech relied on a journal article published in 1993 which specifically spoke of various options that could be tried to treat or prevent restenosis. The article sought to draw parallels between proliferation of cells in cancer tumour and smooth muscle cells in restenosis and accordingly said that the latter could also be treated using anti-proliferative drugs. (This proves my earlier observation on developments in one area affecting the thought process in another related field, however remote). Another option in the form of antithrombotic drugs was also discussed. However, the article did not specifically narrow down its choice to any particular drug nor was it particularly confident that any drug or composition was THE best solution for treatment/prevention of restenosis and this is evidenced in the following paragraph:

“[D]espite 15 years of clinical experience and research in the field of restenosis prevention, this has not yet resulted in the revelation of unequivocal beneficial effects of any particular drug. Other newer approaches likely to receive more attention in the future include anti-bodies to growth factors, gene transfer therapy and antisense oligonucleotides. Whether there is a feasible monotherapy, whether we have to focus on a drug combination, or whether we are only searching for the ‘Holy Grail’ remain to be answered.”

In the aftermath of the publication of this article, the founders of Angiotech felt that one possible approach to preventing unwanted cell proliferation was to inhibit angiogenesis (the process by which capillary blood vessels grow), since cell tissue could not grow in the absence of blood which contains the most important ingredient for growth- oxygen. Accordingly, a targeted search was launched for an anti-angiogenic agent that could be used to inhibit or prevent tissue growth in restenosis. In the process, it was found that taxol had remarkable anti-angiogenic properties even in minute concentrations.

Question: Since the 1993 article had to an extent drawn analogies in a fairly elaborate manner between the method of treatment of cancerous cells and restenosis, would it be right for the Court to debunk the patent on the basis of an “obvious to try” standard?

Discussion: If one were to apply the “obvious to try” standard here, the very fact that the patentees have taken the route suggested by the article should invalidate their patent. But then as it has been reiterated before, the article explores the concept behind the treatment and yet does not zero down on what has to be done to fight restenosis and more particularly, how does one go about achieving it. In addition to this, the article does not even give a practitioner of the art a fair idea as to how much distance, metaphorically speaking, has to be covered before a concrete solution is arrived at. On the contrary, it seems like the perfect example for prevarication and might even wean prospective inventors away from taxol-based inventions since taxol had toxic properties. Consequently, we see that the earlier paragraph which was paraphrased from the article, in a way, laid the foundation for Angiotech’s argument that the then prevalent state of art was inconclusive about any anti-proliferative drug’s ability to ward off or cure restenosis and hence proved the non-obviousness of its invention. This point is crucial for it goes a long way in helping us build a logical structure.

Let’s assume that the logical structure is in the form of a pyramid with the focus becoming sharper as we move towards the polygon vertex, generally referred to as the apex of the pyramid. The apex represents the specific inventive step of the patented invention while the building blocks leading to the apex allude to the path taken to reach the apex and the very foundation of the pyramid refers to prior art. In this case, the information disclosed in the article serve as building blocks for it is clear from the equivocal language that it is far from reaching the apex i.e. if the same information had been submitted as a patent application, it would have been rejected on grounds of lack of inventive step and lack of clarity in specification. This does not necessarily mean that the inconclusive nature of the article justifies the grant of patent to Angiotech because the latter still has to prove that it has gone that extra mile to reach the top and it has done so in a manner which was not predicted by the article.

At this juncture, the sub-issue before the Court was:

Practically speaking, all that Angiotech has done is to see if one of the paths suggested by the article yields positive results and fortunately for it, the trial led to an invention. However, to give due credit to Angiotech, since the tone of the prior art was not conclusive in nature and was pointing in several directions, the very fact that Angiotech had taken one route and arrived at a concrete solution makes its invention seem non-obvious. Had the article been very sunny and concrete about the use of taxol-based anti-angiogenic agents among others, the “obvious to try” standard may have found some application, yet as I had mentioned in the earlier post it is better to stick to the more rigorous standard of obviousness. Thus, broadly speaking, if the prior art discloses to an inventor in reasonably certain terms that a particular solution is feasible and any ordinary inventor would rely on such information to work on a solution, his claims of non-obviousness may be in doubt. (I get the feeling, for some inexplicable reason, that by seemingly “lowering” the standard to an “obvious to try” line, the Courts may have made life difficult for a challenger because this line of challenge is pretty vague and might end up muddling not just points of law, but facts as well. Also, I believe that the “obvious to try” kind of argument is subsumed in the standards of obviousness).

