On Wednesday 9 July, the House of Lords reached a landmark verdict on the long-running Conor v Angiotech case involving a patent for a drug-coated medical stent. Overturning rejections of Angiotech's patent by the Patents Court in 2006 and the Court of Appeal in 2007, the Lords focused on a contentious approach to obviousness that had developed in the case history.

The circumstances of the Lords hearing were unusual, in that Conor and Angiotech had settled their lawsuit over the stent patent between themselves in mid-2007. As such, the case was no longer a matter of rivalry, but of principle. Angiotech took the position that it should use the hearing to reverse the Court of Appeal's quashing of its patent, so counsel from the UK Intellectual Property Office (UK-IPO) was appointed to argue Conor's views.

Key to decisions in prior proceedings was how obviousness had been interpreted in respect of the patent’s claims for the stent's coating. The stent itself had been designed to hold open injured arteries and allow normal circulation. The relevant drug, taxol, was included in the claims to demonstrate that it could treat restenosis: an exaggerated healing response that could actually force damaged arteries to close up, negating the stent's effect. Previous rulings stated that the patent’s wording implied that taxol would make an effective treatment, rather than carefully elucidated this view. Conor had challenged this from a point of obviousness, arguing that this inventive step would be 'obvious to try' for schooled innovators.

Lord Hoffman, however, disagreed: 'In my opinion,' he wrote, 'it is absolutely clear that the teaching of the specification … was that a taxol-coated stent would prevent or treat restenosis.' His ruling restores the patent to Angiotech's body of IP. Taylor Wessing patent group partner, Gareth Morgan, told IP Review Online that the ruling challenged 'the idea that you should view inventions differently depending on how much technical information there is in the claims, which is nonsense anyway as that ought to be covered at prosecution stage. [The ruling] might make patent offices pay more attention to the technical aspects of claims, and if you want to challenge a patent make sure your challenge is on grounds of insufficiency rather than obviousness.'

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