Advanced Bionics AG & Anor v Med-El Elektromedizinische Geräte GmbH

On an appeal from an evaluative obviousness decision, the Court of Appeal should intervene only for an error of law or principle. A judge must assess documentary prior art in its context and purpose, but may identify a general teaching where that teaching is actually disclosed and would be discerned by the skilled reader. The relevant question is whether the claimed step from the prior art was obvious, not whether the patent’s contribution appears important. Secondary evidence such as long-felt want must remain secondary and be assessed in the light of the primary evidence and the circumstances of the industry. Different tribunals may reach different conclusions on a finely balanced obviousness issue without either making an error.

Med-El appealed the decision of Campbell Forsyth, sitting as a Deputy High Court Judge in the Patents Court, which revoked its patent for an MRI-safe cochlear-implant magnet as obvious over Zimmerling. The judge also held that Advanced Bionics would have infringed the patent if it had been valid, but infringement was not argued on the appeal because the obviousness challenge failed.

After the patent was maintained in amended form by the Technical Board of Appeal of the European Patent Office, the Court of Appeal considered the patent as amended. The central issues were whether the judge had misunderstood Zimmerling, applied hindsight or an impermissible stepwise analysis, and wrongly assessed evidence of long-felt want.

1. Appeal dismissed. The Court announced at the conclusion of the argument on obviousness that the appeal would be dismissed. It was therefore unnecessary to hear argument on infringement.
2. Obviousness is a multifactorial evaluation. Consistently with Actavis Group PTC EHF v ICOS Corp [2019] UKSC 15 and Re Sprintroom Ltd [2019] EWCA Civ 932, the appellate court should not intervene without an error of law or principle in the first-instance judge’s assessment.
3. It would be an error of principle to extract a general teaching from documentary prior art divorced from its context and purpose where that teaching was not disclosed in the document and would not be discerned by the skilled reader. That error had not occurred. The judge had comprehensively summarised Zimmerling and was entitled to find that it generally taught rotatable implant magnets capable of at least partial alignment with an external magnetic field. Zimmerling was not confined to axial internal magnets, and it disclosed a diametrically magnetised cylindrical magnet and a variety of possible shapes.
4. The judge was entitled to find that the skilled team would retain the conventional thin disk-shaped implant magnet and apply Zimmerling’s teaching to it. A diametrically magnetised magnet was required for rotation in the relevant geometry, and the matching external diametric magnet followed as an obvious knock-on requirement. The appellate criticisms were disagreements with the evaluation, not demonstrations of legal error or hindsight.
5. The judge had not erred in his treatment of long-felt want. Although awareness of prior art by only two of three major industry participants could, in an appropriate case, constitute secondary evidence against obviousness, the judge found no long-felt want. Other solutions were available, the issue was not pressing, and manufacturers had competing concerns. Even if long-felt want had been established, the judge was entitled to conclude that it would not have displaced the primary expert evidence.
6. The different conclusion reached by the European Patent Office Board of Appeal did not demonstrate error. The Board had not considered the same expert evidence, including the common general knowledge that a diametrically magnetised magnet could be rotated by an external magnetic field.

• Court of Appeal (Civil Division): Med-El’s appeal was dismissed. The Court upheld the first-instance conclusion that the patent was obvious over Zimmerling. Infringement was not considered.
• Patents Court: Campbell Forsyth, sitting as a Deputy High Court Judge, revoked European Patent (UK) No. 3 138 605 as obvious and held that Advanced Bionics would have infringed it if valid: [2022] EWHC 1345 (Pat).