The Hague Local Division has issued a detailed judgment on infringement and validity in a dispute between ACD and MI concerning two patents on RNA probe technologies for in situ hybridisation. Although both patents survived the validity challenges, The Hague declined to follow the more flexible construction adopted by the UK High Court and held that MI’s probes do not literally infringe because they do not meet the requirement that the probe sequences are “non-overlapping”. In addition, the panel rejected ACD’s claim for infringement by equivalence.
The Court began by reaffirming the interpretative principles of the Court of Appeal in NanoString v 10x Genomics. Patent claims are the decisive basis for determining scope under Art. 69 EPC, with the description and drawings serving as aids rather than mechanisms for expanding the claim’s meaning. This framework proved decisive for the interpretation of “non-overlapping”.
The term “non-overlapping” was found to mean what it says: no overlap at all. The Court refused to adopt a functional interpretation under which small overlaps of one or several nucleotides could be tolerated if they had no material effect on probe performance. By contrast to the patentee’s submission that near-zero overlap should fall within the claim, the Court held that the skilled person would understand “non-overlapping” in a literal, absolute sense. The panel also declined to follow the UK High Court’s more flexible reading of the same term in parallel proceedings.
Legal certainty for third parties
The Court held that “in view of the legal certainty for third parties, the Court finds it difficult, if not impossible, to properly construe how much overlap would then still be equivalent.”
The adoption of equivalence would therefore introduce unacceptable uncertainty as to where the boundary of protection lies.
The invention is “not a very significant step”
The Court stressed that, although the patents are valid, “it is also clear that they do not form a very significant step in the development of in situ assays (very shortly put, all ingredients of the claimed inventions were already known, just not in combination).”
Against this background, “the fair protection of the patentee therefore does not require a finding of equivalence”, particularly when balanced against the legal uncertainty noted above.
The accused overlap serves a different technical function
The Court accepted the Defendant’s explanation that the 1–4 nucleotide overlap is included for a “specific technical reason”. MI’s probes use partially overlapping regions of HCR hairpin h1 to reduce the kinetic barrier to branch migration and speed up initiation of HCR amplification. This explanation was “not disputed”.
The Court concluded:
“Thus, in this case, the 1–4 overlap, even though it can be argued that the same or at least a similar technical function and result are therewith achieved, … is not done merely as a workaround of the claimed inventions, but it has an accepted function of its own.… This arguably leads to an improvement to the claimed inventions … which protocol was not envisaged in the patents in any way.”
Because the overlap is technically required for the different way in which MI’s HCR products operate, the feature cannot be considered an equivalent of the claimed non-overlapping arrangement.
On that basis, the Court held that the Defendant does not infringe either literally or by equivalence.
On novelty, the defendant sought to combine disclosures in Collins and Kern, arguing that Collins directed the skilled person to consult Kern for cruciform structures. The Court rejected this combination. It confirmed that, for novelty, a prior-art document can incorporate another document only if it specifically and unambiguously refers to that second document for the relevant technical disclosure.
The generic cross-reference in Collins, which merely mentioned Kern as further background concerning cruciform probes, was held insufficient. It did not direct the skilled person to read the documents as a single disclosure for the purposes of novelty. In my opinion, this approach aligns with established EPO jurisprudence. On that basis, Collins could not be combined with Kern to anticipate the patents.