Following this, both sides in this case submitted expert testimonies by 2 experts each, each of who supported his respective parties through his opinions. Such a situation naturally puts Courts in a quandary forcing them to rely on documentary evidence in the form of journal articles and experimental data. Consequently, Conor submitted 2 PCT applications and the abstract of an article to substantiate its stance. At this point the Counsel for Conor crafted a line of argument which I feel, though not entirely correct, was brilliant. To explain his argument, I would like to bring in the pyramid again. The “obvious to try” line may, at times, be the product of a combination of lack of clarity in the patentee’s specification and the prior literature i.e. if it appears that the patent claims have not reached the apex fully and the steps leading to the apex have been disclosed by the prior art, then the patent, according to Conor, fails on grounds that it was obvious to try. To claim benefit of such an argument, Conor selectively quoted from Angiotech’s specification and concluded that the patent was merely exploratory in nature and did not positively claim that taxol was indeed capable of treating restenosis. In other words, Conor tried to lower its burden by lowering the standard of proving “obviousness”.

Conor further stated that Angiotech did not clarify as to how its method worked nor did it submit experimental data to prove the success of its invention. It also alleged that no concrete connection between anti-angiogenic properties of an agent, here taxol and anti-proliferation of muscle cells was explained in the patent and so the subject-matter of the patent was pure guess work. This, according to it, was sufficient ground to invalidate the patent. The Court of Appeals too went by the same argument as did the district court.

The issue now before the House of Lords was as follows:

“Is it mandatory for a patentee to explain why his invention works?”

Notwithstanding the rhetorical glint in this question, the answer is a no. This question refers to the certainty with which a patentee asserts the success of his invention. The House of Lords did not concur with the Court of Appeals for it said that claim 12 of the patent read with the specification clearly established that the patentee was not speculating about the success of his invention but was emphatic in his claim that his invention would indeed work. This issue has been discussed in earlier posts on SpicyIP; barring exceptional circumstances where the invention sounds so ludicrous that it goes against the laws of nature, a patentee is not required to show why his invention works, all he needs to do is to explain how it works in a manner which enables other practitioners. In fact, it is for the challenger to show that the patent in unworkable. Agreed that the success of the invention is necessary for the patentee to lay claim to any kind of monopoly, but workability of the invention is the sole priority of the patentee and not why it works. Take the case of aspirin for instance; till date, it has not been shown why aspirin indeed works; its metabolic mechanism remains an enigma and yet there are patents on aspirin.

At this point, the Court also ruled that post-publication of evidence of workability of the invention after grant of the patent went against the concept of quid pro quo, which I fully agree with. This is because, one cannot claim monopoly to exclude others and say that the proof of right to such monopoly could be submitted after grant. Also, the concept of priority is deeply rooted in the patentee’s bona fide belief that as on the date of application, his invention as far as his knowledge went, was workable. This is a part of the oath which the applicant submits.

Final Twist
Despite this entire farrago, there was prior art which positively made Angiotech’s patent obvious and which the House of Lords, in my opinion, did not give due attention. The abstract of an article by a Japanese inventor Katsuda, the last item of prior art submitted by Conor, disclosed invitro work which showed that taxol prevented mitogenic proliferation (i.e. growth by cell division) of smooth muscle cells, which was similar to what the Angiotech patent sought to achieve. But Lord Hoffmann dismissed this by saying:

“That also seems to me insufficient to make it obvious that taxol would prevent restenosis.”

If this was not sufficient, I am not sure what else qualifies as “sufficient”. When there exists literature which clearly establishes a relationship between taxol and growth by cell division, which by the way even the patent does not establish, how is the patent non-obvious??? At best, Angiotech could have gone for a Swiss type use claim saying that its use of taxol’s properties to cure restenosis was unique. Though certain important points of law have been clarified in this judgment, I believe that the judgment should have been otherwise in the light of the prior art cited.

Final Observations
1.The patentee does not have a duty to show why his patent works, except in extreme situations when aspersions are cast on fundamental questions relating to laws of nature.
2.If the prior art asserts in positive terms regarding the feasibility of a particular solution, then it must be assumed that it fell within the scope of knowledge of every practitioner of the art and hence may used to prove the obviousness of a patent.
3.The “obvious to try” concept is a part of the concept of obviousness and its application depends on the facts of the case i.e. the level of evidence needed to prove obviousness is not the same in all cases. Where it suffices to show that to venture in a particular direction is itself obvious with no possibility of new results than the ones already known, then no matter what one calls it, one is going by the “obvious to try” standard.

If KSR could be accused of blurring the concept of obviousness in its attempt to be progressive, Angiotech is a step backward; consequently, the locus of obviousness as it stands today can be compared to Salsa. The tragedy in both cases is that while the rest of the world looks up to the US and UK Courts for clarity on patent law, the Apex Courts of both these countries have not risen to the occasion. Interestingly, the Federal Circuit in the US and the Court of Appeals in the UK seem to have better track records for being consistent in their approach with the oft-quoted critique being that their consistency over a period of time is a sign of lack of imagination.