---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-183719"
form_type: "8-K"
ticker: "ENTA"
cik: "0001177648"
company_name: "ENANTA PHARMACEUTICALS INC"
filed_at: "2025-08-20T23:59:59+00:00"
generated_at: "2026-05-17T11:05:25.937393+00:00"
event_type: "litigation"
sentiment: "neutral"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Enanta sues Pfizer in EU UPC for Paxlovid patent infringement

## Summary
- Filed suit in Unified Patent Court (action 35071/2025) alleging Pfizer's Paxlovid infringes European Patent EP 4 051 265.
- Action covers 18 EU countries participating in UPC; patent based on July 2020 application for coronavirus protease inhibitors.
- European counterpart of US Patent 11,358,953, which is already subject to ongoing US litigation between Enanta and Pfizer.
- Hearing expected within 12-month UPC target; decision within weeks thereafter, subject to appeal.
- No damages determination yet; if infringement found, separate proceedings would assess damages.

## SEC filing metadata
- accession: 0001193125-25-183719
- form_type: 8-K
- ticker: ENTA
- cik: 0001177648
- company_name: ENANTA PHARMACEUTICALS INC
- filed_at: 2025-08-20T23:59:59+00:00
- event_type: litigation
- sentiment: neutral
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1177648/000119312525183719/0001193125-25-183719-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1177648/000119312525183719/enta-20250820.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-183719
- JSON: https://secwatch.observer/filing/0001193125-25-183719.json
- Plain text: https://secwatch.observer/filing/0001193125-25-183719.txt

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