The US Court of Appeals for the Federal Circuit reversed a district court’s denial of a motion for judgment as a matter of law (JMOL) of noninfringement, finding that the jury’s infringement findings were unsupported by sufficient evidence and that the district court had improperly delegated claim construction to the jury. Laboratory Corp. of America Holdings v. Qiagen Sciences, LLC, Case No. 23-2350 (Fed. Cir. Aug. 13, 2025) (Lourie, Dyk, Cunningham, JJ.)
Laboratory Corp. of America Holdings (LabCorp) holds two patents with substantially overlapping specifications, both generally directed to methods for preparing DNA samples for sequencing and enrichment techniques aimed at enabling whole-genome sequencing. LabCorp initiated litigation alleging that various Qiagen Sciences kits containing materials used in DNA sample preparation for sequencing infringed its patents. During claim construction, the district court construed several patent terms as follows:
- In the first patent, “second target-specific primer” means a single-stranded oligonucleotide with a 3’ portion that specifically anneals to a portion of the known target nucleotide sequence in the amplicon from step (b), and a 5’ portion identical to a second sequencing primer.
- Also in the first patent, “second adaptor primer” refers to a nucleic acid molecule containing a sequence identical to part of the first sequencing primer and nested relative to the first adaptor primer.
- In the second patent, “target-specific primer” is defined as a primer sufficiently complementary to the target to enable selective annealing and amplification, without amplifying non-target sequences in the sample.
The jury found that Qiagen infringed the first patent under the doctrine of equivalents and willfully and literally infringed the second patent. The jury awarded damages accordingly. The district court denied Qiagen’s renewed motion for JMOL to reverse the damages and the jury’s findings of infringement and validity, and its alternative request for a new trial. Qiagen appealed.
Qiagen raised two noninfringement arguments regarding the first patent, and the Federal Circuit agreed with both. First, the Court held that it was error to allow the jury to apply “plain meaning” and equate a sequence being “identical to another” with being “identical to a portion” of another. Specifically, Qiagen’s accused second target-specific primer (Sample Index Primer, or SIP) was 19 nucleotides long while the second sequencing primer (Read2 primer) was 34 nucleotides. The fact that they shared an overlapping sequence did not make them identical.
Although the district court had treated “identical” as a factual issue for the jury, the Federal Circuit, citing its 2008 decision in O2 Micro Int’l Ltd. v. Beyond Innovation Tech., found that this was a claim construction matter that should not have been left to the jury. The term “identical” must be given its full meaning under claim construction and cannot be interpreted as “identical to a portion.” The Court emphasized that the specification and claims distinguished between full and partial identity: The second target-specific primer must be “identical to” the second sequencing primer while the adaptor primer need only be “identical to a portion” of the first sequencing primer. This difference in specificity was material, and the district court erred in allowing the jury to conflate the two and in denying Qiagen’s JMOL motion on this issue.
Second, the Federal Circuit agreed with Qiagen that its SIP – the accused second target-specific primer – could not qualify as identical to the first primer under the doctrine of equivalents because there was insufficient record evidence supporting the function-way-result test. The Court concluded that LabCorp failed to present exceptional or particularized testimony demonstrating substantial similarity in function, way, or result.
- Function: The claimed primer facilitates specificity during amplification by targeting known sequences. In contrast, Qiagen’s SIP ensures compatibility with the sequencer, not target enrichment or specificity.
- Way: The claimed primer anneals to and amplifies a known target sequence, avoiding non-target amplification. Qiagen’s SIP binds to a common sequence added by a tail, not to any target sequence.
- Results: The SIP amplifies any DNA with the common sequence from the first PCR round, leading to off-target amplification – unlike the claimed primer, which selectively enriches the target sequence.
Qiagen raised two arguments on appeal concerning literal infringement of the second patent. First, it contended that there was insufficient evidence to support the jury’s finding that its Forward Primer (FP) qualified as a “target-specific primer.” Second, it argued that the claimed DNA sequences did not interact with the accused primers in a manner that satisfied certain steps recited in the claim. The Federal Circuit agreed with Qiagen on the first point and therefore did not address the second.
The Federal Circuit found that the district court’s reliance on testimony about the FP was inconsistent with its own claim constructions of “target-specific primer” and “target nucleic acid.” Under those constructions, the FP could not be a “target-specific primer” because it targets a ligated adaptor – an artificial sequence common to all DNA fragments in the sample – rather than the nucleic acid to be analyzed. Moreover, testimony that the FP binds to a small proportion of molecules did not establish that it avoids binding to non-target sequences. Because the FP does not selectively anneal to or mediate amplification of target sequences, the Court found that it failed to meet the definition of a “target-specific primer” and that the district court erred in denying Qiagen’s JMOL motion on this issue.
