In December 2022, a patent infringement case featured an interesting question regarding the possibility of invoking new evidence in proceedings before the Patent and Market Court of Appeal (PMCA).(1) The PMCA highlighted in its judgment that the burden of proof of infringement lies with the patent holder and that a high evidentiary standard is applied.


The holder of a European patent protecting a swab for collecting biological specimens filed a request for an injunction against a distributor of swabs, among other things. During the prosecution of the European patent, the independent claim one had been subject to limitations where, in particular, several new features had been added. One such feature regarded the fibre count in a specific interval. The patent holder based its request on direct infringement and the doctrine of equivalence.

After assessing the evidence presented by the patent holder, the Patent and Market Court (PMC) found that the patent holder had not shown that the claimed infringing swabs fulfilled all the features in the independent claim one. In particular, three features added in the prosecution procedure were not fulfilled. Further, the PMC did not find infringement by equivalence. Therefore, the request was rejected.

The patent holder appealed the judgment and the PMCA granted leave to appeal. During the proceedings, the patent holder invoked several new pieces of evidence, such as certain documentation and licence agreements entered into after the PMC's judgment. The patent holder invoked this newly presented evidence to show that the invention was pioneering and had had significant commercial success. The PMCA first dismissed the new evidence but, notably, later admitted it before the main hearing.


The PMCA decided first to assess whether the patent holder had shown that the claimed infringing swabs fulfilled the feature regarding the fibre count in a specific interval of the independent claim one of the European patent (feature h). The patent holder had claimed that feature h should be understood to relate to a nominal value of fibre density. The PMCA, however, rejected this interpretation with reference to the patent description, which clearly established that it referred to a specific interval where the values were quantified.

The question therefore remained whether the patent holder had shown that the allegedly infringing swabs' fibre density fell within the set-out values of feature h. Prior to the main hearing, both parties had performed tests on the swabs. The tests showed different data on the fibre's density. The results further showed that the density varied on different occasions, as well as between different samples. Since the patent holder could not present any further evidence to refute the results of the distributor's tests, the PMCA found that it had failed to show direct infringement.

In relation to the claimed infringement based on equivalence, the PMCA briefly established that the invention:

  • was of a "simple kind";(2)
  • closely followed the prior art before the priority date; and
  • had been subject to limitations during prosecution.

All these factors limited the possibility to apply the doctrine of equivalence at all. Without further discussion regarding the evidence that the patent holder had presented in this regard, the PMCA did not find infringement based on this ground.


This case stresses the importance of the evidence invoked to support a claim of patent infringement. While the test presented by the patent holder regarding the fibre density showed that the swabs fell within the specified interval, this was not enough to show infringement in view of the evidence presented by the distributor. It seems likely that the PMCA considered that the separate test results invoked by the parties were undeniably close to each other and the base line was above the highest value of fibre density.

Another interesting takeaway from this case is how the PMCA managed the question of new evidence invoked in the proceedings. The PMCA first rejected the new evidence from the patent holder as irrelevant, since the theme of proof referred to legal facts and not evidentiary facts. However, the patent holder persisted and, after changing the theme of proof, again requested that the new evidence be allowed.

The PMCA not only allowed this request, it was also enough for the PMCA to accept the new evidence. More precisely, the change in theme of proof meant that the evidence went from being considered irrelevant to being relevant. The case therefore shows that it may be possible to change the theme of proof and, in principle, request a renewed assessment even after the PMCA has decided to reject the same evidence.

For further information on this topic please contact Wendela Hårdemark or Simon Fredriksson at Westerberg & Partners Advokatbyrå Ab by telephone (+46 8 5784 03 00) or email ([email protected] or [email protected]). The Westerberg & Partners Advokatbyrå Ab website can be accessed at www.westerberg.com.


(1) PMT 7752–20.

(2) In Swedish, "enkelt slag".