KEY PRINCIPLE
The Court of Appeal (CoA) has recently confirmed that a typographical error or any other inaccuracy in a patent claim can only be corrected by way of claim interpretation if the existence of an error, and the precise way to correct it, are sufficiently certain to the average skilled person.
This is to be assessed based on the patent claim, taking into account the description and the drawings and using common general knowledge.
BACKGROUND
This decision was issued in the context of an appeal lodged by Alexion following the Hamburg Local Division’s decision to reject its application for a preliminary injunction against alleged infringers, Amgen and Samsung Bioepis. At first instance, the Hamburg Local Division expressed doubt that the patent in question would survive an EPO opposition (due to lack of sufficiency). This was despite concluding that infringement would likely be found.
A key issue explored at first instance concerned the inclusion of an incorrect sequence in the patent application and the Chemical Abstract Service (CAS) database registry. Alexion had sought to argue that the fact the sequence as claimed was unworkable would have been immediately apparent to the skilled person, who would then know to look at the CAS to locate the proper sequence (where Alexion had subsequently corrected the sequence). At first instance, the court determined that the skilled person would interpret the claims as covering the corrected sequence.
COURT OF APPEAL DECISION
On appeal, the CoA ruled that the error in question, and the way to correct it, would not have been sufficiently certain to the skilled person. In doing so, it applied the test summarised at the start of this article, which closely aligns with the EPO’s strict approach pursuant to Rule 139 EPC and the settled case law of the EPO Boards of Appeal. Rule 139 EPC states:
“Linguistic errors, errors of transcription and mistakes in any document filed with the European Patent Office may be corrected on request. However, if the request for such correction concerns the description, claims or drawings, the correction must be obvious in the sense that it is immediately evident that nothing else would have been intended than what is offered as the correction.”
The decision also confirmed that Alexion’s claim construction advanced during the examination proceedings, and the Technical Board of Appeal (TBA)’s endorsement of the same, were relevant, being indicative of the skilled person’s view at the filing date. This is even though the patentee had “abandoned” these arguments in the context of the UPC proceedings. It is noteworthy, however, that the CoA did not address whether the average skilled person, in the context of claim construction, can be expected to consult databases and publications to check how a perceived error in the claim should be corrected.
The CoA emphasised that this approach to addressing corrections is fair, in that it balances providing adequate protection for the patentee (enabling it to correct errors by way of claim interpretation) with providing a reasonable degree of legal certainty for third parties (only permitting corrections if the error and the correction are sufficiently certain to the average skilled person). It considered it appropriate that the standard is strict, since an error in itself implies some legal uncertainty for third parties.
Based on this claim interpretation, the validity of the patent in question was found not to be sufficiently certain on the grounds of insufficiency, and Alexion’s appeal (to the first instance decision dismissing Alexion’s application for provisional measures) was rejected. Notably, the Court of Appeal chose not to comment on infringement, but it is assumed that no infringement would be found (due to the erroneous sequence).
COMMENTS
This decision is helpful in confirming the UPC’s approach to correcting errors in patents, which expressly aligns with the EPO’s test.
The CoA’s decision also generally aligns with, and builds upon, its guidance given last year in the case of Nanostring v 10x Genomics. In this ruling, the CoA confirmed that the patent claim is the decisive basis for determining the protective scope of a European patent and the description and the drawings must be used as explanatory aids for the interpretation of the patent claim.
This serves as a clear warning to patent drafters to ensure precision and accuracy, given discrepancies may well have a bearing on the patentee’s ability to enforce its patents.
