---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-26-000979"
form_type: "8-K"
ticker: "ABUS"
cik: "0001447028"
company_name: "Arbutus Biopharma Corp"
filed_at: "2026-02-20T23:59:59+00:00"
generated_at: "2026-05-16T01:26:12.240045+00:00"
event_type: "litigation"
sentiment: "positive"
materiality_score: 0.82
calibrated_materiality_score: 0.82
confidence: "high"
source: SEC EDGAR
---

# Arbutus wins partial summary judgment in Moderna patent case; enablement goes to trial

## Summary
- Court bars Moderna's obviousness defense: IPR estoppel applies to '435 Patent, issue preclusion bars routine-optimization and phospholipid-range arguments.
- Arbutus's motion to exclude Moderna's obviousness expert Dr. Anderson granted.
- Moderna's enablement defense survives: Dr. Prud'homme's testimony creates genuine factual dispute; trial needed on whether claims require undue experimentation.
- Moderna's derivation defense dismissed for lack of evidence.
- Court upholds that prior IPR final written decisions trigger statutory estoppel even without appeal; Moderna cannot relitigate previously rejected arguments.

## SEC filing metadata
- accession: 0001171843-26-000979
- form_type: 8-K
- ticker: ABUS
- cik: 0001447028
- company_name: Arbutus Biopharma Corp
- filed_at: 2026-02-20T23:59:59+00:00
- event_type: litigation
- sentiment: positive
- materiality_score: 0.82
- calibrated_materiality_score: 0.82
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1447028/000117184326000979/0001171843-26-000979-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1447028/000117184326000979/f8k_021926.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-26-000979
- JSON: https://secwatch.observer/filing/0001171843-26-000979.json
- Plain text: https://secwatch.observer/filing/0001171843-26-000979.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.