Delaware Court Narrows Moderna's Invalidity Defenses Ahead of Arbutus LNP Patent Trial

"The court rejected Moderna's contention that estoppel should not apply because the U.S. Court of Appeals for the Federal Circuit (CAFC) dismissed its subsequent appeal for lack of standing. The U.S. District Court for the District of Delaware on Tuesday granted in part and denied in part a motion for summary judgment in Arbutus Biopharma Corp. v. Moderna, Inc., narrowing the invalidity defenses that Moderna can assert at a jury trial."

"The ruling comes weeks before the trial is scheduled to begin on March 9, 2026, and follows earlier rulings Judge Wolson issued in the case on February 2. In that earlier ruling, the court held that the phrase "for the Government" in 28 U.S.C. § 1498 means the use of a patented product must be for the benefit of the Government itself, keeping essentially all of Moderna's over $8.2 billion in vaccine sales to the Government in the case."

"The dispute involves four patents owned by Arbutus that relate to nucleic acid-lipid nanoparticles (LNPs), a key technology for delivering messenger RNA (mRNA), such as the mRNA used in Moderna's COVID-19 vaccine. These three U.S. Patent Nos. 8,492,359, 9,364,435, and 11,141,378 are part of the same family and are referred to as the "Molar Ratio Patents." These patents claim specific molar ratio ranges for the four lipid components, a cationic lipid, a phospholipid, cholesterol, and a conjugated lipid, that make up the LNPs."

U.S. District Court for the District of Delaware granted in part and denied in part summary judgment, narrowing invalidity defenses Moderna may present at trial. The court precluded Moderna from challenging several Arbutus patents on obviousness and derivation grounds but found a genuine factual dispute on enablement for a jury to resolve. The ruling precedes a trial scheduled for March 9, 2026, and follows an earlier ruling interpreting 28 U.S.C. § 1498 to require use for the benefit of the Government, preserving Moderna's government vaccine sales. The court also found prosecution history estoppel when Arbutus removed "about" from claimed lipid ranges. The dispute centers on four Arbutus patents covering lipid nanoparticle molar ratio ranges for mRNA delivery, including three Molar Ratio Patents (U.S. Patent Nos. 8,492,359; 9,364,435; 11,141,378) and U.S. Patent No. 9,504,651.

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