Background
Arbutus Biopharma Corporation (formerly Protiva Biotherapeutics) developed foundational technology for delivering nucleic acid drugs — including mRNA — inside lipid nanoparticles (LNPs) that protect the genetic material and ferry it into cells. This technology became critically important as the basis for mRNA vaccine delivery systems, including those used in COVID-19 vaccines. Arbutus held multiple patents on variations of its stable nucleic acid-lipid particle (SNALP) technology.
At issue was U.S. Patent No. 9,404,127, which claimed SNALP compositions with a specific structural characteristic: “non-lamellar morphology” — meaning the lipid particles take on a non-layered, non-sheet-like internal structure. ModernaTX, Inc. petitioned for inter partes review (IPR), arguing that an earlier Arbutus patent (the ‘069 patent) anticipated the ‘127 patent’s claims. The PTAB agreed with Moderna, finding the morphology limitation inherently anticipated. Arbutus appealed.
The Court’s Holding
The Federal Circuit unanimously affirmed. The court applied the doctrine of inherent anticipation: even if a prior art reference does not explicitly disclose a claimed property or limitation, that property is inherently anticipated if it is the natural result of carrying out the process or making the composition described in the prior art. The court found substantial evidence supporting the PTAB’s conclusion that the earlier ‘069 patent, when made using the same formulation process and incorporating the same referenced procedures, naturally produced SNALP compositions with the claimed non-lamellar morphology.
A key issue was whether materials incorporated by reference into the ‘069 patent could be used to establish anticipation. The court confirmed the established rule: when a reference incorporates other documents, those incorporated materials become effectively part of the host reference for anticipation purposes. Because the ‘069 patent incorporated references describing the same formulation process that yields non-lamellar particles, the ‘127 patent’s morphology limitation was inherently disclosed by prior art. The court rejected Arbutus’s argument that the earlier patent required further experimentation to confirm the morphological outcome, finding the record supported the conclusion that the non-lamellar structure was an inevitable result of the disclosed process.
Key Takeaways
- Inherent anticipation applies when following a prior art process will naturally and necessarily produce a claimed property, even if that property is never explicitly named or measured in the prior art reference.
- Documents incorporated by reference into a prior art patent are treated as part of that patent for anticipation analysis — they can supply missing limitations, including structural or morphological properties.
- A patent claiming a structural characteristic of a composition (such as particle morphology) is vulnerable to inherent anticipation if an earlier reference discloses making the same composition using the same process, and that process invariably produces the claimed structure.
- The PTAB’s inherent anticipation findings receive substantial evidence deference on appeal; challengers must establish that the natural result is essentially unavoidable, not merely possible.
Why It Matters
Arbutus Biopharma v. ModernaTX is part of a broader patent war over lipid nanoparticle technology — the delivery system at the heart of mRNA vaccines including those developed by Moderna and Pfizer-BioNTech for COVID-19. Arbutus had asserted that its LNP patents covered the delivery systems used in these vaccines, seeking substantial royalties. This Federal Circuit decision, affirming the invalidity of the ‘127 patent, reduced Arbutus’s patent arsenal and illustrates how inherent anticipation and incorporated references can be powerful tools for invalidating patents on compositions with claimed structural properties.
For biotech and pharmaceutical companies developing nucleic acid therapeutics, lipid nanoparticle delivery systems, or gene therapies, the decision is a reminder that foundational platform patents — particularly those claiming structural or morphological properties of formulations — can be vulnerable if earlier work by the same or other inventors discloses the same formulation process. Patent applicants in these fields should carefully document evidence distinguishing the claimed structure from structures inherently produced by prior art processes.