---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-22-073906"
form_type: "8-K"
ticker: "RIGL"
cik: "0001034842"
company_name: "RIGEL PHARMACEUTICALS INC"
filed_at: "2022-06-23T23:59:59+00:00"
generated_at: "2026-06-24T23:30:17.961673+00:00"
event_type: "litigation"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Rigel receives Paragraph IV notice from Annora for generic TAVALISSE; intends to defend patents

## Summary
- Annora Pharma filed ANDA with FDA for generic fostamatinib tablets (100mg and 150mg base).
- Notice letter includes Paragraph IV certifications alleging Rigel's TAVALISSE patents are invalid or not infringed.
- Rigel states it will vigorously enforce its intellectual property rights related to TAVALISSE.
- TAVALISSE is Rigel's sole approved product; generic entry would materially impact revenue.

## SEC filing metadata
- accession: 0001104659-22-073906
- form_type: 8-K
- ticker: RIGL
- cik: 0001034842
- company_name: RIGEL PHARMACEUTICALS INC
- filed_at: 2022-06-23T23:59:59+00:00
- event_type: litigation
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1034842/000110465922073906/0001104659-22-073906-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1034842/000110465922073906/tm2219181d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-22-073906
- JSON: https://secwatch.observer/filing/0001104659-22-073906.json
- Plain text: https://secwatch.observer/filing/0001104659-22-073906.txt

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