Hanger 18

A patent can only be obtained for an invention if it is novel and involves and inventive step, or (looked at another way) is not obvious. I have been mildly surprised that the way the courts approach this second, higher hurdle has been dictated by a thirty-year old Court of Appeal case, Windsurfing International v Tabur Marine, reference to which is obligatory in just about any judgment which turns on section 1(1)(b) of the Patents Act 1977 (or Article 56 of the European Patent Convention) - though it is not cited in the case .

From now on, the courts will be citing the House of Lords judgment in Conor Medsystems vAngiotech Pharmaceuticals Inc. [2008] UKHL 49. There, the respondents owned a European Patent which designated the UK and covered a stent used in coronary angioplasty. It can be inserted into a diseased artery and a balloon inflated to keep the artery open.

The patent claimed a stent coated with a polymer loaded a drug called paclitaxel, sold under the trade mark Taxol (by which name it is identified in the judgment, as it was in the claims of the patent), which would inhibit restenosis, the growth of tissue that would gradually close the artery up again. Conor argued that it was obvious against the prior art. They pursued a similar claim in the Dutch courts.

At first instance the late Pumphrey J agreed with Conor and revoked the patent. He thought that the mere fact that no-one had used such stents before might make them new but did not get over the inventive step. He thought that it would be obvious to anyone using a stent of this type that Taxol would have to be used to prevent restenosis. Angiotech appealed, but the Court of Appeal (the judgment being delivered by Jacob LJ) dismissed the appeal ([2007]EWCA Civ 5). On 9 July, notwithstanding that the parties had settled their dispute in favour of the validity of the patent, the House of Lords allowed the appeal, the only detailed opinion being that of Lord Hoffmann (of course, who else?).

His Lordship remarked that. as in the case of many product claims, there was nothing inventive in discovering how to make the product: the inventive step lay, if it lay anywhere, in the claim that the product would have a particular property. Was it obvious to use a Taxol-coated stent for the purpose of inhibiting restenosis? The invention was as set out in the relevant claim, and it was the non-obvious of that which had to be considered. Whether it was obvious that Taxol would have the desired effect was not the issue: no-one could have exclusive rights "in the notion that something is worth trying or might have some effect".

The judge had therefore, unsurprisingly according to Lord Hoffmann, asked whether it was obvious to try the prospective invention without any expectation of success. His Lordship referred to this as an oxymoronic concept for which he knew of no precedent in the law of patents. The Court of Appeal had upheld the judgment on the grounds that the patent contained no "disclosure", but Lord Hoffmann saw no reason why, "if a specification passes the threshold test of making the invention plausible, the question of obviousness should be subject to a different test according to the amount of evidence which the patentee presents to justify a conclusion that his patent will work ...". Neither the judge nor the appeal court considered what Lord Hoffmann considered the important question, whether it was obvious to use a Taxol-coated stent to prevent restenosis.

Jacob LJ had rejected this approach on the grounds that the patent did not demonstrate that Taxol actually worked to prevent restenosis. Lord Hoffmann preferred the approach of the Dutch court in the litigation in the Netherlands, considering that the law does not require a demonstration of the effectiveness of the claimed invention, and there was no reason not to apply the ordinary principles of obviousness to the claimed invention.

The IPKat suggests that Lord Hoffmann is trying to claw back the inventive step test "from the jaws of analytical oversophistication", and that the "obvious to try" test is a valuable tool to help gauge the degree of inventiveness involved in an invention, though not the only one.
His Lordship also referred to the products great commercial success. Historically, commercial success was a good indication of non-obviousness, but again it can be nothing more than an indication and the test needs to focus on the invention set out in the claims and as patented.