In a significant patent ruling issued January 6, 2025, the Federal Circuit affirmed the Patent Trial and Appeal Board's (PTAB) decisions in Laboratory Corporation of America Holdings v. Ravgen, Inc., Case Nos. IPR2021-00902 and -0154, upholding the validity of claims related to non-invasive fetal DNA testing methods. The case centered on whether there was sufficient motivation to combine prior art references in an obviousness challenge.
LabCorp had challenged Ravgen's '277 patent through inter partes review, arguing that claims directed to analyzing cell-free fetal DNA (cffDNA) using cell lysis inhibitors would have been obvious by combining a 2001 Chiu article with either the Bianchi patent or Rao publication. The PTAB rejected these challenges, finding insufficient motivation to combine the references.
The Federal Circuit's decision, authored by Judge Lourie, systematically dismantled LabCorp's attempts to reframe factual determinations as legal errors. "Simply put, Labcorp's 'disagreement with the Board's interpretations... does not amount to a demonstration that the Board somehow failed to use the proper analysis,'" the Court stated, citing Eli Lilly & Co. v. Teva Pharms. Int'l GmbH, 8 F.4th 1331, 1347 (Fed. Cir. 2021).
Central to the Board's analysis was its finding that a skilled artisan would have been discouraged from combining the references because Bianchi's paraformaldehyde would create unwanted gaps in cell membranes, potentially contaminating the sample with maternal DNA. The Board also noted concerns about formaldehyde's potential to damage nucleic acids. Even a small amount of DNA leakage – as little as 1% – would have negatively affected the analysis of fetal cell-free DNA.
LabCorp argued that the Board had imposed an improperly heightened standard for proving motivation to combine, failed to consider the references' complete teachings, and improperly added limitations to the claims. The Federal Circuit rejected each argument, finding instead that the Board had properly weighed all evidence and focused appropriately on the cffDNA context required by the claims.
"The Board thoroughly considered the references and expert testimony provided by both parties," the Court noted. Rather than finding legal error in an attempt to gain de novo review, the Court emphasized that these were primarily factual determinations supported by substantial evidence.
Take-aways:
The opinion reinforces the high bar appellants face when challenging the PTAB's factual findings on appeal and the risk of trying to reframe factual determinations as legal errors.
This decision also provides important guidance on motivation to combine analysis in the context of complex biotechnology patents. It demonstrates that the PTAB may properly consider specific technical challenges that would discourage combinations, particularly where, as here, it is supported with undisputed expert testimony, even when individual references might suggest compatibility at a surface level.
The case is Laboratory Corporation of America Holdings v. Ravgen, Inc., Nos. 2023-1342, 2023-1345 (Fed. Cir. Jan. 6, 2025).
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