Aga Medical Corporation v Occlutech (UK) Limited

There is no presumption that disclosure during a clinical trial is confidential. Whether disclosure gives rise to an equitable obligation of confidence depends on the circumstances and the information the recipient knew or ought reasonably to have known was confidential.

For obviousness, the skilled person may take account of withdrawn devices, devices undergoing trials and their known shortcomings. A modification is not non-obvious merely because other modifications were also available. For insufficiency, “full engagement” of a cupped occluder does not require perfect contact at every point. In an added-matter challenge, the court compares the disclosures of the application and patent, including implicit disclosure, by reference to the skilled person.

AGA, the proprietor of a European patent for a collapsible cardiac septal occlusion device, alleged that Occlutech’s devices infringed. Occlutech challenged validity on anticipation, obviousness, insufficiency and added matter, and sought a declaration of non-infringement for a variant device.

The alleged anticipation arose from clinical procedures carried out in Bratislava in 1995. The obviousness challenge relied principally on an earlier presentation concerning a flat-disc occluder. The central issues were whether the Bratislava disclosures were confidential, whether cupping at least one disc was obvious, whether the claim was insufficiently clear, and whether the granted claim added matter.

1. Anticipation. At least some of the devices used in the September 1995 Bratislava procedures had cupped discs. However, the disclosure was not made in circumstances giving rise to an equitable obligation of confidence. There was no express undertaking, no indication that confidentiality was required, and no presumption arising merely because the procedures formed part of a clinical trial. The disclosure was therefore available to the public and anticipated the patent.
2. Obviousness. The common general knowledge included previous devices, including devices withdrawn from the market and devices undergoing clinical trials, together with their technical shortcomings and information exchanged informally at professional meetings. The skilled team would regard the Gu device as promising but requiring modification for use in humans. Cupping at least one disc would be an obvious modification because it increased contact pressure, improved stability and reduced the risk of thrombus formation and embolisation.
3. Insufficiency and construction. “Fully engage” did not require perfect, uninterrupted contact around the whole perimeter. It meant that any gaps were insignificant and unintentional. The specification gave sufficient teaching to achieve that result through the cup shape and a waist approximating the thickness of the septum.
4. Added matter. The application and patent disclosed the relevant subject matter, expressly or implicitly. The cupped feature was an independent benefit and was not impermissibly generalised from the disclosed embodiments. The challenges under section 72(1)(d) of the Patents Act 1977 and article 123(2) EPC therefore failed.
5. The patent was invalid for anticipation or, alternatively, obviousness. If valid, the products would have infringed. The variant containing no occluding fibre within the woven fabric would not have infringed, so a declaration of non-infringement would have been granted subject to appropriate wording.