secwatch.observer — SEC 8-K summary
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Issuer:     ARROWHEAD PHARMACEUTICALS, INC. (ARWR)
CIK:        0000879407
Form:       8-K
Filed at:   2025-09-11T23:59:59+00:00
Accession:  0000879407-25-000007
Event type: litigation
Sentiment:  neutral
Materiality: 0.80
Item codes: 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Arrowhead files declaratory judgment suit against Ionis over '333 patent for plozasiran
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- Arrowhead filed a declaratory judgment action in Delaware against Ionis claiming the '333 patent is invalid and not infringed by plozasiran.
- Plozasiran is Arrowhead's RNAi therapy for familial chylomicronemia syndrome (FCS); Phase 3 PALISADE study showed up to 80% triglyceride reduction.
- FDA PDUFA action date for plozasiran is November 18, 2025.
- Ionis sent a September 3, 2025 letter alleging patent infringement and threatening suit; Arrowhead acted preemptively.
- Arrowhead's complaint alleges the '333 patent claims are invalid for anticipation and lack of written description/enablement.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/879407/000087940725000007/0000879407-25-000007-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/879407/000087940725000007/arwr-20250910.htm
  HTML page:      https://secwatch.observer/filing/0000879407-25-000007

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer