Conor Medsystems Incorporated v Angiotech Pharmaceuticals Incorporated and others

The House of Lords allowed the appeal and held that the question of inventive step must be assessed by reference to the invention as defined in the claim (a taxol-coated stent for treating or preventing recurrent stenosis) and not by reference to the extent of experimental proof in the specification. The court treated article 56 EPC and section 1(1)(b) of the Patents Act 1977 as governing inventive step and rejected the approach that a patent is necessarily obvious if the specification merely establishes that a compound is 'worth trying'.

The court held that post-grant lack of detailed experimental data in the specification may raise issues of sufficiency or support under articles 83 and 84 EPC (and section 14(5)(c) Patents Act 1977) but does not change the proper question for obviousness. The relevant enquiry is whether it would have been obvious to a skilled person to use a taxol-coated stent to prevent or treat restenosis, not whether it was merely obvious to test taxol among many candidates without any expectation of success.

This is an appeal by the patentees, Angiotech, from a decision affirming a first instance finding that European patent 0 706 376 was invalid for obviousness. Conor Medsystems had applied for revocation in the United Kingdom arguing lack of inventive step with reference to prior art including Wolff, Kopia and Katsuda. The patent claimed, inter alia, a stent coated with paclitaxel (taxol) for treating or preventing recurrent stenosis.

Procedural history: the patent was upheld in the Netherlands but revoked in the United Kingdom by Pumfrey J; the Court of Appeal affirmed the revocation ([2007] EWCA Civ 5). Angiotech appealed to the House of Lords. Since the original challenger settled, the Comptroller General of Patents was invited to present arguments against validity.

Nature of the application/relief sought: revocation of the patent on grounds of obviousness (lack of inventive step).

Issues framed by the court:

• What is the correct concept of the inventive step for present claims: is it the product as claimed (a taxol-coated stent for treating or preventing restenosis) or a lower-level ‘idea’ that taxol might be worth trying?
• What is the proper role of the specification and experimental data (for example the CAM assay) in assessing obviousness and sufficiency?
• When is the 'obvious to try' standard applicable and what expectation of success is required?

Reasoning and disposition: the House concluded that the inventive step must be assessed by reference to the claim itself and that the specification here did more than assert mere speculation; it identified taxol as the favoured anti-angiogenic and reported favourable CAM assay results. The Lords rejected the judge's treatment of the invention as merely an instruction to test taxol without expectation of success. They held that absence of extensive experimental proof in the specification goes to sufficiency or support, not to redefine the claimed invention for the obviousness enquiry. On the facts, the cited prior art did not render it obvious to use a taxol-coated stent to prevent restenosis, and accordingly the appeal was allowed.

Appeal allowed. The House held that the correct question is whether the claimed invention — a stent coated with taxol for treating or preventing recurrent stenosis — was obvious, and not whether the specification merely gave an idea worth testing. The patent, fairly construed, taught taxol as the favoured anti-angiogenic and showed CAM assay results; the prior art did not make the claimed taxol-coated stent obvious. The judge and Court of Appeal were wrong to conflate obviousness with insufficiency/support by treating the invention as merely a suggestion to try taxol without expectation of success.

First instance: Revocation claim heard by Pumfrey J (High Court) — patent revoked. Court of Appeal: appeal dismissed, [2007] EWCA Civ 5 (Mummery, Tuckey and Jacob LJJ) — revocation affirmed. Netherlands: District Court of The Hague upheld the patent (decision discussed in the judgment). House of Lords: appeal allowed [2008] UKHL 49.