The Supreme Court does not usually take into account new facts once the appellate court has ruled on a matter. However, in its 6 March 2009 decision in Boston Scientific v. Medinol, the Supreme Court allowed new facts to be introduced and took the opportunity to do away with a doctrine on the partial validity of patents which has come under substantial criticism for not conforming to the European Patent Convention.

Scimed Life Systems (now Boston Scientific Scimed) sued Medinol on the basis of its European patent EP 0 591 199 (also referred to as the "Keith patent") for a balloon catheter with distal guidewire lumen.

In the first instance, the Keith patent was invalidated for obviousness.

On appeal, Boston Scientific changed its position and argued that a particular combination of three elements constituted a novel and inventive step, while in the first instance it had argued that the inventiveness of the Keith patent lay in the inclusion of a semi-rigid centre portion in the catheter (which has a flexible tube-in-tube distal part and a rigid metal proximal part). In support of its position, Boston Scientific proposed including limitations in the main claim.

The court of appeal upheld the lower court's ruling (i.e. that the patent was invalid) but took a different approach. The appellate court held that the particular combination of three features which Boston Scientific regarded as inventive did not have a single inventive concept ("unity") and thus constituted separate inventions. The court of appeal went on to state - although its reasoning on this point is rather unclear - that part of the alleged invention would form part of a divisional application and therefore the patentee was effectively trying to reintroduce subject matter it had abandoned in the context of the patent application at issue.

The Supreme Court rightly overturned this portion of the decision as lack of unity is not a ground for invalidating a patent. The Court held that, without further explanation by the court of appeal, it was (a) unclear how an alleged lack of unity relates to the claimed invalidity and (b) it was unclear why a skilled person would not independently conclude that the Keith patent should have been granted in the amended form proposed in the proceedings.

With respect to the second point, the Supreme Court referred to its Spiro/Flamco decision on partial validity, in which it held that an amended claim is only allowed if a skilled person could independently conclude that the patent could only have been awarded in a certain manner, which may be directly derived from the patent description. This test was generally perceived to be stricter than the criteria in Article 123(2) and (3) EPC, i.e. extension of the subject matter or post-grant broadening of the scope of protection.

After the court of appeal rendered its decision, Boston Scientific used the EPO's central limitation procedure provided for in the revised EPC and changed the Keith patent’s claims. The Supreme Court held that this fact should be taken into account and that the case should thus be remanded to the appellate court for further review. The Supreme Court also held that for this further review, its former doctrine on partial validity no longer applies and only the EPC criteria should be applied. The risk of invalidation of an entire patent in the Netherlands is now somewhat reduced (especially if the patentee prepares a limitation proposal, where appropriate), and the Netherlands is now even more aligned with the other key patent-litigation jurisdictions in Europe.