Angiotech Pharmaceuticals & Anor v Conor Medsystems Inc

Obviousness is assessed by asking whether the claimed invention was obvious to the skilled person, having regard to the state of the art. “Obvious to try” is not a universal test. It is relevant only where the circumstances make it more or less self-evident that the proposed investigation ought to work.

Naming one candidate from a broad class is not ordinarily inventive where the prior art invites the skilled person to consider that class, unless the patent discloses that the candidate is materially different, better, or one of only a few likely to succeed. Commercial success cannot establish inventiveness where it results from subsequent development work rather than the claimed idea.

Angiotech Pharmaceuticals and the University of British Columbia appealed from Pumfrey J’s decision that European patent EP (UK) 706376 was invalid for obviousness: [2006] EWHC 260 (Pat). The patent concerned a vascular stent coated with a polymer containing taxol, intended to treat or prevent restenosis after angioplasty.

The judge held that the inventive concept was the use of taxol in a drug-eluting stent. The prior art, particularly Wolff, disclosed drug-eluting stents for local delivery, anti-proliferative drugs to address restenosis, and a broad class of possible drugs. The central issue was whether selecting taxol, which the patent did not show to be specially suitable or effective, involved an inventive step.

1. Appeal dismissed. Lord Justice Jacob gave the principal judgment, with Lord Justices Tuckey and Mummery agreeing.
2. The inventive concept of claim 12 was a vascular stent coated with a polymer containing taxol, suitable for treating or preventing stenosis after insertion. The CAM assay wording added nothing because taxol was anti-angiogenic by that assay. The wording concerning recurrent stenosis did not materially alter the concept.
3. Common general knowledge included drug-eluting stents, local delivery of anti-proliferative drugs, polymer coatings as drug-delivery vehicles, and research directed towards preventing restenosis. Common general knowledge included approaches known to be under investigation even where their success was unproven.
4. Wolff disclosed drug-eluting stents for local delivery, their possible use against restenosis, and anti-replicate drugs as a class. The patent’s difference was only that it named taxol. It supplied no reason to show that taxol was specially suitable, more effective, or among only a few likely to work.
5. “Obvious to try” was not a universal formula. The statutory question remained whether the invention was obvious, assessed in light of the skilled person, common general knowledge, the difference from the prior art, any motive suggested by the prior art, and the nature of the invention. Here, the patent disclosed no more than a proposal to test taxol, and that proposal was obvious.
6. Commercial success did not assist the patentees because the successful product depended on later work concerning the polymer, dosage, safety and actual efficacy. Kopia also supported obviousness because it specifically proposed taxol for local delivery against restenosis, while drug-eluting stents were a known delivery mechanism.

The appeal was dismissed.

• Court of Appeal (Civil Division) — appeal dismissed on 16 January 2007.
• Chancery Division, Patents Court — Pumfrey J held European patent EP (UK) 706376 invalid for obviousness: [2006] EWHC 260 (Pat).