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The obviousness test for patents

A patent is invalid because it is obvious, on a true and proper construction of the patent’s use. The Court of Appeal recently upheld this High Court ruling. The Court further defined when a patent is invalid because it is an obvious adaptation of prior art.

This case also demonstrates the importance of a comprehensive prior art search before incurring costs and patent filing.

The obviousness test for a patented heart valveTo fully appreciate the case an understanding of the aortic valve is useful.

Events leading up to the court case

Cook Biotech “Cook” filed a patent on 31 January 2001 for an artificial heart valve, within a stent, which can be delivered through a catheter.

Edwards Lifesciences “Edwards” had developed a heart valve product. Edwards wanted to revoke Cook’s patent on the basis of priority. In return, Cook counterclaimed for patent infringement. Note, both inventions generated significant money.

Edwards argued Cook’s patent should be revoked because it was obvious. To justify this point, Edwards used a 1995 U.S. patent for a “heart valve made from cylindrical support and a collapsible valve, mounted to a stent, for implantation in the body by means of a catheter”.

Edwards argued that Cook’s patent was no different. A “skilled person” would see no difference between the two patents.

Cook resisted this argument. Cook stated there was a need for improving methods of valvular function within the body. The 1995 U.S. patent did not cater for this need. In addition, Cook argued their 2001 patent had the valve within a stent, implying one stent. The 1995 patent had the valve mounted to a stent, implied two stents.

The High Court’s decision

The High Court considered if the 2001 patent was an obvious adaption of the 1995 patent. The High Court rejected Cook’s defence, described above.

The court decided that obviousness depended on the use of the stent. The number of stents was irrelevant. So, the High Court:

  • Revoked Cook’s patent on the grounds of obviousness; and
  • Refused Cook’s claim for infringement.

The Court of Appeal’s interpretation

Cook appealed to the Court of Appeal. Cook argued who should be the “skilled person” used by the obviousness test. Cook believed in this case, the skilled person should be the interventional cardiologist. Cardiologists did not see a single stent valve like Cook’s till 2001.

The Court of Appeal rejected this point. The Court stated it was artificial to single out a sole “skilled person”.  Teams perform heart operations. Using the most experienced team member was not proportionate.

Making a clear division between the different parts of a valve, based on the number of stents, was also inappropriate. The underlying purpose was the same. Nothing indicated the surgical team would see otherwise.

The Court of Appeal upheld the High Court’s ruling, and dismissed Cook’s appeal. The Court of Appeal held that it was:

“counter-intuitive to seek to make a clear division between different parts of such a stent on the basis of functionality”.

The obviousness test

The obviousness test required the Court to identify:

  1. The notional “person skilled in the art”, and
    • That person’s common knowledge;
  2. The inventive concept of the claim in question;
  3. The differences between the matter cited and the inventive concept;
  4. And ask do those differences constitute steps that would be obvious, or
    • do the steps require a sufficient degree of invention?

In this case, the Court went further, and added that

“the simpler a solution, the easier it is to explain and the easier it is to explain, the more obvious it can appear”.

The introduction of Cook’s singular stent was a simple solution, easy to explain, and thus, more obvious to the skilled person.

What this case shows

This case shows why due diligence is important. Effective due diligence may have unearthed the 1995 patent, and its similarities.  Cook wasted its development costs. Its competitor Edwards can now exploit its own product.

Always explore settlement.  A licence agreement might resolve the dispute.  Cook could have granted Edwards a non-exclusive licence to exploit the 2001 patent in a defined sector e.g. veterinary sciences.

Cook would have retained its patent ownership.  Then Cook could grant further licences to entities operating in other sectors. Cook would receive royalties, and with the 2001 patent, Edwards would presumably maintain its leading position.

For us, the key commercial consideration when negotiating a settlement, especially in a patent dispute,  is bargaining power .

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